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This is incredible. I mean it's a long way to seeing this in affordable silicon solar cells, but still amazing to me that the materials engineering can accompli

• toomuchtodo 7y ago
  We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. We're rapidly approaching the point where the solar is "almost free" and you're just going to pay for the battery storage (until that cost is rapidly driven down as well). [1] https://www.utilitydive.com/news/los-angeles-solicits-record-solar-storage-deal-at-199713-cents-kwh/558018/ https://www.utilitydive.com/news/los-angeles-solicits-record... (Los Angeles solicits record solar + storage deal at 1.997/1.3-cents kWh)
  • aplummer 7y ago
    I think it would improve the density though creating new applications in or on constrained surfaces (for example, more useful on an expensive car).
  • HereBeBeasties 7y ago
    There's nothing wrong with solar per-se, but it's just not sufficiently power dense if you're talking national scale power usage. https://www.finder.com/uk/solar-power-potential https://www.finder.com/uk/solar-power-potential seems to think that countries like the UK would need more than 10% of their area covering with solar panels to cover their energy needs. I think you'd need to be talking about an order of magnitude improvement in efficiency to really start making it look really feasible as a significant way to change our fossil fuel usage, no?
    • godelski 7y ago
      We also need batteries. But that's why solar is only part of the solution. No single source will solve all the problems in all the areas. I'm a big proponent of nuclear but it's only part. Solar is also what I want to see. But more than the other two I want batteries.
      • plufz 7y ago
        From what I heard from people in the solar business battery is generally not a good idea. Better to invest in a good grid where we can transfer electricity from one place to another (there’s always windy somewhere). And have some sort of backup power plants on the lowest days (like natural gas, biofuel, etc, not co2 free but they wouldn’t be used very often from what I understand). Or alternative “batteries” like pumping up a lot of water in some dam.
        • Gibbon1 7y ago
          I like to point out the efficiency gains and load shifting will also reduce off peek demand somewhat. Industrial users will chase lowest cost if possible. If electricity costs 3X at 1am the price at 11am, no ones going to be running an electric furnace at 1am. Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. So it's slightly pointless argue as some do that lack of current solutions is a reason not to move forward with renewables. Worst comes to worst we already have peaking plants that could substitute for baseload power.
          • deleted 7y ago
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          • godelski 7y ago
            I think there's miscommunication. > lack of current solutions is a reason not to move forward with renewables No one is saying we shouldn't move forward with renewables. Well maybe a certain canine news network, but not anyone here. > Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. What people are saying is there isn't good enough technology yet. So that means that we need to continue funding research. Not being solved means that just building won't be the solution. That we need to spend some serious money researching. That's what people mean by "battery tech isn't there yet". It isn't a defeatist attitude, it is a "continuing and doubling down on research is an important part of the equation" type of attitude. This is typically because that kind of research isn't done by the private sector, but rather government. DOE does a lot of this funding, and even funds a lot of the research being done in the private sector. So being vocal about this means we care and hopefully those in control of allocating that money (probably not by Rick Perry) will spend more on fixing that part of the equation while the private sector does the building out part.
    • ben_w 7y ago
      Your own link says that about 6% of the UK has been built over; although I am unclear exactly what that means [1], this is an achievable level. Of course, I would still agree that it’s good to have a mixture, for example the British Isles have a lot wind power (I’ve heard, but can’t find a reference for the claim, that it could supply most of the European continent). [1] the percentage sounds high enough that I assume it includes all gardens and roads not just the buildings themselves
      • goodcanadian 7y ago
        Here's a good link for you: http://gridwatch.co.uk/ http://gridwatch.co.uk/ It shows current UK grid demand and generation sources as well as historical data.
        • ben_w 7y ago
          Thank you, though — while interesting — that doesn’t tell me how much wind power the British Isles could produce if UK and Ireland built the wind farms necessary to exploit it.
          • deleted 7y ago
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    • llukas 7y ago
      Methodology is flawed. If you switch from burning oil in ice engines to electric you use at least 50% total energy less. So they overestimate area needed.
      • gtirloni 7y ago
        What's that due to? Less energy lost to dissipation?
        • Gibbon1 7y ago
          Thermodynamic cycles and engineering constraints. ICE engines are about 30% efficient at best. Operationally they're usually a lot worse. Where modern combined cycle power plants are pushing towards 60%. A big part of the difference is that stationary plants use multiple stages to wring the last bit of energy out of the fuel. Where piston engines use one stage. They also suffer from mechanical and thermal losses due to their small size. Small size means higher internal surface area to volume and higher operating speeds. Contributes to higher friction and thermal losses. Friction in an ICE is actually significant.
        • llukas 7y ago
          Carnot cycle limiting maximum ICE efficiency to ~40% (can be obtained if you're big electric power plant) vs 95% electric engine efficiency. For practical purposes, ICE has way lower efficiency than 40% and electrics lose some due to the transmission and battery recharge.
        • Robotbeat 7y ago
          For the same kind of reason solar panels only access about 15-20% of the energy that hits them.
          • Robotbeat 7y ago
            I was serious. Solar cells are like solid state heat engines in that they’re fundamentally limited by Carnot Efficiency (which is theoretically high for solar cells as the effective temperature of sunlight is high). If we’re going to use “primary energy” and not useful electrical or mechanical energy, then we’d need to include the energy of sunlight falling on the solar panels, which is about 5 times the useful electrical energy produced. And just like actual heat engines, solar cells are improving. The best cells have achieved 47% efficiency in the lab, comparable to a high performance combined cycle natural gas plant (note that thermal power plants often cheat a bit by listing the efficiency in terms of the low heating value of a fuel, ie the heat produced not counting condensing the water vapor out).
    • NeedMoreTea 7y ago
      UK would do best supplementing wind with solar, rather than going wholly solar. UK is famous for many things, consistent reliable sun isn't one of them. Maybe in 20 years we'll have a more Spanish climate, though I would hope not. Adding solar on every roof that's suitable should be plenty for starters. There's probably dozens of spots around the UK suitable for Dinorwig 10 GWh pumped storage style solutions. NIMBYs permitting. If the UK fully built out offshore wind it would probably have enough to power the whole of Europe. Same goes for Ireland.
      • roryisok 7y ago
        Actually the estimates are that the Irish coast alone has enough potential wind energy to power all of the planet, during peak seasonal wind, and at least all of Europe during the less windy summer season. Building the infrastructure to transmit that power would be a massive undertaking though. Ireland and France are currently cooperating to build an undersea power cable which is going to cost $1Bn, take 5 years, run 575km and have an annual transmission capacity of 6.1 TWh. Annual global energy usage in 2013 was 19,504 TWh, or 3,197 times that.
    • GlennS 7y ago
      Here is a source which says otherwise, and includes references: https://withouthotair.com/c18/page_103.shtml https://withouthotair.com/c18/page_103.shtml Warning this book is quite old now. While the discussion of theoretical limits should probably still hold up, all the economics has been turned upside down since then. Solar and wind costs dropped faster and further than most people's best case estimates, while nuclear costs and timescales just keep going up.
    • imtringued 7y ago
      The problem with solar isn't that it isn't power dense. The problem is that the capacity factor compared to something like wind energy is very low. I'm skeptical of that 10% area claim. They probably made a very basic mistake of replacing all chemical energy with the electricity generated by solar power plants. This completely ignores that we can only turn that chemical energy into heat and then have to convert it to electricity. Depending on the size of the engine the efficiency of this step can range from anywhere between 25% to 50%. So you need 2 to 4 times more primary energy than if your power source generated electricity from the start. Take a look at this chart [0]. As you can see, renewables produce barely any primary energy at all with the exception of biomass, because they don't need to. [1] If we really did increase our renewable deployment 8 fold then Germany would be at 400% renewables at current consumption rates which clearly isn't necessary even if every single car is electric and all industry switched away from fossil fuels. There will still be some processes that depend on fossil fuels as input material but those do not burn the fuels to obtain their energy. Oil products like plastic will most likely dumped in the oce- I mean in landfills. [0] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/paragraphs/images/fig10-germany-energy-mix-energy-sources-share-primary-energy-consumption-2018.png?itok=DHJj3zQy https://www.cleanenergywire.org/sites/default/files/styles/p... [1] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/fig1_installed_net_power_generation_capacity_in_germany_2002_2018.png?itok=dpkm8Ja9 https://www.cleanenergywire.org/sites/default/files/styles/p...
  • hyperpallium 7y ago
    Utility scale cost has been dropping exponentially, but small panels (e.g. 7W phone chargers) haven't. I wonder if the efficiencies will eventually trickle down, or whether the form-factor, other components, retail sales channel and small market for solar phone chargers will prevent this.
    • gtirloni 7y ago
      Way riskier market (consumer goods). It will eventually trickle down though, once it's really mature and countless factories in China have access to it.
    • kragen 7y ago
      I don't build 7W phone chargers, so I could be wrong, but I think there are a couple of factors: · 7Wp of solar panels at this point would cost about US$1.50 if we were talking about the low-cost power modules used in utility-scale deployments. This is, I think, less than the (retail) cost of the case, sales transaction, or power electronics. · Low-cost power modules are less efficient than higher-cost modules, which means you'd need a larger surface area to get 7 watts. Which chargers are you looking at? Searching on Amazon I find a lot of USB battery packs with built-in solar panels, which I can't help but think are basically fake, since a 16%-efficient panel that size would provide less than a watt. (I've probably been influenced by watching a lot of bigclivedotcom videos where he dismantles phony consumer electronics, including USB battery packs that have a tiny fraction of their claimed capacity.)
      • taneq 7y ago
        · Anything is more expensive when you buy one of it than when you buy 10,000,000 of it.
        • sigmaprimus 7y ago
          Not always, especially when working with electronics. Many manufacturers offer development parts at one price, then when you try to scale up production you find the price can be double or triple the original cost. Sometimes the smaller fabricating shops are willing to take slimmer margins as they dont have the bloat of managment, regulatory issues and worker costs such as medical and collective barganing agreements.
  • kragen 7y ago
    Thanks for this great link! I posted a somewhat lengthy analysis of the photovoltaic cost structure, and how it relates to the cost structure of more traditional kinds of power stations, yesterday in https://news.ycombinator.com/item?id=20365309 https://news.ycombinator.com/item?id=20365309. Is the power producer in this case receiving subsidies not included in this price, or is 1.997¢ the unsubsidized price?
  • AnthonyMouse 7y ago
    > We're already below 2 cents/kwh utility scale cost for solar and utility scale battery storage [1]. That price is under optimal conditions. They built in the desert where there are clear skies, lots of sunlight and cheaper land. Plus whatever kind of tax incentives or other subsidies they get in California that conceal part of the cost and may not be available everywhere. The real question is how far can the price continue to fall before it hits a floor. And what happens to the other generation methods as a result of the competition. If people build a bunch of solar farms and storage and replace natural gas plants with them, then there is less demand for natural gas, so the price falls and the remaining natural gas plants stay competitive due to the reduced fuel cost. The "solar takes over everything" narrative is possible, but there is no guarantee of it, and it's probably best not to take it as a hard assumption and make no contingencies for if it doesn't actually work out that way.
    • addicted 7y ago
      Any subsidies solar receives is a tiny fraction of what oil, gas and coal still receive today, without even factoring in all.the subsidies they've received over many years, or the ton of money spent on geopolitics in order to secure fossil fuel supply lines. Or the subsidies and damage they cause when they leak all over the place destroying entire eco systems. And yeah, the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change.
      • waingake 7y ago
        > the massive subsidies they've received by not having to pay for polluting the air, as well as being major contributors to climate change. This this this
      • cyphar 7y ago
        And the massive "subsidies" given by governments by not prosecuting any criminal or civil charges over the fact that gas and oil companies knew about climate change in the 60s and tried to cover it up.
  • BurningFrog 7y ago
    You'll also have to pay for the real estate.
• Retric 7y ago
  It’s also somewhat misleading we already have solar cells over this theoretical limit. They operate by having multiple layers that operate on different frequencies. So, this really more an alternative manufacturing approach.
  • DennisP 7y ago
    But would this technique also work for multi-layer cells?
    • tedivm 7y ago
      Yeah, in this case it appears that they're focused on the single layers simply because it's easier to build one thing than multiple things. This one was focused on the blue/green portion of the spectrum.
      • deleted 7y ago
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  • atonalfreerider 7y ago
    I disagree that the title is misleading. To anyone familiar with solar cell technology, theoretical limits are discussed in relation to the material in question. Multi-junction cells are not something that are commonly discussed outside of those with expertise, so confusing a theoretical limit with efficiency gains through band gap augmentations is not likely. This is analogous to an article about a chemist discovering a way to get more chemical efficiency out of gasoline and someone saying that we can already do that with a richer air-fuel mix using a turbocharger. The two are not comparable.
    • hn_throwaway_99 7y ago
      Whether or not it is "misleading", I'd say, at least to a layman like myself, it was certainly confusing. Why? Because just yesterday there was an article on the front page touting how Toyota was testing putting improved solar panels on the roofs of their vehicles, and that article quoted an efficiency of 34%, well above the "max theoretical limit" given in the present article: https://news.ycombinator.com/item?id=20364348 https://news.ycombinator.com/item?id=20364348. So I guess my question is how would the proposed manufacturing process in this article be an improvement? Cheaper manufacturing costs? Even higher efficiency if you had "multi-junction cells" made using the processed discussed?
• selimthegrim 7y ago
  The origin of the phenomenon lies in the molecular crystalline layer, the hafnium layer they are talking about keeps the excitons separated and intact.
  • selimthegrim 7y ago
    As well as passivates the Si