By J. Matthew Roney

Offshore wind power installations are on track to hit a seventh consecutive annual record in 2013. Developers added 1,080 megawatts of generating capacity in the first half of the year, expanding the world total by 20 percent in just six months. Fifteen countries host some 6,500 megawatts of offshore wind capacity. Before the year is out, the world total should exceed 7,100 megawatts. Although still small compared with the roughly 300,000 megawatts of land-based wind power, offshore capacity is growing at close to 40 percent a year.

World Annual Installed Offshore Wind Power Capacity, 1991-2013

In 1991, Denmark installed the world’s first offshore wind farm, a 5-megawatt project in the Baltic Sea. The country’s offshore wind sector has since alternated between lulls and bursts of activity. Since 2008, Denmark’s offshore wind capacity has more than tripled, topping 1,200 megawatts by mid-2013. Over 350 megawatts of offshore wind power were plugged into the grid in the first half of the year—all of it to complete the 400-megawatt Anholt project, which is expected to meet 4 percent of Danish electricity needs.

Denmark already gets more than 30 percent of its electricity from wind—onshore and offshore—and aims to increase that share to 50 percent by 2020. At about one third the size of New York State, Denmark has the world’s highest wind power capacity per square mile, so it will rely mostly on offshore expansion to hit the 2020 target.