> Enhanced geothermal systems, which require energy to drill and pump water into hot rock reservoirs, have life-cycle global warming emission of approximately 0.2 pounds of carbon dioxide equivalent per kilowatt-hour [11].
> To put this into context, estimates of life-cycle global warming emissions for natural gas generated electricity are between 0.6 and 2 pounds of carbon dioxide equivalent per kilowatt-hour and estimates for coal-generated electricity are 1.4 and 3.6 pounds of carbon dioxide equivalent per kilowatt-hour.
Nothing is really truly zero carbon currently. Solar has manufacturing and maintenance. Nuclear has construction, mining, refinement, containment, etc. It's nice to see the full lifecycle being looked at.
We can't pretend that something essential for the process doesn't matter because we do a classification handwaving. It all counts
Yes, but carbon costs come from burning fossil fuels. If you don't burn fossil fuels to drill wells or build PV panels, then those don't have an embodied life-cycle carbon cost.
I'm being a bit pedantic, but I think its an important point: The life-cycle carbon cost of renewables isn't a fact about renewables. It's a fact about our current energy production mix, which renewables themselves will change over time.
That's a valid point but cement and steel production emit CO2 directly, it's not just from the energy source.
As part of cement making, "The process of 'calcination' splits the material into calcium oxide and CO2."[1] About half a ton of CO2 is emitted per ton of cement.[2]
And with steel: "The prevailing process makes steel from iron ore — which is mostly iron oxide — by heating it with carbon; the process forms carbon dioxide as a byproduct. Production of a ton of steel generates almost two tons of CO2 emissions."[3]
Wind farms use a lot of concrete and steel; by some estimates, more than nuclear.[4] Of course, total emissions is still way less than fossil. Assuming normal lifespan, about 25 lbs of material per MWh[5], so (very) roughly that much CO2. By comparison, a coal plant emits over 2000 lbs CO2 per MWh. [6]
Steel in particular in new plants in the US, the stuff that isn't recycled in arc furnaces, is being made with a mix of hydrogen and CO (both from natural gas), and there's no reason the mix can't be almost entirely hydrogen (only a token amount of carbon is needed, and some of that ends up in the steel). Direct reduced iron furnaces can be converted to run almost entirely on hydrogen.
Cement DOES emit CO2 during manufacture, but it also absorbs it during cure (which, granted, can take decades). That means you can potentially use it for direct air capture in a sort of indirect way. (i.e. you capture the CO2 emitted during calcination, when the CO2 is very concentrated and easy to capture, then the cement itself captures CO2 directly from the air during cure).
I've been doing some googling and it appears that the US isn't actually building new steel plants. The only capacity increase I could find was bringing old plants back online. All the old stuff (other than recycling) uses carbon. Do you have a link showing what I missed?
US Steel has started to look into hydrogen production, but hasn't built anything yet. [0]
Europe has some pilot projects for hydrogen-produced steel but nothing operational. [1]
We certainly should make that conversion, and also ensure that we use green hydrogen for it, but that's a big change and there won't be much economic incentive for it before we have a decent carbon price. "Renewable hydrogen-based iron production can become the least-cost supply option at a carbon dioxide (CO2) price of around United States dollars (USD) 67 per tonne," but "the hydrogen energy used would equal 1% of global primary energy supply." [2]
Carbon capture during cement production of course also lacks economic incentive until we have a carbon price, but I haven't found a specific price it would need.
Then your Googles left you astray. The US has been building Direct Reduced Iron furnaces which are used to feed arc furnace “mini-mills” (which the US also has been building). The US has NOT been building new coal-fired blast furnaces, instead doing DRI furnaces (including hot briquetted iron) and mini-mills. Mini mills are flexible and can use DRI, HBI, and recycled steel as input (usually in the US they use recycled steel scrap primarily as input as it’s cheaper).
DRI/HBI furnaces use a mixture of hydrogen and CO. So they already use hydrogen, but it comes from natural gas. However, this input mix of hydrogen and CO can be changed to be almost all hydrogen (almost CO can also be made electrolytically from CO2, as NASA just did with the Perseverance rover on Mars).
If I have a house run by solar power and walk to the store to buy fruit from 10,000 miles away to feed to my 5 children, my carbon costs are so astronomically high from the last two that the first two don't matter.
I agree! Absolutely!
But also, if transporting fruit 10,000 miles could be done with renewables that will zero that out.
If by the time the children are adults, significant delimited activity has transformed through say, better agricultural practices, more efficient appliances, better building design to that can regulate temperature better, all these small things, then the aggregate decreases
Stop having 5 kids and buying 10,000 mile away fruit, I'm with you. Sure.
But the point of this exercise is to make such things not so high cost so that the freedom to do these things, however much I personally disapprove of it, can be preserved.
That's one of the things the anti-climate change people don't get. They see the current transformations as a restriction of their liberties. No, it's a massive effort to preserve them. If we fail to transform society and cities start sinking into the sea, I assure you, forced sterilization, meat consumption bans, bans on private car ownership, local only food by law, a ban on air travel, it'll all be on the table. We all saw how quickly the shoe dropped on covid last march; from busy streets to boarded up ghost towns in about 2 weeks. We didn't heed the warnings to prepare and here we are still living with the consequences.
>If I have a house run by solar power and walk to the store to buy fruit from 10,000 miles away to feed to my 5 children, my carbon costs are so astronomically high from the last two that the first two don't matter.
>I agree! Absolutely!
No, you're not agreeing with me. You're talking about a family unit as if the net balance matters. That's exactly what I was saying makes no sense.
Nothing has to balance except the whole world. Not people, or families, or industries, or companies, or countries.
I don't know if there is a name for the fallacy, but there's this mental short circuit I think I observe, where people want to compose the parts of something to get a quality of the whole, and it doesn't work.
If you want a blue city, then the way you get it is by making all the parts of the city blue. And recursively, every part of the parts can be painted blue.
But if you want a profitable company you do not get it by making every part profitable. That's stupid and destructive and often people seem to consider it obviously idiotic when it is tried.
Carbon emissions are like the latter, not the former.
If you expect coordinated global action from some kind of global conductor I really invite you to look at the literature from about 1915-1950 or so that culminated in the United Nations. It was typically called "world government" in the literature.
Essentially their highest aspirations were to avoid global war and assist in ongoing nation scale catastrophes, which they have done ok at.
They were pretty cynical about systems that essentially COP is structured under as being ineffective. Which it has been, closing in on year 30 of ineffectiveness.
This problem of global governance for issues like this is still fundamentally unsolved.
It has to work more like slavery, colonialism and chemical weapons; humanity eventually collectively found the idea reprehensible and we are mostly in agreement on the right direction. This is the only method that has worked so far.
You can have inspectors and enforcements but unless the people of the country also find the thing to be dishonerable, their loyalty to their leaders (political, bosses, wealthy, whatever) is the more important loyalty.
They'll stop shoveling coal into the furnace when the global police come by but then do it again after they leave. They have to want to stop intrinsically, not through a punitive threat. They have to be able to thrive and live well by not doing it too.
It's gotta be less work, easier, and pay better.
I mean look, I'm open to trying other things but they haven't been working. This method takes centuries, we still have prison and indentured labor which are effectively slavery, over 200 years later
We don't have that kind of time but also we don't have any other kind of solution
>If you expect coordinated global action from some kind of global conductor I really invite you to look at the literature
"I lost my keys in the dark, but I'm looking under the streetlight because that's where the light is".
I don't understand the frame of mind where you keep arguing about how you don't have a flashlight, I don't have a flashlight, we can't possibly wait until morning, etc. If you can't solve a problem, swapping it for some arbitrary thing you can solve is pointless.
Saying "it has to work" is the sort of thing people say in the movies. Something "has" to work because the script writer decided on it.
Coordinated global action may in fact be impossible. Some people think an effective world government would be a fate worse than unrestricted emissions.
I'm just saying it's the solution by definition. Again, because that's what "global" means.
>It has to work more like slavery, colonialism and chemical weapons
I don't know what I can say for a third time that I didn't say the first two and I feel like you are ignoring.
These are all things that compose like my analogy of painting things blue. If the people in a family did bad stuff, then their family did; if the families in a country did, then the country did, etc.
They are not things that compose via the summation of numbers corresponding to their parts. You don't add up a measure of colonialism produced with a measure of colonialism consumed elsewhere. There is no target threshold for colonialism or slavery or chemical weapons.
Not to mention, from what I read, all three things are very widespread to this day, so if they were like carbon dioxide emissions, it would be a pretty pessimistic sign anyway.
So I am trying to work out the basics of climate change action needed
1. More efficient agriculture
Cutting and clearing land for agriculture is generally destructive - so a) everyone becomes vegetarian, b)
stop growing food in 2 dimensions c) grow more efficient food
(broth and hydroponics)
2. more efficient transport of food
Don't transport food thousands of miles,
don't refrigerate it, don't fly it,
3. transport to move off carbon
Stop flying, more EV.
4. reduce travel
apart from flights and holidays (carbon tax)
commuting is huge contributor- remote working will impact this
4. Building efficiency
Insulation and ground source heat pumps and so on
See also strongtowns - denser living is halley kore efficient t living
If your kids have a negative carbon footprint (this is possible... after all, trees do it... because carbon is a good building material for cell walls), then having more kids is potentially superior to having fewer...
I don't think kids can do photosynthesis. And I can't imagine any way to make kids carbon negative that wouldn't be considered a crime against humanity.
Planting trees isn't the problem. Trees can plant themselves pretty well already, just leave them space that you won't cut and plow every year.
My late grandpa had a small plot of land where he grew tomatoes and other vegetables. Since he died 12 years ago nobody does anything to that land cause he lived far from the rest of the family. It's a small forest now.
Not cutting trees for new farming land and leaving the space is the problematic part. And more kids is kinda at odds with this.
BTW what you're actually doing by planting a tree is burning carbon to move an already existing plant from one place to another.
> BTW what you're actually doing by planting a tree is burning carbon to move an already existing plant from one place to another.
That is true (unless you're actually planting seeds), but generally the idea is that another tree will grow where you took it from, so the end result is more trees.
Yeah but if there are any trees in the region where you plant - a tree would grow in that spot anyway if you just leave it be :)
BTW one of the weirdest examples of "patriarchy" is the preference of city planners to plant only male trees (because they generate less "junk"). Which reduces the amount of new trees growing in and near cities significantly.
Very interesting! I never knew that a fair number of city trees are dioecious. What happens to all the female saplings?
I would imagine that we can actually do a lot to accelerate the process of trees spreading over an area. And even a small speed-up compounds over time.
And of course some species are cloned because it faster and cheaper, so then female saplings aren't a problem. You clone what has higher demand.
> I would imagine that we can actually do a lot to accelerate the process of trees spreading over an area.
Yes I was a little facetious. I don't actually plan to persuade people not to have kids or not to do gardening. But when I see people gathering millions of dollars to use drones to plant trees I can't help but think it's focusing on the wrong (but cool) part of the problem.
That’s not necessarily true. Some places have been ravaged by desertification and so actively planting trees can facilitate a forest where otherwise there wouldn’t be any.
Second, you can choose trees which are particularly good at sequestering carbon for long periods.
We just haven’t historically been very good at it (ie we’ve often historically reduced ecological diversity instead of facilitating it). I think we can do much better, and there are many examples of humans who HAVE done a great job at it (for instance, the man who planted a forest on an island in India). https://m.youtube.com/watch?v=HkZDSqyE1do
Do you think the planet would be better off if everything else was the same but his parents had decided not to have him? So this is why I think we can’t apply a broad average of human footprint to whether someone should decide to have kids or not. Instilling values, such as being a net-positive to the environment and the value of choosing to live a net-carbon-negative life (and support continued climate action), can be more important than just the marginal impact of not having kids at all.
Also, negative-sum thinking ends up in a pretty dark place pretty fast if brought to its logical conclusion.
And it seems pretty obvious what the long term result would be if all climate-conscious people had no kids but folks who don’t give a crap about climate action raise lots of children.
Hello Ajuc and Firad, I don’t literally mean plant trees, what I mean is that unlike fruit-jet-miles, the carbon cost of people isn’t n * constant, people can make choices and take actions including actions that are carbon negative.
Only the leaves (and maybe other green and exposed parts) of a tree do photosynthesis. The rest of the tree provides structure and protection and nutrients and most of the carbon is sequestered in the structure and roots, not in the photosynthetic part.
Human civilization, as it becomes more reliant on solar power, essentially becomes photosynthetic. Already, sustainable harvesting of trees to make long-lived structures can sequester more carbon than a tree does as it decomposes on the forest floor at the end of its life (emitted CO2 and a bunch of methane, which is worse). But we can also do “photosynthesis” more directly by using photovoltaics to produce hydrocarbons from direct captured CO2 and water. In fact, going back to the space meme, this is already done on the International Space Station as a side effect of the life support system. Water is split into oxygen (for the crew) and hydrogen. The hydrogen was originally just vented to space along with CO2 (expelled by the crew) captured from the cabin air, but they realized they could combine the hydrogen with the CO2 and recover the oxygen in the form of water, with the hydrocarbon methane as the byproduct. The methane is vented to space normally, but then they realized they could use the methane and reform it into polyethylene and hydrogen (which can be recycled to capture more oxygen form CO2). The polyethylene could be used in the 3D printers on the space station to produce structures. (NASA hasn’t accomplished this methane to polyethylene goal, yet, although methane-to-polyethylene/polypropylene is done on Earth via methane to methanol, then methanol to olefins). This is, essentially, a synthetic kind of photosynthesis. NASA funded SBIR grants to try to demonstrate this process. And there’s no reason you can’t make any kind of hydrocarbon this way from water and CO2 (hydrogen and CO—which can be made from CO2, as Perseverance demonstrated—are synthesis gases which can be used via the Fischer-Tropsch process to produce any hydrocarbon).
In this way, as the mass of a photovoltaic-centric human civilization (buildings and infrastructure and machines) in the form of carbon fiber and wood and resins grows, it is sequestering carbon in its own structure, just like a tree does. So humans (with their houses and buildings, etc) can, in fact, become carbon negative as we transition to clean energy including for utilizing synthesized (or natural) hydrocarbons (or sustainably harvested wood) for structural materials.
There are a number of replacements for (ordinary Portland) cement, such as slaked lime, Sorel cement, alkali-activated cement, geopolymer cement (sometimes classed as an alkali-activated cement, though the Geopolymer Institute disagrees), and so on. Most of these have lower, zero, or even negative net CO₂ emissions. https://res.mdpi.com/d_attachment/sustainability/sustainabil... "Recent Progress in Green Cement Technology
Utilizing Low-Carbon Emission Fuels and Raw
Materials: A Review" is a CC-BY overview of seven of them from 02019.
There are folks talking about using solar concentrators (like solar thermal plants) but without the steam turbine and electrical generation equipment to make cement.
> The life-cycle carbon cost of renewables isn't a fact about renewables. It's a fact about our current energy production mix, which renewables themselves will change over time.
Sure but we are talking about right now. Things will eventually be swapped out. That's a different conversation though, it's an advocacy and not a descriptive one.
People tend to use things that are marginally adequate way longer than anyone intended. For instance, the ancient Roman gravity dam of Proserpina is still doing its job.
Even if we had say a sleek $1,000 self driving solar car that never needs charging and goes for a million miles without maintenance, there's no guaranteed adoption curve, production capacity, distribution and logistic timeline, consumer acceptance, these are all hard unknown realities regardless of how silvery the bullets are.
It IS relevant right now. If the "lifecycle emissions" of near-term renewables is used to argue against deploying them and instead using existing carbon-emitting sources, then you've delayed progress and made things impossible to resolve except by basically shutting down everything (which would kill people and is politically infeasible).
Decarbonization compounds. That means that "lifecycle emissions" analysis can end up being too pessimistic if you consider changes made in a vacuum. Electric cars require steel and electricity to make, so considered by themselves (while still definitely worth it) don't look as good as they do when you consider we will need to be decarbonizing steel and electricity as well.
Power plants need vehicles and steel as well, so decarbonizing transport and steel also reduces the lifecycle emissions of power plants!
I think people resist this type of thinking because of a different kind of magical thinking: a sort of anti-silver-bullet magic. They have the idea of fossil fuels as fundamental to civilization, like we can't actually get rid of them. But this isn't true. We can eliminate fossil fuel usage just fine.
We should consider fossil fuel as the seed corn. Instead of feeling bad that it takes fossil fuels to do the initial manufacture of geothermal (or whatever), consider it as simply priming the pump, as seed corn. There is no better use for fossil fuels than assisting in manufacturing their total replacements.
You can probably do "time" arbitrage here. The CO2 price is low today so CO2 intensive construction is still viable today but it won't be in the future. Thus your geothermal plant will end up becoming more profitable over time.
Parent is correct that it "all counts," but that doesn't mean it all resolves to the same thing over the long term.
For example, one of solar's key strength is the improvement curve that its on. Carbon, energy and dollar costs are improving. So in a sense, every Kw produced now reduces the costs of Kw produced in the future. Its valid an important to think of lifecycle costs currently, it's also not a full picture.
I believe most decent life cycle analyses these days will include a prediction of carbon intensity of electricity used in the future as one more thing to help compare costs/benefits now vs the future.
As an example burning trash for power gets relatively worse as other energy sources become carbon free, while recycling gets relatively better as the energy required becomes lower carbon and/or cost.
Possibly, though there isn't really a standard way of doing so.
I doubt that any such analysis accounts (nor should it) for technological curves yielded by investing in one technology or another. There are limits to any one calculation.
Life-cycle emissions accounting is useful if we're considering technology options or feasibility assessment for a specific project. But the linked article isn't talking about any specific project. It's talking about whether geothermal is a good tech in general.
In that context the lifecycle emissions stats are less useful because the calculation assumes a rate of indirect emissions (due to construction, mining, refinement, containment, etc.) based on the incumbent power generation tech.
In other words, if geothermal power was more ubiquitous, then the indirect emissions for a new geothermal project would be lower.
So we should be doing calculations of "what percentage of its lifetime power production is required to sequester the carbon it took to create and use it?"
That's almost a peak oil approach, which was both insufficient and the most accurate possible.
We can only state things in terms of stuff which currently exists. The future will yield different results because new techniques and technologies will come along. But we can't rely on or predict them.
There's a lot of "pons and fleischmanning" when talking about future energy use - mass scale geo-engineering or sucking carbon out of the atmosphere technology, it has to be avoided. The technologies don't exist yet. We have to use real-world stuff.
Using current reality for future projections is inherently defective because of the innovation factor and routinely leads to bad predictions (such as peak oil[1]), but it's the only reality we have and is sadly as good as we're going to get. Anything else (such as say next-gen nuclear) has to be regarded as a fiction in the calculations until it actually exists.
It's messy, sloppy, and requires a large trashcan but the alternative is to get to results that rely on things that literally do not actually exist. Kinda like how the people planning Operation Downfall (the land invasion of japan during ww2) weren't told about all the other things in the works (backroom deal to get Russia to declare war on Japan and the Manhattan project), they had to assume those things would continue to not happen.
[1] - The Hubbert peak was essentially that the amount of energy to extract and refine oil would surpass the energy from the oil and thus make it unsustainable so the operations for oil extraction would cease. New techniques have been developed (such as fracking) which have changed this math, but in 1956, using 1956 knowledge, this was the best prediction possible. It's somewhat Malthusian - who was also as "correct as possible" with the best science that 1798 had to offer. He couldn't factor in, say, the Haber–Bosch process from 112 years in the future in his food growth computations.
> Using current reality for future projections is inherently defective because of the innovation factor and routinely leads to bad predictions (such as peak oil[1]), but it's the only reality we have and is sadly as good as we're going to get. Anything else (such as say next-gen nuclear) has to be regarded as a fiction in the calculations until it actually exists.
but are certain that at least one of these fictitious scenarios will come into being. We just have no certainty as to which.
The first step in this is inventing a scalable way of sequestering the carbon from atmospheric CO2. We have been talking about carbon markets for over three decades now and still have not solved the supply side of the equation. It's frankly embarrassing.
Carbon Credits are a thing, but the fundamental problem is that one 1 of carbon credit isn't used to pull 1 ton of carbon out of the atmosphere. Instead they're like brownie points that politicians arbitrarily set the price on.
If there were some large scale way to scrub carbon out of the atmosphere then the market could work, but in their current state they are a joke.
> If there were some large scale way to scrub carbon out of the atmosphere then the market could work
We don't need to wait for that to set up an impactful system. At the simplest, have a serious tax and dump a bunch of the resulting money into research grants and a big reverse auction for capture.
Is it embarrassing? Maybe it’s a shortage of market incentives or maybe it’s just a really difficult problem? We shouldn’t assume we’ll have innovative solutions for everything.
I think a healthier futuristic perspective would be one that considers only some percentage of problems will be solved through innovation, at least in the near term. That way we accept we still could be screwed and need to work harder!
It's embarrassing that we are still using fossil fuels without any plan to deal with the pollution it causes. It isn't like people weren't aware of the problem either, I remember talks in the 80s about the Greenhouse Effect and how we needed to act quickly before the problem got out of hand.
We're already well past the point where if we just stopped emitting we will be ok. We now need carbon capture as part of the solution and thus far nothing has panned out. Nor is there much political will to actually push for solutions. They're just seen as pure cost that will make your country less competitive so nobody wants to be the only country who goes for "truth" in this prisoner's dilemma.
Recycling plastic is a red herring popularized by the fossil fuel industry. Up until recently most of its actual success came from a combination of:
1) China's heavy exports meaning that transporting bulk goods TO China was practically free, because the ships were making the trip while empty anyway
2) China's manufacturing industry growing so fast that they simply, literally could not get enough plastic
3) Dirt-cheap labor costs in some parts of China enabling labor-intensive recycling on razor thin margins
4) Corruption and a disregard for the true costs of environmental damage making waste dumping look far more profitable than it actually was.
AIUI these have disappeared recently, due to China's economic growth, and shift from exports to selling domestically, and their environmental damage starting to seriously catch up with them, all of which resulted in them no longer accepting plastic.
China still accepts plastic for recycling. As you note they make a lot of stuff and so need it and have net exports so lots of ships are going there anyway.
What they banned was people pretending to send recyclable plastic but really just sending them any old junk.
> Objective and rationale, including the nature of urgent problems where applicable:
The reasons for urgent measure: According to the Special Actions of Strengthening the
Supervision and Strictly Striking of Illegal "Foreign Garbage" by the General Administration
of Customs of China, Ministry of Environmental Protection of China, Ministry of Public
Security of China and General Administration of Quality Supervision, Inspection and
Quarantine of China, as well as the Special Actions of Striking of the Illegal Actions of
Imported Solid Waste Processing and Utilizing Sectors by Ministry of Environmental
Protection of China, we found that large amounts of dirty wastes or even hazardous wastes
are mixed in the solid waste that can be used as raw materials. This polluted China's
environment seriously. To protect China's environmental interests and people's health, we
urgently adjust the imported solid wastes list, and forbid the import of solid wastes that
are highly polluted. Protection of human health or safety; Protection of animal or plant life
or health; Protection of the environment.
A waste management scientist in India has a royality free patent of using plastic in asphalt. This is a good way to recycle plastic, but one could pave only so many roads.
We fixed acid rain by exporting it to China. Recycling is kind of a mess at the moment due to China stopping pretending that they were recycling plastic.
We did mostly fix the Ozone hole though, albeit it is still an ongoing process.
If we had an actual market for carbon emissions, people would be very incentivized to come up with solutions that scale better than burying charcoal. But since we're not even incentivizing people to bury charcoal, I'm not very surprised that we made little progress at doing more difficult things.
Yes. But CO2 is a problem because it prevents the heat from the sun from escaping (and there is 1kW/m2 of that). Without excess “greenhouse” gasses excess energy is free to radiate into space.
> We can't pretend that something essential for the process doesn't matter because we do a classification handwaving. It all counts
Funny thing: in France, stats for wind energy include the cost of wiring, and cables are required to be buried. Stats for nuclear just ignore the wiring. I'm pro nuclear, but that always bugged me.
Zero carbon is a nonsensical goal. The carbon cycle is necessary. The issue is whether or not it ends up in an equilibrium pleasant for human life or not.
The first geothermal wells in Germany have exhausted their heat gradient; after less than 30 years … so, unless you’re actually in Iceland or the Canaries or something similar, this might not even sustainable for even one full generation …
> The first geothermal wells in Germany have exhausted their heat gradient
The first hit on google for this phrase is .. this comment, so could you provide a less circular citation please? :)
I do understand that all heat is local, you cannot extract heat faster than it can flow to the point of extraction, which is dependent on the R value of the rock and whether you've drilled into a liquid area or not.
(I wonder if there are some oil fields that have high enough below-ground temperatures to be worth using for this? The drilling is done, a sunk cost, and the wells produce mostly dirty water)
From what I’ve heard you just need to let the reservoir “recharge” for about 30 years to get the heat back. So worst case you need to build twice as many geothermal plants. It’s not that different from nuclear power plants that need to be decommissioned after some decades… except you can just leave borehole and reuse it after a couple of decades or so.
It’s also better than drilling for oil/gas.. where you need to keep drilling constantly to get more oil/gas.
And as some here have pointed out, if there’s an excess of energy, which there will often be in a world with lots of renewables, you can pump heat back down into the reservoir, extending its lifetime.
So as always, at just comes down to cost. And I truly believe that if we put as much money into geothermal as we have with fossil fuels and nuclear power, it’ll be the cheapest and most environmentally friendly way of making power in a decade or two.
They can either recharge naturally (i.e. with earth conduction), but it takes a lot of time.
Or you can also recharge them during the summer, either with solar thermal panels, or on a small measure, by running your HVAC "backwards" (i.e. cooling your home and thus heating the wells)
The wells would recharge even without Earth's existing surrounding heat reserves. Moon (and Sun) induced tidal forces do manifest not only in the body of water but also in the Earth's crust, and the resulting tension/friction is quite a source of energy/heat.
I can't find anything to back this up. If anything, Germany are investing more in geothermal. It's expensive to set up, which is the downside, but it's a great baseload source for power/heat that keeps generating nonstop with minimal operating costs/maintenance for 30-40 years. Nothing about exhausting their heat gradient.
Heath exhaustion in geothermal definitely exists. Even wikipedia mentions it
> Even though geothermal power is globally sustainable, extraction must still be monitored to avoid local depletion.[21] Over the course of decades, individual wells draw down local temperatures and water levels until a new equilibrium is reached with natural flows. The three oldest sites, at Larderello, Wairakei, and the Geysers have experienced reduced output because of local depletion. Heat and water, in uncertain proportions, were extracted faster than they were replenished. If production is reduced and water is reinjected, these wells could theoretically recover their full potential. Such mitigation strategies have already been implemented at some sites.
I assume that some of the places with the largest geothermal investments (ie. Iceland) don't suffer this problem that much.
I just priced out HVAC for a large home in central KY. It worked out to 3 of the highest efficiency American Standard/Trane units (Central Heating and Air) for around 50k or a touch over 70k for Bosch Geothermal. The big caveat for geothermal was the 70k price was guaranteed only if they didn't hit rock when digging. They couldn't give me a guaranteed price if they did hit rock so the choice was obvious. I picked Central Heating and Air.
For horizontal or vertical geothermal loops, the biggest cost is always going to be digging for the loops. Until they make that more affordable, they're going to have a hard time making it more ubiquitous.
There are two classes of systems that go by the name "geothermal".
The article is opining about the deep "High Temp" thermal systems that are found in places like the Geysers field in California, in Iceland, and in New Zealand. Those use heat in a primary way to power heat engines to generate electricity.
You are talking about the other class of geothermal. That class is also known as "ground source heat pumps" for HVAC. Just like a reverse-cycle air-conditioner can heat as well as cool by exchanging heat with the outside air, ground source heat pumps do the same by exchanging heat with relatively shallow underground media. Typically, those have much higher heat capacities than air, which is the competition. Nobody attempts to run heat engines with such Low Temp resources as encountered in ground source heat pump applications...
1. I'm not sure what "if you hit rock" means there.
In general, you want to hit rock, and should hopefully hit it very quickly (40-50ft), because rock generally has much better thermal conductivity than stuff like clay.
2. You hopefully got a loop design report that has real details on the load of your house and the design of the loop and how it meets them. The loop design should hopefully tell you they are mostly drilling in rock :)
Hopefully it all does not look like nonsense (I'm happy to look at it if you like, as are the folks over at forums like geoexchange)
3. The only units you should consider are waterfurnace, climatemaster, and maybe bosch.
Trane, for years, was using rebadged waterfurnace units
At least browsing, it looks like they still are.
In any case, you want someone who does this for real, and Trane ain't it.
Bosch is an okay unit, but they are newer at this, and not obviously better in any meaningful way.
4. The price for single family residential drilling is high in part because it's not what the drillers want to be doing.
The rig setup takes them quite a while, the actual drilling is not that bad.
For multi-family residential (or commercial), where they are drilling 100 holes, it's much more cost effective.
So you are right in that sense - the current way of drilling is not going to bring the cost down.
On top of that, keep in mind you are probably paying significant markup on the drilling because it's being subcontracted.
By "hit rock" I mean the 3 hvac firms I spoke with didn't want to dig through rock, but couldn't nail down a cost if they hit it, which is basically a certainty.
Bosch as a general rule has pretty solid engineering. I've used their kitchen appliances for years and am quite happy with them. Unlike some of the korean vendors (I'm looking at you Samsung and LG, it is easy and fast to get parts when things break).
You're right that they're new at this, but all of the existing major appliances in the home are Bosch. If you buy more than three major Bosch appliances, they'll give you a fairly sizable discount.
When I said American Standard/Trane, I meant for the Central Heating and Air, not for the Geothermal. They're the same hardware and come off of the same assembly line with different stickers on them.
Honestly - you had the conversations and i didn't, but if they really said they don't want to dig through rock, i'd probably run away.
I've got a lot of experience in this, and what you are being given sounds like a bunch of nonsense, and yes sometimes you will get a bunch of nonsense from more than 1 HVAC firm.
Lots do not specialize in geothermal, and see it as a way they can make additional profit off some people.
Concretely: At the price you are being given, the drill price should be fixed and included, excepting them hitting lots of water.
The driller certainly gave a fixed price, based on the local geography and what they are gonna hit. The know exactly what they will hit in terms of rock/etc.
The variable cost thing is not drilling rock or whatever, it's controlling water and sediment.
If they hit lots of water (IE 100+gallons a minute), controlling and remove it can be expensive and unexpected - most cities/etc have strict rules on this (so they can't just run it into the street). This is the thing that is hard to tell for them - it's rare to have good enough data to know exactly whether and where you will hit water, and it can even vary from hole to hole in the same job.
Otherwise, be careful - unlike regular HVAC, Geothermal requires people who really know what they are doing, and not just doing the kind of "finger in the wind" HVAC you can often find for folks doing heat pumps/furnaces. At a minimum, make sure you are using IGHSPA/etc certified folks.
If you want to get more into this, there are lots of knowledgable drillers and installers over in places like the geoexchange forums, and they won't steer you wrong.
As for Bosch, the units they are offering in residential are super basic units last i looked.
They are neither variable-speed pump or variable speed compressor.
They are simply 1-2 stage geothermal units. They appear to at least offer variable speed blowers on some of them, but that's very basic stuff.
This is the kind of unit you would have seen 20 years ago.
I would not pay what you are paying for them.
Nice geothermal units (say, the waterfurnace 7-series) these days have variable speed pumps and compressors.
They match themselves exactly to the load needed by the house over time, and run continuously at part-load, modulating up and down as they day goes on, and end up being both silent and very high efficiency.
They are also much longer life - parts like scroll compressors (and most forms of rotary compressors) are much happier if you modulate load rather than start/stop.
I basically followed your advice and ran far away. That's why I'm getting Central HVAC, which I'm sad about as I like the idea of Geothermal, but it is what it is.
My house was nearly burned down by a cheap Bosch tankless water heater that failed to turn off the flame when the flow of water stopped. You would think that would be a pretty obvious failure mode. Needless to say, we went with a different brand when we replaced it.
The price a year ago would have been more like 20k, but with the crazy price of lumber and all building materials going up, the HVAC companies followed suit :(
Please tell me this is a full build-out of not only the HVAC system, but all ductwork and construction as well? Otherwise, you are getting royally ripped off.
This cost seems high to me. Installed a horizontal loop geothermal system over an acre of land in Northern Ontario. Had the trench dug out with an excavator (approx 12 + ft deep) and the same guy lay all the pipe and back filled for about less than 10k. If you look in the classifieds you can hire an excavator/operator for about $1k a day. The guys did it all over a week. Our whole system came in under $30k. It was a few years back but I don't think it would cost 70k today.
Not sure if you were aware, but the cost of building materials such as wood and also hvac has went up massively. The same central heating and air units a year ago would have cost maybe 20k with a full install. We got three quotes for three different firms that do geothermal.
And as I mentioned elsewhere, if I installed a horizontal loop, I'd have to cut down a ton of beautiful 100 year old trees surrounding the home. I'd rather not do that when there are viable alternatives. The cost of higher electricity usage isn't a big deal as I've got 48 bifacial solar panels on the barn that run to the home.
Consider closed cell spray foam and you will probably make out better with a traditional high efficiency system than you would with geothermal and regular insulation. If you went with geothermal and spray foam your heating and cooling/comfort costs would be less than someones Starbucks habit but I can understand the initial cost might not make sense for some folks.
That's great if you have enough land and don't care about restoring the yard, I was quoted $30K to install on less than an acre, including restoring the landscaping.
Unfortunately, due to the topology, it wouldn't be very viable. I don't want to cut down the hardwood (white oak, maple, walnut, and cherry) forest around the home just to install hvac when there are alternative options.
The real killer was knowing full well the house sits on or around a ton of limestone and the best quote I got told me it would cost a lot more if they hit rock.
It is 4 zones with (effectively) 5 floors and a lot of square footage. Anderson gave us a great deal on high efficiency triple pane argon gas filled windows and I walked the home with a wireless thermometer to check for obvious insulation problems. What else could I do to improve the thermal envelope?
If you have enough insulation, I would recommend getting a blower door test done and see what your ACH50 is (air changes per hour at 50 pascals) to see how leaky your house is.
Improving the envelope is particularly important for geo heating and cooling. It makes sense to include that in the budget for a geo install.
I had a geo system installed last December (GeoComfort with 3 200 foot wells for a 120 year old, 1600 sqft house).
The system works great except that the point where the aux heat kicks in for my house is 25 degrees F. I am working this year to improve the envelope to reduce the need for aux heat.
Your comment is entirely unrelated to the article, which is about using the very hot rock several kilometers underground to drive turbines to generate electricity.
This seems to be all about Geothermal HEATING, which seems pretty tough in most places. I thought Geothermal Cooling is easier/cheaper in many areas? Heat from Geothermal seems really difficult because you have to drill so deep almost everywhere, but that's not the case for cooling, is it?
To heat a home with geothermal, you use a heat pump. It works better than an air source heat pump most places because the ground doesn't get as cold as the air does.
More widely deploying ground source heat pumps for home heating seems more promising than pursuing geothermal electricity generation. The problem with ground source heat pumps is that the lifecycle of the equivalent if 30-50 years, well outside the typical homeowner's planning or payback horizon.
The house I grew up in had a geothermal system (installed when my parents built the house). I was a bit young to know the precise details, but I believe the idea was that the ground loop merely heated or cooled (depending on the season) to the ground's ambient temperature, around 60ºF. From there, it was further heated using traditional methods. I think that meant a heat pump, as you mention, but it might have been oil.
The energy savings in the winter (US-MA) was nice -- heating from 60 is a lot less energy than heating from 30 or below -- but the summer was the real reason I'll absolutely install geothermal in any house I build: basically free a/c. Not having to think about setting the thermostat for a relatively large house down to 72 (or even lower, if you want to freeze your tookus off) is so freeing.
I wish ground source heat pumps were more affordable, I asked my HVAC installer, he said I was looking at $30K+ including returning the yard to the state it was in before they trenched in the pipes. That's 3X the cost of the air source heat pump I ended up going with.
> I wish ground source heat pumps were more affordable
I don't think this will ever be the case. Water-to-water (ground source) and air-to-water (air source) heat pumps are effectively the same thing technically sans some tuning for temperatures, therefore the difference in cost of the heat pump itself is never going to be high.
The cost difference is in installation costs. Air-to-water heat pump installation is as simple as mounting the external unit and routing a few pipes back to interior unit while water-to-water installation is routing the distributed heat exchanger, which is significantly more labor intensive even if you do not account for landscaping (e.g. done as part of greenfield development which will have landscaping done anyway).
Ground-source heating/cooling is quite different from geothermal heat or power. With ground-source, you just have a heat pump like an ordinary air conditioner, but using the ground as the heat sink instead of outside air. A couple of meters is deep enough. It's nothing like prospecting for the rare resource of accessible hot rock or natural steam, as in Iceland.
Same heat transfer dynamics apply to cooling as well. Earth is a really good insulator, that's why it has a steady temperature in the first place. If you dump too much heat in it, it will warm up. That's seen as an advantage when you can harvest the same heat in the colder months using geothermal heat pumps.
Some buildings that have access to the ocean or a lake can use that for heat rejection because those take the heat away.
None of these applications require going too deep in the ground. This article is all about going deep.
Iceland has access to very hot water in shallow ground. They are unique that way.
The systems used for cooling work just as well for heating. Really heating is probably the reason most of them are installed, and then, hey, why not also use it during the summer.
Your comment is entirely unrelated to the article, which is about using the very hot rock several kilometers underground to drive turbines to generate electricity.
For nordic climates: After running the numbers I was surprised by how little benefit I'd get from geothermal drilling + heat pump for a much larger investment (like $30k including internal fitting of water-based radiators) compared to a regular outdoor air/air heat pump for $2k. Ongoing costs would be like 5-8% lower.
Local conditions can dramatically change these numbers. In places where the ground temperature is 20C you use dramatically less energy to heat and cool with a ground source heat pump. Nordic countries have minimal need for cooling and high levels of insulation minimize the need for heating. The worst for heat pumps is simply resistance heating which isn’t that much worse than the a heat pump connected to 5C or less ground temperatures.
On top of this 30k is on the high end for ground source heat pumps.
Define 'much worse'. Even basic heat pumps in traditional air/air split systems can achieve COPs of 3-4 above freezing air temps. The modern mini splits can do that well below freezing.
Nowhere has electric so cheap that a 2x or 3x reduction in the amount of electricity used to heat wouldn't result in massive savings.
The issue with thinking in terms of normal ground temperature is two fold. First heat pumps are removing energy in the winter so the ground might normally be 4C but it drops to say 0C. Second your working fluid never reaches soil temperature, so it might end up at -4C next to the pump.
Anyway, you only receive benifits when air temperatures are below the temperature of your ground loop. If the outside temperature needs to hit -4C before that happens you’re only benefiting from a smaller percentage of the year. Further that benefit is again constrained by the delta between resistance heating and what your ground source is providing the heat pump.
Generally it takes a combination of lower cooling costs in the summer and lower warming costs in the winter to make ground source heat pumps worth it, so being limited to a few months in the winter vs a 20+k installation cost is prohibitive.
Also I assume we are talking Geoexchange (For lack of a better word) not Geothermal. Temperature differentials not radioactive decay
Digging holes and installing infrastructure just costs too much money. Air heat pumps simple, things like being noisy is also getting solved which is awesome.
Your comment is entirely unrelated to the article, which is about using the very hot rock several kilometers underground to drive turbines to generate electricity.
Your comment is entirely unrelated to the article, which is about using the very hot rock several kilometers underground to drive turbines to generate electricity.
Solar water heaters have really fallen out of favor because to make them robust, they are more complicated than you'd think.
It's generally not viable to just run a water pipe onto the roof, due to both freezing and temperature regulation concerns. So you end up with a closed loop system (filled with a glycol solution that won't freeze) and a heat exchanger to get the water into your domestic supply and at a consistent temperature.
Not to mention the service issues of having something "weird" on your house as a critical system.
Nowadays, we have electric heat pump water heaters that are very efficient, so running that in conjunction with solar panels to generate electricity can make a lot more sense in practice.
I wish it was easy to buy a gas hot water heater that also had a few coils of copper in it so I could plumb in whatever kind of energy harvesting heat source I could come up with. It'd be great to tap into the heat my AC throws off, or a closed loop solar thermal panel, or both!
It really is a shame that HVAC contractors want to mark up more efficient or "exotic" options so much higher than the "base" option.
I had my AC replaced a few years back for like $3500, with "least efficient we can legally sell". Doing anything else was going to double the price, even though the wholesale cost difference to the next step up was under 20% of that.
Yeah that's awful. "Value pricing" I suppose. I wouldn't mind it if there was an easy-enough way to DIY so as to "route around the problem" but with the licensing requirements you can't really.
To a degree - I get contractor reluctance. Most people don't care to spend more to do better, so they're never going to have much of an install base to build knowledge from. So they're probably estimating high because of unknowns, and also partly because bidding on higher-end packages just isn't as competitive.
I'd really just like to order my own equipment and pay an HVAC company's "day rate" to come out and install it, and I'll deal with surprises or warranty issues.
Solar water heating is quite popular in the state of Hawaii -- energy is very expensive there since fuel is brought in by boat and of course there's a lot of sun, so it's very cost effective.
I've wondered if there could be a way to use the Earth's heat by drilling a small hole in your back yard a few km deep and somehow embedding a tiny generator down there to take advantage of the heat differential between various layers of rock. Maybe a Stirling engine? I'm thinking like a long thin tube filled with liquid that boils at low temps. The liquid would boil, expand, rise up through an insulated tube, condense at a cooler layer and circulate back down. A little generator could use the constant motion to power a house.
Deep holes are expensive. Oil drilling, the cheapest kind of drilling since it's very common and in soft rock, costs $100-$200 per vertical foot.* A 2 km hole would cost $650,000 - $1.3M. It would not be economical to do this for one house. Then there are operating costs: operating a power plant on the surface is very likely to be cheaper than operating one underground, and temperature difference is bigger. All in all, a traditional geothermal plant (utility scale, at the surface) looks like that for good reasons.
Residential geothermal heat pumps are commercially available. Generating electricity is possible but less practical. Using it to heat and cool your home without fuel is very doable.
It's a decentralized site using ENS so you'd need to run an ETH node and IPFS to view it. Cloudflare was generous enough to do the hard part and host those and serve the sites though the .link TLD to support casual browsing.
You can blame the chicken/egg problem, but ultimately the reason why decentralized systems don't overtake centralized systems is that they don't offer much of an advantage over them, so nobody cares enough to learn how to access them.
I mean, suppose Cloudflare/whatever goes down and the site is inaccessible: would you:
A) Grab the link, and go figure out how to pull it out of IPFS directly
B) Grab the link, and paste it into archive.org
or
C) Go grab a coffee, then come back and refresh the page (because when Cloudflare does go down, it tends to be only down shortly)
B and C aren't perfect, but they're close enough. Doing A takes effort and frankly isn't worth it unless you're doing it as a hobby.
I know how to access these systems yet I steer clear of anything on them. The distributed technologies will never be as fast or reliable as the centralized ones. I'll not go into the quality or nature of the content and ecosystems around them.
https://www.ucsusa.org/resources/environmental-impacts-geoth...
The takeaway
> Enhanced geothermal systems, which require energy to drill and pump water into hot rock reservoirs, have life-cycle global warming emission of approximately 0.2 pounds of carbon dioxide equivalent per kilowatt-hour [11].
> To put this into context, estimates of life-cycle global warming emissions for natural gas generated electricity are between 0.6 and 2 pounds of carbon dioxide equivalent per kilowatt-hour and estimates for coal-generated electricity are 1.4 and 3.6 pounds of carbon dioxide equivalent per kilowatt-hour.
Nothing is really truly zero carbon currently. Solar has manufacturing and maintenance. Nuclear has construction, mining, refinement, containment, etc. It's nice to see the full lifecycle being looked at.
We can't pretend that something essential for the process doesn't matter because we do a classification handwaving. It all counts