The world's largest wind farm was just completed in the Irish Sea — and it's more than twice the size of Manhattan

Ørsted UKThe Walney Extension is the world’s largest offshore wind farm.

The world’s largest wind farm is up and running.

Bigger than San Francisco, it powers more than half a million homes and sits in the Irish Sea, off the coast of England.

The Walney Extension opened last week with a generating capacity of 659 megawatts, and is located between northern England and the Isle of Man. Its 87 turbines, which stand up to 640 feet tall, are some of the world’s biggest in operation. (Taller is generally better for harnessing the wind because wind speeds tend to pick up as you get higher off the ground.)

The project is part of a larger trend of investment in offshore wind farms as a way to produce clean, renewable energy. The first offshore wind farm in the US, a 30 megawatt farm that sits 30 miles off the coast of Rhode Island, was completed in 2016. One recent report estimated that by 2026, 2.3 gigawatts of offshore wind power will be up and running in the US. That would be enough wind energy to light up more than a million more American households.

Meanwhile, the Dutch are proposing a 30-gigawatt farm, complete with its own artificial island, to be built in the ocean between the Netherlands, Norway, and the UK by 2027. So the Walney Extension may not be able to claim a world record for long.

For now, though, the UK’s new wind farm reigns supreme. Here’s what it looks like.


The Walney Extension is an array of 87 turbines in the Irish Sea off the west coast of England. At capacity, the wind farm provides enough power for more than 590,000 homes.

Ørsted UK

The turbines sit less than 12 miles away from Walney Island in England.

Google Maps

The wind farm spans 56 square miles — an area bigger than the island of Manhattan or the city of San Francisco. (It’s about the size of 20,000 soccer fields.)

Orsted, the Danish wind power company that built the new farm, couldn’t even fit the whole thing in this video.


The farm has two of its own electrical substations. It first generated power in August 2017, but construction wasn’t complete until June 2018.

Ørsted UK

Source: Orsted


It took a lot of heavy lifting to get the 261 blades on the farm up and running. Each blade weighs 61,700-75,000 pounds.


Just a single blade rotation from a turbine on the new wind farm provides enough power to take care of an entire household’s needs for more than a day, Orsted said.

Ørsted UK

The turbines, made by Siemens and MHI Vestas, each soar more than 600 feet in the air, more than twice the height of the Statue of Liberty.


The farm is hooked up to more than 186 miles of cables, which connect the wind power to England’s national grid. Here’s what all that cable looked like when it was being hauled out to sea.


The Walney Extension beats existing offshore wind farm records for both power and size. It is 9 square miles larger and 29 megawatts more powerful than the world’s number two offshore wind farm, the London Array, which sits off the southeast coast of the UK.

London ArrayThe London Array

The world’s largest wind farm overall is located on land in China.


Offshore wind isn’t cheap. It costs around 20 cents per kilowatt hour to produce, but the price is projected to tumble to just 10 cents per kilowatt hour by 2022. That would make it roughly three times the price of onshore wind power.

Ørsted UK

As prices for renewable energy sources like wind continue to fall, more people around the world are expected to begin relying on them to power their lives. Energy sources including wind and solar are expected to provide close to half of the world’s energy needs by 2050.

Sources: International Renewable Energy Agency, Business Insider, US Department of the Interior

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