The world's first electricity generating wind turbine was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his holiday home in Marykirk, Scotland. It was in 1951 that the first utility grid-connected wind turbine to operate in the United Kingdom was built by John Brown & Company in the Orkney Islands. In the 1970s, industrial scale wind generation was first proposed as an electricity source for the United Kingdom; the higher working potential of offshore wind was recognised with a capital cost per kilowatt estimated at £150 to £250.