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Floating Wind Turbines Could Unlock Some of America’s Best Renewable Energy Resources

This month, the world’s first utility-scale floating wind turbines started spinning off the coast of Scotland. These new turbines have a key difference from the 4,000 or so offshore turbines that have been installed around the world so far: They are not built into the seafloor. Rather, they stand on floating platforms, attached to the seafloor using only long cables.

This technology could have big implications for the U.S., because some of the nation’s best offshore wind resources are located above water too deep for turbines fixed to the ocean floor.

Take a look at this map of wind speeds in the western US. 


Purple and blue represent lower average wind speeds, yellow and orange represent higher speeds, and the darkest red represents an average wind speed of more than 22 miles per hour (up at around 300 feet over sea level, where the turbine blades go). Credit: NREL

It’s clear from the map that the area off the West Coast is home to some of the best wind resources that America has to offer. For comparison, look at the big yellow streak running down the middle of the U.S. from Canada to Texas. That region, where wind speeds are significantly lower, is home to more renewable energy production than almost anywhere else on earth, and powers more than a third of the electricity consumed in Iowa, North Dakota and Oklahoma.

In fact, there is more wind blowing off the West Coast than we could ever use. According to data from the Department of Energy, West Coast wind could supply three times the electricity needs of the entire United States, or 26 times the needs of California, Oregon and Washington.[1]

That offshore energy is valuable, and not just because there’s a lot of it. Offshore wind could be built right by some of America’s biggest population centers and energy demand. And offshore wind can complement solar energy, since turbines can keep spinning at full power at night and on cloudy days.

But until now, accessing all that energy has been impossible. That’s because the ocean off the West Coast is too deep for fixed-bottom turbines, which can only be realistically installed in depths of up to around 150 feet. Off the West Coast, around 99 percent of all the offshore wind potential is in ocean deeper than that.[pdf]

Because floating turbines are new and expensive (for now), it will take policy intervention to kickstart the technology. But doing so will likely be worth it in the long run. In addition to unlocking all that new wind energy, floating turbines have some big benefits that could eventually make them a core part of a clean, renewable electric grid, both in America and around the world. For example:  

  • Floating offshore turbines should eventually be easier and cheaper to mass-produce and install than fixed-bottom turbines, since they can be assembled in a central location (like a port) and towed to where they are needed, and they don’t require extensive construction on the ocean floor.[pdf] For this same reason, they are also less disruptive to vulnerable ecosystems on the ocean floor.
  • Floating offshore wind may be cheaper to maintain than fixed-bottom turbines, since they can be towed to shore for maintenance, and don’t have ocean floor foundations that need to be repaired.
  • Since floating turbines can be located far offshore, they can have less visual impact for people who live on the coast.


A few types of floating offshore wind turbines. Credit: NREL

Experts predict that as we begin deploying floating turbines they should dramatically drop in price. And as offshore wind gets cheaper, it could become a core part of our energy mix here in the U.S. – eventually playing a key role in getting us off fossil fuels altogether

Policymakers who want to kickstart American offshore wind don’t need to look far for inspiration. Some of the same policies that already helped drive development and reduce the cost of solar energy and onshore wind could also work for floating (and other offshore) turbines. For example, renewable energy standards can be updated with technology “carveouts” to guarantee demand for offshore energy. Work also needs to be done to streamline the process for developing offshore wind projects – the first U.S. offshore wind project, the Block Island Wind Farm off the coast of Rhode Island, needed to get approval from 11 separate state and federal agencies.

With the first floating wind turbines now spinning in Scotland, policymakers should work quickly. Beginning to develop offshore wind now – including using important new technologies like floating turbines – could be an important step toward achieving a clean, renewable grid of the future.

 

[1] Offshore wind potential: https://www.nrel.gov/docs/fy16osti/66599.pdf; current electricity use is from EIA’s electricity data browser: https://www.eia.gov/electricity/data/browser/