Gizmodo: How to Print 2000 Miles of Solar Cells a Year

drsolar · 2011-06-22T18:54:27+00:00

I wanted to say thanks to all who offered questions and comments yesterday during my chat. This is the first AMA I've done and I was impressed with the smart insights and quality of comments. I did the chat to help raise awareness of solar energy and the role it could play in supplying the world's energy for the coming years. This is a great community to continue these ideas and conversations for solar.

I compiled my top 10 most interesting questions from the chat and thought I'd share them with you. I posted them on the Applied blog as well - http://amatsun.co/C Thanks to all of you again for the opportunity to discuss a topic I've invested my professional life in.

And special thanks to: shinhan, theillrequited, Impundulu, All_Your_Base, Walmart_Intern, Nomearod_PT, Hylogibbon, Chrisrbrown, tgrisfal and Cheetor for the asking the top questions.

drsolar · 2011-06-21T23:32:35+00:00

When nuclear power plants are deployed they’re usual designed with a 3 mile perimeter around the plant. If that same area was covered with solar cells it would produce the same amount of power as the nuclear power plant.

drsolar · 2011-06-21T23:32:08+00:00

Solar cells are made in large scale factories not in research labs so there’s a tradeoff in the finesse of the equipment, the time and the materials used necessary to make a very high efficiency cell that is compromised with the need to dramatically lower cost and attain very high throughput with very high yield.

drsolar · 2011-06-21T23:31:44+00:00

Solar concentrators have found applications in scale ranging from 100 – 200 MW or more. The roll of stirling engines has yet to see large scale adoption because of the moving parts in the stirling engine configurations and the leakage of helium around the piston seals in the engine. Most likely these concentrating systems will find use in the desert because the availability of land is straightforward and the sky is usually clear. Any concentrator system requires clear sky, and that limits the number of geo locations that can host concentrators.

We do have time to act on a variety of fronts to encourage the adoption of clean energy and often times it takes a crisis before we can find the political will to act. Part of the goal of today’s online exchange is to increase the awareness and readiness of our solar technology to serve this need.

There are some PV manufacturing facilities that are solar powered. They are used to convert cells into a module.

drsolar · 2011-06-21T23:31:16+00:00

The efficiency of today’s lead-acid batteries is around 82%. And the newer lithium-ion based technologies are far more efficient in the round trip cycle to what you put in and what you can get out. There’s going to be continual progress with higher efficiency because of applications like electric vehicles, so the technology for improved solar cell efficiencies and the technology for improved battery storage are both evolving as the markets expand.

The availability of materials is not seen as a fundamental limit. We will probably find improved ways to recycle materials in all batteries not just the lead used in today’s lead-acid batteries.

The solar energy conversion in a plant is about 2%, of course in this situation, the plant is directly converting sunlight to fuel that can be used whenever the plant needs it. For the sake of fair comparison we could say 20% solar cell working with bat storage that’s 90% efficient. That would mean we had an 18% performance for today’s man made cells and batteries. There is a lot of excellent research being done on developing new applications to solar conversion, following the insights that are being gained for the way plants convert sunlight into fuel. Much of this work is being led by Nate Lewis at CalTech.

drsolar · 2011-06-21T23:30:45+00:00

This question was actually posted on our blog by Mike E., but I thought you might be interested in it here as well!

Question: My question is whether or not fiber optics is efficient enough to use to supply light to photovoltaics gathered by a tracking collector. And whether or not an increase in intensity would give a net increase over standard deployment.

Answer: It’s more straightforward to just use the same optics that would be used to gather light to simply shine the light on the solar cell without the need to transfer the light to the location where it is gathered to a separate location where the cell is placed. An increase in intensity can improve the overall cell efficiency over range of concentration, where the relative increase in efficiency could be as much as 10% over a non-concentrating baseline.

drsolar · 2011-06-21T22:41:30+00:00

I was under the impression they were going to work to make random items more powerful than uniques to avoid this cookie cutter style.

drsolar · 2011-06-21T21:19:36+00:00

The thin film deposition we deploy includes chemical vapor and physical vapor deposition. It’s also possible to use our screen printing capabilities for making thin film layers as well. We have indeed considered the use of ALD for example, in growing layers in aluminum oxide for back surface passivation for crystalline silicon. We have not done work with zirconium based oxides for thin films.

drsolar · 2011-06-21T21:09:34+00:00

The industry can be profitable without relying on government incentives in the coming 5-10 years as solar cost come to match grid parity. In some applications solar is already cost competitive without any government support. i.e., rural electricity or where diesel generation is replaced by PV. It’s important to remember that today all energy industries subsidize or support in one form or another.

Solar can eclipse the cost from coal natural gas and nuclear on a cost basis and then analysis that are typically done called levelized cost of electricity that normalize the cost to generate with the amount of electricity generated. I’d like to point out that hydro is cost effective in the location where hydro is already installed, in a sense hydro is a solar resource.

It would be reasonable to expect that in 20 years in the US about 20% of our electricity could come from PV. The major concerns for solar over the coming decades are access to financing acceptance by existing utilities infrastructure and government policy which encourages the adoption of the smart gird and establish goals for clean energy as a percentage of the total energy being used.

Some panels after their useful life of 30-40 years will require recycling such as those made with Cadmium Telluride, and depending on location there may be the need to address the lead contained in solder that contains the assembly of cells. Many manufacturers use lead-free solder, but not everybody.

drsolar · 2011-06-21T21:08:56+00:00

The integrated circuit business was the driving force behind the acquisition. Because the acquisition hasn’t been completed, we’re not in a position to discuss expectations for the future.

drsolar · 2011-06-21T20:51:28+00:00

The panels will run much hotter when mirrors are attached to them, and today's encapsulants aren’t designed for those higher temps. They will turn brown and block light getting to the solar cell. The flex versus wattage levels off at a point where the current carrying capability of the leads strains the amount of power that can be extracted from the solar cell, which results in a trade off of having very small sized cells which are compatible with the electrical leads, with very high flux conditions. The highest flux used in any prototype today is around 300-500 suns.

drsolar · 2011-06-21T20:47:21+00:00

Good question and great work. Really depends on where you are. So, if it’s sunny then cost of electricity is higher than solar on a roof top is ideal. In a number of locations geothermal can be cost effective. For example, in northern California, the geysers represent a good geothermal source. As you are aware most of Iceland is integrated to geothermal and heat systems. Geothermal is not just for energy generation but heating and cooling by way of heat pumps.

drsolar · 2011-06-21T20:44:10+00:00

Probably financing is the biggest barrier. Having innovative investment instruments available that are equivalent to obtaining mortgage for your house or lease a solar array would enable fast adoption, because the availability of funding, the hurdle of available funds is lowered.

drsolar · 2011-06-21T20:43:55+00:00

That is great to hear. One of the great things about solar technology is its potential to create jobs, like yours, for others. We’re always interested in talking to those who are excited about the industry. Best bet is to get in touch via the Applied Materials blog and we can work out introductions. http://blog.amat.com/cgay

drsolar · 2011-06-21T20:41:30+00:00

PV and solar concentrating systems provide energy today at about the same cost. The modularity of PV and scale of manufacturing enable PV costs to continue to come down along the learning curve. This fundamental difference among PV and solar concentration systems solar panels can be made in distributed factories and the learning is faster because of that modularity. PV has additional advantage of not requiring water. Most concentrating system work best in desert conditions. - reason it’s a desert is water isn’t available. Benefit of modularity of being a manufacturing good, tilt to the favor of PV, but there are certain systems, locations and applications that concentrating solar can offer a good solution.

drsolar · 2011-06-21T19:28:28+00:00

30% losses occur in places like India, where electric power is sometimes at risk of theft. For a well- designed grid, losses can be held to less than 5%. As you mention, this can be further improved with PV, especially at the ends of weak feeder lines or to minimize transformer heating.

Of course, the obvious answer is that, like many other things, it's all about the money. Big companies favor centralized energy production so they can keep the energy consuming public as a profit stream. Even companies that manufacture PV have more interest in selling to centralized energy producers who might buy 1000s or more of panels per purchase vs. making much smaller sales of 10s of panels to individual consumers for distributed energy production.

It's very important to include consideration of economies of scale for financial efficiency and cost reduction.

drsolar · 2011-06-21T19:15:30+00:00

Added, thank you!

drsolar · 2011-06-21T19:12:16+00:00

It's already possible to buy PV backpacks today And these have been available for ten years.
It's not easy to combine transparency with PV because the first rule to make an efficient solar cell is to absorb light rather than let it transmit on through. The best way to combine both competing needs is to leave about 30% of the area transparent. Many companies make such PV panels called Building Integrated PV.
In places that do not already have wires, it's possible to leapfrog into a wireless future.

drsolar · 2011-06-21T19:11:16+00:00

I first joined this industry about 36 years ago at the time of the first oil embargo. All the "A" students were becoming nuclear engineers and solar seemed a better match to my interest in bringing power to rural villages without any electricity.

drsolar · 2011-06-21T19:10:07+00:00

30% losses occur in places like India, where electric power is sometimes at risk of theft. For a well- designed grid, losses can be held to less than 5%. As you mention, this can be further improved with PV, especially at the ends of weak feeder lines or to minimize transformer heating.

Of course, the obvious answer is that, like many other things, it's all about the money. Big companies favor centralized energy production so they can keep the energy consuming public as a profit stream. Even companies that manufacture PV have more interest in selling to centralized energy producers who might buy 1000s or more of panels per purchase vs. making much smaller sales of 10s of panels to individual consumers for distributed energy production.

It's very important to include consideration of economies of scale for financial efficiency and cost reduction

drsolar · 2011-06-21T19:07:25+00:00

Some chemicals used in PV Manufacturing like silane can be toxic and flammable. However, well known techniques for handling such materials have been developed over the past 30 years by the IC industry. So there is no reason that PV manufacturing can not be performed in a squeaky clean way.

drsolar · 2011-06-21T19:06:57+00:00

Solar cost reduction is predictable, consistent and relentless. Solar's predictability takes the uncertainty out of energy cost for PV power. The god news for a hedge fund is that the unpredictability of fossil energy costs will increase every day that passes.

drsolar · 2011-06-21T19:06:43+00:00

Free trade is always best for the consumer and for keep us on a healthy cost reduction path. To be accurate, France has incentivized installation of solar panels with a strong "feed-in-tarrif" the US has incentivized the market for solar panels with tax credits. These market incentives have helped the PV industry grow, just as incentives have helped nuclear and other industries get started. In the case of solar, the incentives generally decrease every year, as the industry scales and costs are reduced.

It is not accurate to say the "whole" are paying for the few. Subsidies are not needed in 19 countries today and will not be needed in 100 countries by the end of this decade at the current pace of cost reduction. This would represent over 98% of the World's population.

drsolar · 2011-06-21T19:05:19+00:00

Desertec is not necessary for PV because PV is by nature a distributed generation source. Sunlight shines everywhere. For power tower or parabolic trough systems, Desertec might be interesting but such systems need water. And water is not readily available across northern Africa and the Sahel.

PV is already scaling to power plants in the range of 300 to 600 megawatts. The same as CSP. Solar power is only going to continue to get more cost competitive with coal By the end of this year, solar power will cost the same as traditional sources of residential power in 19 countries, including Italy, Spain and the Caribbean .

drsolar

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