Last week, Josh posted a sobering article that quoted CalTech's Harry Gray, who announced that solar power was at least a decade away from competing with fossil fuels. Joe Romm, on the other hand, is considerably more optimistic in his Salon essay today, arguing that solar thermal power could become competitive much, much sooner than that—and without major technological breakthroughs:
CSP [Concentrated Solar Power] costs have already begun to decline as production increases. According to a 2008 Sandia National Laboratory presentation, costs are projected to drop to 8 to 10 cents per kilowatt hour when capacity exceeds 3,000 MW. [By comparison, coal and natural gas cost about 5 to 6 cents per kilowatt hour right now.] The world will probably have double that capacity by 2013. The price drop will likely occur even if the current high prices for raw materials like steel and concrete continue (prices that also affect the competition, like wind, coal and nuclear power).
Since all three remaining presidential candidates endorse a cap on carbon dioxide emissions coupled with a system for trading emissions permits, carbon dioxide will likely have a significant price within a few years. And that means the economics of carbon-free CSP will only get better. Improvements in manufacturing and design, along with the possibility of higher temperature operation, could easily bring the price down to 6 to 8 cents per kilowatt hour.
Gray claimed it would take ten years of "intensive research and development" before solar could play a major role providing affordable carbon-free energy, whereas Romm argues that massive new R&D isn't necessary; costs would come down on their own if Congress just helped foster initial market demand—say, through a national portfolio standard that required U.S. utilities to get 20 percent of their power from renewable sources by 2020. I'm not sure how to adjudicate this, although it doesn't sound like the two stances are so far apart.
For an even (ahem) sunnier view of what concentrated solar power could accomplish, do check out this Scientific American cover story from February, which laid out a reasonable plan for a solar-power infrastructure that could provide 69 percent of America's electricity by 2050—cutting carbon-dioxide emissions by 62 percent. (This assumes we electrify our transport with, say, plug-in hybrids.) The major question mark, I think, is whether compressed-air storage in underground caverns can help overcome the fact that the sun doesn't shine all the time. But the piece offered a nice, concrete way of thinking about how the country could actually power itself with renewable energy in a relatively short timeframe.
P.S. The New York Times' Matthew Wald has a nice piece today on some of the new techniques being developed to store solar energy.