This, honestly, should be on the front page. If solar power, which is still on the upward part of the R&D curve, is becoming as cheap as coal, then the days of "advanced society = digging stuff out of the ground and setting it on fire" are numbered. And if it becomes much cheaper then the things we can do with electricity (such as desalinization) increase.
Sempra solar energy project makes advances in costs - Los Angeles Times:
Sempra Generation, a subsidiary of Sempra Energy in San Diego, just took the wraps off a 10-megawatt solar farm in Nevada. That's small by industry standards, enough to light just 6,400 homes. But the ramifications are potentially huge.
"A veteran analyst has calculated that the facility can produce power at a cost of 7.5 cents a kilowatt-hour, less than the 9-cent benchmark for conventional electricity.
If that's so, it marks a milestone that renewable fans have longed for: 'grid parity,' in which electricity from the sun, wind or other green sources can meet or beat the price performance of such carbon-based fuels as coal and natural gas."