"The highest concentration of photovoltaics anywhere in the world is in Germany," he says. "The weather is appalling in Germany. Raining, cloudy and gray all the time. And it works very well there."

Cloudy and gray is a good description of San Francisco in the summer, but it's unusually sunny and clear the day Wheatley, the CEO of Envision Solar, was in town. He was here for EV Week, where he showed off the EV ARC. That's a much easier way of saying "Electric Vehicle Autonomous Renewable Charger." The system, which includes a pile of solar panels, a battery pack, and a 5.5-ton steel plate, is designed to generate and store electricity off the grid. That skirts many of the regulatory headaches that often accompany installing a conventional car charging station, but it comes with an enormous price tag that can be hard to justify.