[HN Gopher] Tandem solar cell achieves 32.5 percent efficiency
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Tandem solar cell achieves 32.5 percent efficiency
Author : quakeguy
Score : 123 points
Date : 2022-12-19 18:51 UTC (4 hours ago)
(HTM) web link (www.helmholtz-berlin.de)
(TXT) w3m dump (www.helmholtz-berlin.de)
| philipkglass wrote:
| 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 wrote:
| 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.
| conradev wrote:
| 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-...
| jacquesm wrote:
| > 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.
| einpoklum wrote:
| 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 wrote:
| 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
| 0cf8612b2e1e wrote:
| 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 wrote:
| Would be a shame to waste all the rest of the product
| just for numbers sake.
| conradev wrote:
| 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...
| hubraumhugo wrote:
| Which solar company has the biggest technological advantage and
| is best positioned for another solar boom? In which one would you
| invest?
| seydor wrote:
| They are so cheap that i think it is unlikely that a minor edge
| matters
| snewman wrote:
| 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 wrote:
| there's a company now that's laying them flat reducing the
| cost significantly.
| tick_tock_tick wrote:
| 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.
| bryanlarsen wrote:
| Another? We're already in a solar boom -- annual deployment
| went from 135GW to 223GW from 2021 to 2022.
| quickthrower2 wrote:
| Can't wait for solar to be like paint, steel, concrete etc.
| - you just have it everywhere and don't think about it. It
| is a no brainer.
|
| Buy a shed? Comes with a panel and a battery and a socket
| inside. As standard.
| sasacocic wrote:
| Anyone know the previous record? Curios how much of an
| improvement this is.
| miohtama wrote:
| > More recently, in summer 2022, the Ecole Polytechnique
| Federale 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 wrote:
| > 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
| barbazoo wrote:
| > 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 Federale 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.
| [deleted]
| [deleted]
| mikeyouse wrote:
| 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-effic...
|
| (Base webpage for the chart: https://www.nrel.gov/pv/cell-
| efficiency.html)
| walrus01 wrote:
| 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
| jacquesm wrote:
| Keep an eye on the panel construction though, the gold standard
| is glass-glass but there are plenty of other materials used for
| the sandwich (and the sealing!) and not all of them will stand
| the test of time.
| krallja wrote:
| The cost of the panels is already such a small fraction of
| residential install cost. My panels were definitely under a
| buck a watt (maybe 15% of the total cost). The installation
| cost (i.e. paying for a team of a dozen guys to dangle in
| harnesses on my steep roof for three days) absolutely dominated
| the invoice (50-60%). The second most expensive was the
| batteries (about 20%). The remainder went into the hundreds of
| other parts (inverter, cut-off, conduit, circuit breakers,
| cables, MPPTs, brackets, safety stickers...) needed for a
| functioning & legal system. And a couple hundred bucks of fees
| to the city for permitting and inspection, and a couple hundred
| bucks for the off-shore engineers to draw the system design
| docs.
|
| I won't make a profit for decades, unless the price of grid
| power shoots up. It would make more sense in a place with
| higher power costs. But I can keep the lights on if there's a
| power outage, without the maintenance costs (and noise) of a
| hydrocarbon-fueled generator.
|
| If you're installing solar for monetary gain, don't put it on
| your roof, buy/lease cheap land and build a solar farm. My
| electricity provider even lets you buy in on syndicated solar
| farm deals, if you don't want to manage the process yourself;
| you get the generated kWh credited back on your power bill!
| slyall wrote:
| There was a story last week about commercial solar farms
| having panel flat on the ground and some people posted about
| putting home solar setups flat (or slightly elevated with a
| brick and tied down).
|
| Saving money with the setup beats getting the last percent
| out of the install. Although probably only some rural home-
| owners are going to be able/allowed to just put the panels
| flat on the ground.
|
| https://news.ycombinator.com/item?id=33926683
| einpoklum wrote:
| 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 wrote:
| It's also relevant to some edge use cases, such as solar
| powered aircraft or solar cars, where space for panels is
| extremely limited.
| tinglymintyfrsh wrote:
| Where does this fit in the chart and with what symbol(s)?
|
| https://en.wikipedia.org/wiki/Solar-cell_efficiency
|
| (The top is 47.1%)
| pavon wrote:
| 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
| einpoklum wrote:
| 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
|
| 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
|
| > 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 wrote:
| 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+sp...
| beaned wrote:
| More solar cell types than I realized. Why is this one getting a
| lot of attention now?
| RhodesianHunter wrote:
| Because it's setting a record.
| walrus01 wrote:
| 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.
| martinpw wrote:
| 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 wrote:
| 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.
| 0cf8612b2e1e wrote:
| 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.
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