What is offshore wind energy?

Offshore wind power is energy generated by turbines located in the sea. The majority of offshore turbines are secured into the seabed in shallow to medium waters on the continental shelf, a short distance from the coastline. For example, in Europe new turbines installed offshore in 2017 are located an average of 41km from the shore and at an average depth of 27.5m. Floating windfarms further out to sea are also starting to become operational.

How much offshore wind energy does the UK have and what is its contribution to the energy mix?

Global development of offshore wind technology has been led by the UK, which has more projects than any other country, with 34% of offshore installations. According to the Committee on Climate Change, the UK currently has around 2,000 offshore turbines, with a total installed capacity of 8 gigawatts (GW); the CCC says these will have to be repowered by 2050 and will likely be replaced with lower-cost, larger and more powerful turbines than the current fleet.

In 2018 24% of the UK’s renewable electricity was generated by offshore wind, an increase of 27.6% on the previous year, and offshore wind accounted for 8% of all electricity generated. (For comparison, 27.4% of renewable generation and 9.1% of all electricity generation came from onshore wind; see our separate FAQ on this power source.)

Where are the UK’s offshore windfarms located?

Most of the UK’s main operational windfarms are located in the Irish Sea off the coast of north Wales and Cumbria, in the North Sea off both the Scottish and English coasts, and in the outer Thames estuary. The Dogger Bank project off the coast of Yorkshire is due to become the UK’s and world’s largest offshore windfarm when it starts generating power in 2023. It will use a new, powerful turbine called Haliade-X, which, at 260m high, has a 12 MW generator and 220m rotor.

As of January 2020, the UK’s and world’s largest offshore windfarm is the Walney Extension. Located off England’s Northwest coast, this windfarm has 87 turbines, capable of powering 600,000 homes. The combined capacity across the Walney project is 1,026 MW.

Scotland is fast becoming a leader in offshore wind technological innovation – including increasing the size of turbines – and is home to the world’s first grid-connected floating windfarm, Hywind, off Aberdeenshire.

How much new offshore wind is planned, how much will it cost and where will new windfarms be located?

The Conservative Party’s general election manifesto of 2019 committed to reaching 40 GW of offshore wind capacity by 2030, including support for new floating wind farms. In its modelling of scenarios for reaching net-zero greenhouse gas emissions in the UK by 2050, the Committee on Climate Change suggests that more extensive electrification, particularly of transport and heating, could require 75 GW of offshore wind in 2050, which it assesses to be feasible.

In the Government’s third Contracts for Difference (CfD) auction in September 2019, the price of offshore wind plummeted to a record low of £39.65 per MWh for the delivery year 2023/24, about 30% lower than the second auction, held in 2017. The Department for Business, Energy and Industrial Strategy confirmed that 6 GW of new offshore capacity will be delivered at this price. Three of the winning bids form part of the Dogger Bank project.

Following an earlier dramatic fall in cost of offshore wind, the Government gave the sector its backing in its Clean Growth Strategy of 2018. This led the Crown Estate, which manages the seabed around England, Wales and Northern Ireland, to announce in November 2017 that it will consider new leasing for offshore wind projects and also that it is no longer accepting applications for extensions of current windfarms, to pave the way for awarding new seabed rights.

Crown Estate Scotland announced plans to lease more of the Scottish seabed to new offshore windfarms in 2018. Three more floating windfarms are in development in Scotland. Floating windfarms can be located in much deeper water than bottom-fixed windfarms, further out to sea, where they can take advantage of more powerful and reliable wind. In June 2019 a Danish firm, Danske Commodities, signed a 20-year agreement to buy power from the floating windfarm Hywind, Scotland, the first deal of its kind.

What is the planning process for offshore windfarms?

In England and Wales, the Secretary of State decides whether to refuse or grant consent for offshore wind projects, as they are defined as ‘nationally significant infrastructure projects’. The decision is made following a recommendation from the Planning Inspectorate. In Scotland, the decision is taken by Scottish Ministers. The Marine Management Organisation is responsible for planning and licensing for marine construction and provides advice and guidance for offshore windfarms. Issues considered during the planning application process include impacts on bird and fish populations, electromagnetic radar interference, shipping and flight navigation, and impact on the landscape.

See also:

What are the pros and cons of onshore wind energy?

How important is onshore wind energy to the UK?


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