March 11 was a good day for solar in California. Fortune reports that for a brief time that day, utility-scale solar accounted for 40 percent of net grid power produced. When combined with rooftop generation, solar probably exceeded 50 percent during high-demand afternoon hours.
Also, according to the U.S. Energy Information Administration, real-time wholesale electric rates dropped to below $0 during that day. Usually, prices are between $14 and $45 per megawatt-hour.
These results indicate that solar costs may be dropping.
In many regions, solar is already cheaper than wind, coal, or gas. Futurist Ray Kurzweil has predicted that market forces will lead to extremely rapid solar adoption over the coming decade.