12 ms·

Tandem solar cell achieves 32.5 percent efficiency

212 points by quakeguy 4y ago

philipkglass 4y ago
Very good! There are more efficient multi-junction solar cells in commercial use, but the existing ones use stacked III-V semiconductors and are very expensive, really only suitable for space applications. This record is for a thin perovskite material solar cell on top of a conventional silicon solar cell. Both materials are inexpensive. The main obstacle to commercialization is keeping the perovskite material stable over long periods of operation. This family of materials is more sensitive to water/oxygen/light than silicon itself, but they need to last nearly as long as silicon for cells used in solar farms and rooftop panels.
- walrus01 4y ago
  Long term degradation and manufacturer warranty for such is indeed a factor. There's a number of poly and monocrystalline Si 156mm cell based PV modules now which are warranted for something like 83% of their original STC rated output after 25 years. Of course you have to also believe that the manufacturer will still be around in the same corporate form in 25 years and able to honor its warranty. This certainly may not be the case if you follow PV industry news and are aware of how many PV panel manufacturers have formed as startups and gone bankrupt in the last 8 to 14 years. edit: the other reply here in the thread asks: > but can be replaced as a layer every, say, 5 years or so? It's not trivial maintenance, but you have to do some maintenance on the panels anyway Typical mass market PV panels are cells permanently encapsulated behind glass sandwiched with a back sheet, it is not practical or possible to replace a layer or modify the cells once they're assembled into a panel. The only maintenance done on a series of ground or roof mounted typical PV panels is to wash them.
  - jacquesm 4y ago
    > Of course you have to also believe that the manufacturer will still be around in the same corporate form in 25 years and able to honor its warranty. I just bought 26 AEG panels for exactly that reason. They were a bit more expensive but my estimate is that AEG will outlive me so that should be fine. Contrast with many other solar panel producers who seem to go out of business ever five years or so.
    - walrus01 4y ago
      Out of curiosity what did you pay for them?
      - jacquesm 4y ago
        225 euros each; but prices have since been going up considerably due to shortages: https://www.zonnepanelen-store.nl/aeg-as-m1202z-bhm6-365hv-glas-glas-365w-mono-zwart.html https://www.zonnepanelen-store.nl/aeg-as-m1202z-bhm6-365hv-g...
    - VaxWithSex 4y ago
      AEG is just a brand?
      - jacquesm 4y ago
        It is to me... https://en.wikipedia.org/wiki/AEG https://en.wikipedia.org/wiki/AEG These panels are produced by AEG Industries: https://www.aeg-industrialsolar.de/about-us/ https://www.aeg-industrialsolar.de/about-us/ A licensee of the AEG brand from Electrolux aka The Solar Solutions Group.
      - jacquesm 4y ago
        Ah I see what you mean now, that was in the context of that it will outlive me, sorry! In that sense 'Volvo' is also 'just a Brand', as is 'Audi' and many others. Still, that's what people will refer to.
  - conradev 4y ago
    Maxeon extended their warranty this year in select markets to 40 years, which is pretty cool: https://pv-magazine-usa.com/2022/02/04/maxeon-40-year-solar-panel-warranty-available-in-select-markets/ https://pv-magazine-usa.com/2022/02/04/maxeon-40-year-solar-...
- einpoklum 4y ago
  What about if the Perovskite degardes, but can be replaced as a layer every, say, 5 years or so? It's not trivial maintenance, but you have to do some maintenance on the panels anyway, so maybe it's practicable. And the price of replacing a detachable layer should be a small fraction the price of the original panels and installation.
  - roywiggins 4y ago
    These layers are wafer-thin. Don't think you're going to be able to scrape off the perovskite and reapply it in situ. https://www.helmholtz-berlin.de/pubbin/news_datei?did=15064 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15064
    - 0cf8612b2e1e 4y ago
      Even if the degradation could be repaired (e.g. after five years, restore a 28% panel to 31% efficiency), at grid scale, does it make financial sense to do the maintenance instead of replacing the panel when it falls below X%?
      - soperj 4y ago
        Would be a shame to waste all the rest of the product just for numbers sake.
        highwaylights 4y ago
        It may not need to be wasted. There’s currently a price floor on used EV’s with degraded batteries because they can be used for home energy storage after their useful road life. There could be a solid secondary market 20 years from now for panels that have dropped to say 20% efficiency where the surface area to yield ratio isn’t a factor (rural areas I would guess).
        lightedman 4y ago
        "There could be a solid secondary market 20 years from now for panels that have dropped to say 20% efficiency" Current drop down to 70% output is roughly 30 years. These panels won't go anywhere for a long time.
- conradev 4y ago
  What is cool is that there are also lots of niche markets between now and that future that can use cheaper, shorter-lived, high efficiency panels. High altitude drones or EVs are much easier to service than satellites: https://spectrum.ieee.org/new-type-of-unmanned-aircraft-aims-to-compete-commercially-with-satellites-and-drones https://spectrum.ieee.org/new-type-of-unmanned-aircraft-aims...
  - hnuser123456 4y ago
    There are hobbyists making solar-powered remote-control planes that are just barely able to charge as much as they draw at noon on a sunny summer day.[1] Even a minor boost to efficiency could push this concept from "doable in ideal scenarios as a tech demo" to "useful in the real world as a way to multiply the range of electric fixed-wing aircraft" [1] https://www.youtube.com/watch?v=xS2iCj-HSqY https://www.youtube.com/watch?v=xS2iCj-HSqY
  - Sparkyte 4y ago
    Imagine you're a truck driver and the whole top of your trailer has solar panels.
    - the_third_wave 4y ago
      Let's say that truck roof covers about 41.5m² (the area of a standard 53' x 8.5' trailer roof). Let's further assume that 41m² of that is covered with PV panels. Using current technology (~21% efficiency silicon cells) and assuming standard irradiation of 1000W/m² this roof would produce ~200W/m² for a total of ~8.2kW. Add a 40' trailer (~31.5m² roof area, ~6.2kW) for a total of ~14.4kW. Using 31.5% efficient cells would raise this to ~22.7kW. Taking the newly releases Tesla semi as an example (~1 kWh/km, ~900 kWh battery pack) this would add about 14 km of range per hour using current cell technology or about 22 km per hour using these new cells. Assuming an average road speed of 80 km/h this would extend the range of the vehicle by up to ~25% for the new cells, ~18% for current cells during daylight hours with standard irradiation and no shading.
      - 4y ago
sasacocic 4y ago
Anyone know the previous record? Curios how much of an improvement this is.
- miohtama 4y ago
  > More recently, in summer 2022, the Ecole Polytechnique Fédérale de Lausanne, Switzerland, first reported a certified tandem cell above the 30% barrier at 31.3%, which is a remarkable efficiency jump over the 2021 value
- wnevets 4y ago
  > Various teams from HZB had achieved a record value in late 2021 with an efficiency of 29.8% edit: the chart from the article is great at showing the progress https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092
- barbazoo 4y ago
  > Various teams from HZB had achieved a record value in late 2021 with an efficiency of 29.8% that was realized by periodic nanotextures. More recently, in summer 2022, the Ecole Polytechnique Fédérale de Lausanne, Switzerland, first reported a certified tandem cell above the 30% barrier at 31.3%, which is a remarkable efficiency jump over the 2021 value.
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- mikeyouse 4y ago
  NREL keeps a detailed chart by technology - it's already updated with HZB's latest which is pretty impressive - the Perovskite / Si Tandem line: https://www.nrel.gov/pv/assets/pdfs/best-research-cell-efficiencies.pdf https://www.nrel.gov/pv/assets/pdfs/best-research-cell-effic... (Base webpage for the chart: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html)
beaned 4y ago
More solar cell types than I realized. Why is this one getting a lot of attention now?
- RhodesianHunter 4y ago
  Because it's setting a record.
- walrus01 4y ago
  There's a vast number of esoteric PV cell types you can't actually buy at any reasonable price, or buy at all at any price, unless you're in an extremely specialized market niche. Note the PDF link above to best research cell efficiencies, which means somebody made a very small number of PV cells in a lab environment. Not something that's produced for sale to end-users in any real quantity.
- Schroedingersat 4y ago
  Has the potential for an upside previously unavailable at low cost. By stacking layers of different solar cells you can surpass the theoretical limit of a single layer which is 32% (or around 28% in practical terms including spaces that aren't solar cell). Single layer silicon is in the 22-25% range now with the 22% modules being the optimal cost in most areas. The modules also only make up a small fraction of the cost of a PV install (around 25-30%), so increasing efficiency from 22% to 32% reduces BOS costs by almost as much as the entire module currently costs Perovskites are also dirt cheap, so are a good candidate for increasing efficiencies. The difficulty is in making them last. Accelerated aging tests are promising but they haven't hit market yet.
  - tuatoru 4y ago
    For those not familiar with the jargon:- BOS: balance of system, i. e., everything else besides the panels (mountings, wiring and connectors, labor and land costs being the main parts of BOS affected by panel efficiency.)
- _fizz_buzz_ 4y ago
  Because this one is very practical and has a really good chance to make it to market. One can build very esoteric structures in a lab environment - which is of course also an achievement - but they are not easily mass produced (too expensive, too unstable, too difficult to manufacture at scale, too unpredictable, etc.).
walrus01 4y ago
Extreme efficiencies in STC W per square cm (or meter) are primarily of interest to things where room to mount PV cells is extremely constrained. Such as on satellites. Look at triple junction GaAs based cells used in satellite applications for example. There are a large number of research-lab-only PV cells made in the last 10-12 years which greatly exceed 23% but are economically unfeasible or impossible to purchase for ordinary use. Some of this tech does trickle down eventually, however. Of more practical real world interest is $ per STC watt for a panel you can buy in a 20-panel pallet load from an ordinary PV wholesaler. Like a figure of $0.28 USD/W for nominally 380W rated 72-cell monocrystalline Si panels for rooftop or ground mount applications. Meaning that a pallet of 20 panels would be somewhere around $2100 to $2200 USD to purchase plus freight. In approximately the last 12 years we've seen things go from if you buy a pallet of "cheap" mass market 72-cell panels, you'd get 320W rated per panel (STC rating of about 4.44W per cell), to now being able to buy something that is 380W rated as mentioned above, approximately 5.27W per cell. All under STC measurement conditions which are only a rough approximation of real world sunlight of course. The same panels typically measure 1.99 x 0.99 meters so you can do the math on the improvement in STC W per square meter if mounting space is a limiting factor. https://footprinthero.com/standard-test-conditions https://footprinthero.com/standard-test-conditions
- einpoklum 4y ago
  This is also relevant to large-scale installations. For a single family home, perhaps you don't care if you use 30% of the roof area or 32.5%; but if you're building a solar farm for a whole city, then those extra 2.5% are a good number of Km^2 which you can save; or have as extra safety-margin production capacity.
  - skykooler 4y ago
    It's also relevant to some edge use cases, such as solar powered aircraft or solar cars, where space for panels is extremely limited.
  - sacrosancty 4y ago
einpoklum 4y ago
So, obviously, there's a difference between efficiency in lab settings and efficiency in the field for mass-produced cells. But - this is an impressive achievement for the Silicon + Perovskite technology. But I have a question to the more knowledgeable here: The chart in the story shows other technologies which achieve significantly higher efficiency figures: https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 specifically, multi-junction cells. Why are they faded-out? Are they not practicable to mass produce and deploy? Only usable in limited scenarios? ---- Partial self-answer: According to Wikipedia, https://en.wikipedia.org/wiki/Multi-junction_solar_cell https://en.wikipedia.org/wiki/Multi-junction_solar_cell > As of 2014 multi-junction cells were expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters.
- walrus01 4y ago
  triple-junction GaAs cells are not something you can or want to buy unless you're building a spacecraft - they're EXTREMELY expensive. https://www.google.com/search?client=firefox-b-d&q=boeing+spectrolab https://www.google.com/search?client=firefox-b-d&q=boeing+sp...
- tuatoru 4y ago
  The chart is produced by NREL, and comes in static and interactive versions: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html The fading is to de-emphasize cells of different technologies.
hubraumhugo 4y ago
Which solar company has the biggest technological advantage and is best positioned for another solar boom? In which one would you invest?
- seydor 4y ago
  They are so cheap that i think it is unlikely that a minor edge matters
  - snewman 4y ago
    They are not cheap after you factor in costs for installation, the framework, land, etc. Increased efficiency means you also need less of all those.
    - soperj 4y ago
      there's a company now that's laying them flat reducing the cost significantly.
      - thombat 4y ago
        Removes the cost of the frame, reduces efficiency. Presumably whether it's a net gain depends upon the site, eg terrain shape, latitude, need for passive cooling, wind-blown dirt, local fauna, etc.
      - aitchnyu 4y ago
        Can we make pedestrian paths using solar panels yet?
- tick_tock_tick 4y ago
  None; they are all hitting up against the same limits with the current technology someone would need to figure out something completely new to trigger another solar boom.
  - 4y ago
martinpw 4y ago
I'm curious how this process works. Is it that the researchers are experimenting with different ingredients and seeing what works best? Or do they have a clear idea what sort of structure they want to build and the research complexity is in how to get the various ingredients to assemble into the required structure? Basically wondering how the researchers go about planning a research program and how clear the goals and timelines are.
- cycomanic 4y ago
  I'm not working in solar cells but do research in optics and have a general understanding of this (also from discussions with people who understand this better). The main limiter for solar cells from silicon is the overlap of the bandgap with the spectrum of the sunlight and also the loss in efficiency when cells get hot. So what people do is they use multiple materials (often in different layers) that cover different parts of the spectrum to absorp most of the sunlight. Researchers tend to have a good idea which these are (although there is research in creating new organic ones), but the challenge is to combine this in fabrication with the silicon and in a cheap easy to fabricate way and with materials that don't degrade over time. So short answer researchers have a general idea what needs to be done, but as usual the devil is in the details. Again not an expert in the exact area, so anyone who is please correct if something isn't right.
- tuatoru 4y ago
  Also not an expert, but from my reading it's all engineering. The physics is sufficiently well understood and variations can be simulated. It's about preventing reflections at various surface boundaries (or more generally, controlling reflections everywhere) and structuring things so that different wavelengths go to the right layers, and preventing recombination, and a zillion other details. Material quality and process control to get the right surface properties are very important. The cells that make it out of the lab are those where the cells are robust and processes can be adapted and scaled to mamufacturing quantities, competitively with current products.
0cf8612b2e1e 4y ago
What is the highest efficiency cell used in production plants today? Is that different than used by homeowners? Edit: I mean widespread usage. One lone 10kw plant using 30% panels was not my intention.
- Schroedingersat 4y ago
  I believe around 22% is standard for PERC which is dominant. TOPCON and HJT are a smidge over 25% but are a bit more expensive for now and use more silicon and silver. Single junction caps out around 28% at the module level so surpassing this at scale requires commercialising a new technology like these perovskite tandem cells. The other benefit is it reduces consumption of the main limiting critical mineral of silver down to insignificant levels by increasing the voltage on the metal layer.
tinglymintyfrsh 4y ago
Where does this fit in the chart and with what symbol(s)? https://en.wikipedia.org/wiki/Solar-cell_efficiency https://en.wikipedia.org/wiki/Solar-cell_efficiency (The top is 47.1%)
- pavon 4y ago
  The article itself has a more up-to-date version of that chart with this (and other) developments. https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092
  - tuatoru 4y ago
    That chart is one of the variants of a chart published and maintained by NREL, the US National Renewable Energy Laboratory: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html Interactive version: https://www.nrel.gov/pv/interactive-cell-efficiency.html https://www.nrel.gov/pv/interactive-cell-efficiency.html NREL's website has a lot of good stuff if you're interested in renewable energy.
yieldcrv 4y ago
Does this cross any thresholds of utility? Not sure what benchmark to be excited about here aside from progress for the sake of progress
- rsynnott 4y ago
  That's... generally how progress works, though.
  - yieldcrv 4y ago
    in other forms of progress the goal post is pretty clear, I believe it is clear here but need it explained to me, let me know if you can help. what is the metric, how close are we to it.
    - rsynnott 4y ago
      I mean, I don't think there is one. There's no magic number that's the goal (or well, I suppose in the broadest possible view there's the theoretical maximum efficiency, but that's a long, long way off). In general, better efficiency is better than worse efficiency. > in other forms of progress the goal post is pretty clear I'm not sure that's true. Incremental progress is fairly common. A 7nm feature size microchip is generally better than a 10nm one (from the same manufacturer, at least; annoyingly, people are increasingly fudging the numbers there), which in turn was better than a 13nm one and so on, as an example.
sfifs 4y ago
Very interestingly, this seems similar to the strategy used by plants to absorb energy from sunlight in the red and blue parts of the spectrum with pervoskite absorbing the blue and silicon the green. However there is no indication this is intentional bio mimicry. Do we not have materials which can absorb the middle green part of the spectrum?
- tuatoru 4y ago
  It's not really very interesting. Those parts of the spectrum are where the energy is concentrated. There's quite a bit in infrared, but it's spread out over a wide range of wavelengths, so difficult to use (except as heat).
  - mcbits 4y ago
    Assuming this[0] is accurate, it looks like solar irradiance reaching the surface is pretty flat from mid-blue up to red, including green. I would guess either there are other evolutionary reasons for reflecting green, or no reason at all and chlorophyll happened to be the first/easiest substance to evolve for photosynthesis. [0] https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spe...
    - adrian_b 4y ago
      The most successful aquatic phototrophs, e.g. brown algae and diatoms, absorb a much larger fraction of the solar light, by having complementary pigments that transfer the energy to chlorophyll. On the other hand, the terrestrial space is dominated by the green plants because here the problem is not absorbing more of the abundant light, but avoiding overheating from absorbing too much light (because the efficiency of photosynthesis is low, so most of the absorbed energy becomes heat, and not only there is much more light in air, but also the cooling is more difficult than in water).
transfire 4y ago
When will we have cheap 30%+ efficiency that will last 30+ years? That seems to me the tipping point when Solar can become ubiquitous.
- stephen_g 4y ago
  Solar is pretty ubiquitous already in a lot of places… Around here (Australia), more than 1/3rd of homes have solar and plenty of commercial premises. The efficiency doesn’t matter much, it’s just the cost. Most people don’t pack as much solar on their roof as they can possibly fit on anyway, so higher efficiency would just mean less of the roof is taken up.
- Casteil 4y ago
  There's always someone pushing for more lol The problem right now isn't so much panel efficiency as the lump cost of doing a project like this and the affordability / justifiability of that.. Especially when solar companies take advantage of people receiving tax credits & gouge on labor pricing.
moloch-hai 4y ago
What are those greyed-out traces in the graph that approach 50%?
- lightedman 4y ago
  Different Solar techs. Highest one being concentrated 4+ junction cells.
m0rissette 4y ago
Wouldn’t 99% be good? Why are we celebrating shitty efficiency?
- detaro 4y ago
  200% would be even better!
- thombat 4y ago
  So a panel that looks like Vanta Black, but also at non-optical wavelengths? Better efficiency is being pursued but the engineering behind real products will always be the result of balancing design constraints: https://en.m.wikipedia.org/wiki/Solar-cell_efficiency https://en.m.wikipedia.org/wiki/Solar-cell_efficiency
- azalemeth 4y ago
  There are a bunch of physical reasons why you can't have a ~100% efficient solar cell – obviously thermodynamics chief among them, but also effects like the fact that the bandgap is finite (yet the sun's black-body spectrum has energy radiated below it) and the fact that solar cells themselves will heat up and re-radiate photons they absorb. For a long time, solar cell efficiency was around ~10-20%. There's actually a theoretical upper limit, the Shockley–Queisser limit, of a bit less than 34% for a single p-n junction photocell. [1] This is a tandem cell – for which higher efficiencies are possible but costs go up. The thermodynamic limit is reached if you have an infinite number of layers. Obligatory plot of progress vs time: https://upload.wikimedia.org/wikipedia/commons/2/25/Best-research-cell-efficiencies-rev220126_pages-to-jpg-0001.jpg https://upload.wikimedia.org/wikipedia/commons/2/25/Best-res... [1] https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limi...
- _ph_ 4y ago
  Shitty efficiencies[1] haven't stopped us from using combustion engines in cars for a century. But while combustion engines use expensive fuel, these solar cells use sunlight, which is free. So which technology should we celebrate? [1]: 20% is already quite a good efficiency for a car in mixed traffic. That doesn't even account for all the energy used to provide the fuel.
NextHendrix 4y ago
These perovskites are notoriously difficult to deposit at scale in a uniform enough layer to be effective, with small variances causing dramatic drops in efficiency. On the cool side, it's theoretically possible to make them translucent (without the silicon substrate ofc) which could make for cool power generating windows in the future. On the not so cool side you really don't want the materials anywhere near you or your water table in the event of a panel being damaged. Lead halide perovskites, methylammonium lead iodide, are insanely toxic and a race to the bottom on price if they become widespread could be an environmental disaster waiting to happen. Not to take from the achievements described here, but there isn't any mention of it. There is some hope in taking the lead out (tin based perovskites) but that tends to result in a drop in efficiency.
joshspankit 4y ago
Can someone please make a website (a wiki?): canibuyoneforunderfiftyusd.com Personally I’d buy most of the products I upvote on HN, but it’s a gamble whether they even have a retail product at all.
- fred_is_fred 4y ago
  You want to buy one solar cell for under $50? What would you do with it.
  - joshspankit 4y ago
    Tinker. Probably build a small solar-powered light, or see how much usage I could get out of a solar-powered microcontroller, or even just see how small of a thing I could make that still collects power. The technological advances we (society) make are endlessly fascinating to me. I just want to have more of them in my hands.

212 points by quakeguy 4y ago

Very good! There are more efficient multi-junction solar cells in commercial use, but the existing ones use stacked III-V semiconductors and are very expensive, really only suitable for space applications. This record is for a thin perovskite material solar cell on top of a conventional silicon solar cell. Both materials are inexpensive. The main obstacle to commercialization is keeping the perovskite material stable over long periods of operation. This family of materials is more sensitive to water/oxygen/light than silicon itself, but they need to last nearly as long as silicon for cells used in solar farms and rooftop panels.

walrus01 4y ago
Long term degradation and manufacturer warranty for such is indeed a factor. There's a number of poly and monocrystalline Si 156mm cell based PV modules now which are warranted for something like 83% of their original STC rated output after 25 years. Of course you have to also believe that the manufacturer will still be around in the same corporate form in 25 years and able to honor its warranty. This certainly may not be the case if you follow PV industry news and are aware of how many PV panel manufacturers have formed as startups and gone bankrupt in the last 8 to 14 years. edit: the other reply here in the thread asks: > but can be replaced as a layer every, say, 5 years or so? It's not trivial maintenance, but you have to do some maintenance on the panels anyway Typical mass market PV panels are cells permanently encapsulated behind glass sandwiched with a back sheet, it is not practical or possible to replace a layer or modify the cells once they're assembled into a panel. The only maintenance done on a series of ground or roof mounted typical PV panels is to wash them.
- jacquesm 4y ago
  > Of course you have to also believe that the manufacturer will still be around in the same corporate form in 25 years and able to honor its warranty. I just bought 26 AEG panels for exactly that reason. They were a bit more expensive but my estimate is that AEG will outlive me so that should be fine. Contrast with many other solar panel producers who seem to go out of business ever five years or so.
  - walrus01 4y ago
    Out of curiosity what did you pay for them?
    - jacquesm 4y ago
      225 euros each; but prices have since been going up considerably due to shortages: https://www.zonnepanelen-store.nl/aeg-as-m1202z-bhm6-365hv-glas-glas-365w-mono-zwart.html https://www.zonnepanelen-store.nl/aeg-as-m1202z-bhm6-365hv-g...
  - VaxWithSex 4y ago
    AEG is just a brand?
    - jacquesm 4y ago
      It is to me... https://en.wikipedia.org/wiki/AEG https://en.wikipedia.org/wiki/AEG These panels are produced by AEG Industries: https://www.aeg-industrialsolar.de/about-us/ https://www.aeg-industrialsolar.de/about-us/ A licensee of the AEG brand from Electrolux aka The Solar Solutions Group.
    - jacquesm 4y ago
      Ah I see what you mean now, that was in the context of that it will outlive me, sorry! In that sense 'Volvo' is also 'just a Brand', as is 'Audi' and many others. Still, that's what people will refer to.
- conradev 4y ago
  Maxeon extended their warranty this year in select markets to 40 years, which is pretty cool: https://pv-magazine-usa.com/2022/02/04/maxeon-40-year-solar-panel-warranty-available-in-select-markets/ https://pv-magazine-usa.com/2022/02/04/maxeon-40-year-solar-...
einpoklum 4y ago
What about if the Perovskite degardes, but can be replaced as a layer every, say, 5 years or so? It's not trivial maintenance, but you have to do some maintenance on the panels anyway, so maybe it's practicable. And the price of replacing a detachable layer should be a small fraction the price of the original panels and installation.
- roywiggins 4y ago
  These layers are wafer-thin. Don't think you're going to be able to scrape off the perovskite and reapply it in situ. https://www.helmholtz-berlin.de/pubbin/news_datei?did=15064 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15064
  - 0cf8612b2e1e 4y ago
    Even if the degradation could be repaired (e.g. after five years, restore a 28% panel to 31% efficiency), at grid scale, does it make financial sense to do the maintenance instead of replacing the panel when it falls below X%?
    - soperj 4y ago
      Would be a shame to waste all the rest of the product just for numbers sake.
      - highwaylights 4y ago
        It may not need to be wasted. There’s currently a price floor on used EV’s with degraded batteries because they can be used for home energy storage after their useful road life. There could be a solid secondary market 20 years from now for panels that have dropped to say 20% efficiency where the surface area to yield ratio isn’t a factor (rural areas I would guess).
        lightedman 4y ago
        "There could be a solid secondary market 20 years from now for panels that have dropped to say 20% efficiency" Current drop down to 70% output is roughly 30 years. These panels won't go anywhere for a long time.
conradev 4y ago
What is cool is that there are also lots of niche markets between now and that future that can use cheaper, shorter-lived, high efficiency panels. High altitude drones or EVs are much easier to service than satellites: https://spectrum.ieee.org/new-type-of-unmanned-aircraft-aims-to-compete-commercially-with-satellites-and-drones https://spectrum.ieee.org/new-type-of-unmanned-aircraft-aims...
- hnuser123456 4y ago
  There are hobbyists making solar-powered remote-control planes that are just barely able to charge as much as they draw at noon on a sunny summer day.[1] Even a minor boost to efficiency could push this concept from "doable in ideal scenarios as a tech demo" to "useful in the real world as a way to multiply the range of electric fixed-wing aircraft" [1] https://www.youtube.com/watch?v=xS2iCj-HSqY https://www.youtube.com/watch?v=xS2iCj-HSqY
- Sparkyte 4y ago
  Imagine you're a truck driver and the whole top of your trailer has solar panels.
  - the_third_wave 4y ago
    Let's say that truck roof covers about 41.5m² (the area of a standard 53' x 8.5' trailer roof). Let's further assume that 41m² of that is covered with PV panels. Using current technology (~21% efficiency silicon cells) and assuming standard irradiation of 1000W/m² this roof would produce ~200W/m² for a total of ~8.2kW. Add a 40' trailer (~31.5m² roof area, ~6.2kW) for a total of ~14.4kW. Using 31.5% efficient cells would raise this to ~22.7kW. Taking the newly releases Tesla semi as an example (~1 kWh/km, ~900 kWh battery pack) this would add about 14 km of range per hour using current cell technology or about 22 km per hour using these new cells. Assuming an average road speed of 80 km/h this would extend the range of the vehicle by up to ~25% for the new cells, ~18% for current cells during daylight hours with standard irradiation and no shading.
    - 4y ago

sasacocic 4y ago

Anyone know the previous record? Curios how much of an improvement this is.

miohtama 4y ago
> More recently, in summer 2022, the Ecole Polytechnique Fédérale de Lausanne, Switzerland, first reported a certified tandem cell above the 30% barrier at 31.3%, which is a remarkable efficiency jump over the 2021 value
wnevets 4y ago
> Various teams from HZB had achieved a record value in late 2021 with an efficiency of 29.8% edit: the chart from the article is great at showing the progress https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092
barbazoo 4y ago
> Various teams from HZB had achieved a record value in late 2021 with an efficiency of 29.8% that was realized by periodic nanotextures. More recently, in summer 2022, the Ecole Polytechnique Fédérale de Lausanne, Switzerland, first reported a certified tandem cell above the 30% barrier at 31.3%, which is a remarkable efficiency jump over the 2021 value.
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mikeyouse 4y ago
NREL keeps a detailed chart by technology - it's already updated with HZB's latest which is pretty impressive - the Perovskite / Si Tandem line: https://www.nrel.gov/pv/assets/pdfs/best-research-cell-efficiencies.pdf https://www.nrel.gov/pv/assets/pdfs/best-research-cell-effic... (Base webpage for the chart: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html)

beaned 4y ago

More solar cell types than I realized. Why is this one getting a lot of attention now?

RhodesianHunter 4y ago
Because it's setting a record.
walrus01 4y ago
There's a vast number of esoteric PV cell types you can't actually buy at any reasonable price, or buy at all at any price, unless you're in an extremely specialized market niche. Note the PDF link above to best research cell efficiencies, which means somebody made a very small number of PV cells in a lab environment. Not something that's produced for sale to end-users in any real quantity.
Schroedingersat 4y ago
Has the potential for an upside previously unavailable at low cost. By stacking layers of different solar cells you can surpass the theoretical limit of a single layer which is 32% (or around 28% in practical terms including spaces that aren't solar cell). Single layer silicon is in the 22-25% range now with the 22% modules being the optimal cost in most areas. The modules also only make up a small fraction of the cost of a PV install (around 25-30%), so increasing efficiency from 22% to 32% reduces BOS costs by almost as much as the entire module currently costs Perovskites are also dirt cheap, so are a good candidate for increasing efficiencies. The difficulty is in making them last. Accelerated aging tests are promising but they haven't hit market yet.
- tuatoru 4y ago
  For those not familiar with the jargon:- BOS: balance of system, i. e., everything else besides the panels (mountings, wiring and connectors, labor and land costs being the main parts of BOS affected by panel efficiency.)
_fizz_buzz_ 4y ago
Because this one is very practical and has a really good chance to make it to market. One can build very esoteric structures in a lab environment - which is of course also an achievement - but they are not easily mass produced (too expensive, too unstable, too difficult to manufacture at scale, too unpredictable, etc.).

walrus01 4y ago

Extreme efficiencies in STC W per square cm (or meter) are primarily of interest to things where room to mount PV cells is extremely constrained. Such as on satellites. Look at triple junction GaAs based cells used in satellite applications for example. There are a large number of research-lab-only PV cells made in the last 10-12 years which greatly exceed 23% but are economically unfeasible or impossible to purchase for ordinary use. Some of this tech does trickle down eventually, however. Of more practical real world interest is $ per STC watt for a panel you can buy in a 20-panel pallet load from an ordinary PV wholesaler. Like a figure of $0.28 USD/W for nominally 380W rated 72-cell monocrystalline Si panels for rooftop or ground mount applications. Meaning that a pallet of 20 panels would be somewhere around $2100 to $2200 USD to purchase plus freight. In approximately the last 12 years we've seen things go from if you buy a pallet of "cheap" mass market 72-cell panels, you'd get 320W rated per panel (STC rating of about 4.44W per cell), to now being able to buy something that is 380W rated as mentioned above, approximately 5.27W per cell. All under STC measurement conditions which are only a rough approximation of real world sunlight of course. The same panels typically measure 1.99 x 0.99 meters so you can do the math on the improvement in STC W per square meter if mounting space is a limiting factor. https://footprinthero.com/standard-test-conditions https://footprinthero.com/standard-test-conditions

einpoklum 4y ago
This is also relevant to large-scale installations. For a single family home, perhaps you don't care if you use 30% of the roof area or 32.5%; but if you're building a solar farm for a whole city, then those extra 2.5% are a good number of Km^2 which you can save; or have as extra safety-margin production capacity.
- skykooler 4y ago
  It's also relevant to some edge use cases, such as solar powered aircraft or solar cars, where space for panels is extremely limited.
- sacrosancty 4y ago

einpoklum 4y ago

So, obviously, there's a difference between efficiency in lab settings and efficiency in the field for mass-produced cells. But - this is an impressive achievement for the Silicon + Perovskite technology. But I have a question to the more knowledgeable here: The chart in the story shows other technologies which achieve significantly higher efficiency figures: https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 specifically, multi-junction cells. Why are they faded-out? Are they not practicable to mass produce and deploy? Only usable in limited scenarios? ---- Partial self-answer: According to Wikipedia, https://en.wikipedia.org/wiki/Multi-junction_solar_cell https://en.wikipedia.org/wiki/Multi-junction_solar_cell > As of 2014 multi-junction cells were expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters.

walrus01 4y ago
triple-junction GaAs cells are not something you can or want to buy unless you're building a spacecraft - they're EXTREMELY expensive. https://www.google.com/search?client=firefox-b-d&q=boeing+spectrolab https://www.google.com/search?client=firefox-b-d&q=boeing+sp...
tuatoru 4y ago
The chart is produced by NREL, and comes in static and interactive versions: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html The fading is to de-emphasize cells of different technologies.

hubraumhugo 4y ago

Which solar company has the biggest technological advantage and is best positioned for another solar boom? In which one would you invest?

seydor 4y ago
They are so cheap that i think it is unlikely that a minor edge matters
- snewman 4y ago
  They are not cheap after you factor in costs for installation, the framework, land, etc. Increased efficiency means you also need less of all those.
  - soperj 4y ago
    there's a company now that's laying them flat reducing the cost significantly.
    - thombat 4y ago
      Removes the cost of the frame, reduces efficiency. Presumably whether it's a net gain depends upon the site, eg terrain shape, latitude, need for passive cooling, wind-blown dirt, local fauna, etc.
    - aitchnyu 4y ago
      Can we make pedestrian paths using solar panels yet?
tick_tock_tick 4y ago
None; they are all hitting up against the same limits with the current technology someone would need to figure out something completely new to trigger another solar boom.
- 4y ago

martinpw 4y ago

I'm curious how this process works. Is it that the researchers are experimenting with different ingredients and seeing what works best? Or do they have a clear idea what sort of structure they want to build and the research complexity is in how to get the various ingredients to assemble into the required structure? Basically wondering how the researchers go about planning a research program and how clear the goals and timelines are.

cycomanic 4y ago
I'm not working in solar cells but do research in optics and have a general understanding of this (also from discussions with people who understand this better). The main limiter for solar cells from silicon is the overlap of the bandgap with the spectrum of the sunlight and also the loss in efficiency when cells get hot. So what people do is they use multiple materials (often in different layers) that cover different parts of the spectrum to absorp most of the sunlight. Researchers tend to have a good idea which these are (although there is research in creating new organic ones), but the challenge is to combine this in fabrication with the silicon and in a cheap easy to fabricate way and with materials that don't degrade over time. So short answer researchers have a general idea what needs to be done, but as usual the devil is in the details. Again not an expert in the exact area, so anyone who is please correct if something isn't right.
tuatoru 4y ago
Also not an expert, but from my reading it's all engineering. The physics is sufficiently well understood and variations can be simulated. It's about preventing reflections at various surface boundaries (or more generally, controlling reflections everywhere) and structuring things so that different wavelengths go to the right layers, and preventing recombination, and a zillion other details. Material quality and process control to get the right surface properties are very important. The cells that make it out of the lab are those where the cells are robust and processes can be adapted and scaled to mamufacturing quantities, competitively with current products.

0cf8612b2e1e 4y ago

What is the highest efficiency cell used in production plants today? Is that different than used by homeowners? Edit: I mean widespread usage. One lone 10kw plant using 30% panels was not my intention.

Schroedingersat 4y ago
I believe around 22% is standard for PERC which is dominant. TOPCON and HJT are a smidge over 25% but are a bit more expensive for now and use more silicon and silver. Single junction caps out around 28% at the module level so surpassing this at scale requires commercialising a new technology like these perovskite tandem cells. The other benefit is it reduces consumption of the main limiting critical mineral of silver down to insignificant levels by increasing the voltage on the metal layer.

tinglymintyfrsh 4y ago

Where does this fit in the chart and with what symbol(s)? https://en.wikipedia.org/wiki/Solar-cell_efficiency https://en.wikipedia.org/wiki/Solar-cell_efficiency (The top is 47.1%)

pavon 4y ago
The article itself has a more up-to-date version of that chart with this (and other) developments. https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092 https://www.helmholtz-berlin.de/pubbin/news_datei?did=15092
- tuatoru 4y ago
  That chart is one of the variants of a chart published and maintained by NREL, the US National Renewable Energy Laboratory: https://www.nrel.gov/pv/cell-efficiency.html https://www.nrel.gov/pv/cell-efficiency.html Interactive version: https://www.nrel.gov/pv/interactive-cell-efficiency.html https://www.nrel.gov/pv/interactive-cell-efficiency.html NREL's website has a lot of good stuff if you're interested in renewable energy.

yieldcrv 4y ago

Does this cross any thresholds of utility? Not sure what benchmark to be excited about here aside from progress for the sake of progress

rsynnott 4y ago
That's... generally how progress works, though.
- yieldcrv 4y ago
  in other forms of progress the goal post is pretty clear, I believe it is clear here but need it explained to me, let me know if you can help. what is the metric, how close are we to it.
  - rsynnott 4y ago
    I mean, I don't think there is one. There's no magic number that's the goal (or well, I suppose in the broadest possible view there's the theoretical maximum efficiency, but that's a long, long way off). In general, better efficiency is better than worse efficiency. > in other forms of progress the goal post is pretty clear I'm not sure that's true. Incremental progress is fairly common. A 7nm feature size microchip is generally better than a 10nm one (from the same manufacturer, at least; annoyingly, people are increasingly fudging the numbers there), which in turn was better than a 13nm one and so on, as an example.

sfifs 4y ago

Very interestingly, this seems similar to the strategy used by plants to absorb energy from sunlight in the red and blue parts of the spectrum with pervoskite absorbing the blue and silicon the green. However there is no indication this is intentional bio mimicry. Do we not have materials which can absorb the middle green part of the spectrum?

tuatoru 4y ago
It's not really very interesting. Those parts of the spectrum are where the energy is concentrated. There's quite a bit in infrared, but it's spread out over a wide range of wavelengths, so difficult to use (except as heat).
- mcbits 4y ago
  Assuming this[0] is accurate, it looks like solar irradiance reaching the surface is pretty flat from mid-blue up to red, including green. I would guess either there are other evolutionary reasons for reflecting green, or no reason at all and chlorophyll happened to be the first/easiest substance to evolve for photosynthesis. [0] https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spe...
  - adrian_b 4y ago
    The most successful aquatic phototrophs, e.g. brown algae and diatoms, absorb a much larger fraction of the solar light, by having complementary pigments that transfer the energy to chlorophyll. On the other hand, the terrestrial space is dominated by the green plants because here the problem is not absorbing more of the abundant light, but avoiding overheating from absorbing too much light (because the efficiency of photosynthesis is low, so most of the absorbed energy becomes heat, and not only there is much more light in air, but also the cooling is more difficult than in water).

transfire 4y ago

When will we have cheap 30%+ efficiency that will last 30+ years? That seems to me the tipping point when Solar can become ubiquitous.

stephen_g 4y ago
Solar is pretty ubiquitous already in a lot of places… Around here (Australia), more than 1/3rd of homes have solar and plenty of commercial premises. The efficiency doesn’t matter much, it’s just the cost. Most people don’t pack as much solar on their roof as they can possibly fit on anyway, so higher efficiency would just mean less of the roof is taken up.
Casteil 4y ago
There's always someone pushing for more lol The problem right now isn't so much panel efficiency as the lump cost of doing a project like this and the affordability / justifiability of that.. Especially when solar companies take advantage of people receiving tax credits & gouge on labor pricing.

moloch-hai 4y ago

What are those greyed-out traces in the graph that approach 50%?

lightedman 4y ago
Different Solar techs. Highest one being concentrated 4+ junction cells.

m0rissette 4y ago

Wouldn’t 99% be good? Why are we celebrating shitty efficiency?

detaro 4y ago
200% would be even better!
thombat 4y ago
So a panel that looks like Vanta Black, but also at non-optical wavelengths? Better efficiency is being pursued but the engineering behind real products will always be the result of balancing design constraints: https://en.m.wikipedia.org/wiki/Solar-cell_efficiency https://en.m.wikipedia.org/wiki/Solar-cell_efficiency
azalemeth 4y ago
There are a bunch of physical reasons why you can't have a ~100% efficient solar cell – obviously thermodynamics chief among them, but also effects like the fact that the bandgap is finite (yet the sun's black-body spectrum has energy radiated below it) and the fact that solar cells themselves will heat up and re-radiate photons they absorb. For a long time, solar cell efficiency was around ~10-20%. There's actually a theoretical upper limit, the Shockley–Queisser limit, of a bit less than 34% for a single p-n junction photocell. [1] This is a tandem cell – for which higher efficiencies are possible but costs go up. The thermodynamic limit is reached if you have an infinite number of layers. Obligatory plot of progress vs time: https://upload.wikimedia.org/wikipedia/commons/2/25/Best-research-cell-efficiencies-rev220126_pages-to-jpg-0001.jpg https://upload.wikimedia.org/wikipedia/commons/2/25/Best-res... [1] https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limi...
_ph_ 4y ago
Shitty efficiencies[1] haven't stopped us from using combustion engines in cars for a century. But while combustion engines use expensive fuel, these solar cells use sunlight, which is free. So which technology should we celebrate? [1]: 20% is already quite a good efficiency for a car in mixed traffic. That doesn't even account for all the energy used to provide the fuel.

NextHendrix 4y ago

These perovskites are notoriously difficult to deposit at scale in a uniform enough layer to be effective, with small variances causing dramatic drops in efficiency. On the cool side, it's theoretically possible to make them translucent (without the silicon substrate ofc) which could make for cool power generating windows in the future. On the not so cool side you really don't want the materials anywhere near you or your water table in the event of a panel being damaged. Lead halide perovskites, methylammonium lead iodide, are insanely toxic and a race to the bottom on price if they become widespread could be an environmental disaster waiting to happen. Not to take from the achievements described here, but there isn't any mention of it. There is some hope in taking the lead out (tin based perovskites) but that tends to result in a drop in efficiency.

joshspankit 4y ago

Can someone please make a website (a wiki?): canibuyoneforunderfiftyusd.com Personally I’d buy most of the products I upvote on HN, but it’s a gamble whether they even have a retail product at all.

fred_is_fred 4y ago
You want to buy one solar cell for under $50? What would you do with it.
- joshspankit 4y ago
  Tinker. Probably build a small solar-powered light, or see how much usage I could get out of a solar-powered microcontroller, or even just see how small of a thing I could make that still collects power. The technological advances we (society) make are endlessly fascinating to me. I just want to have more of them in my hands.