What is offshore wind power?

Offshore wind power or offshore wind energy is the energy taken from the force of the winds out at sea, transformed into electricity and supplied into the electricity network onshore.

If you look out to the North Sea from the UK’s East Coast, you’ll see line upon line of these immense white wind turbines.

You can discover more about the technology used to harness the wind’s energy by reading our article on how wind turbines work.

Is offshore wind power a renewable energy?

Yes. Offshore wind power is a constantly renewable and infinite energy source, and the conversion of wind into power creates no harmful greenhouse gas emissions. As we work to tackle climate change and reduce greenhouse gases, offshore wind power will play an essential role in our future electricity generation.

What are the advantages and disadvantages of offshore wind power?

Advantages

Distance from local populations, therefore cancelling worries about noise from the rotation of the wind turbine blades and reducing the impact on local environments.
Space to dramatically increase the number of wind farms and therefore clean energy to homes and businesses. See below for net zero targets.
Job creation – the government estimates that a step rise to 40 gigawatts (GW) of offshore wind in the same period will support up to 60,000 new jobs. Our own analysis in the Job That Can’t Wait report, shows that the country needs to fill 400,000 jobs in the energy sector in the next three decades to deliver net zero by 2050.
On top of being clean and green, offshore wind power is cost-efficient so electricity bills will reduce.

Disadvantages

Worries about the effect on birds and marine life. Here, the effect unchecked climate change poses to wildlife needs to be balanced with ongoing research into habitat loss, disturbance and collision. The Royal Society for the Protection of Birds (RSPB) acknowledges the bigger picture, saying: “Switching to renewable energy now, rather than in 10 or 20 years, is essential if we are to stabilise greenhouse gases in the atmosphere at safe levels.” Wind farm developers work closely with local environmental groups, through a consultation process on the siting and scale of wind farms.
Some potential disruption during infrastructure creation, although the integration of interconnectors means less disruption than multi projects.

How much does offshore wind currently contribute to the electricity mix?

According to energy trend figures from the Department for Business, Energy and Industrial Strategy (BEIS), the share from offshore wind generation increased from 8.5% in the second quarter of 2021 to 11.2% in the second quarter of 2022. That compares to 6.4% for solar and 10.3% for bioenergy and waste.

10 January 2023 saw the record for the highest ever level of wind generation at 21.62GW, providing over half our daily electricity – while a day in November 2022 saw wind contributing its highest ever share to the electricity mix (70%).

In the US, the offshore wind pipeline grew 24% in 2021 (compared to 2020) due to falling offshore wind prices, federal action and state-level commitments.¹ The National Renewable Energy Laboratory estimates that the offshore wind technical potential is more than 2,000 GW of capacity, which is 7,200 terawatt-hours per year of generation.²

Which country currently produces the most offshore wind?

The UK has the largest installed capacity of offshore wind in the world, with around 10GW in operation off its coasts. The North Sea is seen as the engine room of the UK’s green and resilient future economy, leading the world in offshore wind technology.

Germany is the second country with cumulative installed offshore wind capacity, with China a close third.

Hornsea 1 in the North Sea is the world’s largest offshore wind farm. Off the coast of Lincolnshire, it has 174 turbines, covers 407 square kilometres and provides 1.2GW of green energy. That’s enough to provide sustainably-sourced electricity for more than a million homes.

The UK and its European neighbours have been working together on the flow of green and clean electricity from offshore wind farms. You can read more about the engineering feats involved in interconnectors.

Are there plans to increase offshore wind generation in the UK and US?

Yes, the UK government has set an ambitious target to deploy 40GW of offshore wind by 2030 – four times more than the 10GW we currently produce and enough to power every home at current electricity usage levels. The UK currently produces enough offshore wind power to provide electricity for 7 million homes.

The Climate Change Committee has advised the UK will need 140GW to meet net zero by 2050; as demand will increase as we shift to clean energy to drive our electric vehicles, heat our homes and power our energy intensive industries, such as data centres.

To enable this additional clean energy to be connected to homes and businesses, the UK's electricity grid is undergoing the biggest overhaul in generations.

Find out more about The Great Grid Upgrade

Similarly, President Biden issued an Executive Order that focuses on building clean energy jobs for Americans, including expanding the offshore wind industry. The Departments of Interior (DOI), Energy (DOE) and Commerce (DOC) announced a combined goal to deploy 30 GW of offshore wind in the US by 2030, while simultaneously creating tens of thousands of green energy jobs.³

Offshore wind: what new technologies are in the pipeline?

Floating wind farms

Floating offshore wind turbines are an exciting technology development. These will allow wind farms to be tethered to the seabed and positioned further out to sea in deeper waters where winds are stronger, thus boosting offshore wind power capacity even further. In the US, about 75% of offshore wind projects plan to use semi-submersible platforms.²

Taller wind turbines

And the offshore wind industry will be propelled forward – literally – by the creation of taller wind turbines with huge wind blades. The Haliade-X 13MW has been successfully tested and will be supplied to Dogger Bank wind farm, off the Yorkshire coast. A single sweep of its 107-meter long blades will be able to power the average UK household for more than two days.

Interconnectors

Interconnectors– huge deep undersea cables that bring electricity onshore – are playing an increasing role in developing capacity between the UK and its European neighbours, and reducing electricity costs for homes and businesses.

In 2020 alone, National Grid’s interconnectors prevented more than 1 million tonnes of CO₂ emissions, equivalent to planting 50 million trees or taking almost 700,000 cars off the road.

By 2025, we will have 8GW of interconnector capacity to Norway, Denmark, France, the Netherlands and Belgium, which we estimate will prevent around 100 million tonnes of CO₂ emissions between now and 2030.

In addition, two new electricity undersea highways from Scotland to England, SEGL1 and SEGL2, will be operational by 2030.

US seabed lease with potential for 3GW of capacity

In the US, National Grid and partner RWE Renewables secured an area called OCS-A 0539 in the New York Bight offshore lease auction, with a winning bid of $1.1 billion. This seabed lease has the potential to hold about 3GW of capacity, which is enough to power 1.1 million US homes. The project is expected to be functioning by the end of the decade.

Will Hazelip, Head of New York Joint Venture Projects at National Grid Ventures, says: “This is a very exciting opportunity as we continue to make strides towards clean energy. We look forward to expanding the scope of renewable energy and utilizing our capability in electric transmission to deliver clean energy at scale in our region.”

What are the challenges to increasing offshore wind generation at this scale?

Minimising the impact on local communities and creating positive relations, while creating the infrastructure to transport extra electricity from the coast to cities cost-effectively, all while creating local jobs, are some of the challenges.

We welcome the ambition and believe that, while challenging, it's achievable. The scale of projects in the pipeline is unprecedented. And it’s a stretching target that will need the right regulatory, planning and policy framework to support the requisite investment, both on and offshore, without losing the good will of communities.

There is a huge increase in the amount of electricity cable that the industry needs to produce to support this – enough cable to run from Portsmouth in the UK to Perth in Australia!

_{Last updated: 10 Aug 2022

The information in this article is intended as a factual explainer and does not necessarily reflect National Grid's strategic direction or current business activities.}