Matt Yglesias is in Germany, where the law requires local utilities to buy electricity from you if you install solar panels on your roof and generate excess current during the day:
This raises the overall price of electricity a little, but it has a dramatic impact in making solar power viable at scale. So dramatic, in fact, that Germany is a world leader in solar power despite not being sunny at all. If you took a similar policy framework and deployed it in places like Nevada, California, Arizona, New Mexico, and Texas where they have tons of sun it would be hugely effective. And much larger portions of the United States manage to be sunnier than Germany.
I don't know about those other states, but California passed a Net Energy Metering law back in the 90s. So the Germans have nothing on us. And yes, it's a very good idea that makes small-scale solar installations economically worthwhile.