From the wind farms that dot our landscapes to the vast installations off our coastlines, both offshore and onshore wind power play a central role in the transition to a carbon-free electricity system.
The technology that onshore and offshore wind turbines use to generate electricity is essentially the same. Where the two differ is in their position, size, scale and how the electricity they generate is transferred.
Simply put, onshore wind energy is the power that’s generated by wind turbines located on land driven by the natural movement of the air. You’ll often see onshore wind farms in fields or more rural areas, as they’re usually constructed in less-populated areas where buildings and obstacles don’t interrupt the air.
Onshore wind has been capturing and converting wind power in some form since the 1880s (to make corn or drive pumps), but the opening of the Delabole wind farm in 1991 heralded the commercial era of onshore wind in the UK.
Today there are more than 1,500 operational onshore wind farms across Great Britain, generating over 12 gigawatt hours (GWh) of electricity for the national electric system. In 2020 onshore wind contributed 11% of the UK’s electricity needs, with a total 34.7 terawatt hours (TWh) generated – more than enough to power 18.5 million UK homes for an entire year.
Reduced environmental impact
An onshore wind farm’s construction and operation creates significantly less emissions than other energy sources, while the sites they’re placed on can still be farmed.
Offshore wind farms generate electricity from wind blowing across the sea. They are considered more efficient than onshore wind farms, thanks to the higher speed of winds, greater consistency and lack of physical interference that the land or human-made objects can present.
The UK is the world leader in offshore wind. As of 2020 there were nearly 2,200 wind turbines across 35 offshore windfarms off the coast of England, Scotland and Wales. In the same year they produced 40.7 TWh – up 27% from 2019 – and contributed 13% of the UK’s electricity needs.
Full power: the world’s largest wind farm
The Hornsea Phase 2 offshore wind farm will become the largest wind farm in the world, when operational in 2022. It will generate 1.3GW of green energy from 165 8MW wind turbines, which is enough to supply 1.4 million homes.
By 2050 the UK will consume more than twice the amount of electricity than today*, driving the need for four times more clean energy generation and double the grid capacity. The UK government has outlined ambitious plans to increase our offshore wind capacity to 50GW by 2030, which would more than triple the current output.
To make this happen, there are a variety of solutions in the pipeline, including:
Instead of individual wind farms connecting one by one to the shore, Multi-purpose interconnectors (MPIs) will allow clusters of offshore wind farms to connect all in one go, plugging into the energy systems of neighbouring countries and making it even easier to share clean energy between countries.
We’re already very involved in the development of this new generation of interconnector.
Unlike existing offshore wind farms, these revolutionary ‘floating farms’ don’t need to be fixed to the sea bed, instead using anchors to keep them in place, similar to a boat. This means they can be positioned in much deeper sea areas, meaning there’s more room for bigger turbines that generate larger amounts of power.
Energy Islands will play a part in the evolution of offshore wind infrastructure by acting as state-of-the-art ‘clean energy hubs’. They will enable the connection of offshore wind to multiple countries via MPIs, while also serving as a platform for the production and delivery of green hydrogen.
Last updated: 30 Mar 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.
The windiest part of the UK is offshore, out at sea, so putting windfarms out there is the perfect source of renewable energy for us. Find out more about the advances being made in offshore energy and how we'll be using it to generate much more clean energy for a net zero future.
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