Exxon Mobil has agreed to collaborate with Toyota and General Motors, creating the world's biggest alliance of car makers and fuel providers working to get fuel cell-powered vehicles into their product range within three years. Exxon is an important partner, as both carmakers want to generate hydrogen for the fuel cell from petrol. While Ford, DaimlerChrysler and Honda have all committed themselves to building small fleets of fuel cell cars by 2004, this trio promises to come out with a fuel cell-based model by 2003 ( Green Futures , No 27, March/April 2001).