Offshore wind is a relatively new technology, so costs will reduce and the technology will advance, helping offshore wind to be more efficient and cost competitive in the near term. But this exciting technology is already being incorporated into government's energy planning around the world.
More than 91% of the world's offshore wind power is currently installed off northern Europe, in the North, Baltic and Irish Seas, and the English Channel. Most of the rest is in two "demonstration" projects off China's east coast.
Offshore wind is an essential component of Europe's binding target to source 20% of final energy consumption from renewables, and China has set itself a target of 30 GW of installations off its coast by 2020. The United States has excellent wind resources offshore, and many projects are under development.
The key benefits of offshore wind are:
- The wind resource offshore is generally much greater, thus generating more energy from fewer turbines;
- Most of the world's largest cities are located near a coastline. Offshore wind is suitable for large scale development near the major demand centers, avoiding the need for long transmission lines;
- Building wind farms offshore makes sense in very densely populated coastal regions with high property values, because high property values makes onshore development is expensive sometimes leads to public opposition.
Although offshore wind is often the most talked about part of the wind sector, today it represents about 2% of global installed capacity. In 2014 1,713 MW of new offshore capacity was added, bringing the total to 8,759 megawatts.
At present, more than 91% (8,045 MW) of all offshore wind installations can be found in European waters; mainly in the North Sea (5,094.2 MW: 63.3%), Atlantic Ocean (1,808.6 MW: 22.5%) and in the Baltic Sea (1,142.5 MW:14.2%). However, governments outside of Europe have set ambitious targets for offshore wind and development is starting to take off in China, Japan, South Korea, Taiwan and the US. The GWEC-led FOWIND consortium is developing an offshore wind roadmap for India, and other markets, such as Brazil, have raised interest in future offshore development.
While electricity from onshore wind farms is already cheaper than conventional power in an increasing number of markets, relatively high costs remains the biggest challenge for offshore wind development. However, according to a study commissioned by EWEA in 2015, offshore wind cost could be reduced to EUR 90/MWh (USD 94) by 2030. The report says that the sector will have nearly reduced the levelised cost of energy to EUR100 per MWh by 2020, by which time cumulative installed capacity in European waters is expected to have tripled to 23.5 GW. Key actions to reduce cost include: deploying larger turbines to increase energy capture (a 9% saving); encouraging greater competition (7%); commissioning new projects – keeping volume up (7%) and tackling supply-chain challenges (3%).
At present, the average offshore wind turbine size is 3.7 MW, average water depth 22.4 meters and average distance from shore 32.9 km.
In 2014, 1,483 megawatts of new offshore wind capacity came online in Europe, a 5.34% decline over the 2013 market. The total now stands at 8,045 MW, and offshore wind power installations represented 12.6% of the annual EU wind energy market in 2014, down from 14% in 2013.
Overall, 408 new offshore wind turbines in nine wind farms and one demonstration project were fully grid-connected at the end of 2014. 54.8% of all new capacity was installed in the UK (813 MW). The second market was in Germany (529 MW or 35.7%), followed by Belgium with 141 MW (9.5%).
Our projections show that by 2020, offshore wind will be about 10% of global installed capacity.
 Offshore Wind in Europe: Walking the Tightrope to Success, Ernst & Young, 2015.
For more information about global offshore development worldwide see latest Global Wind Report (Chapter on Global Offshore) here.