The wild new technology coming to offshore wind power

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Wind power is one of the world's fastest-growing renewable energy sources, and soon its reach might expand even further.

This week, California held an auction for five sites off its coast that could house the first floating wind turbines in the US. The auction sites together cover 370,000 acres and sold for a total of $757 million to five companies.

You read that right: developers are making moves to build wind turbines that float while tethered to the sea floor.

There are already a few demonstration projects around the world for floating offshore wind turbines, but the technology is entering a new phase, with more governments setting goals for installations and larger projects entering the planning and permitting stages. California could be a major testing ground for the technology.

Floating wind turbines face engineering, bureaucratic, and logistical challenges, but if they're deployed at scale, the technology could be a major, consistent power source to coastal communities. So this week, let's dive into floating offshore wind: what it is, what it would take to actually happen, and what California's auction will mean for wind power globally.

The technology

In November at MIT Technology Review's EmTech MIT, I spoke to Alla Weinstein, CEO of Trident Winds and a major player in the push to realize floating wind power.

The ocean has more energy than we've ever needed, as long as we can capture it and use it," Weinstein said at the event.

One of the major benefits of offshore wind is that it can provide more consistent power than other renewable energy sources, Weinstein said. Fluctuations in wind speed still happen, but overall the effect is less dramatic than it tends to be onshore. (In general, wind doesn't fully drop off at night like solar power does.) That consistency is key to building an electricity grid powered by renewable energy sources.

Large traditional offshore wind projects, in which turbines are fixed on the ocean floor, dot the coast in the UK, China, and Germany. But not everywhere is suited to building such wind farms. In California, the continental shelf drops off steeply near the coast, and waters are over a thousand meters deep just a few dozen miles offshore, ruling out conventional wind power, which is practical up to depths of about 60 meters.

The solution, as Weinstein sees it, is to build floating turbines. Offshore wind power is following a progression that oil and gas companies charted with drilling rigs: moving from onshore to offshore to floating installations, Weinstein said.

Weinstein has been involved in some of the world's first demonstration projects for floating wind power, including a 50 megawatt installation in Scotland. In total, about 125 megawatts of demonstration projects have been installed globally, and another 125 megawatts are under construction.

And the pipeline is growing quickly. In total, over 60 gigawatts of offshore wind projects across the world are in the planning stages, with South Korea, the UK, Australia, and Brazil among the top countries in planned capacity.

This illustration depicts six offshore wind turbines. The left three are traditional fixed foundation, while the right three are floating models.JOSHUA BAUER, NATIONAL RENEWABLE ENERGY LABORATORYA milestone, and what's next

Now, California is joining the list of governments jumping into the floating wind farm game.

The state auctioned off 370,000 acres of the ocean, which was divided into five sites across two areas off the coast of California. The sites are in water up to 1,300 meters deep, and will require floating wind technology. My colleague James Temple published a story diving into the auction earlier this week.

Companies bid on sites that could collectively house enough wind turbines to generate as much as 4.5 gigawatts of electricity, enough to power over 1.5 million homes. In total, the sites sold for $757 million, with the largest site fetching nearly $174 million.

The auction represents a new phase for floating offshore wind. Less than a decade ago, Weinstein told me at EmTech, people didn't take the technology seriously when she proposed plans to build farms in the state. People looked at me and said, you've got to be crazy, why are you doing this, this is not going to work,'" she said.

Now, companies could start the journey to building US floating wind farms in earnest. But the auction is just one of a series of many steps between conception and power generation. Companies have years of planning and building ahead before they start generating electricity from the sites. Securing the permits alone could take five to seven years.

And new challenges seem to pop up everywhere you look. The California sites are about 20 miles off the coast, and building transmission lines that can handle and disperse what's generated from offshore wind farms would be a major undertaking and could be prohibitively expensive. Ports may need to be completely reconfigured to handle putting together and moving the massive turbines before they're tugged out to sea. And not everyone is happy about plans to build wind turbines, even dozens of miles off the coast.

Earlier this year, the Biden administration announced a goal to build 15 gigawatts of floating offshore wind power by 2035 and cut costs by over 70%.

The second part of that goal is probably the most important piece of this puzzle, as cost might be the key deciding factor on whether or not floating offshore wind can make a dent in renewable energy goals.

Estimates are tricky because the technology is so new, but the US Department of Energy pegs the cost of floating offshore wind at about $200 per megawatt hour. That's significantly more expensive than the agency's estimates for land-based wind ($30), solar ($35) and even fixed offshore wind ($80).

As the technology becomes more widespread, costs could come down. Other renewable energy technologies like solar and lithium-ion batteries have seen steep cost declines as they've scaled. But with all the other barriers ahead, there's no guarantee that floating wind power will follow the same trajectory.

The California installations, along with other major commercial projects around the world, could be the proving ground for floating offshore wind, determining whether it will become a significant part of the coastal energy mix. Make sure to check out James's story for more on the promise and challenges of floating offshore wind and what the technology might look like in California and around the world.

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