Electric cars and solar panels: Which one's the gateway drug?

We probably should have seen this coming.

It seems that a lot of the 100,000 or so U.S. drivers with plug-in electric cars use solar power to charge their cars.

But which comes first, the photovoltaic solar arrays or the electric car?

A great story on the indispensable daily digest Green Car Reports noted that “thus far, we've not seen any surveys that address which comes first, the plug-in car or the solar panels, but we do have a few data points showing the crossover between electric-car ownership and having solar power on your house.”

Apparently, California’s Center for Sustainable Energy processes that state's rebates for both its solar incentives and the incentives for plug-in cars. In February 2012, they surveyed 1,419 plug-in electric car owners and found that “a remarkable 39 percent then currently owned a solar photovoltaic system. Moreover, a further 17 percent were seriously considering a solar installation within the next year.”

Green Car Reports notes that the vast majority of survey respondents were then Nissan Leaf drivers, meaning the survey was not limited to owners of $109,000 Tesla Roadsters.

Another straw in the wind comes from a BMW survey of drivers who participated in its first electric-car test program, and found that more than 30 percent of BMW EV customers invested in residential solar.

“So from early data, it appears that electric-car owners are far more likely to have photovoltaic solar panels to generate power than the average U.S. household,” according to Green Car Reports.

As we’ve reported in previous newsletters, the environmental benefits of electric vehicles and hybrids go up when they’re charged from renewable sources. So, which comes first, installing solar panels on your home or buying an electric car?