Two of the world’s largest wind turbines, with blades 60 meters (196 feet) long, have been installed off the Yorkshire coast, a sign of a growing trend toward producing colossal wind turbines to boost generating capacity. The 6-megawatt turbines, manufactured by Siemens, are so large that they had to be installed using a specially built ship, Siemens said. The pair of turbines is being erected on an experimental basis to gauge how they perform, but the operator of the offshore wind farm, the Denmark-based DONG energy group, has plans to install dozens more so that production will reach 210 megawatts at the site, located about five miles offshore. DONG says it intends to eventually install 300 of the massive turbines by 2017 at various offshore locations in the U.K., including some in deeper waters. Energy analysts say the 60-meter Siemens turbines reflect growing interest among wind energy companies to deploy ever-larger turbines, with plans in the works to manufacture turbines 100 meters long.