Europe is taking the wind out of American sails by pushing ahead with the development of wind power, an increasingly popular source of energy, says the International Energy Agency, the Paris-based energy unit of the Organisation for Economic Co-operation and Development. For four straight years wind energy has been the world's fastest-growing renewable energy source. Germany installed 800 MW last year, compared with only 150 MW installed in the U.S. By the year 2010, the U.S. is expected to install 10,000 MW, compared with 40,000 MW in the 15 countries of European Union. But some specialists are even more optimistic. They forecast 100,000 MW for Europe installed by 2020, some 10% of its power needs.