Hacker News new | past | comments | ask | show | jobs | submit login
Vertical farming does not save space (lowtechmagazine.com)
277 points by oftenwrong on Feb 18, 2021 | hide | past | favorite | 441 comments

Artificial lighting saves land because plants can be grown above each other, but if the electricity for the lighting comes from solar panels, then the savings are canceled out by the land required to install the solar panels. The vertical farm is a paradox unless fossil fuels provide the energy. In that case, there’s not much sustainable about it.

This entire piece is based on the assumption that the only sources of energy are solar panels and fossil fuels. This is false. According to the US Department of Energy, 19.6% of the energy produced in 2019 is nuclear. In that same year, 7.1% was from wind, 7.0% was hydroelectric, 1.4% from biomass, 0.4% geothermal. Only 1.7% was photovoltaics! https://www.eia.gov/tools/faqs/faq.php?id=427

If we look into the relatively near future, fusion energy is going to account for a rapidly increasing share of energy production by the end of this decade. https://www.youtube.com/watch?v=KkpqA8yG9T4

> If we look into the relatively near future, fusion energy is going to account for a rapidly increasing share of energy production by the end of this decade.

I really don't think by the end of this decade there will be any commercial fusion production. I'm sure we will be closer but it is still some decades away.

ITER proposes to follow up their current research reactor with a successor (DEMO) which they plan to start building around 2040 and begin operating in the 2050s. Then they expect DEMO to be followed by their first commercial power station, PROTO. They probably won't even start building PROTO until the 2050s or 2060s, so we could easily be looking at 2070-2080 before it comes online.

Now, there are other teams working on fusion, there is always the possibility some other team could leapfrog ITER. It is also possible that with increased investment timelines might come forward. But I'm very confident that come 2030, the amount of fusion power in the commercial energy markets is going to still be zero.

When I read that timeline, it doesn't sound serious to me. If you're planning to do something in 40 years, then you don't have the faintest clue how to do it now, which means you don't know when you will know how to do it. It could be 5 years or 1,000 or never. You don't know what you don't know.

"First commercial fusion power station will start construction between 2050 and 2060" is mostly guess, but it is an educated guess based on some trends/predictions/achieved work.

But compare it to "First commercial perpetum mobile power station will start construction between 2050 and 2060" or "First FTL spaceship will be launched in 2050s".

The educated guess for the last 50 years was 20-30 years away

My wife showed me once a chart of both founding and the estimation of the fusion spark (plus net energy). It explained pretty good why the estimation had changed.

My impression is that if humanity had focused on the question and not the politics we would already have fusion capacity.

But do not forget, we still do not know if it is financial benefit to use fusion in the future.

For the last 60 years even! Fusion power was ~20 years away in Stanislaw Lems Summa Technologicae in 1961.

This is mostly because it has not been funded to the level required for that timeline to be accurate.


Funding at the level in that chart would not have given us fusion. That chart is based on a crash program to develop tokamaks, but assumed tokamaks work better than they actually do. The main product of that crash program would have been tears and frustration, not practical fusion.

One can turn this around and say that fusion not getting the funding in that chart is evidence it was not seen as a promising place to invest. One cannot simply presume it's a good investment and ignore any evidence to the contrary.

> But compare it to [perpetual motion or faster-than-light space travel].

That's a completely inaccurate comparison - perpetual motion and faster-than-light violate fundamental physical laws as we understand them. Net-positive power from fusion is fully within the laws of physics – we've got an example in the daytime sky, and trillions in the nighttime sky. The difficulties with fusion come with shrinking it to a scale that humans can build.

I think you misunderstood the GP comment.

I understand the GP comment as saying "First commercial fusion power station construction will start 2050-2060" is different from "Perpetual motion machine construction will start in 2050-2060" or "FTL spaceship construction will start in 2050-2060" for the very reasons you gave (among others).

You read the GP as saying something different from what you are saying, but I think you are actually both saying the same thing.

What fusion does is come close to ignoring the laws of engineering and economics. That's not quite the same as ignoring the laws of physics, but either of those is capable of rendering a technology a nonstarter.

Specifically, for fundamental reasons DT fusion will have much lower power density than a fission reactor, and so have to be much larger, and therefore have to be much more expensive.

I would compare it to a space elevator (for earth, not the moon). Do you think we can attach a timeline to that?

Musk somehow got a bunch of those right. Not as complex, but still filled with unknowns.

My gut tells me that fusion power is better analogized to a space elevator than reusable rockets.

But you're suggesting what I already alluded to as a reason for doubting that economic fusion power will ever happen - he's the type of person who would be pursuing fusion if it seemed feasible. It's not that he's the only one, or that he knows about nuclear physics, but it's the sort of risk he would plausibly take if he didn't know of a good reason why it can't be done. Also, of course, you need power for Mars bases.

I'm not a huge SpaceX watcher, but I suspect it's harder to build electric cars than rockets. Yes, rockets are crazy expensive and time consuming but the fundamental principles are relatively understood.


Tesla's continual hitting of projected targets is much more impressive to me.

You're generally right though: the maturity, risk, and timelines of fusion are much greater than either of these. Better suited to long-term gov't/military spending.

But the general principle applies. Everything is measurable and can be modeled with a predictive distribution. The more unknowns, the more variable the distribution is.

We have fusion making consistent and significant gains right now.

We have wind and solar making even faster gains, and being real, right now as well.

Sure, but solar won't be enough to power us forever, and doesn't scale like fusion eventually will.

We will have energy needs orders of magnitudes more than we do right now within the next 20 years. I'm all for solar, but fusion will be necessary just in terms of dealing with climate change and the energy needs that alone will bring with it. Carbon sequestration, water desalination, etc... are all going to need serious energy behind them and will be knocking on humanity's door before the 2050s.

So what is the plan for the nuclear waste (neutron capture from the hull activates it badly)?

The nuclear waste problem is drastically overstated and, like almost every other aspect of nuclear power, is generally fear-mongered and cherry-picked as some sort of "gotcha".


From the article: "the U.S. has produced roughly 83,000 metrics tons of used fuel since the 1950s—and all of it could fit on a single football field at a depth of less than 10 yards."

I'd be more comfortable with a nuclear waste storage facility in my area than I would be with a coal power plant polluting the same given area.

The radioactive strength and decay time is not that long, right?

I don't know about commercial by 2030 but leap frogging ITER doesn't seem far fetched at all because of the all signficant advances in superconductors achieved after ITER was planned out. Also, if the new superconductors do work out, it's very likely that all other forms of energy generation and grid level storage will become almost immediately obsolete and any additional focus moving forward would be only on improving the efficiency of fusion. The remaining use cases for solar would probably then be on small off-grid type situations.

I'm a nuclear engineer working at a laboratory known for fusion research. Commercial fusion power at any scale is not happening by 2030. 2040 or 2050 are more realistic and may still be a stretch.

What signs do you see that it might work at all (and that it's not a hopeless endeavor)? As a layman it's so hard to understand how something so hot and so confined could ever be made to react reliably with continuous fuel and energy production to produce power on a large scale.

I don't think anyone is proposing continuous fuel (even fission reactors typically don't work like that - you have to shut them down to swap out the fuel rods periodically). The idea is that you inject (say) some deuterium into a blast chamber, it explodes like a miniature thermonuclear bomb, and you gather the explosive energy in vaguely the same way a internal combustion engine (like in cars) gathers energy from fuel-air bombs in its engine cyliders.

And we already know (roughly) how to build that, it's just that the version we know how to build is so ridiculously, impractically huge that you could fit a small city in its blast chamber... because it runs on actual, non-miniature, thermonuclear bombs. The difficulty is scaling that down to something that doesn't have a upfront cost measured in multiples of the world GDP before it starts generating power (in quantities measured in multiples of current global electrical consumption, and likely multiples of global energy consumption period).

The blast chamber that you chuck nuclear weapons in is not a good analogy, I suspect we don't know how to build such a thing that has a net positive energy yield when you factor in how much energy it takes to build a thermonuclear weapon and the terrible thermal efficiency such a contraption would have. Inertial confinement fusion is basically a more manageable version of this idea and we still haven't hit breakeven there. Magnetic confinement fusion is widely believed to be the more viable path to commercial fusion energy anyway. Right now fusion is largely a game of chasing margins to get things efficient enough that first the plasma is self sustaining (ignition) and then second yields a net positive of energy. ITER or its successor will hopefully achieve the first goal (ITER was originally supposed to but is no longer targeting full ignition, at least initially), then hitting the second goal is what will be needed to be practical as a power source.

Also, just to add to your point there are (basically) continuously fueled fission reactors, see e.g. CANDU as well as some more exotic actually continuously fueled designs that use liquid fuels. Continuously fueled designs would probably be more desirable if they weren't such a proliferation concern but that's a different story.

Wait, are you saying we know how to build a World Wonder that produces infinite energy, but we’re not doing it? What’ll we do if Ghandi builds it first?

Because we don't have enough energy demand to make it worthwhile. Even if we had enough money (and political will) to fund it, we'd be better off spending it on a space elevator, since we can actually use that enough to cover the costs.

With the only issue being that we don’t actually know how to build a working space elevator yet. Last I heard anyway.

Stars and fusion nuclear weapons exist.

And I'm only half joking. The energy yield of fusion is there and the basic physics are pretty well understood. Progress has been agonizingly slow but steady. We generally understand what needs to be done to get there, but it's a slow and complicated process that will take a long time and several more expensive, large-scale tests like ITER to push it along. The payoff is still a ways away and the up front costs are high, so barring investment on the scale of the Manhattan project it is something we will have to continue slowly grinding away at. The upside is fusion research is truly pushing the bounds of engineering, which will continue to yield benefits in other areas along the way.

Edit: I'll also add that we have already built fusion reactors, we just haven't gotten them efficient enough that they generate enough energy to sustain themselves.

>barring investment on the scale of the Manhattan project

The Manhattan project cost about $30 billion in today's dollars, I believe.

We have IPOs that raise close to that amount of money these days (e.g. Alibaba).

It's half a percent of federal spending in 2020 (admittedly not a normal year).

GameStop has lost over $30 billion from its peak valuation.

Your matter of fact claim that there's not enough capital in today's world for fusion power development really makes me wonder.

Once upon a time, I read a comment by someone somewhere that "everyone" (who is "in the know") knows fusion break-even is infeasible, but the research is relevant to maintaining nuclear weapons stockpiles.

Besides, if fusion power was possible...wouldn't Elon Musk be working on it?

Comparing the raw numbers in terms of cost I don't think quite gives the right picture, you have to think about scale of investment. Whole (large) towns and biggest-in-the-world facilities were raised and the brightest minds committed. And it would likely take longer. Maybe a better comparison would be to the Manhattan project and the atomic weapons research apparatus in the decades that followed. Current input to fusion research is a big monetary investment worldwide, but I think in terms of effort it's not quite the same scale especially if you talk about the whole world committing to that degree.

I will add that I'm not sure it would be worth committing this amount of resources solely to fusion. Obviously I think it's worth pursuing long term, but not necessarily at that scale given the costs it would have in terms of other scientific research. I never claimed the amount of capital isn't there nor meant to imply it; it probably is possible (by 2040-2050, 2030 seems impossible to me) but not realistic barring some dramatic changes in the world.

Regarding why wouldn't Elon Musk be working on it... let's ignore that several other prominent billionaires have invested in fusion. But currently fusion is not an appealing private investment outside of philanthropy. There are a lot of up front costs and uncertainty for a payoff that is way down the road. Whether it's worth investing in is up to him, but "whether or not Elon Musk is doing it" is not a good measure of viability.

Regarding the comment that everybody in the know thinks breakeven is infeasible, that's certainly not the prevailing nor even a common view with the people I know working on fusion. Opinions are mixed on how far we are from breakeven and how far we are in terms of the technology required to achieve it, but as I noted previously the basic energy yield of fusion is there and the route to get there is mostly clear, if long. ITER has little cross-application with nuclear weapons, that would be facilities like NIF which aren't the main focus of research towards power production.

I'll add that I have no skin in this game, my research is unrelated to fusion I just happen to talk with those guys a lot and took some classes in grad school. I see none of those sweet gubbment fusion research bucks.

>you have to think about scale of investment

That's what I was doing...

>currently fusion is not an appealing private investment outside of philanthropy. There are a lot of up front costs and uncertainty for a payoff that is way down the road

As opposed to the Mars rocket business? As opposed to money-losing biotech? Bitcoin, now representing around $1 trillion in total? Is the disinterest in long term investments why the US government is thinking about issuing 50 and 100 year bonds, as well as the 30 year that already exist?

In 2021, saying that significant capital is only available to non-speculative investments with short term payoffs sounds like something from another dimension. One without the GameStop hearings.

Elon Musk isn't literally the sole litmus test of whether fusion is feasible; he just represents the general zeitgeist. If a few billion dollars would make it happen in the near future, how could it be that everyone is disinterested? Especially now that taking climate change seriously seems to be snowballing.

> As opposed to the Mars rocket business?

SpaceX talks a lot about Mars, but so far they've mostly stuck to Earth orbit, because that's where the money is. They are starting to do some Moon-related stuff – because both NASA and space tourists will pay to go there. Even Starship, which was designed as a vehicle to get to Mars, most of its actual use is going to be Earth orbit or lunar, it is going to be very many years before its Martian use cases outnumber its Earth/Moon ones.

SpaceX will probably fund a few unmanned trips to Mars out of their own pocket – land a couple of Starships containing supplies that might be useful to future colonists. But I'm sure straight after doing that they'll be knocking on NASA's door suggesting that NASA pay them for some Mars missions... imagine how many (and how big) rovers you could fit on a Starship.

Musk has said he wants SpaceX to develop the necessary transport technologies to support colonisation of Mars – and they'll try to use non-Mars-related revenue sources to pay for that development. But he's also said the role of actually setting up a Martian colony (as opposed to just providing transportation to get there) won't fall to SpaceX.

I have a theory – which could just be wild speculation on my part – at some point Musk is going to set up something like a "Mars Colonisation Foundation" as a non-profit tasked with colonising Mars. And when he dies he's going to leave it the vast bulk of his assets to it (I'm sure he'll leave his family enough to live comfortably, but they don't need billions to do that). And the "Foundation" will end up owning a big chunk of SpaceX, and will be a major customer of SpaceX, but will remain separate from it. It will actually try to pay for the colonisation of Mars, not SpaceX themselves. And it will stick at it as long as it takes (even if it takes a few lifetimes to pull it all off.)

It's not a few billion dollars, it's hundreds, and probably decades before it pays off. Private investors have dabbled with alternative approaches to fusion that promise lower costs, but none of them have really panned out and it's pretty much all fallen to government sponsored research.

I expect private investment will pick up eventually, when the technology is a little closer to market. I'm not at all disagreeing that we should be investing more in it and that it's looking increasingly urgent, it's still a relatively small effort compared to other things.

Well, ITER will cost 22-65bn. It's much more ambitious than the Manhattan Project IMHO.

> GameStop has lost over $30 billion from its peak valuation.

This isn't how market cap works.

I know what market cap is, and that they didn't really have the opportunity to sell the company for that much, but it still provides a sense of scale.

A very misleading one.

The only way significant progress on commercial fusion is likely by 2030 is if it's approached by industry and government similarly to how COVID vaccine development was -- everyone drops everything and throws everything they've got at it. Another example of similar financial and institutional commitment would be the Apollo program.

This level of commitment will probably only happen if climate change (and the related ecological and economic collapses) are taken as seriously as COVID, which is unlikely since, once the effects become obvious as COVID, it will be too late. And even COVID has large numbers of people denying reality.

Even if a massive commitment to fusion started now, by 2030 we'd likely only have a promising proof-of-concept or two, with several more failed projects on the side. Wide-scale deployment would still be years away even with many companies tooling up to start building pilot commercial reactors while assuming high financial risk, since profitability would be far from guaranteed.

[edit] Another point of comparison would be semiconductor manufacturing advances over the past 10 years. Tens of billions were spent researching and building factories, and in the end only a few companies made it to 7nm. And that was a clearly profitable endeavor iterating on already proven techniques!

That's interesting, do you think that SPARC and HTS advancements like for example VIPER cables point towards a faster path to market for fusion than ITER?

No, because the fusion reactors using HTS still have horribly lower power density. The ARC design has a power density 40x worse than a PWR primary reactor vessel, and involves far more difficult engineering. How is this going to be cheaper than fission, which itself is not competitive?

Fission is only not competitive because of regulation and safety measures, is it not?

Not. Nowhere has it done well. It's just too complex with too many interdependent parts. Construction has proved to be beyond the competency of those trying to build plants. And now, it's just too late. The iteration time for nuclear designs is measured in decades, going up against renewable and storage technologies iterating in periods of a few years.

Fusion would make fission look dead simple. If fission reactors cannot be constructed on schedule or budget, how bad would fusion reactors be?

If you think regulation is the problem, explain just which regulations you mean.

It was an honest question. I don't know which specific regulations, I've never built one but I have heard those who did lament the cost and trouble in even obtaining a site.

From what I can see fission reactors are doing just fine in France and Belgium. I don't know the specific numbers but the French don't seem worse off economically, despite having the greenest grid on the planet.

Fission has a number of disadvantages over fusion that make it a reasonable possibility of it being economically more viable than fission.

Because there's no compounding risks it is way more attractive to mass produce smaller reactors.

Once the key hurdles are solved it will be a simple calculation to decide how much investment will yield how much return, that means it will be an interesting investment opportunity.

Contrast this with fission, where a project is usually just one or two reactors, with tens of billions invested, loads of risk, slow and steady reward with various threats.

It is not the complexity that makes power plants intractible, we build more complex things than fission reactors every day. Its the lack of supply chain because of the unsteady build rate.

The iteration time of fusion reactors is measured in years, not decades by the way. Tokamak Energy is building its third iteration in 12 years, and plans to start the 4th in 2025.

Obviously we aren't there yet, but if it's possible, and a relatively small company like Tokamak Energy can build a proof of concept, then I don't see why we wouldn't have thousands of reactors spread through cities all over the world within the next 20 years.

It was a leading question, pretending to claim that regulation was the cause. Nice walkback, though.

Nuclear is in a bad state in France. Their recent attempts to build new reactors have gone massively over budget. Existing reactors are aging and it looks like they cannot replace them.

Fission has some disadvantages over fusion, but those disadvantages won't make fusion cheaper than fission (the costs of fuel and waste disposal for fission are minor compared to other costs.) Fusion is inherently much lower in power density than fission, which will make the nuclear island much more expensive to build. It will require a minor miracle for fusion to be competitive with fission, never mind the cheaper sources of energy that are beating fission.

> Tokamak Energy is building its third iteration in 12 years,

They haven't built a fusion reactor. They have built experiments that are smaller and less complex that what a fusion power plant would have to be. Small fission reactors iterated well too; they weren't commercial power plants.

The chance that we have thousands of fusion reactors all over the world in the next 20 years is indistinguishable from zero.

> Nuclear is in a bad state in France. Their recent attempts to build new reactors have gone massively over budget. Existing reactors are aging and it looks like they cannot replace them.

This is a political problem which has nothing to do to with technology or costs themselves.

Most infrastructures are aging and in a bad state in France, and the skills and knowledge to build or replace it has long been lost.

Add on top of this politically strong ecologist-extremists who decided that nuclear is evil and must be gone, and who will do everything to sabotage any project.

To take a counter example, nuclear is doing fine and growing in many countries, including China.

> This is a political problem which has nothing to do to with technology or costs themselves.

No, nowhere in the world is nuclear power economically competitive. Construction costs are about 3x-4x the cost per kW compared to solar or wind. [0 page 11][1]

> nuclear is doing fine and growing in many countries, including China.

No, net nuclear plants in Asia are not increasing. [0 page 4]

[0] https://www.diw.de/documents/publikationen/73/diw_01.c.69857...

[1] https://www.eia.gov/todayinenergy/detail.php?id=45136

> No, nowhere in the world is nuclear power economically competitive.

I only said that the problems in France are mostly due to politics, and so that we cannot use this specific example as an argument. This does not imply any affirmation from me about the absolute costs.

> No, net nuclear plants in Asia are not increasing.

Your link (0) page 4 only shows that the construction rate is not especially increasing lately.

Page 5 of your document (0) shows that almost all reactors < 25 years old are in Asia, which contradicts your affirmation. And it also shows that the number of reactors < 5~10 years old is bigger than the ones of about 10~25 years old, which implies a growth.

I don't have the knowledge or patience to read this further, but it is a very interesting read anyway, thanks.

> I only said that the problems in France are mostly due to politics

The problems in France are because they screwed the pooch on building the latest reactor design. This wasn't politics, it was failure to execute.

> It was a leading question, pretending to claim that regulation was the cause.

I just stated the opposite, are you calling me a liar? And then you mock me for crediting your argument, does that make you feel good? Are we like fighting or something?

> It was a leading question, pretending to claim that regulation was the cause. Nice walkback, though.

Not cool.

I mean, when I first read tinco's comment, I thought what you thought. But either reading is plausible.

If you're going to call someone a liar, maybe just don't reply.

> From what I can see fission reactors are doing just fine in France and Belgium.

They aren't, France has had nuclear for geopolitical reasons, not primarily economic ones. And now that these plants are old, they won't be replaced with new ones (save 1 big project that is already way over budget and won't be price competitive once it is live).

And we will soon find out that renewables are not reliable enough and require a higher degree of planning than we are typically good at.

Texas recently is a prime example, wind turbines froze and gas turbines had co2 regulations that made it difficult to ramp up. Other issues aside these were major contributing factors and indicative of the challenges many states will have.

We can't control the weather and many of these renewable are dependent on it. In comparison every fossil or nuclear based energy source has well developed supply chains, control and planning. Issues will be likely compounded because severe weather often times means increased energy needs as well.

Texas's problems have very little to do with renewables.

There were some wind turbines that froze, but wind power output overall is actually exceeding projections for this time of year. Not to mention that wind turbines can be winterized to withstand temperatures like in Texas right now. They just didn't because they didn't expect such low temps and it costs money.

It looks like renewables accounted for about 13% of the under-generation. Mostly it was issues with coal and nat gas as well as a nuclear plant going offline.

That's not to say that there won't need to be more storage technology or backups for renewables to become a large slice of the power pie.

That's fair. I was basing on incomplete information and retract :)

Canada has winter every year. Thus doesn't happen there. Canada has wind turbines, too

Help me answer this:

If it's 'likely' to happen, then why are we not allocating 10's of billions towards it right now, to accelerate it so that it happens in 5 years?

Many, many things can be done in parrallel. Some effort would be wasted, bit it'd be worth it.

If fusion works, it's basically going to be priceless in terms of impact and value.

Even starting to account for climate change ... we could suck Co2 out of the air on demand.

It's not likely to work in the sense of being profitable to build the reactors. There are fundamental engineering constraints that make it unlikely to be competitive.

What makes you think fusion power will be cheaper than solar, wind, fossil fuels or fission?

Efficiency isn't really a good metric when the fuel is free. We see that in solar power where expensive high efficiency devices lose out to cheaper less efficient ones. It's more about capital cost and operating cost per unit of energy.

To elaborate on the topic, there is ample evidence that nuclear energy is by far the most expensive source of energy, when you take into account the government (for example here in France) entirely subsidizing the construction and hypothetical demolition.

I say hypothetical because french attempts at "safely dismantling" nuclear power point are not going so well and are over-budget by an order of magnitude.

Then these people who can't even build/dismantle a plant (see the many Areva scandals) would like us to believe they can build an underground storage area for highly radioactive materials that's gonna be safe for at least 100 000 years? Despite growing evidence of the contrary

There's also growing evidence that nuclear and renewables tend to be incompatible, mostly because nuclear means a grid with huge centers of energy production, far away from energy consumption (the opposite is true with renewables).


I'm always kind of curious as this "expensive" line of thinking. Yes, nuclear is expensive. Extremely expensive. But is it more expensive than a week's worth of catastrophic grid collapse due to global warming? We have the ability to build nuclear plants. We can reprocess the waste to make more energy with. We can get better at it to drive down the price. It's more reliable as a base load than any renewable.

My state gets over fifty percent of its energy from nuclear power plants. I pay a few pennies more per kWh than neighboring states. I'd pay a few more pennies than that to figure out the rest of this issue.

> But is it more expensive than...

Like you, i don't believe price to be an argument of concern. I'm merely stating this because over and over, both in French media and on HN, i've seen stated that nuclear is the cheapest energy which is a blatant lie.

> We can reprocess the waste to make more energy with.

Source? From my limited understanding, all nuclear research that produced either less-dangerous waste or re-usable waste was shut down decades ago because there was no foreseeable way to turn that into weapons. The nuclear industry is deeply tied to the military industrial complex and (neo)colonial extractivism (see Françafrique networks for references).

> It's more reliable as a base load than any renewable.

Source? Here in France there's uncountable accidents/scandals in the nuclear industry and reactors are often stopped for weeks/months at a time. The same cannot be said about hydro power (dams) for instance.

> I'd pay a few more pennies than that to figure out the rest of this issue

Economic incentives is only part of the problem in my view. We in the industrialized world are aiming for ever-growing (ideally infinite) energy production and consumption, which necessarily leads to ecocide and other environmental damages. Don't you believe reducing our resources/energy footprint as a society is a more sustainable way to address the problem? There are many strategies we can put in place to reduce energy consumption, but these would contradict basic tenets of capitalism. For the most obvious example (from HN's perspective), see planned obsolescence or how/why we build more devices every few years than there are humans on earth (and yet we keep on having to buy new ones, which is severely damaging the environment).

>Source? From my limited understanding, all nuclear research that produced either less-dangerous waste or re-usable waste was shut down decades ago because there was no foreseeable way to turn that into weapons. The nuclear industry is deeply tied to the military industrial complex and (neo)colonial extractivism (see Françafrique networks for references).

The existence of La Hague site in northwest France has been very successful at nuclear reprocessing.

>Source? Here in France there's uncountable accidents/scandals in the nuclear industry and reactors are often stopped for weeks/months at a time. The same cannot be said about hydro power (dams) for instance.

It's not uncountable. There have been like ten in the entire country over the past fifty years.

>Don't you believe reducing our resources/energy footprint as a society is a more sustainable way to address the problem?

No. The one actual resource we can make and use is energy. We need to use less consumables. Energy isn't a consumable in our timeline. So many things are predicated on significant increases in clean energy. We could literally suck carbon out of the air with enough energy.

Reprocessing went out of fashion because it's economically pointless. Separated plutonium from spent fuel has negative value -- it costs more to fabricate fuel from it than it would to use freshly enriched uranium.

Efficiency is also a bad metric if the inputs are different.

Usually when I see "efficiency" used in a pro-nuclear argument it's not used in any rigorous way, though. It's just a vacuous cheer word.

Yes. Even fossil fuels contain far more nuclear energy than chemical energy so the engines we use are ~0% efficient if you actually count that as part of the input, even though we could, in principle, build an engine which does use it. How then do you compare two different nuclear fuels for efficiency?

You don't compare them for efficiency. That's a useless thing to do. You compare for other metrics that actually matter, like cost.

I know. It was just a rhetorical question to further show the unhelpfulness of efficiency.

If ITER proves its style to be a success (what may happen this decade, but I'm not holding my breath), we can expect a decade (about half the time of the original) to just complete the first generation of commercially viable reactors (what ITER will not be).

After that, lithium supplied T grows exponentially with the reactor usage, with a doubling time of a bit less than a decade. So, if it becomes the bottleneck (what means, if people to everything else right) you can expect some 3 or 4 decades before fusion even becomes a major power source.

It would take far longer than a decade, and I think likely would never happen at all.

One problem with ITER is that it’s only point is to demonstrate ignition. It’s completely unfeasible as an actual power plant. I’m not saying it’s not useful, but rather it has a close to 0% chance of producing a scalable power plant, whereas some of the other smaller scale operations are less likely to reach ignition, but if they do so more likely to result in a viable design at scale.

It's purpose certainly is to demonstrate net positive energy production.


Thereby the machine aims to demonstrate, for the first time in a fusion reactor, the principle of producing more thermal power than is used to heat the plasma. The total electricity consumed by the reactor and facilities will range from 110 MW up to 620 MW peak for 30-second periods during plasma operation.[6] Being a research reactor,[3] thermal-to-electric conversion is not intended, and ITER will not produce sufficient power for net electrical production. Instead, the emitted heat will be vented.

It could demonstrate net power production, at a power density 400 times worse than a fission reactor. It will not have, and not demonstrate, the tritium breeding blankets necessary for a commercial reactor. And the materials in the first wall (CuZr alloys) are not suitable for a reactor operating in near steady state.

The other thing to remember is that there is a lot of land that isn't suitable for farming for one reason or another that can be used for solar.

It's such an important point that's the core value proposition of vertical farming. Arable.land is unlikely to keep up with the combination of population growth and climate change. That's the whole point of the exercise! Solving that problem!

World popolation is around 7.8 billion, and is projected to peak around 11 billion. Given that of all agricultural land only 23% is used for non-feed crops (producing 82% of global calorie supply) that doesn't sound like an existential problem, even if you assume that climate change makes much more land unarable than it makes arable.

Not solving it unless you solve the other problems such as where the energy comes from how do you deal with waste where do you get the water from.

Farmland utilization is on the downtrend everywhere except Africa though.

doubtful, as little far back as a decade there was considered to be over 2.7 billion hectares of land available that would was considered usable, this is mostly in areas like South America, sub-Saharan Africa, and Central America.

Global Warming may actually open areas previously unsuited for certain crops; evidence pointed to much warmer climates in Europe with grapes further North in mans short existence, and the impact on existing uses is not fully understood.

The simple fact is, every time someone suggest were are running out of food or have too many people or water is not wet anymore we find out that it simply is because we don't look further than we are standing.

The biggest reason people starve today is repressive governments that respect neither the person or private property. that one percent, the ruling elite of the world, loses its grip in highly informed, rights driven parts of the world but they sure do fight to keep the pie to themselves even there.

but isn't aquafarming vastly superior to vertical farming for that problem statement?

This is a surprising concept missed by many, especially in energy. Since places solar is the best. Some wind. Some hydro. Some nuclear. The world isn't homogeneous. I see the same thing with farming. Indoor and vertical farming allows you to farm in the middle of the dessert. In Africa where hippos eat your crops. Closer to population centers where you reduce emissions from transportation and increase food security (longer roads mean more chance of food trucks getting stopped, due to accidents, climate, whatever). You can't compare these things on singular metrics. You have to look at the whole picture. In some instances things will be better, other instances worse. You have to balance complex equations.

Very important point. Included in this land, which a lot of people seem to forget about, is the roofs of buildings! This is currently a huge amount of area that just absorbs sunlight and converts a good chunk in to heat.

There is also a lot of land used for something else that can also be used for solar, ie. house roofs, roads, parking lots.

> can be used for solar.

And there are many other renewal energy sources.

Like geothermal power in some areas or water (fall or tide) based power in other areas.

And you can put this power sources in a lot of places which are fully unusable for farming.

> lot of land that isn't suitable for farming

We're talking about powering a hydroponic greenhouse. The alternative to "Solar Powered LEDs" isn't "plant things in the ground". Its "make a glass window on your roof".


"Plant things in the ground" is also cheaper, though it does suffer from potentially poor soil conditions. Still, it seems to me that spreading fertilizer across soil (and conditioning the soil into a growable state) would be cheaper and easier than making large-scale indoor hydroponics.

> lot of land that isn't suitable for farming

> We're talking about powering a hydroponic greenhouse. The alternative to "Solar Powered LEDs" isn't "plant things in the ground". Its "make a glass window on your roof".

I think what they were getting at is that you can take land wholly unsuitable for farming or greenhouses (e.g. severe slopes), apply solar panels, and then funnel that energy to a vertical farm. Since the vertical farm does save space in the abstract (just not necessarily once accounting for space needed for electricity generation), the scheme overall is still a more efficient use of land.

> Since the vertical farm does save space in the abstract (just not necessarily once accounting for space needed for electricity generation)

I severely doubt that.

Solar panels are maybe 30% efficient. So 10-acres of glass-roofs need to be replaced by 30-acres of solar panels just to account for this inefficiency (let alone other inefficiencies: such as wiring, inverter, batteries, and LEDs). Maybe 50-acres of solar panels to be anywhere close to comparable against 10-acres of glass roofs once we include other inefficiencies.

> Solar panels are maybe 30% efficient. So 10-acres of glass-roofs need to be replaced by 30-acres of solar panels

Not remotely. Plants are also extremely inefficient, converting only about 1% of the solar energy that falls for their use. [1]

Most of this inefficiency is from solar energy being in the form of frequencies that the plants can't use, but solar panels can. So the panels can capture this energy, then funnel into the red and orange lights that are most efficient for plant growth.

I've read a bunch on this, and haven't been able to find an authoritative source for what the efficiency conversion is -- how many acres of solar panels power how many acres of vegetables, and is it greater or less than 1:1? -- but it's certainly not as simplistic as "solar would need 3x more land because they are 30% efficient."

1. https://phys.org/news/2012-01-energy-conversion-solar-cells....

The article's numbers are that 1m^2 of wheat needed 20m^2 of solar panels.

That implies a 5% efficiency in the "total solar captured area" of the solar panel + LED lights compared to just sticking the plats out in the sun, which is totally independent of the plants own efficiency in photosynthesis.

(I guess coming from a site about Low Tech, their slant on the numbers might be questioned, but they certainly hold up to initial scrutiny from here...)

> I've read a bunch on this, and haven't been able to find an authoritative source for what the efficiency conversion is -- how many acres of solar panels power how many acres of vegetables, and is it greater or less than 1:1? -- but it's certainly not as simplistic as "solar would need 3x more land because they are 30% efficient."

I own a townhome, so my only real ability to grow plants is through a grow-light connected to electricity.

As such, I've spent some time calculating the PAR values of a decent grow-light, as well as the amount of PAR that natural sunlight gives. Plants need a ludicrous amount of PAR (basically blue + red lights, green not needed cause green just bounces off of plants).

Sunlight is mostly broad spectrum: broader than plants need and therefore a source of inefficiency (green light is wasted) that LEDs can somewhat replace.

Grow-lights have a benefit that they can be placed very close to the plant (maybe just 1-foot away) to "focus" the energy a bit better. Nonetheless, the amount of PAR / PPFD from a typical day sun (or even a cloudy day) far exceeds what you'd get from 500W or even 2000W grow lights.


Its just a hobby of mine, and I'm not growing anything especially hard (just Basil, which is really easy to grow... but Basil is a summer plant that really wants sunlight).

Still, once you start calculating PAR and actually mapping out how much electricity your "emulated sunlight" needs, you'll realize how grossly inefficient that "solar panel -> electricity -> LED" plan really is.

EDIT: Natural sun is like 2000 PPFD or something FAR in excess of what most plants need. Still, a good growlight solution might hit ~1000 PPFD constantly. Lets take this 650W LED and think about it: https://allgreenhydroponics.com/collections/american-made-le...

You'll get ~500 to ~1000 PPFD across a 4'x4' or 16-square foot area from that 650W LED (and most of that light is focused on the center: you'll want to overlap your lights a bit for more consistency).

Then think about how much solar panels you need to power a 650W LED for the 16-hours / day your typical plant would want (to account for the lesser PPFD indoor plants get, you run the lights for a bit longer than sunrise-sunset).

Just some napkin math. Nothing serious here: just guestimating the area in my head.


EDIT: Now it should be noted: I've heard of good hydroponic greenhouses that have the "do both" approach: glass roofs to let the sun in most of the time, and LEDs to augment the natural sun (cloudy / rainy days, as well as winter-settings when you have fewer hours of sun). The sun isn't nearly as consistent as we'd like, but... that means that you need something aside from solar power powering those LEDs.

But the concept of building a all-LED underground (or "inside a building") without any natural light just... seems grossly inefficient to me. Such a setup only seems useful to those growing contraband IMO.

We can also increase yield and desirable traits by providing the right wave lengths at the right point of the plants lifecycle, we can make the basil more intense, the lettuce bushier and more red. And we can control the environment to easier prevent vermin without pesticides, bad weather, etc. We also do large scale installations in the desert under ground where we previously couldn’t farm at all.

I was an engineer at a company called Heliospectra, we specialized in this and I personally built systems that on an industrial scale enabled above light/environment control down to umol of individual wavelengths every minute based on variables such as sensor feedback, algorithms for specific types of plants and traits as well as learning to adapt based on the environmental daily patterns from sensor feedback over time. It was actually quite fun to work on, I do still keep in contact with the company.

I'm not sure if you noticed, but your argument is that I'm not doing a good enough job accounting for the space needed for solar, and the thing you're trying to counter is that if you _ignore_ the space needed for [solar] then vertical farming makes sense. Those are two completely logically independent ideas which can't be used to refute each other regardless of their respective veracities.

> "Plant things in the ground" is also cheaper, though it does suffer from potentially poor soil conditions.

"Poor soil conditions" to include "soil" that is alkali dust, sand, dry for eleven months out of the year, frozen solid and under multiple feet of snow for more than half the year, and so far from either a river or reliable groundwater that any and all water used must be trucked in. In tanks. On trucks.

Plus, you only get to dump more fertilizer in the water if you filter it back out again.

> "make a glass window on your roof".

Doesn't work as you can't stack plants with it nor can you grow them underground.

Where are you placing these solar panels? Why can't those locations be rooftop hydroponic farms instead?

Because rooftop hydroponic farms have to be tended to almost daily, or at least for planting/harvesting. Solar panels don't need nearly as much maintenance and allow you to concentrate the actual growing operations for the economies of scale.

Do you mind if I ask why you're so against the idea?

> Do you mind if I ask why you're so against the idea?

Because it is clearly inefficient to convert sunlight -> electricity -> simulated sunlight.

But you're ignoring the inefficiency of building separate hydroponic operations on individual rooftops and driving around to all of them, etc. Also as SamBam mention above, you don't have to make a simulated sun. Instead it can work as sun -> electricity -> narrow-spectrum-light-that-plants-convert-at-higher-efficiency. You might even genetically modify plants to be more productive with the smallest spectrum possible.

Or the obvious solution: put hydroponics on traditional close to ground greenhouses... Potentially best of both worlds, if they are sufficiently distributed on outskirts of cities.

Hydroponics is how many commercial growers operate their greenhouses

Or maybe something like what's being investigated for greenhouses on Mars (which gets less than half the sunlight that Earth receives) using mirrors and optical fiber cables to redirect light.

Yes! I wonder if there is a way to make a light battery? :)

Light has a tendency to zoom off at, well, the speed of light, and colliding with objects causes it to lose energy. There have been some experiments in slowing down or "stopping" light although they involve some elaborate setups that almost certainly use more energy to trap the light than you'd get from storing it.

You could also store it in or orbiting in a black hole, but good luck getting it back in its original form! https://en.wikipedia.org/wiki/Photon_sphere

Right, which is why it doesn't make sense yet for countries like the US, where there is enough open land and connective infrastructure to grow plants with free sun energy.

If you were to use solar, then you'd need a country that has a lot of land that would be better used on solar panels rather than farmland, so maybe one that is mostly tundras or deserts.

I was really only addressing the notion that vertical farming took up more land. If we have as much extra land as you say, the point is irrelevant anyway.

But you need to remember that there are real costs to industrial farming on land. The use of pesticides, fertilizers and topsoil loss. There are a lot of benefits to vertical farming if it can be made to work economically.

Well, the primary costs today are water and labor. Fertilizers and such don't really cost much, which is why we always just overfertilize and now are causing runoff problems.

Considering the pressure on the environment and biodiversity, and the disappearance of wilderness, I think we don't necessarily want to exploit more land.

IMHO a key point of the article is that solar is not really a suitable source of electricity for vertical farming. There are other sources of clean electricity that more suitable in order to reap the benefits of vertical farming (less transport and less use of land, and also less water and pesticides).

Surely it is easier and cheaper to make the land arable or a greenhouse or whatever than equivalent vertical farm + solar. KISS

How exactly do you do that in say the desert? Solar is KISS in many situations.

It's being done in North Africa e.g. Tunisia — https://www.hortidaily.com/article/9128081/newest-semi-close...

A while back I saw a plan for a greenhouse that used solar desalination to provide water for plants but don't know if was ever built

edit: Looks like they exist https://www.researchgate.net/figure/The-seawater-greenhouse-...

Are greenhouses in deserts harder to build or maintain than PV farms and power lines in the same desert?

Not a rhetorical question, I genuinely don’t know. I assume it varies by desert, but farming and power are both way out of my domain.

My understanding was that you put the solar in the desert, so that you can put the vertical farm somewhere else where soil, water, transport logistics is easier.

So the question is whether a greenhouse/farm in the desert is easier than solar in the desert connected through grid to vertical farm somewhere else.

I have no data. My guess is the ongoing logistics of piping electricity out of the desert is easier than fertiliser into the desert and produce out to where people live.

It is, I’ve worked on large scale projects to enable farming in deserts using underground vertical farms.

Where can I learn more about these underground vertical farms in the deserts?

Hmmm, that’s a good question, I couldn’t find much information publicly available and I can of course not disclose internal. But there’s a little in this annual report from 2015. There’s an rudimentary illustration on the second page. Unfortunately it doesn’t include many of the details which I found most impressive, we had just started the project in 2015, so that might be why.


I'm also just an armchair intellectual speculating here...

Not "per se" a knock against greenhouses, but definitely one of the things you're looking for is a closed system rather than the sort of greenhouse you'd get in many places in America, where it's just a robust plastic tent-on-a-concrete-slab, and they don't care much if the water runs off. In a desert you'd be really concerned about making sure the whole works has very, very low water-losses.

The key thing to make this useful is to conceptualize it not as the sort of area, like the Nile, where they've already got an ample water supply. To make this useful, it's best to think of something where there's basically no water supply at all, and we're trying to crack the problem of "okay, how could we grow crops here?" Something that right now, is just bone-dry barren desert. Most of the solutions we rely on in the wetter world just don't really care much about water loss.

Something that could fit the definition of a greenhouse, with windowed ceilings, might well be a viable solution. But I do suspect there's some correlation between making a grow site more bunker-like and lowering water loss (especially if it's recessed into the earth).

The other huge upside of a truly sealed system is it's another approach to pest control. Sealing the system could potentially completely eliminate the need for pesticides and herbicides. Right now those have huge negative externalities.

Some type of semi-reflective coating to keep heat low and closed loop systems? I wonder how expensive and actually complex would it be to find nano-scale substance that would reflect most of wasted light spectrum while allowing the one needed...

Or a solar panel that is transparent to red and blue, and only captures green light?

Or restoring native habitat.

You can’t put solar on land while restoring native habitat. Wind power is much closer to minimal impact outside of bats and birds.

Commercial nuclear takes up a lot of space, to the point where replacing it with solar is surprisingly close.

For example the the Brunswick nuclear power plant in North Carolina, covers 1,200 acres or 4,860,000 square meters for 1,858 MW = 382 w/m2. It’s stated lifetime capacity factor is 75% which is much higher than solar, but that’s ignoring the long construction and decommissioning process afterwards.

You can find both higher and lower energy density examples, but I personally was surprised how close they where.

That's the whole land belonging to the site, most of which is nature, not the plant itself, which looks like less than 200 acres, including the car parks.

In any case, it's not close at all either for that specific example or in general, not least considering that a nuclear plant can produce 24/7 and that solar often does not reach peak production because of the weather.

"A solar PV facility must have an installed capacity of 3,300 MW and 5,400 MW to match a 1,000-MW nuclear facility’s output, requiring between 45 and 75 square miles. For comparison, the District of Columbia’s total land area is 68 square miles." [1]

[1] Nuclear Energy Institute @ https://www.nei.org/news/2015/land-needs-for-wind-solar-dwar...

Look through several nuclear locations and ~1000 acres is fairly typical. In theory they could be more compact, but security concerns etc means nobody puts 2GW of nuclear on a 200 acre site.

1,000 acres, https://en.wikipedia.org/wiki/Beaver_Valley_Nuclear_Power_St...

1,782-acre, https://en.wikipedia.org/wiki/Byron_Nuclear_Generating_Stati...

2,767 acres https://en.wikipedia.org/wiki/Callaway_Nuclear_Generating_St... for just 1,190 MW.

Some are significantly more compact for example 391-acre https://en.wikipedia.org/wiki/Catawba_Nuclear_Station, but that’s surrounded by water.

To put this in comparison, a solar farm would need 50,000 to 100,000 acres to match the net output of those nuclear plants. Plus the land used for energy storage, which would typically involve damming rivers which has its own set of ecological effects.

And it's possible to build much denser plants. The Shin-Kori facility in Korea is massive energy relative to the land it uses. Nuclear power is far more energy dense than solar or wind. This is just thermodynamic fact.

Try running the numbers for actual lifespan.

Callaway is 1,190 MW on 2,767 acres at 87.70% over it’s useful lifespan, but that’s ignoring permits + construction = 10 years and decommissioning which takes ~30 year. Even a generous 55 year operating lifespan is still reduced to 87.7 * (60 / (60 * 10 + 30)) = 48% capacity factor. Using a 20% capacity factor for solar (aka non tracking in a good but not great area).

That’s 1,190 MW * 48/20 = 2856 MW. A very good modern panel is hitting 220w/m2 add spacing, equipment etc, and 110w/m2 is a safe bet. That’s 2856 * 1000 * 1000 / 110 = 26,000,000m2 or 26 km2 or ~6,424 acres solar vs 2,767 acres nuclear. Lower efficiency panels bump that by 25% or so.

Clearly a win for nuclear, but not a 100,000 acre win.

PS: That said, this is largely a moot point as even with reprocessing we would quickly run out of fuel with large scale indoor farming.

30 year decommissioning is a very pessimistic assumption. Also most new nuclear plants have operating lifetimes closer to 80 years than 55.

You also have to adjust for the overproduction necessary to make intermittent sources a reliable primary provider of electricity. In far north or southern latitudes, angle of inclination is such that solar panels collect ~70-50% less energy than near the equator. This gets worse with seasonal fluctuations, which are more extreme the closer to the poles you get. Add weather on top of this and it can drop even further.

This might not seem like too big an issue, but keep in mind that most of the world's electricity consumption is in North America and Europe. These places don't have as good weather for solar.

100,000 acres is roughly the ratio that the article came up with, a factor of 75.

> PS: That said, this is largely a moot point as even with reprocessing we would quickly run out of fuel with large scale indoor farming.

No, we wouldn't: https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

30 year decommissioning is somewhat optimistic average based on current plans.

https://en.wikipedia.org/wiki/SAFSTOR “For nuclear power plants governed by the United States Nuclear Regulatory Commission, SAFSTOR (SAFe STORage) is one of the options for nuclear decommissioning of a shut down plant. During SAFSTOR the de-fuelled plant is monitored for up to sixty years before complete decontamination and dismantling of the site, to a condition where nuclear licensing is no longer required. During the storage interval, some of the radioactive contaminants of the reactor and power plant will decay, which will reduce the quantity of radioactive material to be removed during the final decontamination phase.”

For example, Crystal River 3 (Florida) “Duke Energy announced in Feb-2013 that the Crystal River NPP would be permanently shut down.” “Systems Removal & Building Remediation(2070–2072)“ and that’s if things go well. https://en.wikipedia.org/wiki/Nuclear_decommissioning

As to indoor farming.

“It’s not just that the 4 billion tons of uranium in seawater now would fuel a thousand 1,000-MW nuclear power plants for a 100,000.”

That sounds like a lot, but of you want ~100w of power per m2 that’s 0.1GW of power per km2. So your 1,000 GW power plants are only replacing 10,000km2 of farm land. Meanwhile agriculture takes 51,000,000km2 worth of land. In other words replace 20% of global farmland and you got ~100 years worth of uranium from all the worlds oceans, it’s replaced by rocks.

But, “And those rocks contain 100 trillion tons of uranium.” gives you 2,500 years which is not bad, but that’s not going to be replaced.

PS: You might be able to beat 100w/m2 indoors, but remember this is also for 20% of farmland.

> But, “And those rocks contain 100 trillion tons of uranium.” gives you 2,500 years which is not bad, but that’s not going to be replaced.

How did you arrive at these figures? I think you missed a conversion from pounds to tons.

Current global uranium consumption is in the hundreds of millions of pounds annually - hundreds of thousands of tons. And this is without reprocessing. Nuclear power already generates 10% electricity globally. Even if we assume a 200x increase in consumption from 200 million pounds to 20 billion pounds that still only 10 million tons of consumption annual. 100 trillion divided by 10 million is a lot more than 2,500.

But surely they don’t just own the “nature” land for the fun of it. I assume it could not be used for other things, like housing, or another nuclear power plant!

The difference with solar/wind space requirements is so big that it does not matter.

If the land is reserved and left to nature that is still a positive thing because that helps the environment and biodiversity. But I'm sure that they could put solar panels on it if they wanted.

The point is that this land is not required for production and in any case solar require much, much more land, so, no, it's not even close.

Winds density is off the charts as you can use the ground around it for crops or even solar panels. https://thumbs.dreamstime.com/b/wind-turbines-corn-fields-ae...

Wind still requires a huge area covered with wind turbines to match a single nuclear plant. Each of which takes space, needs to be accessible, and needs to be connected to the grid through some facility. I would not call that a density off the charts... (see link in my previous comment as well)

It doesn't really make sense to talk about land usage that just so happens to be owned by a nuclear plant, or even certain fixed land requirements for a nuclear plant. It only makes sense to talk about the limiting behavior of land usage for various types of power plants.

Solar has hugely larger requirements than nuclear however you look at it, contrary to what was suggested above.

How much land does rooftop solar require?

You're saying that a couple of 50 year old reactors when including a safety zone and adjusting for lifetime capacity outputs about twice the maximum power of commercial solar panels before adjusting for capacity factor.

When you adjust PV for capacity factor the difference ends up at over an order of magnitude.

Thought: Put PV inside the "safety zone" to increase output and use "unusable" space.

You’re skipping permits +construction ~10 years and decommissioning which seems to take 30+ years on average though few have actually finished the process. https://en.wikipedia.org/wiki/Nuclear_decommissioning

75% capacity factor * 50y / (50y + 10y construction + ~30y decommissioning) = 42% capacity factor which is higher than solar but not by that much.

But let’s assume you’re at a 1.5x capacity factor advantage. So 1.5 GW of solar = 1.0 GW of nuclear. 1.5GW / 220w/m2 = 2.9 square miles of panels plus panel spacing and whatever infrastructure is needed. Double it to be really pessimistic and your under 6 square miles.

>"So 1.5 GW of solar = 1.0 GW of nuclear."

That's not how it works. PV capacity factor is 11-12% to the 90-95% of nuclear meaning you need to install about an order of magnitude more PV effect not 1.5x.

Also one batch of PV panels equivalent to a reactor cost 6x as much and with a lifetime of 20 years to the 60 for a nuclear reactor so you will need to replace these at least twice. All 32.5 Million of them.

Replacing panels is just a cost question which dramatically favors solar. 2c/kWh is massively better than any nuclear reactor ever built or operated.

As we are talking land use, construction and decommissioning is a major hit to nuclear. But with solar you can operate continuously by just swapping panels and replacing wires etc as needed.

Basically, in steady state a 50 year nuclear power plant spends the first 30 years with the previous reactor being decommissioned, and it’s last 10 years with it’s replacement being built. Effectively you need 1.8 locations for a single power plant.

Also, I used a specific 75% capacity factor over it’s operating lifespan in that calculation. Some are higher, but the trend is down over time so you want to use an old reactor as your baseline. Here is 72.5% Decommission date 29 June 2020 https://en.wikipedia.org/wiki/Fessenheim_Nuclear_Power_Plant

Just no. Reactor buildings take up a small fraction of the total site area. Constructing additional reactors on existing sites has been done for about as long as nuclear power has existed and multiple reactors coexist simultaneously at the same site.

>"Replacing panels is just a cost question"

Sure, I bet you won't need more than 2 guys and a pickup truck to install, maintain and replace the 120 million panels it would take to create the equivalent to a site with 4 modern reactors. After all, that's only 35 000 panels to install every day if you want to build the site in 10 years. Everything is magical with solar.


That's a hypothetical figure for 2050.

There are actual current contracts that agree to sell solar at under 2c/kWh. Construction of multiple reactors on the same location is very common, constructing a new reactor next to a reactor being decommissioned isn’t.

https://en.wikipedia.org/wiki/Crystal_River_Nuclear_Plant https://en.wikipedia.org/wiki/Rancho_Seco_Nuclear_Generating... https://en.wikipedia.org/wiki/Shippingport_Atomic_Power_Stat... https://en.wikipedia.org/wiki/San_Onofre_Nuclear_Generating_...


I mean in theory sure it seems like it should happen, but in practice not so much.

Please link. I've read about some far future contracts relying heavily on public subsidies but even those were at a higher price. At that price, earnings would (depending largely on geography) be something like 160-400 USD / 1.8m² panel over a 20 year period. This needs to cover panel cost, inverters and electrical infrastructure, installation&decommission, land rent, loss due to some prematurely dead panels, administration etc.

I would presume it's a matter of very few new nuclear reactors being built. Some smaller sites will be decommissioned regardless though.

Subsides are common for all forms of electricity generation, but LA’s 2019 1.997c/kWh power purchase agreement is hardly the far future. https://www.pv-magazine.com/2019/06/28/los-angeles-seeks-rec...

Anyway to use a specific example Capacity factor 26.6% (average 2015–2018) https://en.wikipedia.org/wiki/Topaz_Solar_Farm.

Bulk panels are $0.29 per W or 290$ per kW. PS-P72-330W https://sunelec.com/

If 1kw is worth 0.01997 $/h * 24 * 0.266 * 365 * 20 = 930$. Of course they don’t instantly break exactly in year 20. They lose efficiency over time so averaging ~90% over 25 years which is ~100% over 22 years. https://sunelec.com/wp/wp-content/uploads/2020/09/P72_outlin...

I can’t find an exact breakdown of costs spent on panels vs interest, instillation, inverters etc. But, at most we are talking about fractions of a cent worth of subsides to hit 2c/kWh.

>"0.01997 $/h * 24 * 0.266 * 365 * 20 = 930$"

That's a calculation based on 1kW of installed capacity, which is about 3 of those 345W panels so the earning per panel over its lifetime (in sunny southern California btw) is about $310.

Also the $ sign goes in front of the number.

Also, here's a B.Sc. paper from my alma mater (English abstract in the paper) http://www.diva-portal.se/smash/get/diva2:1236618/FULLTEXT01... that puts the current all inclusive production cost of nuclear power in Sweden (incl. funding for permanent spent fuel storage) at $0.03/kWh. That's an actual cost for stuff that actually exists today.

The inability to replace nuclear plants is actually the driving factor behind it's poor public perception. If you keep running untested 50 year old power plants on the brink of failure why would anyone be surprised that some of them do end up failing? If you could just turn the old plants off and replace them all accidents would have been prevented.

One more thing it saves:

Transportation (!) from miles away, as a skyscraper could feed a city or a part of it.

Yes, please include the cost of nuclear power in the considerations.

(The joke here is that the true cost is undefined because we here in the US have no method to store the long-term hazardous waste it produces. Current cleanup costs for just the military reactor waste are estimated at $500B, for civilian reactors the costs are said to be higher.)

1. We have nuclear waste already

2. We will continue to have nuclear waste if we want to have nuclear weapons

3. You can store all the waste you need to store in a football field (https://www.energy.gov/ne/articles/5-fast-facts-about-spent-...)

Nuclear waste management is messy, but it's something we need to solve no matter what. It is now a sunk cost we have to deal with because of what we have already done and what we plan to keep.

So if we already have to pay the fixed cost, we should reap as much benefit as possible.

Rarely does one hear the sunk cost fallacy advocated so enthusiastically.

The sunk cost fallacy is about continuing to incur additional sunk costs. The parent is arguing that we're going to have to pay $X/year to manage the nuclear waste we've already incurred and that the cost is fixed--adding more nuclear waste isn't going to increase the cost. Whether those claims are true may be up for debate, but it's certainly not a sunk cost fallacy.

He's arguing (to paraphrase) "Because we've already incurred such costs we should continue or even expand the policy which caused them."

Claiming that hazardous nuclear waste represents a fixed cost no matter how much you generate is simply absurd.

Do you have any data that says the cost (ie. money or security) is materially increased from this point forward given the space to store is truly small.

No, because the US currently has no such long term storage facility in operation.

In the short term nuclear energy is expensive, but in the long term nuclear energy is one the cheapest sources of energy available. Source - https://www.youtube.com/watch?v=cbeJIwF1pVY

(this is even more true when you consider the cost of externalities)

I don't see how nuclear can win over the long term.

Solar and wind are simple and very amenable to mass production. Many parts of them are usable for other purposes -- we need generators for things other than windmills, inverters for things other than solar powerplants, etc. This means we're not making things as a one off, but doing mass manufacturing, and the different users all reap benefits.

They're easy to produce, which means there's lots and lots of competition, which pushes down price.

They're easy to install, scale and maintain.

They're easy to iterate, because it doesn't take billions to test a new design on a small scale.

They don't need most of the parts nuclear has -- if you think of it a windmill contains parts a nuclear plant needs too, but unlike nuclear doesn't have all the nuclear stuff along with it, which isn't cheap.

The way I see it, nuclear could have been successful but is going the way of the mainframe -- today mass computing is done on huge amounts of commodity hardware, and in the same way large, purpose built plants are already being overtaken by mass production of panel after panel being churned out of a factory, and that's not going to get any better for nuclear.

Nuclear's non-intermittency is why it wind in the long run. Once intermittent sources fulfill demand during peak production hours, the actual cost of adding each usable watt goes up dramatically. If your goal is to run a primarily fossil fuel grid, supplemented by renewables that's fine. That's what Germany is doing.

But if your goal is to actually eliminate carbon emissions, you need to factor in the cost of storage. And there really no feasible plan of storing the amount of energy required at the moment.

If your goal is to actually eliminate carbon emissions, nuclear presents a much more realistic option. We keep celebrating Germany, but in reality their carbon emissions per KWh of electricity is not actually very good. It is worse than Britain. And it's ~7x worse than it's neighborhood to the west, which we tend to ignore for some reason.

Nuclear's cost is almost entirely in the infrastructure, and it's paid over a very long time period. The business plan for nuclear is to spend a decade or two paying back your loans, after which you make big $$$ because the plant costs relatively little to run.

The ideal plan for nuclear is to pump out power at 100% 24/7. You save nothing by being idle, and you want to pay off your loan as soon as possible.

All that goes to hell once cheap renewables show up, because the moment wind or solar can sell power cheaper, a rational person would buy it from renewables. Which means that if the sun is shining, you're either not selling at all, or selling much less or cheaper than you'd like to. And so your loans now get repaid much later.

At some point a bank looks at that and figures that the proposition of maybe making a profit 30 years in the future isn't that great of a deal. That's a long time, for all the bank knows, solar might be dirt cheap by then and kill nuclear for good before it gets to making a profit. Probably better to put billions to some safer use.

Politically it's not a lot better -- nuclear costs $$$, and takes a long time to build, which means that if you're the one who got the country into nuclear on a large scale you can't really expect to see a benefit within your term. Worst case it goes wrong and is an expensive boondoggle, which doesn't bode well for reelection.

Nuclear may make sense if you think "emissions are paramount, screw money". But there's not a lot of people who'd be willing or even able to risk billions in such a manner.

Yes, nuclear hardly costs any more to run at 100% capacity than it does at 50% capacity. That's why decarbonization with renewables as a primary source doesn't make much sense.

Solar and wind are both intermittent. Wind is dependent on the weather and experiences situations with near zero production for long stretches of time. Solar is also weather dependent, and has day-night cycles on top of it.

This is fine if you're not actually looking to decarbonize a grid, just trying to opportunistically shave off carbon emissions here and there in a primarily fossil fuel grid. But if you're actually trying to eliminate fossil fuel use this is not a good approach. Theoretically we could store excess energy, but no scalable storage solution exists at the moment. That leaves nuclear power plants to serve as a dispatchable source. But as you pointed out, nuclear plants are just as cheap to run 24/7 as it does to run intermittently. So why not just build the nuclear plants and skip the renewables?

The issue as I see it is that pretty much nobody is looking at decarbonizing a grid, money be damned.

Unless your power production is run by the government, generation is done by companies looking to make a profit. Solar and wind companies don't mind in the slightest that they're screwing up the business model of nuclear. The fact that their production is intermittent isn't important to them -- it's already accounted into their business model, and nuclear's lack of ability to deal with that and grid stability is somebody else's problem.

If you think nuclear is the solution here you must be prepared to pour many billions of tax money on supporting its existence even though it's currently unprofitable. China can do that, because China's government has the long term control and lack of concern about public opinion to get such things done.

Politicians in democratic nations in general lack such a luxury. They know that they can get kicked out of power before their first plants get built, and then the successor either pulls the plug on the project entirely, or keeps whatever got built, but almost definitely nowhere near close to the full capacity needed.

You'd have a hard time skipping the renewables, because you'd essentially have to forbid them. You'd have to go there and make a law that you can't build solar even though it would produce power that's twice as cheap, or take craploads of tax money and subsidize nuclear. I suspect neither is going to look very good in the news.

Introduce carbon taxes and all of a sudden nuclear becomes a lot more viable. Existing plans for renewables are for them to exist in a primarily fossil fuel grid, supplementing them when the conditions are right. Make it so that using fossil fuels for even 20% or 10% of electricity generation is prohibitively expensive, and people will switch to nuclear power.

Last time I checked France was a democratic nation. So was Belgium. Both of those have achieve majority nuclear power generation, and France over 70%.

The cynical reality, though, is that you're right. People would rather make a token effort on intermittent sources, while continuing to burn fossil fuels for most of their energy. The damage to the environment caused by the continued use of fossil fuels in this approach, though, will eventually take a toll. But that toll will mostly be borne by poor people in the global south, not in the countries that had the capability to build nuclear but chose to primarily use fossil fuels supplement it with intermittent sources.

"Last time I checked France was a democratic nation. So was Belgium. Both of those have achieve majority nuclear power generation, and France over 70%."

That was the past. The dynamics have changed, and renewables are much more competitive now. Nobody is building more nuclear right now. True, there's paranoia, but there's also economics.

And I'm not talking about fossil fuels either.

Here's what I expect to happen today with a carbon tax: it'll kill fossil fuels, and give a huge boost to renewables. Nuclear won't benefit nearly as much, because renewables can sell each GW/h cheaper and are much faster and easier to build. We'll get a grid full of solar panels and wind, and probably serious instability. This is because the people that build powerplants don't care about the system as a whole, but about making profit within it.

At that point you can subsidize nuclear, heavily tax renewables, or subsidize storage. My view is that the last one is the long term solution because nuclear won't outcompete renewables long term.

> That was the past. The dynamics have changed, and renewables are much more competitive now. Nobody is building more nuclear right now.

Uh... https://en.wikipedia.org/wiki/Nuclear_power#/media/File:Nucl...

> Here's what I expect to happen today with a carbon tax: it'll kill fossil fuels, and give a huge boost to renewables. Nuclear won't benefit nearly as much, because renewables can sell each GW/h cheaper and are much faster and easier to build.

This is overly simplistic. Eliminating carbon emissions is not just about generating more clean energy. It's about replacing the energy that fossil fuels currently provide. It's hard to do that with intermittent sources.

> At that point you can subsidize nuclear, heavily tax renewables, or subsidize storage. My view is that the last one is the long term solution because nuclear won't outcompete renewables long term.

Perhaps, if we have a miraculous breakthrough in energy storage. But unless that happens, we'll end up building nuclear power to fulfill off-peak demand. And since nuclear power is just as cheap to run 100% of the time as it does to run part of the time it'll just make the bulk of renewables redundant.

If you have 100 GW of solar solar panels plus nuclear plants generating 100 GW for nighttime use, it's just as cheap to run the nuclear plants 24/7 and ditch the solar panels.

That map isn't particularly meaningful. Sure, stuff is being built technically. But as far as I know, the main places where it's being done for real are China and India.

The UK for instance has one powerplant actually in construction and it already got a bad rap because it's a bad deal economically.

Besides that, I think you're missing my point. My point is that you have to deal with reality, and reality doesn't really align with the way you want things to work. For instance, you said:

"So why not just build the nuclear plants and skip the renewables?"

My question is: "Who 'we'"? In a lot of countries, there's no "we" that applies. There's a government that sets the rules, and private enterprise that builds the plants. If "we" is the government, then they don't build powerplants themselves. They may allow them to be built, but a company still has to want to.

And if "we" is the commmercial enterprise, then nuclear is far too big for anybody to build it out of sheer altruism or good PR. That's big money territory and it must make a profit.

If you simply impose a carbon tax, private enterprise will just go and build solar. We have no storage? Those companies won't care. It's not their problem to solve. They'll build whatever makes the most money, which is almost definitely not nuclear.

If you want nuclear to happen you'll have to force it somehow, and I'm not seeing any particularly attractive ways of doing so. You want to be the politician who runs on a campaign of forbidding or heavily taxing solar and wind at the same time as dumping billions of $ into nuclear construction? Yeah, that'll go great, I'm sure.

> If you simply impose a carbon tax, private enterprise will just go and build solar.

Depends on how high the carbon tax is. Put it at a high enough rate that the country needs to go 100% carbon-free and people will build nuclear because that's the only solution (besides geographically limited things like geothermal and hydro) that can feasibly bring carbon emissions to zero.

Renewables are cheap when going from a mostly fossil fuel grid to a 50/50 renewable and fossil fuel grid. But bringing fossil fuels below 50% without the help of nuclear or hydroelectricity is extremely difficult. Any plan to do so basically assumes that some future breakthrough will make storage cost a fraction of what it does today.

> We have no storage? Those companies won't care. It's not their problem to solve.

Yeah, that's why there's no plan to actually decarbonize with renewables.

And if we actually want to stop climate change, yes it absolutely a problem that needs to be solved.

> If you want nuclear to happen you'll have to force it somehow, and I'm not seeing any particularly attractive ways of doing so. You want to be the politician who runs on a campaign of forbidding or heavily taxing solar and wind at the same time as dumping billions of $ into nuclear construction? Yeah, that'll go great, I'm sure.

Pass a carbon tax such that building a nuclear plant is less expensive than running solar during the day and natural gas at night. Renewables depend on fossil fuels until we make a breakthrough in storage.

I think you're still missing what I'm saying. Yes, running a grid 100% on renewables is probably extremely difficult. Yes, nuclear may be the optimal way forward today. But I still think the most likely outcome is the renewable grid anyway.

Why? Because there's no "we". There's no central planning. What there is is a bunch of self-interested parties that don't care about the entirety of the problem. Everybody will go with what makes the most sense to them, the result will be suboptimal, and then once things go wrong the country will have to fix the problems somehow.

Your plan may make sense in China where the government can indeed implement a central plan, costs and opinions be damned. But it seems extremely unlikely to happen in most western democracies because the politics won't support it.

"Yeah, that's why there's no plan to actually decarbonize with renewables."

What I'm trying to say is that there's no global plan whatsoever. In most countries we don't have the ability to implement any kind of comprehensive central policy. We have multiple parties that can nudge things in one direction or another but none of which has full control over what happens.

"Pass a carbon tax such that building a nuclear plant is less expensive than running solar during the day and natural gas at night."

But the problem is that there's no single party in charge of solving that problem. You pass a carbon tax. Fossil fuels die. Companies will build solar, because it makes them money. Companies won't build nuclear because it's expensive to build and solar is eating their lunch. The powerplant building company cares nothing about the economics of keeping the country powered 24/7, they care about the economics of building their plant. If their business model works okay while selling nothing at night, then it works, and that's that.

Then we'll get blackouts at night, solar companies will shrug "not our problem", and the government will have to scramble to find a solution.

> The powerplant building company cares nothing about the economics of keeping the country powered 24/7, they care about the economics of building their plant. If their business model works okay while selling nothing at night, then it works, and that's that

It doesn't work like that.

Contrary to your repeated insistence that there is no central planning, there is indeed extensive government planning in electrical grids. You can't just say "we'll only give you power during X hours of the day" to your customers. Likewise, you can't just tell customers who don't live near a dam that they won't be getting electricity when it isn't windy.

Wholesalers can do this, because they sell to other grid companies who actually sell to consumers. But no, if we have solar and wind and these sources aren't producing enough electricity then they have to burn gas and pay the carbon taxes. And if the carbon taxes are high enough, it's less expensive to build nuclear plants that emit no carbon and don't suffer from intermittency.

I think COVID-19 has shown that most countries with multi party systems can implement comprehensive policies centrally.

That's an interesting counter-argument but I don't think it works very well. In fact that's pretty much how I expect things with nuclear to go.

Where you have strong central government control -- there you can have comprehensive plans. Where you don't, you can't.

Which is why Covid-19 is a clusterfuck in the US -- because the US doesn't have strong enough central control (and heck, Trump didn't care anyway). Even with Biden at the helm his power is limited and he has to convince the various states to act, and Congress hangs in a very delicate balance.

Also, the fact that a country can do one thing doesn't mean it necessarily can do another. That you have centralized healthcare and can command a country-wide response to covid-19 doesn't mean you have centralized power generation and can command a country-wide decarbonization.

Sure, things can be restructured, laws can be passed, power generation can be nationalized, but none of that is quick nor easy and by no means guaranteed to happen even if it would result in the best outcomes.

Plus as far as the public is concerned, covid-19 is a lot more understandable and immediate of a concern. Climate change is more of a vague and slow moving threat, and that makes it much harder to do dramatic things in response.

One can look at Sweden and the green parties strategy for dealing with grid instability. Government are interested in a stable grid so they pay fossil fueled power plants to operate in backup mode. That way the power plant get paid twice, once by the government and then for any power that they manage to sell.

The second part to the plan is to spend a lot of tax money expanding the power lines to nearby country in order to increase the capacity for importing energy from nearby countries coal based power plants.

As a conclusion I agree that the people that build power plants don't care about the system as a whole. The government however do care about stability and mine is perfectly fine with spending tax money on that. Politically, voters are not going to be upset that money is spent on grid stability, even if then ends up in the hands of owners of fossil fueled power plants.

Storage solutions are advancing fast enough that your argument cannot succeed. What you are saying used to be sort of plausible, but the sell by date on it passed long ago.

Right, as evidenced by the extensive storage infrastructure being deployed /s.

The US has 25 GWh of storage, as compared to an hourly electricity consumption of 500 GWh. Literally less than ten minutes of storage. Almost all of it hydroelectric, which is a big infrastructure project on par with building nuclear power plants

I'm sure you're eager to talk about how thermal storage, or concret weights with pulleys, or compressed air is going to be 100x better than current solutions. But until those things move out to prototypes and I to mass production, they represent potential solutions not actual solutions. Like fusion. If the next attempt at fusion works, great! But building out infrastructure assuming it's going to work is extremely unwise.

> Right, as evidenced by the extensive storage infrastructure being deployed /s.

Invalid argument.

> The US has 25 GWh of storage, as compared to an hourly electricity consumption of 500 GWh. Literally less than ten minutes of storage. Almost all of it hydroelectric, which is a big infrastructure project on par with building nuclear power plants

Irrelevant point.

Storage was marginal in the past because there wasn't much of a business case for it. With renewables crashing in price and fossil fuels being phased out, that is changing. There are now strong market forces pushing development of storage technologies. Your insistence of carrying over the market conditions of the past into the future leads you astray.

California has already saturated the daytime energy demand on sunny days. So does Hawaii. The market forces already exist. But people aren't building storage. Because it's not feasible, short of a decisive breakthrough in storage technology.

Maybe one of the proposed storage solutions will pan out. But building out trillions of dollars of infrastructure projects on the hope that a future breakthrough will make storage feasible is very risky. Fusion has been 10-20 years away for the past 50 years. General artificial intelligence has been 10-20 years away for the past 50 years. Between:

1. Going with a known solution, that already generates more electricity than solar and wind combined and one we have 70 years of experience working with.

2. Going with a solution contingent on a massive technological breakthrough to actually work.

When the stakes are as high as climate change, I cannot even remotely justify going with #2 over #1 even if the costs are potentially lower on paper.

> The market forces already exist.

And that is a recent thing there. The global market is still developing, and technologies don't materialize instantly. CO2 taxes are still low (or zero) just about everywhere.

But hey, I hope you are also not going to claim nuclear will be cheaper in the future, because I could reflect that argument right back at you. And I could observe that, unlike with renewables and storage, nuclear has a horribly bad historical experience curve.

> Maybe one of the proposed storage solutions will pan out. But building out trillions of dollars of infrastructure projects on the hope that a future breakthrough will make storage feasible is very risky.

It's only a $$$ risk. We absolutely know the storage is possible, we just haven't confirmed how cheap it will be. Worst case is we spend a bit more. This is fine. Investments are not guarantees; one is always gambling.

No, it's not "worst case we spent a bit more". Total global lithium ion battery production amounts to less than one hour of storage for the United States alone. Things like pulleys and synthetic methane remain in the prototyping stage.

By this logic why not just use fusion? It's possible. We don't know which exact approach we'll use (lasers, magnets, etc.). We don't know how cheap it'll be, but hey it'll happen eventually right? No.

It's not "worst case we spend more money". It's "worse case we never solve climate change". And that's a pretty bad worst case.

We're already at the point where markets are starting to see saturation with renewables. But this unfounded aversion to nuclear power is hampering actual progress to decarbonization. The cost of waiting around and hoping for storage to become viable is not just the cost of building those storage systems, but also the continued release of fossil fuels as we wait for that to happen - and who knows when that will happen, if ever.

No, it is "worst case we spend a bit more". We absolutely know that storage is possible. Pumped thermal electricity storage, for example, uses only well understood technologies.

We solve climate change by raising CO2 costs high enough. Again, this is not a go-no go thing, it is just haggling over the price.

> We're already at the point where markets are starting to see saturation with renewables.

This just means CO2 taxes aren't high enough. BTW, they'd have to be $300-400/ton for new nuclear to compete with gas in the US.

No, pumped storage is not feasible. It's both geographically limited, and it's not available at the appropriate scale. Estimates for how much storage would be necessary for renewables to work range from 12 hours to weeks of storage depending on the solar and wind mix. The US has ~25GWh of hydroelectric storage. There are no active hydroelectric storage projects at the moment, only proposals [1]. This is why proposals to decarbonize through intermittent sources always assume a nearly-free mechanism of energy storage.

It's easy to make renewables look cheap if you assume some wundertech makes storage free. Will thermal storage, synthetic methane, or who knows what else fulfill this need? Who knows, but they don't yet. Thus renewables only present a solution coupled with an engineering breakthrough. It's like assuming moore's law held true and developed an app that assumed it'd run on a 1THz single-core processor presumably developed a decade in the future. Seems reasonable in 1995, but that's have been a very bad bet.

1. https://en.m.wikipedia.org/wiki/Pumped-storage_hydroelectric...

Pumped THERMAL storage. This is not pumped hydro. Rather, it involves a heat pump, for example compressing argon near-adiabatically, transferring the heat to a hot store (cooling the argon in the process), then expanding the argon back to the starting pressure. The argon is now around at mildly cryogenic temperature, and the cold is transferred to a cold store (liquid hexane, perhaps).

To recover energy, this is reversed, with the temperature difference driving the cycle in the other direction. Detailed calculations with inefficiencies show an overall round trip efficiency of 60% or better could be achieved. All the temperatures are below the creep limit of ordinary steel, so this system would require no exotic materials whatsoever.

It's also possible to design a thermal storage system without the cold store, using the ambient environment as a heat sink when running the generator. In that case, adding a backup heater (burning hydrogen, say) would make the store double as a backup generator at extremely low extra capital cost.

Right and who can I call to install 1 GWh of thermal storage? I can't, because this technology only exists in prototypes. The only actual use of thermal storage is in solar thermal energy, which hasn't experienced the massive drop in price that photovoltaic solar has.

You or I could go out today and buy off the counter parts, build a scale model of a pulley system, and use it to store power. We could have done that a century ago.

To the best of my knowledge, fusion only demonstrated net-positive energy production this decade, and hasn't yet reached ignition in a man-made device.

They're not the same.

Yeah you and I could built a simple pulley system and store gravitational potential energy. Physics works, I know I'm not surprised. But we couldn't use it to store moderately enough energy to be useable to decarbonize our energy footprint. And building them at scale is a gamble on unprecedented application of technology.

It's like trying to be carbon neutral through burning biomass. Yeah, it works as a general principle. But the energy density just isn't there. The US consumes about much energy each year as we'd get from clear-cutting the entire country over the span of a single year. And the plants take longer than that to grow. Sure, we could try more exotic things like dumping iron into the ocean and harvesting algae blooms. But as a general principle, biomass energy source doesn't scale well.

Same with energy storage. Nuclear isotopes are a great store of energy. The best we know how to tap into in term of energy density, that's why we use it on submarines. Chemical energy like methane is good, but the sabatier process isn't that feasible and it needs a pre-existing source of carbon dioxide. Electrochemical storage like batteries is great for systems that need to store a relatively small amount of energy, like cars and electronics. But it isn't available at nearly the required scale. Hydroelectricity storage is better for scale, but still not good enough. And I'm sure you can name other proposed systems like pulleys, hydrogen, compressed air, an d more. But the point is that until they've demonstrated commercial viability let alone beaten competitive solutions it's a big assumption to factor these into solutions to climate change.

Are people accepting contracts to store X GWh of electricity in pulleys, or or compressed air and operating those projects successfully? Until then, these do not represent presently available solutions to climate change. I'd be happy to be proven wrong, but until then saying we have a realistic plan to provision enough energy storage to decarbonize through renewables is counterfactual - at least save for places like Norway or Iceland that have dispatchable sources of renewable energy nearby in the form of geographically dependent hydro and geothermal power.

Biomass has low energy density, but that has nothing to do with non-biomass renewable sources, or with storage. The implication that the low density of biomass carries over is a deception.

The argument that nothing that hasn't been commercialized can be considered is a double standard. Nuclear on the scale needed to replace fossil fuels is also currently impossible. The infrastructure to build it isn't there, and the breeder reactors that would be needed to fuel it aren't commercially available either.

> Biomass has low energy density, but that has nothing to do with non-biomass renewable sources, or with storage. The implication that the low density of biomass carries over is a deception.

No, it's not deception. Both solar and wind suffer from low energy density, especially as compared to nuclear. 200 Watts per square meter isn't all that good energy density.

> Nuclear on the scale needed to replace fossil fuels is also currently impossible.

Again, France just mysteriously doesn't exist in the alternate reality that hardcore renewable supporters live in. Globally, nuclear generates more than solar and wind combined.

To make nuclear energy successful you need to stop fear mongering, and invest in improving technology. With scale, it will make far cheaper and reliable energy source than anything on earth. But it will hardly happen when politicians tirelessly promote solar & wind, while increasing the regulation of nuclear energy. And politicians act this way because of said fear mongering, which affects the public deeply.

Why bother?

What reason is there to believe a generator with blades attached to it is going to lose to a generator with a containment building and reactor attached to it?

Isn’t the issue that the windmill also needs a large battery to meet demand?

That is solar - wind can work through geographic distribution alone without so much as a potato battery. A local area may be becalmed by wind but since temperature differentials produce wind and the earth rotates into and out of the sun the only things which would lead to no wind render the power generation question a moot point.

Grid scale batteries make wind cheaper by allowing less overproduction but they do that for everything by assisting grid balance and acting as a form of high frequency trading which is productive in ways other than increased market liquidity.

Storage is needed, but storage has finite cost, and the cost is falling rapidly. Nuclear's window of opportunity is now closed.

Far from it. After years of promotion, investment and development, wind and solar energy prices dropped 10-20x in the last decades. Same cost reduction can very well happen with nuclear power, and it'll take far less space than solar and wind, will disrupt the nature less, and will be much more reliable and predictable, capable of producing energy on demand and not requiring any storage.

Nuclear had many decades in which its cost could drop. That failed to happen. Unlike with renewables, nuclear never had relentless cost decline. Its learning curve has even shown negative learning, with costs rising with time rather than falling. There's something about nuclear that just keeps it from getting cheaper. The scale and complexity of nuclear plants probably has something to do with it, and also the maturity of the non-nuclear side.

For the past 40+ years there was an non-stop ongoing attack on nuclear energy. See "china syndrome" for more info.

Fear-mongering is _the reason_ for the absence of progress and rising prices, not some technical obstacles.

Fear mongering must be incredibly powerful, if it has universally stopped nuclear from getting much (or at all) cheaper, everywhere in the world, in multiple cultures.

Much more plausibly, the technology itself is to blame.

All of that is irrelevant to the argument that wind wins because it’s simpler, which is what I was trying to engage with.


Although there are other options like pumped hydro (pump the water back up the hill) though clearly that has logistical limits.

Because it is cheaper to build many blades and posts. Plus economies of scale - wind is more factory scale in efficency as it is mostly assembly. The containment building alone is construction scale and is inherently pretty one off in requiring geology and planning as opposed to "look at weather patterns and slap it down".

I am personally of the point of view that if we went on a nuclear power plant building spree back in the day to replace coal plants/provide for growing needs and used breeder reactors to deal with waste we would be far better off. Renewables are cheaper per kWhr now however. For the future, who knows if fusion or renewable will work better for terrestrial grid applications once fusion reaches the point of a positive energy balance?

We're a century into nuclear reactor technology.

Today is the long term, and the costs are still uncontrolled.

the US has 80000 tonnes of spent nuclear reactor waste. SpaceX launch cost in 2017 was $2700/kg. presumably lower now.

by my math, that's $215bn to launch all our nuclear waste into space. Is there a reason that's not a viable option?

It's not the safety. One could conceivably put a glas she'll around the burnt fuel and it would survive reentry.

But first of all, the cost is still massive, even with SpaceX. And furthermore, you'd just put it into (decaying) low earth orbit that way. Further away would be even more expensive.

Finally, spent fuel still contains a lot of energy and should be recycled. This in turn is a very nasty and expensive procedure.

I still think that declaring that waste is a waste.

That is potential future fuel.

The danger of launch failure making the planet uninhabitable.

lol, good point. that's the sort of thing that's easy to forget about when your involvement on a topic is limited to typing out comments on HN.

How do you imagine that would happen? Even if a rocket fails catastrophically, pulverizing the nuclear waste, distributing it evenly across earth, how do you imagine that would make the planet inhabitable? Is the planet inhabitable now, after all the atomic bombs that exploded and all the nuclear waste that went into the ocean?

And what do you think drives the latest Mars rover, Perseverance?

It also doesn't take water into account. You can build solar panels in a desert and send the power over high-voltage DC lines with minimal losses. Trying to pump water into the desert and grow food outdoors, with constant losses due to evaporation, is far less efficient. You also need to bring in fertilizer, fuel to operate equipment, workers, and fuel to ship the harvest back out of the desert to bring it to market.

Way overshooting the confidence on fusion here.

It's placing something that quite literally simply does not exist on the balance sheet.

A physicist who died 55 years ago said it'd be commercially deployed by 1975. 1954 was the "too cheap to meter" claim by an investment banker who worked for the Truman administration. That's still quoted today, said 2 years before Elvis debuted on Ed Sullivan.

We're all supposed to treat it like it's a valid opinion. While instead, 46 years after the predicted free energy for all bonanza, rate payers are getting hit with taxes to keep nuclear going. It's in practice, in actual reality, a more expensive option.

Continue to research. March on with science, sure. But as a matter of public policy and planning, relying on it is pure fantasy.

I don't know why hn is so koolaid-drunk on this stuff. It's a cult with 70 years of failed predictions. It's apparently like any other cult where wrong predictions make the true believers even more fanatical.

We're amidst planet altering climate change, this is really not the time to fuck around.

Yeah, last time I checked everyone was still on the "viable fusion is constantly 20 years away" meme.

Fusion is still 20 years away.

It’s like 20 years away!!

>This entire piece is based on the assumption that the only sources of energy are solar panels and fossil fuels. This is false.

Right, and more than that, it appears to be relying on the old fallacy that a solar panel takes up "land" the same way a field of corn does, to the exclusion of other uses.

That is not necessarily the case, especially when we're imaging strategic uses of space that might become more prevalent in the future. Solar panels can go on top of things, including other solar panels in the form of vertical solar farms.

If we talked about pages of books the same way we talk about solar panels, you could claim that War & Peace takes up an acre of space.

Nuclear energy is the Amiga of energy sources.

Ahead of its time, it was unjustly rejected and persecuted by the ignorant masses. Its advocates are bonded by the quiet pride that at least they weren't unthinkingly siding with those masses. (And they're right!) Meanwhile, as the Amiga stagnated for terribly unfair reasons, other, scrappier technologies like the i386 and UMG-Si grew from being worthless boondoggles (except in special circumstances, like spaceflight) to being actually far better and cheaper. But the Amiga advocates keep the faith, sharing their suffering and resentment. They inevitably try the alternatives a little and perhaps even start to like them. Gradually their denial recedes, decade by decade.

But they know that however much fab costs go down and leave their beloved Amiga behind in the dust, you'll never be able to run nuclear submarines and Antarctic research stations on solar panels.

Yeah, don’t bother with reading articles that exclude the largest source of clean energy in US.

Such articles have an ideological bias.

Yeah, ideologically biased like the President of Exelon (quoted from December 2018):

“The cost of new nuclear is prohibitive for us to be investing in,” says Crane. Exelon considered building two new reactors in Texas in 2005, he says, when gas prices were $8/MMBtu and were projected to rise to $13/MMBtu. At that price, the project would have been viable with a CO2 tax of $25 per ton. “We’re sitting here trading 2019 gas at $2.90 per MMBtu,” he says; for new nuclear power to be competitive at that price, a CO2 tax “would be $300–$400.” Exelon currently is placing its bets instead on advances in energy storage and carbon sequestration technologies.

They might have an ideological bias, but if the prevailing ideology is anti-nuclear then ignoring that bias isn't going to get you very far. Biden has committed us to moving the energy sector off of carbon in the next 15 years, which means we're going to build a lot of $CleanEnergy really soon, and if the ideological landscape doesn't change it very likely will be a whole lot of solar and wind (what is 15 years minus the amount of time it takes to build out a nuclear power plant?).

> what is 15 years minus the amount of time it takes to build out a nuclear power plant?

If the last European projects are to be taken as models, it's a negative number (Olkiluoto 3 started in 2005 and not online before next year at best...). Not better for Flamanville 3, maybe Hinkley Point C will be achieved a bit faster...

No problem with nuclear until you have a problem, then it's a catastrophe

Fusion sounds great in theory, but even if they manage to make it viable, it'll cost billions to create even one plant, and how much power does it produce theoretically?

I mean if I put on my idealist sci fi glasses, I can see a future where we have infinite energy for free, in which case we will see a lot more energy-wasteful endeavours like vertical farms, air conditioning and cryptocurrencies. But we're not there yet, and we won't be there yet for a long time.

Energy production, also with renewables, increases year over year, but keeping right on it is energy consumption.

Examples from my own country. We're building big wind farms in the North Sea. But at the same time, Google and co are building data centers that use up a lot of their capacity already. And another thing happening at the same time is a push to reduce our dependency on natural gas for heating and cooking (because emissions and international politics / dependency on Russia). And the other push is towards electric vehicles. So thirst for electricity only goes up, probably faster than new energy sources can be built (renewable or otherwise).

This trend will continue, wouldn't be surprised if electricity consumption will double in the next decade.

A YouTube video is not the ne plus ultra of scientific presentations, you know.

I remember the first time that someone was telling that fusion would be producing a lot of power by the end of the decade, but I can't remember whether this was the 70s or the 80s.

Considering that humans have yet to produce one joule of net energy from fusion, and the longest anyone has ever run a fusion reactor was 20 seconds, I think you're wildly optimistic.

Indeed, I would say that if America today had working plans for a commercial fusion power plant handed to it by benevolent aliens, between a deliberately broken bureaucracy and the awesome power of the fossil fuel industry, I would be quite surprised if the first plant opened by January 1, 2030. (And I'd suspect that literally billions of kickbacks and graft would have to be paid for the gatekeepers to allow it in.)

(Other more rational, less kleptocratic countries might do better - I'm looking at you, Germany - and paradoxically, fully authoritarian states might also do better.)

>fusion energy is going to account for a rapidly increasing share of energy production by the end of this decade

Like it did "by the end" of 4-5 previous decades...

It's the perennial "soon" technology...

Author also makes mistake because he assumes all land to be equal. Then second assumption is that power source has to be in the same place as the farm.

Vertical farm can be set up in a place where normal farm would not be possible. One can also imagine that solar panels can be placed on a piece of land that would not be suitable for growing crops.

There is loads of empty land on the world. Land that is worth a lot is close to where all people are and in places where it is fertile and ideally flat.

I came here to point out nuclear and fusion also. Lets say you can get the energy cost to near zero, the the 200+ euros left per meter sq could be cut down by looking for construction or scaling efficiencies and even the fact that if energy is near zero from nuclear or fusion power, it might end up lowering construction costs if it can be diverted into use in heavy machinery. I'd love to see this same experiment powered by a small Thorium prototype reactor.

Even so, how does free sunlight with longer transport compare to the cost of electricity with short transport.

I imagine electricity, regardless of source, is still the most expensive factor.

to add:

- 95%+ reduction in water usage

- no need for any pesticides because... boom no pests

- no need for any other treatments to reduce disease

- can be powered in any way

- does not need to have complex freight

Sure it doesn't "save space" if you make a ton of win/solar farms. Sure. But its not about saving space as much as solving a huge logistics problem, water problem, pesticide problem, and even the taste problem (food harvested recently will taste better than frozen food transported for weeks/months)

Don't know how old you are but it's very likely that your children or their children will get old before fusion energy becomes reality.

I don't think competitive fusion power will ever be a reality, unless one is talking about fusion in the core of the Sun.

Nevermind that land used for energy often isn’t suitable for farming, so … even with the hypothesis, limited as it is, it’s flawed.

Less suitable than empty air 10 feet above the ground?

How is vertical farming powered by solar panels better than building the same artificial growing environment at ground-level and powering it with sunlight?

Because you can put the solar panels above a parking lot. You can't directly compare land area for growing with land area for solar panels, qualitatively, they are two very different lands. We have more of the latter.

Yes this could save a lot of arable or environmentally significant land, even if it didn't save a net m^2

I don't know about the US, but in Canada, you have at least three provinces that produce way more hydroelectric power than they can consume. Vertical farming would theoretically make sense in places like this where power is cheap, low carbon and plentiful.

Not only that, but, even if we were just talking straight solar, solar panels don't have to be built on arable land. There's a lot more land available for building solar panels than there is available arable farmland.

It's also ignoring that there are places that are suitable for solar but not suitable for farming. Take the Sahara desert for example, lots of sun, a solar farm would thrive!

Now try planting something there....

Fusion is 30 years away, not 10. Always has been.

Why can't you just open the windows. I'm imagining some victorian-like device which reflects sunlight around indoors

A lot people miss this point, so thank you for bringing it up. It drives me nuts that it's so prevalent out there!

Woah great video. Thanks for sharing!

This article is more about indoor farming than vertical farming (is it even vertical if there's only one row?). I grow lettuce indoors. It serves as a nice houseplant and fresh source of salad greens for lunch. It's fairly new, so the cost isn't that much different than just buying lettuce. Once I start building my own "pods" instead of buying the brand-name pods, though, I expect it'll be a bit cheaper than buying 4 bags of lettuce every week (although it doesn't produce enough to fully replace buying greens).

Mine produced ~4 bags over 6 weeks for an energy cost of ~$5 and a negligible amount of water. I think I can get the per-plant cost down to ~$0.50 once I start using my own seeds, so around $10 over 6 weeks to replace 4 bags of salad at around $3 each... a grand savings of $2. We're moving around 4 bags of greens a week between 2 adults, so I'd need to 6x that to replace all the greens we're eating, which gets the savings up to ~$2/week.

The cost savings is negligible -- I do it because it's neat and I like having a houseplant I can eat. It's also MUCH easier for a residential system to offset its energy usage than a commercial setup (I have way more square footage on my roof than I would ever "grow" inside my house).

The calorie argument is more compelling, but how many thousands of years did it take for people to get wheat so calorically dense? I think it's going to take time to develop nutrient-rich crops specifically tailored for indoor farming.

I understood the point to be more about the energy inputs. The gist of it is: plants are more efficient at capturing energy from the sun directly than indirectly via solar panels -> light bulbs -> plants (which seems obvious, when you state it that way).

The only thing that makes vertical farming make any financial sense, today, is the access to cheap (subsidized) fossil fuels.

> plants are more efficient at capturing energy from the sun than solar panels -> light bulbs -> plants are

This is a counterintuitive misconception that I mention elsewhere in this thread. Plants aren't optimized for raw sunlight utilization, because that's not the bottleneck for growth or survival. Plants deliberately reflect away 90% of the sun's energy (https://en.wikipedia.org/wiki/Photosynthetic_efficiency) because other factors are more important: https://www.quantamagazine.org/why-are-plants-green-to-reduc...

> deliberately reflect away 90% of the sun's energy

They'll have that same efficiency with artificial lighting too… At least until our grow lights stop emitting light in the green spectrum (not something I expect to see anytime soon).

Grow lights are quite good at only emitting light in certain parts of the spectrum, and have been for some time now.

Just looking at some spectrum charts for grow lights... They certainly vary, but not in any uniform fashion.

There is an exception to this: there is a standard LED graph which shows up quite frequently, identified by it's peeks in the deep reds, yellow, and dark blue, with a marked trough at cyan.

The cost of transporting the conventionally grown plants would have to be accounted for as well, but I'd be pretty surprised if that got anywhere near tipping the scale over to vertical farming.

I wonder if that could be solved more easily. Build sufficient rail network and hydrogen/electric/other zero-carbon trucks to move produce from production to there and then train it in. And this is really a sector we could fully automated almost already.

Switch hydrogen for methane and produce that methane in a bioreactor from the food scraps. These technologies are already here, no need to wait for a future hydrogen car.

Also, building a zero-carbon transport system would be generally useful for transporting things other lettuce. And that's probably like 80% of the way toward a zero-carbon transit system. I think you have a good point.

Have you written comprehensively about the system you've set up and how it works? I've thought about a Zipgrow system or similar: https://shop.zipgrow.com/products/small?variant=316809164227..., but, as you can see, it's fairly costly to set up. I don't think it'll be cheaper than the grocery store, but it also seems fun and like the final product may taste better.

I'm just using a 9-plant Aerogarden Bounty right now (think it was ~$175 on Black Friday). My wife says I can upgrade to an indoor Tower Garden or Lettucegrow if I do 3-4 cycles on this thing without getting bored.

I also built six 4ftx4ft raised (dirt) beds in our back yard a few years back. I plant fairly densely (usually using 1x1 squares for most things, 2x2 for tomatoes) and I'm thinking about trying one of the tower gardens as a replacement for a single 4x4 bed this growing season. It's been a minute since I ran the numbers, but I think you can plant 20-25 plants on one tower vs maybe 4-16 in a single bed and theoretically not have to weed/water as much (but then you get pump maintenance/ph balance/feeding/cleaning instead).

Look at BA Kratky. My variant consists of 10Gal mixing tubs (Lowes $6) a bit of blue dow foam board, toothpicks, and rapid rooter growplugs Barina grow lights. Masterblend, CaCO3, and Epsom salt. Six trays (one per week. Pest pressure and growing season makes leafy greens not practical.

I think I'm following your build. It seems like Kratky requires a lot more space up-front than an aeroponic system that you refill over time, but it's good to know that I can get even lazier if I clean out some space in the garage.

I haven't written about mine, but I built one using an aquarium pump, a couple of food grade bus tubs (the kind wait staff use to clear restaurant tables), a couple LED panels, and some basic plastic cups. I grow basil, lettuce, bok choy, cilantro, and it doubles as a good setup for getting vegetable starts going in early spring. It was probably a couple hundred bucks to get going, but it's low maintenance and I get produce and herbs on demand.

If you're looking for something more cost effective, you might want to consider building your own with some LED strips and a driver. You can get higher quality components and a lot more power than kits typically sold by companies.

I'm building a 2ftx2ft indoor herb garden for my apartment right now. I found the LEDgardener to be a good resource and forum for getting started.


Is that including amortizing the space it uses in the house? That's not really free.


Kind of free? There was nothing in that space before.

Applications are open for YC Summer 2023

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact