In the late winter of 2003, I watched out my window as a fuel truck idled below, belching black smoke. A hose, snaking through the frozen grass, stretched from the back of the truck to the side of our house. I’d just been marching in Washington, D.C., under a banner that read “No War for Oil.” And now here I was, guzzling petroleum at home in Somerville, Massachusetts. At that moment, I vowed to find some way to kick my addiction—and not only because of the war. The black goo in my basement was a nonrenewable, climate-killing nightmare.