Officials in Copenhagen, Denmark, helped to inaugurate the world’s largest offshore windmill park this month. The park has a capacity of 40 megawatts of electricity — four times more than the second-largest offshore windmill park in Sweden — and will supply about 3 percent of the city’s energy, powering the equivalent of 32,000 homes. In total, more than 5,600 windmills produce about 10 percent of Denmark’s electricity, selling at about 4 cents per kilowatt hour. Soeren Krohn of the windmill manufacturers association said wind power production in the country was expected to double by 2005.