Wow. I hadn't realized that Al Gore gave a speech recently calling on us to move to 100 percent renewable sources of electricity in ten years. That's audacious seemingly to the point of madness. Why focus so exclusively on cleaner electricity generation rather than on a balanced approach that involves efficiency (i.e., using less electricity) and also the transportation, heating, etc. sectors. After all, replacing a conventional car with an electric one -- or a bus with a trolleybus or tram -- reduces emissions regardless of how you get your electricity.
In that sense, it makes way more sense to put some of our existing dirty electricity infrastructure to use in the short-term as a substitute for our currently lamentable transportation infrastructure, while we switch the nature of our electrical infrastructure on a more tempered pace. Of course there's nothing wrong with big ideas to expand the overton window, so I don't think it's terrible to see some folks pushing radical ideas, but on the other hand I do worry about the public becoming polarized between a "holy shit we need to do something crazy and extreme" faction and a "that sounds crazy and extreme so let's do nothing" faction. It's more important to start taking some concrete steps down the path to mitigation than to spend too much time drawing up the outlines of ecotopia.