chrnb writes "Last year, the Danish island of Samso (pronounced SOME-suh) completed a 10-year experiment to see whether it could become energy self-sufficient. The islanders, with generous amounts of aid from mainland Denmark, busily set themselves about erecting wind turbines, installing nonpolluting straw-burning furnaces to heat their sturdy brick houses and placing panels here and there to create electricity from the island's sparse sunshine. By their own accounts, the islanders have met the goal. For energy experts, the crucial measurement is called energy density, or the amount of energy produced per unit of area, and it should be at least 2 watts for every square meter, or 11 square feet. 'We just met it,' said Soren Hermansen, the director of the local Energy Academy, a former farmer who is a consultant to the islanders."