San Francisco is evolving. ...at least in terms of its boats to Alcatraz, which will now be replaced with the world's first sun and wind powered ferries.
"The slickest feature? The triple-hulled vessel will have a 45-foot high retractable wing covered in solar panels that can generate 20 kilowatts of electricity to help take the load off the two diesel engines. 600pax_tri_side_lr The wing also generates some 170 hp on its own as a sail. When conditions get hairy and the wind hits 30+ knots (that's when many sailboats start to de-mast), the wings fold up, all beetle-like, and the ferry operates like one of its older counterparts All this is based on a similar ferry that's already been in operation in Sydney for a couple years." - Business Blog