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'd 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.