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Breakthrough solar cell captures CO2 and sunlight, produces burnable fuel (uic.edu)
595 points by Mz on July 30, 2016 | hide | past | favorite | 147 comments



"Nanotechnology" again. It's just surface chemistry, people. It's nice that they can do this in the lab, but as usual, the PR is excessive. "The ability to turn CO2 into fuel at a cost comparable to a gallon of gasoline would render fossil fuels obsolete." At least get to pilot plant stage before issuing statements like that.

Especially since UC Berkeley announced a similar breakthrough last year.[1] Wikipedia points out that artificial photosynthesis was first achieved in 1912, and some of the same claims were made back then. There are lots of artificial photosynthesis projects. One of the best was in 2011, the first "artificial leaf"[3]. It ran for 44 hours.

The usual questions apply. How efficient is this? Does the catalyst get used up, or crud up with contaminants, and if so, how fast? What limits the life of the system? What are the costs like? (Excessive catalyst cost has been a problem.) Is this better than all the other groups doing similar work?

Artificial photosynthesis may be useful someday, but this probably isn't the big breakthrough that makes it a commercial product. That may come, though.

[1] http://newscenter.lbl.gov/2015/04/16/major-advance-in-artifi... [2] https://en.wikipedia.org/wiki/Artificial_photosynthesis [3] https://www.acs.org/content/acs/en/pressroom/newsreleases/20...


> as usual, the PR is excessive

I think articles that over hype lab results make it to the top of HN because there is no downvote button and flagging them doesn't seem appropriate. I wish there was a "meh" option.


"Meh" is about right. Various people have been making fuel-from-water-powered-by-sunlight announcements for years. This group is not the only one working on this. Lots of research groups have something that sort of works, but has some practical problem, such as the cell lasting only 40 hours.[1] But the press release ("Researchers at the University of Illinois at Chicago have engineered a potentially game-changing solar cell that cheaply and efficiently converts atmospheric carbon dioxide directly into usable hydrocarbon fuel, using only sunlight for energy.") is written as if they just achieved the big success that makes it commercially feasible.

There are startups in this area. Here's HyperSolar. They have their own proprietary "nanoparticle" technology.[2] They announced success in 2012. No product yet.

That's why reports of "breakthroughs" in this area have to be viewed skeptically. There have been a lot of claimed breakthroughs that didn't pan out.

This problem looks more like a long, slow slog to something that works well enough to use. Silicon solar cells were like that. Efficiency has slowly improved since the 1950s. Manufacturing processes have slowly improved. There was no "breakthrough"; the curves of efficiency and cost per unit over time are smooth, not discontinuous.

[1] http://phys.org/news/2015-09-efficiency-solar-hydrogen-produ... [2] http://www.hypersolar.com/application.php


Is it excessive? It certainly doesn't seem to be BS. It's published in a reputable journal (which doesn't make it true). It discusses several of the questions raised by Animats directly (though I wouldn't say it answers them conclusively).

I do agree that the university press release isn't going to critically evaluate the work of its own researchers. That's too bad, perhaps, but it hardly renders the original result uninteresting.

Artificial photosynthesis may be old, but the advances in this work appear aimed at overcoming precisely the problems Animats raised, like catalyst preservation and efficiency.

Put another way, just because a university gushes about the work of its faculty doesn't mean the faculty's work is crap.


It's a long and arduous way from the lab to scale, and that's where the real hurdles are.


I think the main reason is the exact same one why wireless energy transmission, instant cures for cancer, harebrained windpower schemes and so on get hyped. They all fall in the 'wouldn't it be great if this were real, therefore it must be real' category.

The number of solar cell 'breakthroughs' that you read about in a given year is >= 5 or so, but 3 years later nobody even remembers what they were about. Meanwhile, the real improvements are incremental and process cost related, and those improvements then get eaten up by tariffs.


A high rate of comments without upvotes degrades a story's ranking, you seem to have done the right thing. I don't know exactly how much flaming there has to be before that kicks in, though.


+5, meh.

Slashdot voting options!


Or just a "Bullshit" option.


With the majority of articles about cutting edge science, very few HN readers would be qualified to state whether or not it's a breakthrough or bullshit. The option would protect HN from the bullshit, but it'd also hide the breakthroughs that people believed too good to be true. I think that'd be an overall drop in the quality of what we read here.


You're not wrong, but maybe on HN at least many of those people can be counted on not to vote out of reflex, unless they do really bring something to the table.

The other simple, sad fact is that the big breakthroughs that have some initial traction issues stick around. Often people point to the very early history of SR/GR, but it's worth pointing out how that turned out. When a shocking breakthrough is actually a shocking breakthrough, it ends up producing results that speak for themselves.

Until then, when it comes to extreme claims, so many more are just "bullshit" than "breakthrough". Our lives are finite, so it's not wise to ignore the role of triage in those lives.


Don't care, Dislike, Disbelieve, Downvote, Doesn't belong on HN. It just feels like a spectrum. Maybe we could rate each thread on a scale of 1-30, ranking where we think it should be on the page?


Or maybe pick from a number of descriptors just like the ones you listed, and if one breaches a certain threshhold, it gets tagged with "Widely Disbelieved" or the like.


>At least get to pilot plant stage before issuing statements like that.

To be fair, making statements like that can help you get to that stage. It sucks that this is how it works, but playing the game is understandable.


>"The ability to turn CO2 into fuel at a cost comparable to a gallon of gasoline would render fossil fuels obsolete." At least get to pilot plant stage before issuing statements like that.

They don't really say that they are cost comparable to gasoline, they just make the obvious statement that if something were as cheap as gasoline that would be a big deal.

I guess hyping these advances is supposed to make it easier to get funding for further research in the area. The sceptic in me expects them to hit the market right after the first fusion power plant comes online (another technology that is hyped for decades as "just around the corner").


To be fair, I never read anything about fusion being 'just around the corner'.

The most optimistic estimates I know of talk about commercial viability in a 30-50 year timeframe.


The initial expectations for fusion were even more ambitious and with good reason.

Fission was first done in 1938, by 1956 there was a commercial reactor.

Given that sort of time frame and the fact that fusion research was well underway it seemed that a decade or two was all that was needed.

Then you had breakthroughs with Tokomaks and so on, each time it seemed that fusion was potentially close.

There's a really good book called 'The Sun in a Bottle' that goes into more detail.


Well Lockheed Martin claimed they'll have a 100MW fusion reactor small enough to fit on a truck up and running by 2017 and a fully operational grid-ready machine by 2023:

http://www.americansecurityproject.org/lockheed-martin-outli...


To be fair, I never read anything about fusion being 'just around the corner'.

We've finally gotten a little smarter about the hype.

There were great expectations for fusion about 40 years ago. Here's a shady group https://en.wikipedia.org/wiki/Fusion_Energy_Foundation that used the hype to raise money: In 1977, Executive Director Morris Levitt asserted that nuclear fusion power plants could be built by 1990 if the U.S. spent $50 to $100 billion on research.


>There were great expectations for fusion about 40 years ago.

I was at the NY world's fair, I think it was 1960 (56 yrs ago). I remember walking through an exhibit that showed fusion. They had a chitload of capacitors in a bank that dumped all the power into a big electric spark. It looked impressive and sounded great. They implied fusion was almost ready.


I was approached by nuclear fusion advocates during a 1981 Anit-Nuke demonstration in NYC. I have always been scientifically-minded, so it actually set me on a course of reading up on all things nuclear. A lot of the marchers were not generally educated on nuclear science.

Aside from military uses of nuclear science, there are a lot of obstacles to developing anything nuclear, fission or fusion. I think we would be further along, and better off, if less scare and more education were available about it.

Solar energy, the production, usage, maintenance and storage of panels, wiring, and battery banks are now a safety concern given that more than 25 people a year have died in Australia alone just installing and maintaining them (cleaning them). This is only the roofing aspect of it. What about the production and storage of batteries, the materials and chemicals used to produce panels, etc...

Roofing claims more deaths worldwide than nuclear energy has by many orders of magnitude. I believe this bias is due mainly to fear and ignorance, and the contemporary phenomenon of zero-risk. We don't apply the same risk analysis to nuclear that we do to other fields.

An example of how this is coming to bite us back is the discovery of the benefits of certain germs after most developed nations embraced anti-septics to an extreme (hand sanitizers, strong kitchen and bathroom cleaners to name two). The biome and snot are in!

Even Fukushima was a confluence of old reactors, on a seaboard and a tsunami which claimed almost all of the fatalities if you allow for theoretically higher rates of thyroid cancer and others. Taking a middle position, or better a geometric mean of Greenpeace's and others maximum claims vs. the nuclear industry's playing down of casualties in the three (Three Mile Island, Chernobyl and Fukushima) major nuclear incidents to date, you arrive at a very safe industry that has operated for over 50 years in over 30 countries.

Fission reactors that don't need water cooling would allay any need to be near seaboards or water, and their shutdown on failure makes them even safer with no reliance on an outside water source or power as a potential risk.

The number of students studying nuclear science tripled from 2004 to 2013, yet the labor statistics show a -4% job growth vs. environmental sciences 11% growth, or a 15% spread. The nuclear engineer job pays roughly 33% more. I still think it is our best bet to date, but I am not saying like others, just pick one. Let's keep at the alternative 'green' energy-producing technologies and nuclear, not either/or.


The thing with falling-of-roof deaths is that they are poisson distributed. If 25 people fell off roofs then maybe if we are unlucky 50 people will fall off roofs this year. But no amount of bad luck will ever make 10,000 fall off roofs the year after.

Deaths from fusion and nuclear on the other hand are very unpredictable. It is easy to imagine that year after year, no people die. And then suddenly millions of people die. That means that equating actual danger with observed-deaths-so-far is just not possible.


Millions of people? Where do you get that number? We've had two devastating accidents with nuclear reactors, and one that came close to being devastating. All three were older designs that were more dangerous than the designs we could build today. The combined death toll is in the hundreds to thousands, at best. You don't get up to millions of deaths unless we start firing nuclear weapons at each other.


Exactly why I chose the geometric mean with the nuclear industry claiming less than a 100, and Greenpeace reaching for 850,000, that ballparks you to 9200. If you try and include hypothetical deaths decades later, you would also need to include coal-burning plants particulate causing respiratory diseases affecting longevity, and the fact that there is typically a higher radiation level on the perimeter of a coal-burning plant than right outside an operating nuclear power station. Nuclear looks better with each passing year in spite of the back pressure.

Also, I am not sure of the choice of the Poisson distribution suggested above. Roofers are experienced at walking on rooftops, and die due to, well, accidents. That and roofing work is fairly consistent. This number would follow some sort of normal or Poisson distribution, but homeowners are typically only used to a ladder to clean rain gutters out, not roofing or rooftop walking.

Death of roofers/installers during initial installation were the numbers I was quoting from Australia. I think homeowner fatalities will top the roofers in areas with increasing solar panel installations. I would think a Weibul distribution with a Beta of 0.5 would better suit this scenario to model all of the inexperienced homeowners cleaning their solar panels monthly, and then dropping off (no pun intended) after reports and education on working at heights diffuses into the populace.


The most optimistic estimates I know of talk about commercial viability in a 30-50 year timeframe.

Yes, and they have been saying that for 50 years . . .


Thirty to fifty years, if you fund it properly. We don't: http://i.imgur.com/sjH5r.jpg


There's actually some new breakthroughts that have been made in the last couple years that have pushed it to closer to 15-20 years. A group out of MIT has designed a new reactor type that shows promise, http://news.mit.edu/2015/small-modular-efficient-fusion-plan... there's also a lecture they did for and MIT alumni association down in silicon valley back in February on YouTube.


> Does the catalyst get used up, or crud up with contaminants, and if so, how fast? What limits the life of the system? What are the costs like? (Excessive catalyst cost has been a problem.)

If you had actually read the whole article before commenting you would know the answer to these questions. Your questions about efficiency are however valid.


I read the article and the answers certainly weren't clear to me.

'20x cheaper than some other catalysts' what does that mean exactly?

'special fluid keeps catalyst sites clean' does it get used up in the process? Is the fluid expensive and hard to manufacture?

The devil is in the detail here.

How exactly does this compare to other state of the art similar approaches? 10x cheaper? 2x cheaper? on par?

I think it's pretty valid to argue the article is doing some vague hand waving without actually saying if this is meaningfully better than other approaches.


I agree with your skepticism but even if the article included more stats there would still be many questions. The only way to prove conclusively that this is a viable method would be to produce it at scale.


Serious question: Is there a sassy phrase in the hardcore research world for over-hyping discoveries? Like how we can identify "vaporware" as a concept since we have a word for it.

If not there really should be


The press release at least attempted to answer some of your 'usual questions'.


It directly answered several of them, in actuality.


If this technology's been around for so long, I wonder who's been suppressing it?


From the title I thought the article was going to be a sarcastic description of plants.


Even if it's completely inorganic, plants (or algae cultures, etc) are a necessary comparison for anything like this, but that never seems to come up. It's like announcing the invention of the motor car without comparing it to a horse.


> Even if it's completely inorganic, plants (or algae cultures, etc) are a necessary comparison for anything like this, but that never seems to come up.

Probably that's because plants are typically only 2-3% efficient when it comes to their use of sunlight, and then it's still a long way (energetically and logistically) to usable fuel or electricity. Plants are really not a good comparison benchmark here.


Given that we are currently using plants such as corn to make biofuel (at an industrial level, not just in the lab), I think it's actually a very valid comparison.


I can't help but picture life of the next millenium to be "men that understand nature":


Can anyone comment in a knowledgeable way about the chemicals involved?

1. tungsten diselenide

2. an ionic fluid called ethyl-methyl-imidazolium tetrafluoroborate

Just offhand I see selenium in #1, and fluorine and boron going into #2. There's some expense there, and some handling and exposure dangers. If you have a lot of these cells around, are there public health dangers either in handling or in disposing/recycling old ones?


WS2 should be a relatively inert wafer/flake, the desirable property is the so-called van Hove singularity in the electronic density of states that makes it ideal for solar cells.


Key facts:

> In fact, he said, the new catalyst is 1,000 times faster than noble-metal catalysts — and about 20 times cheaper.

> The combination of water and the ionic liquid makes a co-catalyst that preserves the catalyst’s active sites under the harsh reduction reaction conditions,

No mention of efficiency compared to photovoltaic cells.


There are some efficiency numbers in the abstract of the "Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid." article:

Conversion of carbon dioxide (CO2) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO2 renders many electrochemical and photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO2 conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24%, and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light-harvesting artificial leaf platform that concurrently oxidized water in the absence of any external potential.

Copyright © 2016, American Association for the Advancement of Science.


The efficiency is around 4%, as in Figure 2 from the paper. SFE is solar-to-fuel efficiency.

From the paper, " We also calculated the solar-to-fuel conversion efficiency (SFE) for our photochemical process (Fig. 2C), obtaining a value of ~4.6% limited by the maximum efficiency of the PV-a-si-3jn cell (~6.0%) (13, 20). This SFE is higher than that of the water-splitting reaction (~2.5%) previously measured using an identical triple-junction photovoltaic (PV-a-si-3jn) cell (20). "

https://d2ufo47lrtsv5s.cloudfront.net/content/sci/353/6298/4...


For comparison, most crop plants get 1-2% solar to biomass efficiency on the high end.


I'm more interested with comparison to plants harvested for biodiesel.


The key difference in my opinion is that this process would not be competing for land with existing crops. We could do both.


Yes it would, sun rays only hit the ground once.


There are plenty of areas of this planet where plants don't grow because the climate is too harsh (not enough water and/or extreme temperatures)


I understand your point, but this system also requires water, and therefore does compete at that point as well. Higher temperatures also have a negative effect at the efficiency of solar panels, but they are indeed a lot more resistant (typically lower temperature=better efficiency for solar panels).


Cold, water, sunlight, no crops, existing infrastructure for moving fuels. Alaska? There's even high CO2 there from wood stoves (Alaska is 4th per-capita).

http://www.eia.gov/environment/emissions/state/analysis/


Alaska is so enormous and sparsely populated that I doubt much that the residents do will have a significant impact on the ambient CO2 levels, compared to a state like Texas or California, which are about 80 and 250 times more population dense for their size.

I agree with all the rest of your factors, though high CO2 is likely not a mark in Alaska's favor. My main concerns with Alaska would be suitably large cleared land area to collect sunlight without damaging the environment, and not having panels get covered in snow in the winter.


I wonder if they could use sea water?


Really, you can't think of any places where there's sunlight and water but no crops are grown?


This development is exciting, but the complexity of the chemicals involved looks scary. I wonder if it will impede the adoption. Anyone with the domain expertise to comment on this?


This is wonderful!

We're surrounded by life forms that turn water, CO2 and sunlight into energy. I figure there must be some way to harness this process.

I wonder how much power a large tree takes in from its leaves. If we could interface with its root system, perhaps we could extract newly created starch, and either store it or burn it off.

Image a huge concrete power plant with large trees growing out of it.


No, that's not likely to happen. Photosynthesis is pretty inefficient, typical plants have a radiant energy to chemical energy conversion efficiency between 0.1% and 2%. Most commercially available solar panels have more than 10 times this efficiency.[1]

[1] http://physics.stackexchange.com/questions/109739/is-plant-p...


Sure, but I bet your solar panels don't manufacture and maintain themselves.

To the GP's point, the total cost of ownership of a plant that makes gasoline-level fuel is going to be more about water and land than anything else.

But the efficiency of solar panels, considering their subsidies, the rare minerals used in their manufacture, their delivery and their maintenance... I'm confident it's a lot less than e.g. coal, even accounting for pollution costs, because if it really were cheaper all-around we'd be using it everywhere!


If you look at trajectory, coal is in decline and solar panels are being installed at a great clip. The decline in coal is mostly due to natural gas, but in the US, generation from solar tripled between 2013 and 2015.

https://www.eia.gov/electricity/monthly/epm_table_grapher.cf...


>> "don't manufacture and maintain themselves"

Well, for any kind of industrial operation you'll want to plant the trees.. then there is the 10-20 year growth period that's kind of a problem for planning flexibility.. and then you need to chop them down and move them to the power plant which is a non-trivial and costly logistical constraint.

All the while the solar cell sits there and produces energy without any intervention. That's a big difference.. Also, wood does not scale well, there is just so much space for forests.


Solar cells don't just sit there without intervention, and have larger up-front capital and labour costs than planting an orchard, or more appropriately, fuelwood or timber forests. And have a lifespan of 20-25 years.

Plants are a pretty neat technology, all told.


I dont know how much they differ but planting trees has lots of cost. I estimate the cost of planting is something like $3 per surviving tree. (Cause you usually over plant assuming many will die).


Depends on the tree.

For some forestry applications, seeding is done from the air.

Note that if you're growing wood for fuel, you're not worried about grafting stock, or the net health (much), or overcrowding (you can thin later if necessary), etc.

Planting orchards is, as it happens, pretty expensive. But that's also a pretty high-end case, and the expected life is generally 20-50+ years. Upwards of 300 in cases (olives, grapes, and citrus).


I was not referring to orchards, but for regular logging industry. Those cycles are about 60-80 yrs between harvests.


Yes. But on the other hand, oil is extremely convenient for storage and transporting. Perhaps we can achieve a more efficient way of converting atmospheric CO2 to oil than photosynthesis. (And while there, complex oil instead of simple sugars)


There is a simple way:

1. Plant tree 2. Wait 20 years 3. Chop tree 4. Burn tree in steam engine and generate electricity.

However, that's a long time for a relatively small amount of energy (not even counting logistics losses here). Most trees are just not very efficient at converting solar energy/CO2 into fuel (wood). There are better results being looked in with algae that might result in fuel some time, but it's still in research.


Algenol looked quite promising. Apparently they got 8000 gal/acre/year from their trial. Somehow they never quite get to commercial production though. http://www.ethanolproducer.com/articles/12005/green-expectat...


There are WAY better plants than trees for this. Switchgass is often listed as one of the best options.

You literally just cut it down, let it dry for a bit, and throw it into the exact same plants that burn coal.


Isn't what you're describing called biodiesel? Palm oil, rapeseed oil, etc.

The problem is that however much humans need electrical energy, they need food a hell of a lot more. Electrical energy has to come from the land we're not feeding ourselves from, i.e. deserts, grasslands, rooftops.


I believe we have plenty of food. We could put panels in our backyards, but solar panels are rather expensive, and it's usually more convenient paying a power company and forgetting about the matter than setting up our own mini power plants.


It's actually a major approach under the name biomass. Despite releasing carbon when wood is burned, the tree has taken in significant CO2 over the course of its life. In addition, decomposing wood byproducts are going to release carbon anyway as they decompose, I believe. Places with excess wood byproduct can generate power onsite.

It's not going to replace other power sources, but it is commonly done.


paper: http://science.sciencemag.org/content/353/6298/467 (paywall), but it's available on sci-hub.cc



One way to make a system like this one more efficient/cost effective would be to draw the CO2 from ocean surface water which has a much higher concentration than the atmosphere, depending where you are in the world.


Flue gases with a high CO2 content are better than cheap; people will actually pay you to get rid of them. And we have a lot of them (this is kind of the problem in the first place). If you look at something like the exhaust from an oxyfuel turbine, you can get 70/30 N2/CO2 with relatively high purity.

For this reason, I'm always skeptical of atmospheric capture projects. It's just got to be more efficient to capture from a mixture with 20% (or more) CO2 than from a mixture with 0.04%.


Actually if the CO2 absorbent is efficient it is not much harder to capture CO2 from the atmosphere than from flue gas. The key really is the CO2 flux rate which wind provides.

The real advantage of atmosphere capture is you can do the capture where the cost is lowest, not where the CO2 is emitted.


> The key really is the CO2 flux rate which wind provides.

Indeed. This brings us to the issue of volumes. A useful carbon capture plant needs to capture at least 100 000 tons of CO2 per year (then we need "just" ~ 10 000 such plants). This means each of these minimal plants has to process an air volume of 250 billion cubic meters of air per year. At an air speed of 1 m/s (you can't flow too fast or there is no time for reaction), and assuming a wildly optimistic 50% capture from the filtered air, you need a reaction area of over 15 000 square meters.

Mind you, that's the area of the membrane which processes air. Add the auxiliary stuff around it, you can add at least another factor of 100 to the area, so each of your 10 000 plants have to be 1.5x the maximum planned size of the Tesla Gigafactory. And we're being optimistic.


Couldn't the membrane be folded or stacked so you achieve that amount of surface area in a far smaller floorplan footprint?


If I understand it correctly, all the membrane area has to be exposed to direct sunlight.


Cool idea to go straight to the source. I wonder if the same type of technology would be applicable. Likely not based on rate of reaction.


My guess is that existing CCS technologies (such as amine-based separation) are much more efficient at high CO2 concentrations.


So it's 20x cheaper than the noble gas version — what's the absolute cost? I assume it's not cheaper than pumping fossil fuels yet, but I'm curious to know how far away it is.


Yeah, this sentence in the middle of the article:

> The ability to turn CO2 into fuel at a cost comparable to a gallon of gasoline would render fossil fuels obsolete.

Doesn't actually say that this is at a cost comparable to a gallon of gasoline :)

Sly words.


I don't get the "sly" part; talking about implications of the work is important, as well as future goals, and the sentence is extremely clear. You'd have to be an idiot to think that they're claiming to be that cost effective, and generally that type of person would not have made it through the intro paragraphs.


It would be pretty shocking if it was already cost comparable, of course :-).


Sure, but there is a big gap between "we can see a path to getting there with mass production" and "sure would be nice, wink"


In addition to lack of performance numbers, they misstate the amount of sunlight hitting earth by a factor of 10- it's supposed to be 1000 W/m2, not 100.


If you look at the (random) chart I found here[1] some places in the US are getting 6 - 7 sun hours (hours of insolation) so 7000 / 24 = 291 watts / square meter / day. So using a figure of 100 is quite reasonable when you consider that lots of places don't get that much sun.

1. http://www.solarpanelsplus.com/industry-professionals/insola...


Insolation is usually given as peak power with no clouds or other shade when talking about solar panels (unless you specifically say you're talking about average power over a 24hr period). I think it's probably just a typo in the article.


100w is closer to reality for most places. 1000W per meter squared is an ideal case for some near-equatorual desert at noon with very clean air.


Sorry, no.

100W/m2 is highly unusual for any place on Earth. Take the most overcast midday conditions you can imagine and they'll exceed 100W/m2 by a comfortable margin. That can be in Germany, Canada, Colombia, or Antarctica. If it's sunny, it's very close to 1000, no matter where you are. Partly cloudy can even exceed 1000, since clouds can reflect additional sunlight onto the ground.

Then there's of course nighttime, which is 0 W/m2.

You will have to work really hard to find conditions of 100 W/m2, which is why they standardize on 1000, itself quite straightforward to find anywhere on Earth.

"10% sounds right" is specious.


For Germany the yearly average is 110 W/m² or so. Clear summer days go to >1000, but nights and bad weather days push the average down. Maybe they meant that in the article, maybe they missed a zero.

If they meant it, it seems like an odd comparison without data if the cell scales with power. If it doesn't, it can't properly utilize bright days and would miss out on most of that average power.


Sorry, yes.

You're only counting the peak hour of the day. And yes, there's also nighttime, morning, afternoon, and evening.

And guess what, nighttime is not zero. The moon gives off some light too.


Moonlight is 0.00 watts per square meter. It's almost a million times dimmer than sunlight.


Isn't it counterproductive to turn it into fuel to be burned? It seems like that would leave us at best at no net new carbon dioxide, when we really should be sucking CO2 out and sequestering it away. How about we turn it into bricks or something...


It's counterproductive in the sense that you'd be guaranteed to reduce carbon emissions more (globally) if you were to instead just not burn fossil fuels at all. If you took the solar cell part and just used that electricity to displace carbon fueled power plants, you'd end up ahead.

That said, for a little while at least, having liquid fuels is inherently given a bonus relative to electricity only. Of course, you can just make those from the original fossil fuel sources as well...

Honestly it seems like a bit of a mess since each team solving problems locally rarely has all the expertise needed to see the impact globally. I certainly don't, though I've been studying it for many years.

I very much appreciate that things like the CA-GREET models have been trying hard to make it easier to apply wide systems analysis expertise to understand a small part of the overall system without spending years doing the math. But probably it will end up needing to be solved by AlphaGo...


Well, there is nothing out there that can equal the energy density of fossil fuels, which would be essential for powering trucks, buses, airplanes, ships, tanks ....

And if we ever get batteries to be competitive, it's a long, long way of.


A car using this stuff wouldn't need to refuel as frequently as one that uses a battery (environmental concerns are an orthogonal issue)


like how a tree uses solar energy to turn air (CO2) into wood?


Ever heard of concrete? ;)


Interesting that it's a combination of hydrogen and carbon monoxide that it produces. Wonder what the safety implications are.


As it says in the article:

"the artificial leaf delivers syngas, or synthesis gas, a mixture of hydrogen gas and carbon monoxide. Syngas can be burned directly, or converted into diesel or other hydrocarbon fuels."

Hydrogen and carbon dioxide are the feedstocks for the Fischer-Tropsch process, which produces conventional hydrocarbon fuel:

https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...

In other words, H2 and CO are exactly what you want!


Probably also worth noting that syngas is the primary input for the Haber-Bosch method used to generate the ammonia feedstock for most of our synthetic fertilizers. If you just take the CO and pump it underground then you are actually producing fertilizer for agriculture using a carbon negative process.


> ... take the CO and pump it underground then you are actually producing fertilizer for agriculture

Interesting. How does the CO fertilize the plants?


The hydrogen is combined with atmospheric nitrogen to produce ammonia. Usually we source it from natural gas, so all our fertilizer is incredibly carbon intensive to make whereas this would at least be carbon neutral.

At the end, you'd just oxidize the CO back to CO2 before release, like a catalytic converter does, or use the CO as a chemical building block to produce hydrocarbons.


I assume he meant carbon sequestration.


Yes, my prose was a bit less clear than I had intended. You can oxidize the CO and be carbon neutral or sequester it and be carbon negative.


That's syngas, which is very useful; you can use it to make natural gas, petrol, and the whole range of petrochemicals we're used to.


Prior to the use of natural gas, such a mixture was used for lighting and cooking:

https://en.wikipedia.org/wiki/Coal_gas

I guess it won't be much different than natural gas from a safety standpoint.


Ehh, I would rather breath natural gas. https://toxtown.nlm.nih.gov/text_version/chemicals.php?id=18


Could a catalytic converter be used to create CO2 from CO?

edit: I forgot what it took as input for a sec there..


> Could a catalytic converter be used to create CO2 from CO?

You don't need a catalytic converter, you can just burn it. But breathing a sigh of relief that we can "safely" dispose of the CO in this way is missing the point rather badly.


CO is easy to convert to CO₂, just burn it and feed the CO₂ back into the process.


I'd love to see how this would work in my use case. I enjoy brewing alcohol and if I could capture and tap into that with a system like this I'd probably get a better yield then the average user.

It would be cool.


Another interesting concept from Daniel Nocera a few years ago (Sun Catalytix), seemed to be full of promise as this one.

http://www.forbes.com/sites/michaelkanellos/2014/08/26/mit-c...

It looks like these great promises never quite reach the level where they can get to market and create the impact they claim. Trust me, I really wish it were different, and I root for each and evey one of them to succeed. Maybe military and big corp. snatch the tech before they reach consumers (most likely).


This is good finding, but anything substantial will take some time to materialize. But good we are trying to find ways to suck the excess CO2 from the atmosphere.


One of these days, some cleverclogs is going to present to the press a black box that stores electrical charge (and even gives back almost all of it when asked politely) with an energy density almost as good as liquid fuels.

If he can shut up about it containing liquid fuels that are synthesized on the spot, they'll eat it up and hail the finding of the battery holy grail.


I think what would make for a larger breakthrough is a process which produced a replacement of cement aggregates from air or sea water at gigantic industrial scales.


I wonder what the effeicency is compared to growing and burning trees (which of course, also capture CO2 and sunlight and turn them into burnable fuel).


I don't want to poo-poo this achievement, but is another burnable fuel really what we want at this point?


I'm going to say yes, very much so.

Remember the carbon here is coming from the atmosphere, so it's carbon neutral and won't contribute to climate change.

If the process can be scaled up to produce a gallon of gasoline for less than the costs of extracting crude from the ground and refining it - then it will quickly kill off new investment into the fossil fuel extraction industry. As opposed to alternate energy technologies, like electric cars which will take a long time to replace internal combustion engine cars. It would use all of the existing infrastructure, so all it has to be is cheaper for market forces to work their magic.

That's a very big IF, however, so don't get your hopes up.


If it captures CO2 and can make something like methane or butanol, hell yes. Hydrocarbons have great energy density and simple ones burn clean. If you take the carbon out of the atmosphere, you are net 0 when you burn it back in.


Yes, because burnable fuels are usually far more energy dense than batteries, and also as others have pointed out because this process is carbon neutral. Maybe someday we'll have significantly better batteries, but until then..


But it's CO2 in, CO2 out...

It's more like using sunlight to recycle CO2...


It could be pumped underground to capture the CO2 permanently.


If we had ways to take more CO2 out of the atmosphere, and this was close to carbon neutral, there's no reason to use something like this.


You're "burning fuel" in your own body as you sit there in your chair typing.

So, yes.


I can think of another way you can take sunlight and CO2 and produce a burnable fuel...


You mean growing trees for wood fuel...


> Breakthrough solar cell captures CO2 and sunlight, produces burnable fuel

Is it called "A Tree"? Those things are ancient!


Is it scalable to drive a Car?


[dead]


Personal attacks are not allowed here. Please don't do this again.

We detached this subthread from https://news.ycombinator.com/item?id=12194564 and marked it off-topic.


Because we care about rigor and accuracy in this forum, and would prefer to be aware if and how the article title and content don't reflect reality. If these comments bore you, skip them.


There is nothing rigorous about the ongoing fantasy that random HN commenters know things that no one else does.


I have regularly found that random HN commenters often turn out to have years of professional experience in the industries they are commenting on. Its one of the fun parts of reading HN.


But it'd be great to have an "ignore user" function for those few who just google their skepticism.


You might want to get the "Hacker News Enhancement Suite" extension. It's incredibly useful for cases like this, for instance I have tagged Animats (the creator of this sub thread) as "faux expert" after reading some of his crypto posts (a topic I know something about) that were written as if he was an expert, but completely and dangerously wrong.

Not knowing anything about chemistry, I would've been inclined to believe his post if it wasn't for the Hacker News extension suite, and I can read from someone who actually knows the field


If their recently-googled skepticism is accurate, then I don't care how cursory it is - it saves me the five minutes of looking up the same sources myself.


That observation is circular and incredibly dangerous, though, for self-evident reasons including this thread.


Add unsweetened shebenchnach. C


How many times per year do we see this? I'll give a shit when I can buy a panel of these cells off Amazon.


More `burnable fuel` doesn't seem to be part of any answers to climatic change though.(haven't read the whole article yet)


> Authors: Mohammad Asadi, Kibum Kim, Cong Liu, Aditya Venkata Addepalli, Pedram Abbasi, Poya Yasaei, Patrick Phillips, Amirhossein Behranginia, José M. Cerrato, Richard Haasch, Peter Zapol, Bijandra Kumar, Robert F. Klie, Jeremiah Abiade, Larry A. Curtiss, Amin Salehi-Khojin

I wonder how many of the scientists who made this discovery would be banned from entering the United States by Donald Trump and the Republican Party.


Possibly none. Those names don't suggest foreign birth let alone religion or race. Plenty of native-born Americans have such names.


Don't know of course, though it appears to be a "diverse" group who worked on the project. The salient point is Trump has made it clear he was talking about illegal entrants and delaying entry for individuals coming from areas where terrorism is endemic, until a vetting process is established. There are a great number of professionals from Muslim countries regularly admitted who contribute to American society and culture and that would not change.


> and delaying entry for individuals coming from areas where terrorism is endemic, until a vetting process is established.

I hate to even further the discussion on this off-topic subject, but the above is simply not true. Here is the official statement (still published in it's original form) directly from Donald Trump's website:

> Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on.

This is a far cry from "individuals coming from areas where terrorism is endemic". Regardless of your stance on politics, what that statement suggests is blanket discrimination based on religious belief.

https://www.donaldjtrump.com/press-releases/donald-j.-trump-...


Well, it appears to be policy in evolution. I based my comment on what Trump has said in his most recent appearances, and quite credibly that's not yet reflected in the online published material.

Realistically campaigns of all stripes frequently change positions and policy is hardly set in stone. I expect we'll witness numerous "corrections" from all candidates as the election season moves along.

BTW during the Republican and Democrat conventions just concluded, both candidates mentioned policies of this kind. It might be worth the effort to listen to both party's candidates' acceptance speeches since that would represent their current positions.




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