Electric cars are only as green as the means by which they get their power.
While producing zero local emissions and propelled using efficient electric motors, ideally that electricity would be from a renewable source, rather than by burning fossil fuels or even using nuclear.
That's not always possible, but as far as Tesla Motors CEO Elon Musk is concerned, our best option for clean energy is shining down on our heads: Solar power.
Speaking at the National Clean Energy Summit in Las Vegas, NV (via PVTech), Musk told the gathered audience that sustainable energy was a necessity for the future--the alternative being massive economic collapse.
Discussing the release of carbon dioxide from burning hydrocarbons, Musk said, "We're essentially running this massive chemical experiment on the oceans and atmosphere.
"Why are we running this massive chemical experiment on our oceans and atmosphere when we know we're going to have to find an alternative anyway?"
Musk proposes that by taking a relatively small section of the U.S, such as a 100 miles by 100 miles section of the desert in Nevada or Utah, carpeting it in high-efficiency solar cells could supply power for the entire United States.
Whether states would want such a massive array in their back yards is open to debate, but provided efficiency is high enough and cost low enough, Musk sees it as the ideal way to go.
His views aren't without vested interest--Musk is chairman at SolarCity, one of the country's largest solar installers, having installed 28,000 photovoltaic systems since 2006. Big corporations like WalMart and Google have already bought in to SolarCity, either as customers or as investors.
Musk also understands that better batteries are required to store the energy generated by solar power.
"You can put solar panels at point of use... We need to pair that with energy storage in order to have 24 hour a day power. How to lower cost for batteries for grid storage is going to be important as well."
With individual solar panels on individual buildings, such massive arrays as suggested by Musk may not even be necessary--but the concept is still the same--the more solar we have, the cleaner our energy will be.
And by cleaning up the energy used to power electric cars, the old "yeah, but where does the electricity come from?" argument would quickly become a thing of the past.