Scientists Design Solar Cell That Captures Nearly All Energy of Solar Spectrum
rdmag.com
rdmag.com
(36% eff in practical application due to system losses)
What's the maximum?
What's the current standard?
Most solar panels are 15% or better. The best residential cells are 22.2%[3], the commercial cells are 25.3%. The theoretical maximum efficiency of single-layer silicon PV cells is ~32%.
[1]: https://www.nrel.gov/pv/assets/images/efficiency-chart.png
[2]: https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limi...
[3]: https://us.sunpower.com/sites/sunpower/files/media-library/d...
Edit: and they are usually triple junction.
I recall hearing the theoretical max was somewhere around 36%, though it could well be my memory is faulty. I think this was from a video from around 2005. Is this "theoretical max" going up over time or do I misremember?
I'm not sure whether these limits apply to non-planar geometries.
[0]: https://en.m.wikipedia.org/wiki/Thermodynamic_efficiency_lim...
The most expensive, high efficiency cells, like those on spacecraft, are 3 layer. They are too expensive to be practical on Earth.
http://www.spectrolab.com/solarcells.htm
http://www.azurspace.com/index.php/en/products/products-spac...
https://solaerotech.com/products/space-solar-cells-coverglas...
Multi-junction cells similar to these have so far reached efficiencies up into the mid-40% range with optically concentrated sunlight under experimental conditions, though such high efficiencies have not been reached in mass production.
Multi-junction cells represent less than 0.01% of annual PV cell production. About 95% of annual PV cell production is based on different variants of single-junction crystalline silicon, with current commercial cell efficiencies in the 16-25% range. The 30% cells for space use also sell for more than 1000x the price-per-watt of a simple 16% silicon cell.
A theoretical "infinite-junction" solar cell could achieve up to 68.7% efficiency under full-power illumination from the sun on a clear day, or up to 86.8% efficiency on a clear day under optically concentrated sunlight:
https://en.wikipedia.org/wiki/Solar_cell_efficiency#Thermody...
The theoretical limit for single-junction silicon cells is 29.4%:
http://ieeexplore.ieee.org/document/6557081/
SunPower has reached just over 25% efficiency industrially for its best cells, which are single junction silicon using advanced cell structures.
The highest conversion ever achieved experimentally for single-junction silicon is 26.6%, announced just a couple of weeks ago:
http://www.sciencedirect.com/science/article/pii/S0927024817...
The experimenters combined two leading industrial techniques for high efficiency silicon cells (interdigitated back contact structure, like SunPower uses, and heterojunction cells using amorphous silicon, like Panasonic/Tesla use) to reach the 26.6% record.
What does an increase of 10% mean? That I could get 10% more Watts from the same area of panels?
How much do we need? Would a houshold in Canada need much more panels than one in Mexico?
Is 15% or 20% already enough to power a whole 1-family-house?
Are batteries or PV panels the bigger problem here?
If you are space-constrained, like on a rooftop, 10% more power from the same area of panels could be significant. It's a step function. It goes from "not enough room for desired wattage" to "enough room for desired wattage" very abruptly. Once you've reached "enough room for desired wattage," further efficiency improvements matter much less. You don't care a lot whether you have 25% or 40% leftover roof space after installing the panels. Paying for further efficiency improvement is worthwhile only if it offsets enough costs elsewhere to lower systemic costs (from using e.g. less mounting hardware, less connecting wire, less installation labor.)
The higher the industry-average efficiency, the less of a constrained-space advantage there is for expensive, higher-efficiency modules. That is, SunPower had a more compelling advantage when they were selling expensive 19% panels and cheap Chinese panels were at 12%. But now that SunPower offers expensive 22% panels and cheap Chinese panels are at 15%, more households can now reach their desired wattage-per-roof targets without paying for premium-efficiency.
If you just want to zero out your household's annualized average electricity consumption, because e.g. you have a net-metered grid connection, adding batteries to a PV system will increase the expected financial time-to-payback. If you are off-grid you need batteries to use solar power after dark but should make every effort to cut your non-daylight power needs before sizing the battery system. Batteries are currently a lot more expensive per watt-hour delivered than the instantaneous output of solar panels. In an intermediate case, where you don't get full net metering but are still grid connected, there are a few but not many cases where household batteries yield positive financial ROI at current prices. You could make the numbers work for a modest fraction of Hawaiian households and smaller fractions of households in Germany, California, and Australia.
If your efficiency increases by 10% you get 10% more output. With a current efficiency of 10%, increasing it 10% would mean your now at 11% efficiency.
If we talk about an increase of 10 percentage points, we end up with with 20% efficiency effectively doubling the output (100% increase).
The title of the press release is "Scientists Design Solar Cell That Captures Nearly All Energy of Solar Spectrum". That title is not "Scientists develop new multijunction cell", but instead implies they've designed something novel.
First paragraph: "Scientists have designed and constructed a prototype for a new solar cell that integrates multiple cells stacked into a single device capable of capturing nearly all of the energy in the solar spectrum. The new design converts direct sunlight to electricity with 44.5 percent efficiency, giving it the potential to become the most efficient solar cell in the world."
That describes a multijunction cell, without mentioning that the idea is decades old. They describe an efficiency of 44.5%, without mentioning that other multijunction cells beat that efficiency years ago.
I think you need to reread the article. Mentioning multijunction cells in the fourth paragraph is not a sufficient description of prior art.
That being said, I'm generating my own electricity and my panels will run for a very long time. The best is cranking the AC and still watching the meter run in reverse during really scorching days.
Another benefit to think about is you've effectively locked in your electricity rate. With some companies that might not be a big thing, but here in CA PG&E has been relentless with their rising kwh costs.
We ran the numbers on our house with an energy audit and found that the return on insulation, an attic fan and window replacement was literally like 2-3x solar.
The other thing to look at is solar hot water. It's not sexy, but that has been high ROI since the 80s.
[1] https://cleantechnica.com/2015/06/08/california-rolls-out-de... [2] http://instituteforenergyresearch.org/solar-energys-duck-cur...
The high price per kWh means it is economic for these places to upgrade their panels to newer ones that get closer to their rated output (e.g. in low light conditions etc). Hence the market for used panels.
Source: looking at the explanations on used panel shop's website - I think it is reliable.
Hawaii's primary source of electricity is oil.
There's a 30% tax deduction one time for the total cost. My loan payment is less than my precious monthly power costs including taxes and fees ($15 a month to be hooked up to PG&E).
One friend had to take a hit in the selling price as a concession to buyout part of the lease.
We will end our reliance on fossil fuels not by forcing masses of people to change their lifestyles and inconveniencing them, but by developing green energy tech that is simply more efficient and cost effective than fossil fuels. Once this happens the transition away from carbon based energy sources will be swift.
Given the rate of progress, I believe we'll see widespread adoption of renewable energy far before climactic conditions on earth become dire for humanity.
2020? 2030? 2040? 2050? 2100? Plus or minus five years? Will we have a linear decline to that level? When do you think that decline will start? Is there a particular model you're thinking of?
What degree of GHG concentrations/temperature increase will be the limit of what you consider to be 'not dire for humanity'? Is it compatible with your expected model of GHG emissions?
Are the billion people living in the Indian subcontinent included in your definition of humanity, or are we talking about North Americans and Europeans? If yes, will we be willing to shelter environmental refugees from impacted areas?
I'd really love to believe that everything will turn out fine - but while I've ran into many optimists, I've yet to run into one that is willing to quantify the reasons for their optimism.
Boats and Aircraft are going to be hardest to transition and will likely make up a large chunk of that 10+%. Bio fuels may take some of this, but it really depends on overall demand for liquid hydrocarbons.
Electricity and home heating are going to change from market forces.
Cars have many options, but oil is going to get expensive (as in 2-3x current price not 10x) which will push alternatives.
Electric trains can take over most long distance trucking and shorter distance is easier to transition. This will be a fairly fast transition if oil spikes again in ~2030-2040 combined with some form of carbon tax.
PS: Plastics / fertilizer and other chemical processes are going to be the wildcard IMO. But, they don't involve burning carbon so they are also less important.
20% by 2070-2090, on the other hand, is a lost cause. That would put atmospheric at 580 PPM by 2080. That's >4C of warming, if we don't hit any positive feedback loops.
I'm not particularly concerned about plastics. They can be synthesized from biomass.
US coal use is down to where it was around 1930. Petroleum is around 1960's usage levels. https://www.eia.gov/todayinenergy/detail.php?id=26912
Natrual gas has spiked, but it's realitvly speaking less of a global warming threat due to C(x) H(x) turning into H20 (x) + C02 (x) which produces less CO2 per heating vs just C into CO2 from coal.
So, while there are a huge range of predictions. What happens in the next 20 years is more important than what's going on 40 - 60 years from now.
Note it does break down into more CO2 than the wieght of Methane because Oxygen molecules are heavy.
The real risk is if warming the arctic starts to release a lot of stored methane, which would be very bad.
The way I see it, the limit is at 1 billion people if we want to preserve current situation, and even less if we want to let the nature regenerate.
[0]http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2004_...
I didn't know that about fuel cells though, interesting.
This will add ~777 GT of CO2 to the atmosphere. Which will put us at ~500 ppm CO2 (We just passed 400 ppm). That would be warming between 2.5C and 3C.
If you want to hit a 95% reduction in GHG emissions, you're also going to have to:
* Shut down every single fossil fuel power plant over the next 25 years.
* Build enough renewable/nuclear powerplants to replace all of our fossil fuel power sources, twice over. (Assuming we switch to electrical transportation.)
And, the elephant in the room:
* Halve all current trans-continental shipping and air travel. It is currently responsible for ~6-7% of our GHG emissions. (And if it were to grow unconstrained, would likely double in volume in the next 30 years.)
* While bringing our other emissions down to nearly zero.
We can clearly do all this, but it would require significant changes in our lifestyles - something that optimists tend to not be willing to accept.
a) incredibly rapid adoption of renewables
b) a Manhattan project to find a way to pull carbon out of the atmosphere starting within ~1-3 decades, once it becomes beyond obvious we've already emitted far too much and the consequences of inaction are more than human civilization can bear
We'll never make enough food... we'll never have enough energy... we'll never get along...
Things are always bordering on the end of the world yet we survive.
Time and time again, cries of "Too many people!!!"... how will we feed 1 billion people?
Advances in farming, logistics, technology, etc...
What's being done now? More advances in farming, vertical farming, AI, etc...
Except for advances in vertical farming, green energy, advances in urban planning allowing people to live denser and more packed together...
We'll all be dead because earth can't handle the population... cira'1968:
https://www.nytimes.com/2015/06/01/us/the-unrealized-horrors...
"Dr. Ehrlich was so sure of himself that he warned in 1970 that “sometime in the next 15 years, the end will come.” By “the end,” he meant “an utter breakdown of the capacity of the planet to support humanity.”
So... by 1985, we will all be dead because DOOM!!!
Time and time again...
Now... can we all "get along"? Christians, Muslims, Chinese, Russians, etc? THAT isn't a technology problem - that's a humanity problem.
Can we feed everyone? We sure can... and advances in tech continue to push the envelope and there is no reason to believe that we can support many multiples of what we have now.
Is there an upper limit? Undoubtedly... are we near it? Hardly...
...all the ones we never heard of.
Visible light would probably be a hazard. Would be pretty great for "beam in the sky" special effects though.
https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
The European Union reports aggregates a bit differently, but agriculture is only 10% there too (see Figure 3):
http://ec.europa.eu/eurostat/statistics-explained/index.php/...
Neither the USA nor the EU are undergoing deforestation at present, and electrical heating can substitute for the vast majority of applications currently served by fossil-combustion heat. That's why most research and headlines about GHG reductions in the developed world focus on transport electrification and electricity decarbonization.
In poorer parts of the world, where automobile use is less common and/or fewer people have grid tied electrical service, deforestation and agricultural emissions make up a larger share of total anthropogenic emissions. But most of the world's anthropogenic emissions, and most of the low-hanging mitigations for emissions, come from geographic regions that commonly have grid tied electrical service and other modern amenities.
And even if we get to that point we still would not be carbon-neutral due to the remaining sectors. And possibly due to new natural sources (permafrost) we're already locked into due to the warming that is already in progress.
So the point is that just inventing our way to replace the current grid with green sources is insufficient for meeting the climate budget within a few decades.
You replied pointing out that electricity and transportation are not the only sources of emissions -- not sure if it was intended as a rebuttal because OP didn't say they were. I noted that electrical heating can generally substitute fossil heating, that the developed world isn't undergoing deforestation, and that agriculture is a much smaller source of developed-world emissions compared with fossil combustion. Neither I nor OP said or implied that "just inventing our way to replace the current grid with green sources is sufficient for meeting the climate budget."
We're obviously going to blow past the "safe" 2-degree-rise-by-end-of-century cumulative emissions target. In the long term, if complex civilizations survive, I expect large scale atmospheric carbon removal efforts (enhanced silicate weathering and similar). Otherwise feedback processes and anthropogenic emissions apart from fossil combustion are probably going to amplify ~4 degrees of end-of-century warming to more like 7-9 degrees of warming by end-of-millennium. After that it'd take ~100k years to restore the pre-industrial atmospheric CO2 concentration status quo by natural sinking mechanisms alone.
Half the roof here would provide plenty of power, the problem is that it would be expensive.
If there's someone with knowledge of the numbers, I'd be interested to be shown otherwise.
http://www.renewableenergyworld.com/articles/2013/08/calcula...
Fixed-tilt utility scale systems just recently fell to $0.99 per watt-peak in the US:
https://www.greentechmedia.com/articles/read/Sunshot-1-Per-W...
You can buy 124 acres of land in California's sunny Imperial County, near existing solar farms, for $95,000:
http://www.landwatch.com/Imperial-County-California-Land-for...
If you turned that land into a solar farm you could fit about 16 megawatts of fixed-tilt solar arrays on it. 16 MWp of installed solar equipment would cost $15.84 million at $0.99/watt and the land is $0.095 million. Land accounts for only 0.6% of the combined costs. (A 16 MWp farm is small by utility-scale project standards and probably would not cost only $0.99/watt because of dis-economies of small scale. I cited $0.99/watt to set a conservative bound on how much cost the land component represents in a utility scale solar project.)
Maybe that will change, but it doesn't need to change, because we still have plenty of places to stick solar.
I meant something more like a polymer, bought by the bucketful and mixed in as an additive.
I know some academic research labs have looked into arrays of microlenses & prisms, which sound interesting, but I haven't heard of any commercial products. Googling for micro prisms and solar cells will show you some projects.
Ultimately, I think it's just much easier to install a simple rectangular slab with two wires coming out. And the costs of solar cells are so cheap that they're probably comparable to the cost of the optics you'd want to lay above them.
I also imagine that balancing the current-voltage characteristics of the cells could be challenging when light at different times of the day has different spectra (e.g., you wouldn't want diminished performance in reddish sunsets).
Maybe it's just all those things together. But it sure seems like if we wanted to it wouldn't be that hard to ramp up production and drive costs down a couple fold. Not that I know how.
That said, if you increase production scale you can expect module costs to fall significantly. That's what Chinese manufacturers have actually done:
http://pubs.rsc.org/en/Content/ArticleLanding/2013/EE/c3ee40...
A lot of talk about solar trade has highlighted "unfair" competition from cheap, low-quality Chinese modules. But China also has companies making high-quality modules (LONGi, Jinko Solar, Yingli, and Trina Solar were identified as top performers in DNV GL's 2017 PV Module Reliability Scorecard, along with longer-established Japanese, Korean, European, and American manufacturers) and still making them cheaper than European/American/Japanese producers. The greatest difference is scale.
Recently-bankrupt American solar manufacturer Suniva is trying to get the US International Trade Commission to impose a minimum $0.78/watt price on imported solar modules:
https://www.eenews.net/stories/1060057180
https://www.pv-tech.org/news/breaking-suniva-asks-trump-for-...
Suniva made good modules. But it was manufacturing only 200 megawatts of modules per year. And its modules were not more efficient or durable than good imports. The large, high-quality South Korean manufacturer Hanwha Q CELLS is guiding 5500-5700 megawatts of shipments this year. The large, high-quality Chinese manufacturer Jinko Solar is guiding 8500-9000 megawatts this year. American solar manufacturers can't turn a profit so they don't scale up. And they don't scale up so they can't turn a profit. Jinko Solar and Hanwha can stay in the black at price levels that will bankrupt small producers lacking the same economies of scale.
It's materials processing. They're only "basically sand" in the sense that glass or microchips are. The key step is purification of silicon, which is like distillation in the liquid/solid phase. It's very energy-intensive. This then gives you a solid cylinder of pure silicon.
To make cells, you slice this like a ham. Except it's extremely hard, so you need a diamond saw: http://www.asahidia.co.jp/eng/wp-content/uploads/2015/05/B51... and, like sawing wood, the material from the cut ("kerf") is wasted.
A surprising amount of recent cost reductions have been due to making the cells thinner and making the cut as thin and clean as possible.
They are then run through some annoyingly toxic chemical processes, given an antireflective coating, have silver wiring attached, and packaged into a glass or polycarbonate fronted housing.
One would imagine most of the research dollars being into how to make multi-junction cells cheaply, rather than into other much lower efficiency cells.
So far, they don't. Plus, concentrating panels don't work under cloudy skies, so...
Is this the problem that Insolight have a potential solution for?
This doesn't make intuitive sense to me. If you could pay $50 for a bucket of goop you can slather on your roof that would capture 1% of the incident light energy hitting it forever, would everyone do so?
by your standard "hell yeah" as that means the equivalent of $2.5k per roof (I multiplied the $50 for 1% by 50 to conpare apples to apples) to capture 50% of the energy which is far better $ per KWh than offered by anyone else!
The issue is that for many people they would prefer to capture more than 1% and they are willing to pay more per kwh in exchange for getting more kilowatt hrs. So they would prefer to pay a large premium, thereby showing that it really doesn't just come down to cost per KW-hr installed.
there are other factors.
If you could pay $50 for a bucket of goop you can slather
on your roof that would capture 1% of the incident light
energy hitting it forever, would everyone do so?
by your standard "hell yeah" as that means the equivalent
of $2.5k per roof (I multiplied the $50 for 1% by 50 to
conpare apples to apples) to capture 50% of the energy
which is far better $ per KWh than offered by anyone else!
The issue is that for many people they would prefer to
capture more than 1% and they are willing to pay more
per kwh in exchange for getting more kilowatt hrs. So
they would prefer to pay a large premium, thereby
showing that it really doesn't just come down to cost
per KW-hr installed.
That's the argument from economics. The argument from product availability: regular planar unconcentrated multijunction cells for terrestrial use don't exist. You can't buy them, because there's no market for a $10,000 500 watt cell when $200 300 watt cells are sold. https://www.wholesalesolar.com/solar-panels
You can get them for space applications, presumably at incredible expense: http://www.spectrolab.com/DataSheets/Panel/panels.pdf
Concentrated multijunction panels for terrestrial use exist, but are only used in utility-scale installations, since you don't do two-axis tracking with rooftop solar. (Dual tracked solar panels cast shadows on each other, so they have to be spaced much farther apart, and consequently have bad space utilization)
The only figure of merit in a PV system is cost per kilowatt-hour installed. Right now, all rooftop solar installations are single-junction. If multijunction cells resulted in a lower cost per kilowatt-hour installed, then they would be used, but they don't, so they aren't.
Do you see why nobody who wanted any appreciable amount of solar energy would put my "$1 for a roof's worth of 0.1% efficient solar collection" on their roof? They would naturally choose the "$50 for a roof's worth of 1% efficient solar collection" goop over that one (if those two were the only two choices), even though it's 5x worse per kilowatt-hour?
I hope this explains what I'm talking about. A lot of people want more than 0.1% efficiency because they'd like to collect more energy than that...
In any system analysis, you have to consider all the relevant factors. If you wave away important factors for the sake of argument, you get the wrong answers, and end up in long arguments on internet forums, repeating yourself a lot.
Let's game out some scenarios using your numbers. The choices are between a $1 array that gives 100 watt-hours, ($0.01/Wh) or a $50 array that gives 1000 watt-hours. ($0.05/Wh)
Rooftop solar, grid power is $0.001/Wh: You don't buy either array, since neither is cheaper than grid. This is true for most of the industrialized world.
Rooftop solar, grid power is $0.025/Wh: You buy the 100 watt-hour array, since the power it produces is cheaper than grid power. You don't care about total wattage, since you can get all the watts you want from the grid. This is true of places where either electricity is expensive, or PV is subsidized. (Hawaii, Germany, etc)
Rooftop solar, grid power is $0.1/Wh: You do buy the 1000 watt-hour array, since it saves you from having to buy expensive grid watt-hours. There is no place on Earth where grid power is more expensive than both single-crystal and multijunction PV.
Rooftop solar, offgrid: Here you do strongly care about array output... but you're only offgrid in very rural locations, where land is cheap. In practice, off grid solar is never limited to just rooftops! If you need more watt-hours, you build bigger arrays, rather than paying five times as much per panel.
Space: You need every milliwatthour, and each gram of spacecraft costs hundreds of dollars anyway, so multijunction PV suddenly becomes price competitive.
You left something out of your analysis: people can have an ethical reason to assign a cost of $0.1/Wh to grid power, because they consider environmental externalities they're not paying for, to be something they actually are paying for. If forced to, they may use the grid, but they might treat its cost higher than the listed cost.
You've summarized things well in your second sentence: "In any system analysis, you have to consider all the relevant factors."
As both your and my analysis show, it is not simply the dollar per kilowatt-hour that informs purchase decisions.
If a certain cheap solar array manufacturing process was extremely toxic to the environment, the environmentalist might not buy it at any price.
it's a complicated, not simple analysis.
http://onlinelibrary.wiley.com/doi/10.1002/aenm.201700345/ab...
The cell is assembled in a mini-module with a geometric concentration ratio of 744 suns on a two-axis tracking system and demonstrated a combined module efficiency of 41.2%, measured outdoors in Durham, NC. Taking into account the measured transmission of the optics gives an implied cell efficiency of 44.5%.
Since this is a concentrating cell, compare to the concentrator cell records tracked on NREL's PV efficiency records chart:
https://www.nrel.gov/pv/assets/images/efficiency-chart.png
The current record for 4-junction-or-more concentrator cells is 46.0%. This isn't a record-setting cell even if the implied efficiency holds up under standardized test conditions.
This cell like all high-concentration cells is unlikely to see mass market acceptance on Earth. The module needs precise two-axis sun tracking to work effectively even under perfect clear-sky conditions. That's significantly more expensive than fixed arrays or single-axis sun tracking as used by conventional large scale PV. And there's a vicious feedback loop: since two-axis tracking is significantly more expensive, it doesn't get developed/scaled, so the cost gap gets even wider over time WRT its competitors.
But that's not actually the worst problem of high-concentration PV for terrestrial use. The worst problem is that HCPV can use only direct normal irradiance. Ordinary non-concentrating PV cells produce very nearly 25% of its rated output if it receives 25% of test-condition illumination under non-ideal conditions (due to some combination of clouds, air pollution haze, dusty glass, etc.) Concentrating cells will produce close to 0% of rated output under the same non-ideal conditions. Few regions have clear enough skies to work with HCPV, but those same regions tend to be dusty, which the concentrating optics cannot tolerate. Mechanical and optical complications make HCPV higher-maintenance than ordinary flat PV and more expensive to install initially.
That's why there were a dozen+ companies working on concentrating PV in 2008 and all of them are now bankrupt or have exited HCPV manufacturing. Eking out another cell-level improvement wouldn't have rescued the value proposition of their complete systems. The refined polysilicon price spike that made exotic technologies look briefly promising only lasted a few years and then it became clear again that crystalline silicon is very hard to beat.
Isn't that usually the case? :-(
https://www.seas.harvard.edu/news/2017/02/long-lasting-flow-...
When the good news is a mixed bag, like this article under discussion (high efficiency solar cell... but not a record setter and touted numbers required concentrated sunlight) then the abstract is more informative than the press release.
When the "good" news required severe compromises on one or more key axes, then both the abstract and the press release (if there is one) will usually hide the important compromises. It's fun to guess which common pitfall the reported advance fell into before you read the full paper that reveals the bad news not found in the PR/abstract.
Caveat: if the press release is about something that the general public can't contextualize easily -- metrology, basic research before applications, algorithms... -- then the press office rolls a die to randomly determine whether they should claim that the new advance may one day cure diseases, cure pollution, or make your cell phone run longer between recharges.
In other words, is a solar cell something that captures energy from photons and converts it into usable electricity? Or from some subset of photons?
I cannot wait for the era of super cheap electricity!
Also, as the article notes, they won't be available in large sheets but only small milimeter chips - which require light concentration and thus sun-tracking mechanism.
I hope an American firm implements the underlying science into a manufacturing process, and any Chinese firms that want to use the process pay a fair and equitable license for the technology.
Because Americans live in the atmosphere that Chinese CO2 emissions go to?
Not saying they should, but that would obviously be the reason?
However, Chinese solar cell firms have been dumping cheap and sub-standard solar panels on America for years in an attempt to destroy the American industry, so I am less excited about specifically Chinese solar panel firms gaining access to this technology.
I suppose it marks me as a bit of a chauvinist in this case but I would prefer if those who conduct themselves as adversaries do not also enjoy the benefits accorded a friend.
The country receiving the goods can refuse to buy if the quality is poor, or there are safety risks, or the workers are being exploited or the manufacturing process is environmentally unsustainable.
Poor countries have little freedom to turn down wealthy customers.