More government financing for solar power?

Hasn’t the Solyndra scandal taught us anything? What is the appeal of solar power anyway?


Dear Control Engineering: After reading the story that the DOE is giving more money to solar power companies, I have to ask what we’ve learned from the Solyndra debacle? What is the appeal of solar power anyway?

While it might be interesting to get into political discussions, I’ll leave that whole area for others. But we can look at what solar power represents. If you think about it, with the exception of geothermal and nuclear, all power generating technologies are ultimately solar. Plants grow as the result of the sun, and plants become the source of all fuels one way or another.

Photovoltaic panels, meaning devices that create electrical current when placed in sunlight, convert light to power with varying levels of efficiency. Most cost-competitive technologies fall into the 15% ballpark. That means under decent conditions, they can produce about 12 W per square foot. There are major chunks of the south-east U.S. where such a panel could do that easily for around six hours per day. This approach doesn’t require boilers, creates no emissions (at least in operation), demands very low maintenance, etc. Moreover it’s infinitely scalable. Small installations are just as efficient as big ones, so it makes sense to cover the roof of your plant with panels. Ultimately one of the most appealing benefits is that solar generation creates power during times of the day when demand is highest.

For now, the cost is still too high when compared to conventional methods (e.g., coal), but the cost per watt is coming down. Solyndra’s schtick was that it was making cylindrical panels instead of flat ones, so they could use light coming from more angles. That was supposed to increase efficiency. There are also various thermal technologies that create steam using sunlight.

Perhaps you think that 15% isn’t all that efficient. But, compare it to using an equivalent amount of surface to grow corn and turn it into ethanol. How much energy do you think you’ll get from that? When it’s all said and done, how many Watts will you get from that space? I guarantee that it won’t equal the 21 kWh you could get from a one-square-foot panel in a good location over a year.

Political questions and embarrassments aside, there will likely be more efforts to promote solar power using various technologies. The advantages are far too appealing and practical to ignore.

Peter Welander,

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