Slashdot Mirror
MIT Study Outlines a 'Perfect' Solar Cell
Daniel_Stuckey writes A new MIT study offers a way out of one of solar power's most vexing problems: the matter of efficiency, and the bare fact that much of the available sunlight in solar power schemes is wasted. The researchers appear to have found the key to perfect solar energy conversion efficiency—or at least something approaching it. It's a new material that can accept light from an very large number of angles and can withstand the very high temperatures needed for a maximally efficient scheme. Conventional solar cells, the silicon-based sheets used in most consumer-level applications, are far from perfect. Light from the sun arrives here on Earth's surface in a wide variety of forms. These forms—wavelengths, properly—include the visible light that makes up our everyday reality, but also significant chunks of invisible (to us) ultraviolet and infrared light. The current standard for solar cells targets mostly just a set range of visible light.
Most important is cost/kwh? How about comparing it to the total cost, over time, of other sources of energy. (for instance, factor in the loss of fossil fuel and pollution or warming of the Earth, or the handling of radioactive waste from nuclear...those typically are not included in the cost/kwh, but should be. Of course, if you're a shiphead and are only interested in money and don't give a ship about anyone else, then yes, cost/kwh is the most important thing.
This system uses blackbody emission to re-radiate absorbed photons within a specific bandwidth, which can be selectively optimized for.
However, since it uses blackbody emission, it does not explicitly NEED light as the energy source. Any kind of heating will suffice. This is really just a very fancy means of converting entropic energy into something useful. Could be very useful when coupled with radio-isotope decay systems, for instance. (This, coupled with existing RTG tech, could produce more efficient RTGs)
Sadly, it requires that large numbers of useful photons be produced from the emitting blackbody source, which means it needs some pretty non-trivial temperatures. This isn't going to be something that is used in normal residential settings.
As I read the MIT statement the researchers claim is that their technique collects energy as heat from all available wavelengths. Then a conventional solar cell is used to generate electricity from the photons emitted from the heated collector. I didn't see anything about how much more efficient this is than generating electricity directly, but presumably it's better since the solar cell responds best to a specific wavelength which can be controlled by using the heated collector. Obviously to make it work need a concentrator.
With solar panel prices now at $500 per KW, most of the system cost is now the installation cost. So improving efficiency lowers installation cost (less panels). Current panels being sold are about 15-18% efficient, best lab panels are over 40% efficient and the theoretical peak is about 65% efficient. Improvements in installation systems and in panel efficiency could easily lead to solar generated electricity being sold for less than $0.04 per kWh from the current $0.08 per kWh (including subsidies).
Panel technology improvements:
http://bxhorn.com/wp-content/u...
Waterfox - a Firefox fork with legacy extension support, security updates and better privacy by default.
There's a bunch of research going into reducing the costs. There are huge areas where the installation cost can be reduced. Integrated and standardized framing, cheaper roof mount systems or even integral mounting systems that become the roofing material, flush roof mount with tracking, integrated, cheaper and more efficient micro-inverters, etc. In fact solar city just dumped about 50 million bucks into some heavy research on just that and the beauty is that because they are an installer and directly involved in the research they can test each idea directly and have first hand knowledge on where the expensive parts of the process are and what works and what doesn't. The quickest way to drive down install costs is to get the inspectors, the engineers, the installers and the panel designers all in the same room which they can do. If they can drive down the install cost they'll be greatly simplifying the install process which will in turn drive down the inspection costs and a bunch of similar follow on costs. And of course they aren't the only one pouring money into installation cost reduction.
There's a ton of waste in residential installs right now because they are using 100 year old methods. With real research going into this I expect they'll be able to at least halve the installation costs. If they succeed at that they'll drive solar power prices below the cost of coal almost immediately. This doesn't include the other things that are being researched like technology that will heat the panel just enough to dump snow in the winter, better heat tolerance and things like automatic tracking without having to move the panel (tilting the cell in the frame or focusing lens/prisims).
There's so much money being poured into research it's pretty darn cool IMO. Solar PV is getting more research than almost any other industry out there because of it's potential. Companies like Solar City have been turning down investment money because so much is pouring in that they can't invest it all.