Is SunPower King of Sun Power?
Who’s the leader of the solar pack?
“SunPower,” says SunPower founder, Richard Swanson, not surprisingly. But Swanson makes a good pitch for his product in a new video at MIT’s Technology Review.
He points to a couple of reasons for SunPower’s claim: use of a tracking system to follow the sun and superior design with all electrical leads on the back of the solar cell.
OK, positioning the array to follow the sun improves the output of any PV cell. It’s a method first used by sunflowers (and other plants).
Swanson claims that SunPower cells generate about 50% more electricity than conventional PVs.
There are two words in the previous sentence that should have set off alarms: about and conventional. Is 3% about 50%? Could be. And what, exactly, are conventional solar cells. Answer: anything I decide them to be. (Not for nothing did my wife go to law school.)
And, in fact, there’s plenty of disagreement. According to the folks over at Go Green Solar, “Sanyo solar panels outperform SunPower.”
There’s a caveat here, too, however. The data they’re using come from a solar installation company, not an independent lab.
Moral of the story? In solar, as in all things, caveat emptor.
I’ve read lots of good things about both SunPower and Sanyo, but, let’s be real here. There is no simple, unbiased ranking of PV cells that can tell you which manufacturer is the best for your location, electrical needs and piggy bank. Get bids from several installers, ask for references and then contact them.
And, watch the video, anyway. It may not be a documentary. But, on the other hand, it doesn’t mention John and Kate once.
I think Navigant Consulting has some good data on performance. I have contact info if you want it.
There is a real, unbiased ranking. That’s the actual sales in MWs. Here they are as of end of April (in CA, according to the CSI) and instruction how to calculate as of yesterday, if you wish (rankings haven’t changed much).
http://ecdfan.blogspot.com/2009/05/csi-snapshot-as-of-april-29th-2009.html
Mr. Swanson is wrong about solar power, though. PV solar makes electricity only for a few hours a day (assuming no clouds), while real power plants work 24 hours. 7 fays a week.
Look at this spreadsheet:
http://www.eia.doe.gov/oiaf/ieo/excel/figure_6data.xls
World electricity generation is 20 trillion KWHs, of which renewables (basically, hydro) is 4 trillion KWHs. Now, let’s say cumulative PV installed capacity is 15GWs. Those 15GWs, working only during the day, generate about 15 billion KWHs a year, or 0.015 trillion KWHs. Thus, solar electricity generation is just 0.4% of the renewables electricity generation (and less than 0.1% of total electricty generation). Not surprising, given that PV is a very expensive way of generating electricity as PV is nowhere near grid parity today.
Thanks for commenting.
The info you cite is for sales in California. Market indicators (who’s buying what) offer a very a narrow view of the real world. See: booming housing market in Phoenix 2 years ago.
Also, the data you cite are for just one state — an important one, but still not the full picture.
PV, especially tracking PV, provides electricity for between 6-8 day and more depending on location. And PV doesn’t stop producing electricity because of clouds as you imply.
“Grid parity” is a term of art dressed up in an expensive suit. I have yet to see a good cost accounting of energy sources that includes long-term costs, public health costs (30,000 premature deaths a year from coal in the US alone), government subsidies (including casualties of oil wars and billions for nuclear), water usage, etc., etc. Oh, yes, and costs associated with the effects of global warming.