IF YOU WANT TO KNOW about the energy sources of the future, ask the man who’s been there: Arnie. Last December, Arnold Schwarzenegger, the time-travelling Terminator turned “Governator” of California for two terms, posted a Facebook rant explaining why he was on a crusade for clean energy. “I don’t want to be like the last horse and buggy salesman who was holding out as cars took over the roads,” he wrote, beneath a photo of gleaming solar panels. “I don’t want to be the last investor in Blockbuster as Netflix emerged. That’s exactly what is going to happen to fossil fuels.”

California, where Arnie ran the show from 2003-2011, now sources more than a quarter of its energy from wind, solar, geothermal and hydroelectric dams. The state is also home to Silicon Valley, a hotspot for disruptive innovations. For anyone seeped in start-up culture, where stagnation is death and you’re only an app away from overturning a legacy industry, renewable energy looks like the next big thing – Electricity 2.0.