Wind power is the world’s leading source of renewable electricity, excluding hydropower, with 238,000 megawatts of capacity installed at the start of 2012. Thus far, almost all of this wind power has been tapped on land; worldwide just 4,600 megawatts of offshore wind farms were operating as of mid-2012. Offshore wind capacity is growing quickly, however, expanding nearly six-fold since 2006. Twelve countries now have wind turbines spinning offshore, and more will be joining them to take advantage of the powerful winds blowing over the oceans.
More than 90 percent of offshore wind installations are in Europe. Denmark erected the world’s first offshore wind farm in 1991—the 5-megawatt Vindeby project. Offshore wind grew sporadically through the 1990s, as Sweden and the Netherlands also added capacity. Denmark added 400 megawatts of offshore capacity from 2001 to 2003. Since then, however, despite several other countries joining in, the United Kingdom has totally dominated the market. Of the 520 megawatts of new offshore wind capacity installed in Europe in the first half of 2012, roughly 80 percent was in the Irish Sea and North Sea waters of the United Kingdom. The rest was built by Belgium, Germany, and Denmark. (See data.)
By the end of June 2012, the United Kingdom had 2,500 megawatts of offshore wind, over half of the world total. And the country hosts the world’s largest operational offshore wind farm, the Greater Gabbard project in the North Sea. All but 11 of its 504 megawatts were installed and connected to the grid by mid-2012. The United Kingdom also has the largest offshore wind farm under construction: close to one third of the London Array’s 630-megawatt first phase was installed by early May 2012. If approved, Phase Two would bring the project total to 1,000 megawatts.
Outside Europe, only China and Japan have operational offshore wind farms. Although its first offshore project was not installed until 2010, China already ranks fourth behind the United Kingdom, Denmark and Belgium, with 260 megawatts. The government’s goal is 30,000 megawatts of offshore capacity by 2020. This could generate the equivalent of roughly one fifth of China’s current residential electricity consumption.
Japan, with just 25 megawatts of offshore wind power capacity, is developing a pilot 16-megawatt floating wind farm project off the coast of Fukushima. Elsewhere in East Asia, South Korea also has big plans for offshore wind, targeting 2,500 megawatts by 2019.
While the U.S. trails only China in land-based wind generating capacity, it has yet to install a single offshore turbine. For more than a decade, the developers of Cape Wind—a proposed 470-megawatt project off the coast of Massachusetts—have been obtaining permits and fending off legal challenges from groups opposed to the project. As of August 2012, the Federal Aviation Administration (FAA) was again reviewing Cape Wind to determine whether its turbines could have an adverse effect on aircraft radar systems. (The FAA affirmed multiple times during both the Bush and Obama administrations that the project would be safe, only to have its determinations appealed by project opponents). Even so, developers still aim to begin construction in 2013.