Tuesday Review: Solar Future

Solar Future, Scientific American, January 2008.

I'm cheating for the review this week. I've been delayed getting the next book read, so instead, I'll be reviewing something that has been covered elsewhere before. The Scientific American article in the January 2008 issue on powering the US on solar.

The short coming with the plan presented, I believe is that it focuses entirely on a single source of fuel. While there certainly is enough solar energy falling on a relatively small surface area to provide electricity,even at current efficiency rates, it seems short sighted to rely so exclusively on just one source when there are so many available. They also focus almost exclusively on centralized generating facilities, focusing not at all on more localized options such as rooftop systems to supplement grid power.

As the authors of the report included discuss, there are still some technological limits with solar. Particularly with providing electricity overnight and during extended overcast periods. While they do suggest the use of both solar thermal plants, the claim is that such plants need to be improved from current 7-hour running without solar input to 16 hours.

An additional proposal is the use of compressed air stored underground in conjunction with natural gas generation to allow unneeded electricity to be stored and used as later. This similar to the German system that uses pumps to move water between a lower and upper reservoir to allow on demand generation using hydroelectric turbines.

What is well taken in the plan is the need for a massive infrastructure upgrade to more easily enable long distance distribution without the associated losses of AC transmission. From the 109,000 miles of proposed DC transmission capability, it would appear that the authors envision a new and extensive distribution network to feed local AC grids.

The cover states "could free the U.S. from foreign oil," which isn't covered in detail to discuss the massive change in automobile's that would need to take place in order to achieve that. The plan presented is also lacking in implementation specifics in terms of policies that would speed the development and spending on this rather modestly priced 420-billion over 36 years project.

The article succeeds as a technology review of current photovoltaic, solar thermal and compressed air state of the art, but assumes that more development is still necessary to provide the vision outlined.

The economy of residential solar, an example

Lou Ann Hammond of CarList has written an article about the economics of installing solar for her home, with the intent of being ready for a plug-in electric vehicle should they ever see mass production. She includes an analysis of the capital costs, rebates, tax credits, and various ROI calculations. Everything is specific to Southern California, and some of the tax information and credits change in the next year.

Based on her numbers, it certainly appears that a residential solar-electric system can be a good investment that has a reasonable ROI, assuming a lifetime on the panels of 25 years.