Giant offshore wind farms may power the future. Gables firm designs next generation
In a Coral Gables office, engineers are drawing up plans to build massive floating platforms the size of U.S. Navy destroyers that may hold the key to the country’s green energy future.
The platforms are designed to hold the newest generation of offshore wind turbines, goliath structures that stand taller than the Golden Gate Bridge and generate so much energy that a single rotation of their nearly 400-foot blades could power a house for two days.
One day, much of the the country’s energy could come from offshore wind farms, where turbines harvest the energy from strong ocean winds and convert it into clean, renewable electricity for homes and businesses on the mainland. If and when these these kinds of structures wind up off the coast of South Florida remains uncertain. But the technology itself is promising enough that the U.S. Department of Energy expects wind power to play a key role in cutting the carbon emissions from the U.S. power grid and heading off the worst effects of climate change.
But there’s a major challenge to ramping up offshore wind power: Most ocean winds blow over water that’s too deep to erect today’s turbines. That’s why companies like Esteyco, a Spanish engineering firm that operates in the U.S. out of its office in Coral Gables, are developing floating platforms that can support massive turbines in the swells and storms of the deep sea.
In March, Esteyco became one of eight companies that won the first round of a Department of Energy grant competition that invests in companies developing floating platforms for offshore wind turbines.
“We’re hoping to help develop the domestic supply chain for these very large floating wind platforms,” said Nate McKenzie, technology manager for offshore wind research at the Department of Energy.
The grant competition, called the Floating Offshore Wind Readiness (FLOWIN) Prize, has three phases, with a final group of three winners eligible to win over $1.6 million each in cash prizes and research support from the energy department. As a Phase 1 winner, Esteyco has already won $100,000 to develop its technology, which it calls the Wheel Platform.
“The idea is to use these resources…to develop how this would work from the perspective of design, construction, installation, local supply chain, and overall demonstrate that it can be a good competitive solution with potential to general local economic benefits,” said José Serna, Esteyco’s chief technology officer.
A massive engineering challenge
The engineering challenge to design these platforms is almost as massive as the platforms themselves.
Floating wind platforms have to hold towering turbines upright in rough seas, while being compact enough that they can be assembled in a harbor and towed out to sea by tugboats. Each platform weighs between 5,000 and 15,000 tons, according to McKenzie. “The US Navy destroyer is about 10,000 tons right now, just to give you an idea of scale,” he said.
And the platforms aren’t like anything else on the water today. “It’s not quite ship building. It’s not quite oil and gas platform fabrication,” McKenzie said. “It’s some hybrid of those two things.”
Esteyco’s Wheel proposed platform consists of two lightweight concrete rings, one nested inside the other, which together weigh about 7,000 tons. While they’re being assembled and towed, both concrete rings would float on top of the water, sticking no more than 16 feet (5 meters) below the surface. That allows them to be built even in shallow harbors and shipyards.
But once the platform gets out to the open ocean, the inner concrete ring drops 160 feet (50 meters) below the surface, acting as a deep, steady counterweight. The outer concrete ring stays at the surface and supports the wind turbine. When wind and waves rock the turbine back and forth, the concrete ring deep underwater stabilizes the platform and keeps it upright.
Esteyco plans to test the Wheel platform with a pilot project in the Canary Islands set to be completed in 2025. “This will bring relevant lessons learned for their eventual application in the U.S.,” Serna said. “We plan to test not only the floater but also the construction strategies that will make it possible to build these units with quite reduced harbor infrastructure.”
Unlocking new territory for turbines
Almost all offshore wind turbines today are built on underwater pillars that stretch down to the bottom of the sea. Right now, companies typically won’t put wind turbines in water deeper than about 200 feet (60 meters) because it’s too expensive to build underwater foundations any deeper than that, according to McKenzie.
But that leaves a lot of wind unharvested, McKenzie said. About a third of all the offshore wind energy that turbines could hypothetically collect in the U.S. can be found over shallow waters less than 200 feet deep. The other two-thirds of US offshore wind energy is blowing over water deeper than 200 feet, including the entire west coast, big swaths of the east coast, and four out of the five Great Lakes.
The Department of Energy hopes that floating platforms, like the Wheel platform that Esteyco is building, will allow companies to place wind turbines in deeper waters.
“By being able to access that wind at those deeper water depths, it enables deployments in regions that would not otherwise be possible,” said McKenzie.
Esteyco plans to deploy its first U.S. platforms on the West Coast, either in Southern California or in Northern California near Oregon. Florida isn’t at the top of the company’s list of potential sites, because the state doesn’t get as much consistently strong wind as other parts of the coastal U.S.
But McKenzie says floating platforms could one day be useful in Florida. Roughly 80% of Florida’s offshore wind energy can be found over water deeper than 200 feet, where turbines would likely be built on floating platforms, according to a 2016 report from the U.S. National Renewable Energy Laboratory.
Despite the cleaner energy they provide, land-based and nearshore wind farms have drawn considerable opposition, including from Florida Republicans. The concerns often focus on spoiling pristine views, but critics also mention threats to birds and marine life. “We don’t want offshore anything,” Anna Paulina Luna, a congresswoman who represents a district that includes Clearwater in southwest Florida, told the Washington Post.
The Department of Energy has set ambitious goals for floating offshore wind power. McKenzie said the department wants the U.S. to build enough floating wind turbines to produce 15 gigawatts of energy by 2035. That’s roughly 375 times more than the current output of all offshore wind turbines built or under construction in the U.S., which totals 40 megawatts, according to a 2022 report from the energy department.
“With floating offshore wind, it’s really a long-term play,” said McKenzie. He said early pilot projects from companies like Esteyco will pave the way for turbine construction to speed up fast in the future
“We need to do these near-term projects so that we can get on the learning curve, lower the costs and really enable the long-term deployments at a scale which is commensurate with our long-term energy goals,” he said.
This climate report is funded by Florida International University, the Knight Foundation and the David and Christina Martin Family Foundation in partnership with Journalism Funding Partners. The Miami Herald retains editorial control of all content.
This story was originally published May 2, 2023 at 5:30 AM.