Over at Gristmill, Gar Lipow critiques the recent Scientific American grand solar plan (also linked to here): … First, the grand plan contains almost no demand reduction, other than what would occur as a side effect of less fossil fuel use, plus electrification of transport. However, we know there is a huge potential for inexpensive efficiency improvements. At the low end, the McKinsey group calculates (PDF) that we could reduce by around 11% in absolute terms at a savings. My own book suggests that efficiency improvements alone could reduce emissions by more than 60%, at a cost lower than the current cost of coal electricity.
Secondly, we can use non-electrical solar to displace a lot of generation. Even in existing buildings, low temperature solar thermal could replace a lot of electricity used for space, hot water heating, and other low temperature purposes. (SciAm does already suggest a smart grid, including low temperature storage of climate control energy in buildings.) In new buildings passive solar is the next cheapest choice after efficiency.
Third, under-using wind costs the SciAm plan a lot. I understand why the authors concentrated on solar. Solar potential in the U.S. is hundreds, perhaps thousands of times current U.S. consumption. Commercial wind potential, in contrast, may be as little as ten times projected U.S. consumption in 2100. But wind electricity is also currently much cheaper than solar electricity. In addition, studies have shown that wind, when produced at multiple sites a great distance apart, has potential to provide a certain amount of very reliable power, even before storage is used….