The race is on to make solar power conversion more efficient, hence more affordable. The greater the efficiency of turning sunlight into electricity, the cheaper the electricity will be per watt.
Sunlight is an "extensive" energy source, meaning that its collection is inherently diffused over large areas. That fact should somewhat moderate enthusiasm for solar power's uses. We use enormous amounts electricity intensively - electric motors, for example. Hence, unless sunlight can be converted to electricity at an extremely high rate, the best use of solar power will be to provide power for extensive uses.
Over most of the United States, sunlight falls upon the earth at an average rate of 1 kilowatt per square meter per hour. (1 KW equals 3,400 BTUs, if you ever want to convert solar energy into petroleum-energy equivalents.) That's with a blue sky overhead. Cloud cover reduces the intensity and of course at night there is nothing. That means, of course, that to use solar power at night or bad weather will require a storage medium as well as power generation excess to daytime's needs.
Until fairly recently, solar panels were able to convert only about 20 percent of sunlight to electricity. However, the Defense Advanced Research Projects Agency, DARPA, announced last summer that it has achieved 42.8 percent conversion efficiency. This is a new record.
Now nuclear engineer Lonnie Johnson, famed inventor of the Super Soaker (true) claims he has invented a new kind of solar cell that will convert at 60 percent.
For the near term, solar power will be best used for heating or cooling of homes or businesses, which will require much less intensifying of solar energy than running electric motors. So the solar-powered automobile won't be feasible in the near future, nor will high-intensity industrial motors use solar power primarily. Even so, as efficiencies of batteries improve then so will storage of solar energy, and as solar-conversion rates continue to improve, it will be win-win all around.
However, there is no silver bullet. Increased use of solar energy will be one tool in the kit, but other technologies will continue to play major roles.
Wednesday, January 9, 2008
Will Solar Power Become Economical?
By Donald Sensing
Subscribe to:
Post Comments (Atom)
Posts
4 comments:
In addition to the developments you mentioned, there also appears to be progress on the manufacturing front. Nanosolar has announced it can now produce thin film solar panels for as little as 99 cents per watt (see link).
Regarding energy storage, new developments in flow batteries (e.g. vanadium redox batteries) show great promise with one firm, VRB Power in Vancouver, building a large battery for a 33 MW wind farm in Ireland. The battery will allow load shifting from non-peak demand to higher demand periods.
http://blog.nanosolar.com/
http://en.wikipedia.org/wiki/Vanadium_redox_battery
http://www.vrbpower.com/
Actually, the really cool (sorry) thing about this invention is that it's not a solar cell... it's a Stirling Engine replacement with no moving parts. It doesn't particularly care where the heat comes from. Theoretically, it could even replace steam turbines in power plants (just as an example; I don't have any idea if that's remotely practical).
Likewise, I suspect that as with a Stirling, you could reverse the process, and use it as a heat pump. Again, I can't say whether it would beat out existing designs... but the concept is rather neat.
Thanks, John. I had seen the Nanosolar web site before, but didn't include it here because my emphasis here was conversion efficiency rather than manufacturing economy. Nano's panels are more afficient than the old wafer designs, but as I understand it, they are not breakthrough level.
This is related to Solar Power Kits that it is to be noted that nanosolar has announced that it can produce thin film solar panels , and as far as energy storage, new developments in flow batteries show great promise with one firm. I recommend that every home should have solar power kits.
Post a Comment