Panel with photovoltaic material layered on silicon hits 33% efficiencies
arstechnica.com
arstechnica.com
The dirt has necessary trace elements, but the carbon? That's all from CO2.
You can't have DNA without phosphorus, for example, and many plants can't make nitrogen from air. Don't get me started on magnesium (needed for chlorophyll)
element %, dry wt.
oxygen 45
carbon 44
hydrogen 6.3
nitrogen 1.3
silicon 1.2
potassium 0.9
calcium 0.25
phosphorus 0.16
magnesium 0.16
sulfur 0.15
chlorine 0.15
aluminum 0.11
sodium 0.03
iron 0.009
manganese 0.006
zinc 0.003
boron 0.001
copper 0.0005
molybdenum 0.0001
> Be aware that elemental concentrations in plant tissue can vary widely for a given crop depending on the stage of growth and environmental conditions and for different crops, yet plants can still appear normal and healthy. For some elements the range of sufficiency is wide and for others the range is narrow. A good deal of caution needs to be exercised in diagnosing mineral deficiencies based only on plant tissue analysis.
Appreciate the cite though.
That's important for farming, not that important when discussing the makeup of plants overall.
Useful sampling for crops is usually done post harvest, since that's the output and what we actually care about. Even after harvest, crops will change depending on the conditions endured during processing and shipment.
https://e360.yale.edu/features/indigenous-maize-who-owns-the...
It is wild that this is a thing.
We stopped doing this and moved to artificial fertilizers in the 20th century because it vastly improved crop yields, and is cheaper.
This species of corn has weird roots halfway up which drip goop down on the ground. The goop contains nitrogen fixing bacteria from the soil which pull nitrogen out of the air to fertilize the soil.
It is massively different from what you say. It would vastly reduce farm runoff while increasing yields. All facts contained within the article.
Also it is corn, and not beans...? Beans is used in crop rotation in service of corn harvests. What if all of a sudden you don't have to rotate crops?
This is a big deal. Don't pooh-pooh it.
I'm pooh-pooh'ing the idea because this isn't any more practical than rotating beans to restore a field was. These microbes don't fix nitrogen anywhere fast enough to supply acceptable yields. You end up with fields giving out 3-4x less end product with this strategy vs. using artificial fertilizer. You're not going to feed the worlds population with replenishing crops.
Being a plant is, locally, a winner-takes-all market.
So there is a very strong incentive for carbon-efficiency.
I suspect this is soon to change.... With CO2 levels around 280 ppm, the biggest challenge for many plants is finding a carbon atom - in fact, many plants grow just as fast under just 10% brightness sunlight.
Now that CO2 is up at 420 ppm, it's far easier to find carbon, so now the evolutionary race will be on to collect more sunlight and grow faster. And plants have done this before, ~20 million years ago, so somewhere there are probably some recessive genes just waiting for their moment to shine again, and natural selection will make them spread like wildfire.
It is though. Or if you like, it's transforming carbon from "in the ground" to "not in the ground", which is fundamentally the only thing that matters, since you're adding to a closed system.
The point I was making is that cash crop farming is not a self-contained system even if the earth as a whole mostly is. (Much) more carbon goes into its production than comes out in the crop. Most of that takes the form of operating machinery, but there's also the production of fertilizers, and also the incremental loss of carbon in topsoil through tillage and erosion.
I am singling out maize (and, well, soy) because the scale of it is absolutely crazy; also on the whole most of the product isn't for direct human consumption (animal feed and ethanol). (Also BTW I work on software for running machinery which operates in those fields.)
Anyways, this is intrinsic to farming, which is an extractive process. The question is how to more smartly manage it in the long run.
- 40% goes to ethanol production
- 40% goes to livestock feed
- rest is human consumption and misc industrial uses
Source: https://www.ers.usda.gov/topics/crops/corn-and-other-feed-gr...
> Do you have a source on that?
It's not solar radiation forcing that has made things relatively cooler, but it is cooler than 20M years ago. Of course, we could actually reach those temperatures again soon.
https://environmental-geology-dev.pressbooks.tru.ca/chapter/...
See fig 3.1.2.
"The present rate of solar warming is about 8% every billion years. That’s 0.008% every million years or 0.0000008% every century."
For example, wood is a great food resource for fungi, but it took millions of years for wood-eating fungi to evolve after wood.
Trees and stuff will be far slower, yes.
When there's a big shock, specialists have a harder time, and generalist species have an edge. So, when an ecosystem is destabilized or totally transformed, generalists tend to take over. The thing about generalists is that they adapt to new environments quickly. Once they live stably in a new environment long enough, they begin to adapt to it more stably, and specialize, leading to new speciation.
Songbirds are a great example of this; they exploded out of Australia some 40 million years ago, spread everywhere, and then specialized like crazy into their new environments. They likely out-competed a lot of pre-existing local species as they spread out. Humans are also a great example - we spread everywhere as successful generalists, and started the process of biologically specializing in our new environments without fully speciating. In the case of humans, we know pretty precisely about the wave of megafauna extinctions that accompanied our spread.
https://blogs.scientificamerican.com/history-of-geology/http...
https://en.wikipedia.org/wiki/Holocene_extinction#Historic_e...
Wild mammal biomass is estimated to be about 83% lower due to humans. Reduction in biomass isn't exactly synonymous with extinction, but they aren't totally unrelated either.
https://www.theguardian.com/environment/2018/may/21/human-ra...
Most trees probably grew in swampy areas and the water they fell into would have been lower in oxygen. The material would have built up in the water and mud.
Atmospheric CO2 levels in the pre-tree era 400 Myears ago was something like above 6000ppm, compared to 280ppm in the pre-industrial era. Even burning coal formed during this time like mad, 90% of the atmospheric CO2 is still just gone.
ie. Your data and the prior comment aren't necc. in conflict.
[1] https://www.nature.com/articles/nclimate3004
We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAI (browning).
About 85 percent of Earth’s ice-free lands is covered by vegetation. The area covered by all the green leaves on Earth is equal to, on average, 32 percent of Earth’s total surface area - oceans, lands and permanent ice sheets combined.
https://bmcplantbiol.biomedcentral.com/articles/10.1186/s128...
https://extension.okstate.edu/fact-sheets/greenhouse-carbon-...
This isn't new knowledge. We've known this for over 100 years.
"An increase in ambient CO2 to 800-1000 ppm can increase yield of C3 plants up to 40 to 100 percent and C4 plants by 10 to 25 percent while keeping other inputs at an optimum level."
In our current breadbaskets plants are going to be losing a chunk of the day in the middle of the growing season when it is too hot to photosynthesize on a regular basis, and the tradeoffs of what land is desertified and what land is defrosted is unlikely to be a net gain. The gains from increased CO2 are starting from in a hole and I'm not expecting to break even, let alone see faster or greater biomass on average, let alone at the rate we see in experiments using our current climate and future CO2 levels.
Yellow corn literally does not come to full harvest if there are too many cloudy days. This happens once a decade maybe. It needs a growing season longer, and with more light than we have here.
Just 300km further south, in Ontario, this is not a problem.
(Bear in mind that the days shorten fast as fall approaches here)
Bi-colour corn can get two crops.
My point is, we already... without genetic engineering, just by selective breeding, get wild variations in growth rate, and yields, and harvest times... with just a decade or two of selective breeding work!
And my second point is, the most fertile land is going to become usable, if temps continue to rise. All that bog in Northern Canada.
We just need crops suited to shorter growing seasons, and very long days at equinox.
Canada is already mostly farmland. It will be interesting to see where this goes.
Also, while I did bring up agriculture and it's fair to point out that it's going to get better over the next thousand years, agriculture is only about 2% of the Earth's plant biomass. While the rest of the biomass will be affected by the heat and benefit from the CO2, unless we start engineering the phytoplankton and the forests and all the other plants around us, it's not going to benefit from it.
Re: Canada's gain, there is a lot of land between 50 and 70 degrees north. The questions are (a) how much land in the north are we trading for how much land in the south? and (b) how does the productivity of the northern land compare to the productivity lost in the southern land?
But not to tailor crops, for areas that are currently permafrost.
There are billions of acres of permafrost bogs/peat in Northern Canada. They are even a concern, for as they thaw, they offgas.
Think of these areas as you would think of coal, in terms of CO2 being released.
But! That peat and bog is immensely fertile. If, outside of the growing season length issues, warmer temperatures come, then that is very, very rich, fertile farmland.
But we need specially tailored crops, which would never be created otherwise.
I know these models are not that mich related, but when we can't look at the wheather of tomorrow, I question the precision of a model looking 1000 years into the future a bit. It will get warmer, for sure. But _how much_ is IMHO subject to interpretation.
You say you know these models aren't that much related, but you still question the precision based on weather models. So do you, or do you not think they are much related?
If you throw a marble into a pit I can't easily predict which path it will take, but I can tell you where it will end up with which likelihood.
That ... Is pseudoscience. And elsewhere is the big greening earth lie big oil was peddling circa year 2000.
The level of idiocy and denialism is incredibly depressing
https://www.npr.org/templates/story/story.php?storyId=542535...
Remember that photosynthesis is a two stroke process. Fixing carbon tends to happen at night, so both sides are subject to optimization, and the day side has way more variation (seasonal etc) so you can't just say "RuBisCo sucks so PSI/II must be very suboptimal".
OTOH, plants (i.e. trees) can live for hundreds of years, they are self-replicating, they extract their own minerals from the ground, require very little energy input to put in place, play an crucial role in the water cycle [1], reduce the albedo effect [2], cool the air [3], provide a habitat for a multitude of species, and bring joy to our hearts.
Oh, I almost forgot, they also fix carbon! And they do all this for free, the only thing you have to do is, you know, not cut them down.
I would say that's a pretty good deal.
[1] https://sustainablefootprint.org/nederlands-trees-and-the-wa... [2] https://en.wikipedia.org/wiki/Albedo#Trees [3] https://www.epa.gov/heatislands/using-trees-and-vegetation-r...
https://www.nrel.gov/docs/fy22osti/81172.pdf#page=5
Some types of panels have increased capacity after being in the field for years. Degradation is not a significant economic concern at this stage of the process.
This translates to about
* 0.999^25 = 97.5% to 0.989^25 = 75.8% output after 25 years.
* 0.999^50 = 95% to 0.989^50 = 57.5% output after 50 years.
Many regions of the world are getting dryer. You might just be seeing a global warming side effect as there is less cloud cover.
* The actual silicon is degrading
* The cover glass is getting dirty/frosted/delaminating/optical adhesive is no longer clear
* Electrical failure of a whole cell - for example it is cracked, yet the panel still appears to work due to the bypass diodes removing a whole cell from the circuit.
Sure - from the users point of view it doesn't matter, but from an engineering point of view, the cause of failure gives some clues how to prevent it.
> For normal incidence, approximately 4 % of the light is reflected; this value is determined by the refractive index of the glass. For most glasses with a refractive index of 1.5, reflection losses at the surface result in an approximate 4% decrease in light intensity.
But I would bet it is cheaper to buy insurance for such infrequent events.
Long story short: scientific researchers, especially those in well funded laboratories are incentivized by the wrong metrics (in all fields, not unique to solar) and in this field the only metric that matters is efficiency. It doesn't matter if your cell decays by 50% in a day, it reached some great potential in a new way, here's the way for a high impact publication.
Want to work on the other problem though? Lifetime, resiliency? Cheap and affordable and non-toxic materials?
Good luck getting proper funding and exposure. Why? Because scientific papers are a closed mafia, where a set of the most influential scientists (doesn't matter how many scientists the planet has, the moment you start entering a niche the number of people is very low) in their field review the submitted papers. Don't have high efficiency or you're not breaking science? Forget a high-impact journal. You're back at B-tier, C-tier papers, but those won't get you funding and status. Not great for your career.
So what do you do? You play fool and focus your efforts and many many millions of euros to get the next perovskite cell that can reach high 20%s with some twist at least or go for the 30%+ ones.
Just to express how sad and toxic the world of scientific research is (not even mentioning the insane amount of fake data that gets published every day, the politics, etc): instead of being a researcher I now prefer being a web developer writing forms list and tables.
As a society we have decided that (e.g.) physics should/shall solve our problems with better technology. But that is not what pure academic science is about, or what pure academic scientists care about.
You want to iteratively improve technologies? Give more funding to proper engineers, not physicists/chemists, even if they're sometimes in the 'school of electrical engineering'.
If you've been in this field, I'll gladly listen to your experience.
FWIW you've helped me understand some of why we keep seeing these efficiency publications that never make it to production. What is impressive is the degree to which cost has reduced as a result of economies of scale and I wonder what the bottom is there. Compared to the price of solar panels even 16 years ago (when I did my previous large installation) it is amazing to be able to get panels at todays' prices for what I perceive to be much better quality panels.
But inverter quality seems to have gone down compared to what I was buying back then, though they too are cheaper.
Scientists tend to be interested in 'neat cool solutions' or 'neat cool problems' and there should be separate funding for 'important problems with boring solutions' that sits separately to current science funding. I agree leave the small-scale iteration to industry.
Materials science departments are often called "Materials Science and Engineering". How do they fall in your categorization?
Without disrespect intended, your words sound like those of someone who has never spent any time in graduate school in a engineering program in physical disciplines. The lines can be blurry.
My comment was worded strongly, I meant more that funding could come from different streams fo4 different purposes.
Since there's also a much bigger solar industry today than in 2007, you also see more practically-minded research coming out of corporate centers (Longi, Oxford PV, GCL System Integration, and others working on perovskite cells and perovskite-silicon tandems). Since they care about shipping real products, they are focused on solving lifetime and durability issues. Of course since this research can give a big commercial edge as single junction silicon reaches its efficiency limits, you'll also only see the really promising work published after it is patented.
It makes sense that researchers should be considering metrics other than efficiency as well for new materials or architectures, and there's no reason why this is a uniquely industrial pursuit.
Grandparent's comment resonates - efficiency claims seem to be the only ones generating press releases.
One thing I've found frustrating is that solar installers don't seem to understand, or want to share, the fundamentals. They do it one way, the cookie cutter way.
For example, most sites are space-constrained and that leads to concern about efficiency. I'm less space constrained, but that doesn't seem to change their ideas.
Most people have fixed-pitch roofs, so angles are what they are. Being flat, I choose the angle, and direction. There's very little data though on the best angles or the best direction. Are adjustable angles useful? Should I bias the direction to the west to compensate for morning/afternoon consumption patterns? All i get are blank stares.
On the up side, being forced to figure it out is interesting. And over the next few years I can generate actual data, testing various approaches, to see what actually is the most useful approach.
Sure, panel efficiency gets all the glory, but there's a lot more involved once you start building a system, and I think more practical research could be done there.
[1] one interesting point is the cost of the frame versus the cost of the panel. If I just "lie the panels flat" the frame price is negligible. Sure the panels are less productive, but Does spending the frame money on more panels offset that? Is overall production (not effeciency) better or worse? Factoring in summer as well as winter production.
[2] my city allows me to feed power into the grid, giving me about 40% credit. They are effectively a very large, 40% efficient battery, with no capital cost or maintainence cost. Plus they are long term, I can "charge" the battery in summer, use it in winter. I've yet to find an installer though that understands why this is good - they all balk when I say 40%.
When you look at it from a financial perspective in a net metering setup it is a bit less efficient, but when you look at it as if netmetering no longer exists (which I expect will happen here soon) then it suddenly comes out way ahead. It also has the added advantage that it avoids generating a lot of power when the power price is potentially negative.
My daily surplus in summer months is 80 KWh give or take, but during the winter, even with all this generating capacity I'm still running short. But proper insulation helped to cut down the gas consumption considerably and now energy costs for the whole house (about 2000 sq ft, freestanding) is < 300 euros / month including last winter's gas prices. Next winter should be better still (because I now have 18 more panels).
Total installed capacity is 16 x 265 (older panels) and 34 x 370 (newer, glass-glass panels). Inverter capacity is 4 KW on the high roof and 17 KW on the low one, with about 12 KW of output during the peaks in the summer.
Best day of the year so far made 99.8 KWh, worst days can be a few KWh so then you really need the grid. Average power draw of this house when we're careful is ~300 Watt, but cooking is a pretty big (and usually short) exception to that as is running the water cooker (but that's only a minute or two and during the day doesn't begin to approach the amount of power generated).
One downside of having panels flatter is that they foul up, some 3d printed clips helped with that but it isn't perfect.
I've heard of the flat-flat problem of pooling water, so I'd likely be at least 10 degress of angle.
20x480 is a pretty good system to start with! And yes, insight comes with time, I'm lucky in that I already did a ton of this stuff while in Canada 20 years ago so now I can re-use that knowledge. One of the better things I did here is to create a covered space next to my garage that uses the panels as roofing. Two birds with one stone: very nice covered space and glass-glass panels allow some light to shine through and it helps keep the panels cool because there is plenty of airflow underneath them. Mounting them flush with some polymax in between to make it all watertight was a bit of a job though.
Some research suggests you should replace all solar panels every 17 years because the tech will have advanced enough to make it worthwile.
So a smidge below 450W at 33%
https://acee.princeton.edu/wp-content/uploads/2017/09/SolarD...
The intensity of the Sun’s energy is about 30 percent greater at the top of the atmosphere, but various gases and aerosols reduce the intensity by absorbing sunlight as it travels through the atmosphere toward the Earth’s surface. Where the Earth’s surface is flat on a clear day at sea level, with the Sun directly overhead, the average intensity of direct sunlight is about 1,000 watts per square meter.
Satellites have modestly better solar resources to work with since there is no atmospheric attenuation.
The average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter.
You get about 1,000 W per square meter at sea level https://www.solar-electric.com/learning-center/solar-insolat...
The mean global average is between 164 watts to 340 watts per square meter over a 24-hour day, for example.
In many other climates, 1000 is honestly a generous estimate. (Presumably they're aware and that's why they hedged by specifying peak power).
Other patterns (wind, hydro, geothermal etc) feel clumsy, high maintainance and localized. Tapping secondary feeds rather than the universal primary feed.
For sure, solar panel efficiency, total environmental impact, economic costs of manufacturing and recycling, storage etc are all relevant dimensions. They see much attention and, inevitably, innovation.
In the scheme of things the fossil fuel binge will be but a blip, succeeded by a long period where humanityp enters its solar powered phase.
The "blip" refers to the fossil fuel induced climate change. Reaching sustainable equilibrium with other parts of the biosphere is still an open issue.
I bought $UAN at $7-$9 and I'll continue buying between $75-$85. It's sort of a long call on natural gas - and for me a long call on ESG ridiculousness proliferating quickly.
The nat gas bull run will rise again with the wide scale institutionally backed ESG funds that get pointed toward solar deployments.
I don’t understand the chemistry you state. My understanding is silicon tetrachloride is an intermediate for producing polysilicon, and is used multiple places in the process in a recycling through the hydrogenation reactor. It’s not a by product. Do you mean to produce polysilicon you need 4x the silicon tetrachloride? That’s approximately true. But chlorinated ferrosilicon is typically the route for production and this can be achieved without natural gas, if that was where you got your nat gas assertion.
Read the uses section.
It doesn’t make sense that silicon tetrachloride is a byproduct of purifying silicon. Why would you leave the silicon atom attached to the chlorine if the silicon atom is what you are after. The ratio makes sense - there’s one silicon atom and four chlorine atoms, but the statement that it’s a waste product is strange to me as it’s not. It is a intermediate and you do have to house it, and you can leak it and that’s not great (but as they state in the article you linked it’s not stable around water so I wouldn’t lose a huge amount of sleep over it’s pollution.
Natural gas is a transition fuel, not the end game.
>I’m of the mindset that you should be weary of and ignore the comments of software developers, physicists, and electrical engineers’ viewpoints on the hard sciences unless the prove otherwise as it relates to energy.
Ah yes, physicists viewpoints on the hard sciences are particularly untrustworthy.
And here is the claim mentioned above:
>For every 1 pound of polysilicon you make, you make 4 pounds of the nasty stuff-silicon tetrachloride.
>Okay, so some green hippie nutbags will tell you that you can just recycle this silicon tetrachloride stuff into new polysilicon because it requires less energy, but that’s bullshit because it costs a lot to do so.
Wow! Very convincing arguments!
Ok now a random google search:
https://www.globenewswire.com/news-release/2021/03/05/218770...
>Silicon tetrachloride is the colorless inorganic fuming liquid and is used to produce high purity silicon. It can be produced by using several methods and compounds including chlorine, metal silicon, and coke among others. Moreover, it can be also produced as a byproduct after treating metallurgical grade silicon to form polysilicon. For each ton of polysilicon, 3-4 tons of silicon tetrachloride is generated. Polysilicon manufacturer’s further process the waste silicon tetrachloride generated and reuses it after processing. This saves the energy cost and raw material cost however, required an expensive set of machinery to process waste silicon tetrachloride.
Wait a minute. So there is one process where it is an undesired byproduct and another process where it is actually the primary input?
>Hence polysilicon manufacturers prefer silicon tetrachloride instead of raw silica to save on cost, energy, and time. Moreover, the government from various countries has enforced laws to prevent unauthorized dump of toxic silicon tetrachloride. For instance, in China, 98.5% silicon tetrachloride produced as a byproduct is required to be recycled which compels manufacturers to adopt silicon tetrachloride as a raw material for polysilicon production.
Turns out China is a green hippie nutbag country.