Offshore turbines confirm half-century vision of renewable electrolysis
During the energy crisis of the 1970s, the founder of the first U.S. wind engineering program told the U.S. Congress that wind turbines could eliminate the United States' dependence on water power. outside . University of Massachusetts engineering professor William Heronemus foresaw turbines that harnessed strong winds blowing offshore and used the electrolysis of seawater to store their renewable energy in the form of hydrogen fuel.
A worker walks out of the aisle leading to a production rig that electrolyzes seawater from wind into hydrogen produced by French company Lyhfe.
PETER FAIRLEY
Half a century later, Heronemus' vision had sprouted sea legs. The underlying technologies for floating giant turbines are evolving rapidly, expanding the accessibility of offshore wind energy with stronger winds over deeper waters. And in recent weeks, the first platform-based electrolysis plants have been pushed to sea.
Countries are counting on the abundance of offshore wind and the flexibility of hydrogen to meet their climate and energy security goals, and combining the two technologies will bring cost and operational advantages.
Last month, a French hydrogen producer towed the world's first floating hydrogen production platform to a test site 20 kilometers off the coast of Normandy. Nantes-based Lhyfe began operating a 1-megawatt platform at the port of Nantes Saint-Nazaire last year using energy onshore, producing 400 kilograms of green or renewable hydrogen per day. They are now ready to plug in a 2 MW floating wind turbine at the French offshore energy test site SEM-REV.
And Chinese state media reported last week that researchers there had plugged a hydrogen production platform into a wind farm off the coast of Fujian province. According to a recent review, nearly a dozen additional floating electrolysis demonstration projects are underway in the waters of Japan, Europe and Scandinavia.
Lhyfe offshore project manager Stéphane Le Berre says what is driving interest in offshore hydrogen production is risk aversion and reduced expected costs. Countries are counting on the abundance of offshore wind and the flexibility of hydrogen to meet their climate and energy security goals, Le Berre said. This technology offers cost and operational advantages.
This 2 MW floating wind turbine at the French offshore research site SEM-REV, designed by BW Ideol, is the premise for a 1 gigawatt floating power plant to be installed in Scotland.PETER FAIRLEY
European governments have developed a program to develop a combination of offshore wind plus hydrogen . In January, Germany announced that it had designated space in North Sea territorial waters for a green hydrogen project with a capacity of 1 GW. Two months later, the Dutch government said it would require contractors for the North Sea wind power plant to include a 500 MW offshore electrolyzer.
During a visit to Lhyfe's floating plant last month, just before it left the harbor, Le Berre told IEEE Spectrum that offshore hydrogen production was included in Lhyfe's mission. Lhyfe begins onshore hydrogen production in 2021, but the 1 MW electrolysis plant in coastal Normandy south of Nantes uses seawater from the local harbour. Bouin plant water purifiers remove salts and other dissolved contaminants that can corrode the electrolytic catalysts.
Last year, Lhyfe raised 110 million euros ($118 million) in an initial public offering and accelerated onshore expansion. It currently has three 5 MW plants under construction and is developing projects in excess of 100 MW in Denmark and Sweden.
To start moving abroad, Le Berre said, Lhyfe had to miniaturize equipment and increase reliability.
“A hydrogen plant plus pipeline is a 5 to 10 times cheaper investment than a power substation plus a cable.”
—Stéphane Le Berre, Lhyfe
Lhyfe's offshore demonstration instrument reuses an existing wave energy testing platform with approximately 200 square meters of open deck—a tight space for the electrolyzer, water refinery and transformer needed to using 20 kilovolts from the floating wind turbines of the SEM-REV test site. Electrolyte developer Plug Power, based in Latham, NY, collaborated on a hardware redesign to make the device suitable.
Meanwhile, tweaks to the control system of the electrolyzer are needed to ensure correct operation amid the expected jostling at SEM-REV, where waves can exceed 13 meters. For example, sensors must be recalibrated so that the system can weather the impact waves but remain off in the event of a potentially dangerous spike in internal gas pressure.
Preparing for the rigors of offshore operations also spurred exclusive upgrades to water treatment—which Lhyfe identified as the weakest link of the hydrogen platform.
Weather and competition for vessels can make access to offshore rigs difficult or impossible for weeks or months, making it possible to clean the reverse osmosis filters on a monthly basis. is not possible. So Lhyfe has added technologies to both prevent and remove deposits. “We had to design the systems so that in about six months, there was no maintenance, no operation,” says Le Berre.
The goal, Le Berre said, is to make sure the platform works in really bad weather, so that Lhyfe will see what's working—and what needs improvement. That will give Lhyfe an edge in bidding for offshore projects, he says, as floating wind power becomes competitive with the immobilization of turbines on the seabed—a tipping point he predicts around 2030. .
Why go to the trouble of producing hydrogen offshore in the first place? Why not bring electricity to shore and produce hydrogen there?
For hydrogen suppliers, the overseas advantage is avoiding the costs and allowing delays associated with locating hydrogen production in densely populated places like Europe and Japan. Le Berre adds that it took Lhyfe a year to find an insurance company willing to pay for their first factory.
Meanwhile, for offshore wind producers, Lhyfe's project to add electrolysis and a hydrogen pipeline to shore will reduce their energy supply costs as wind parks move further offshore. “A hydrogen plant plus pipeline is a 5 to 10 times cheaper investment than a power substation plus a cable,” Le Berre said.
Technological developments that could boost hydrogen's offshore advantage China's plant kicked off this month using a new electrolysis unit designed at the Chinese Academy of Sciences that eliminates the need to process water. The membrane-based technology, reported last year in the journal Nature, spontaneously generates steam, selectively transfers it towards the electrolytic cell, and re-liquefies it for separation with a liquid. catalysis.
Le Berre said Lhyfe is not waiting for improvements to plan to expand overseas. He says they already have a partner lined up for a 10 MW project on an offshore rig in Northern Europe—a project that he promises will be able to “make an official reveal” soon.
In the long term, Le Berre says Lhyfe hopes to bring some benefit to the ocean. Splitting seawater to produce hydrogen also releases an equal amount of oxygen, which is lacking in many coastal waters due to sewage and fertilizer runoff. According to Le Berre, such combating oxygen dead zones spurred Lhyfe's launch in 2019: "We wanted the ocean to actually retain as much of this oxygen as possible."
