CNN
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Wind power has been rising significantly in recent years, and now accounts for about 8% of the world’s energy production. By the end of the decade, it will be the second-largest renewable source after solar, having surpassed hydropower, according to the International Energy Agency.
Wind turbines are more efficient than solar panels — they harness, on average, about 50% of the energy that goes through them compared to about 20% for solar — but are more dependent on location. Offshore turbines benefit from stronger winds and are more efficient than those on land, but they are also more expensive to build and maintain.
In the UK, where wind power generation in 2024 was the largest energy source for the first time, a startup called Drift is looking to extract even more power from offshore wind by effectively chasing after it — in a racing yacht.
“We make renewable energy in the ocean using sailboats, and deliver that energy to ports across the globe,” says Drift’s founder and CEO Ben Medland. Drift has built two prototypes, just over 17 feet (5 meters) in length and first demonstrated them in 2022 at the Sail GP sailing league in Plymouth harbor in the UK.
The high-performance catamarans are equipped with hydrofoils that lift them out of the water as well as an underwater turbine, which looks like a propeller but works in the opposite way, by capturing energy as the vessel sails through the water. That renewable energy is fed to a device called an electrolyzer, which converts seawater into hydrogen gas and stores it aboard, ready to be offloaded. It can then be used as a clean fuel to power industrial processes or for cars, planes and ships.
“This is a first-ever class of mobile renewable energy,” Medland continues. “It doesn’t need grid infrastructure. It doesn’t need cables under the ocean. It doesn’t need foundations or anchors or anything like that. These are, if you will, ‘free range’ wind turbines.”
A $24-million yacht
Humans have used wind to propel ships for millennia, and wind-powered vessels are having a renaissance as a method to decarbonize global shipping. Drift aims to go one step further: “Our company’s philosophy is very simple — why can’t a ship produce renewable energy rather than using energy to move through the water?”
One key component in Drift’s technology is an algorithm that hunts for what Medland calls “Goldilock conditions” — wind that is strong enough to generate energy without being dangerous: “The Goldilocks algorithm sails 6 million virtual miles in 0.02 seconds to choose the next mile of optimized route — that kind of data wasn’t available just 10, 15 years ago,” he says. “When you add all of that together (with the onboard technology), you’ve got what’s effectively a fishing boat for energy.”
For now, the prototypes only produce a few kilowatts of power, comparable to a small urban wind turbine. Drift is working on a new design in the 1.5-megawatt range, comparable to a larger wind turbine about 300 feet (91 meters) in height, which will be in the water “in the next two years” and from which commercial models will derive. These ships will be 190 feet (58 meters) long and produce up to 330,000 pounds (150,000 kilograms) of hydrogen gas per year.
That capacity would still be lower than the average of newly installed turbines, which in the US was 3.2 megawatts in 2022. But Medland says that the ships will have a higher efficiency compared to wind turbines, meaning their potential would be “more equivalent to a three or a four-megawatt turbine or a seven-megawatt solar park.”
The cost of that first ship will be prohibitively high, around £20 million (about $24 million), due to the amount of research and development that will go into it. At scale, that will decrease to “single digit millions,” Medland says, adding that he estimates Drift could get initial orders for more than 40 vessels.
Drift will sail in international waters, in locations such as the North Atlantic and the Caribbean. The ships will bear a country flag and meet maritime standards. Initially they will be crewed, but the aim is to make them autonomous. The ships will have six crew, and will need to offload the hydrogen at port once a week on average, or up to every 10 days if optimal weather is further away from shore.
They will be operated on behalf of Drift’s clients, which Medland says are likely to be mainly heavy industries, island nations wanting to increase their power output, and maritime transport companies, including cargo or cruise ship operators looking for alternative fuels. He says that the first commercial fleet will make hydrogen more cheaply than “if you were to connect an electrolysis unit to the grid in the UK,” and that parity with the cheapest hydrogen, made from fossil fuels, will be achieved by 2030.
Drift says that the vessels wouldn’t be limited to making hydrogen, but could also be modified to produce green ammonia or green methanol. They could also power on-board data centers or carbon capture, and even help with ocean exploration: “Our ships move around a little bit like a butterfly in a garden,” says Medand. “It looks random, but it’s actually just very efficient,” which means they could also generate and gathering data from parts of the ocean that are rarely accessed, helping with weather models and mapping marine life.
Lateral thinking
Academics in the field of renewable energy and transport who are not involved with Drift expressed cautious optimism about the technology when approached by CNN for comment.
Making hydrogen generation mobile instead of static is “impressive lateral thinking,” according to Tristan Smith, professor of Energy and Transport at University College London, who says that the lack of availability of this new energy commodity is a real problem that needs creative and innovative solutions.
The challenge and key question, Smith adds, is whether Drift’s solution can compete in terms of cost at the point of consumption relative to other ways of producing and transporting hydrogen, or other fuels made with it, such as ammonia.
Autonomous energy harvesting vessels have been suggested in the past, says Alasdair McDonald, a professor at the School of Engineering of the University of Edinburgh, in Scotland. He points at designs proposed in the past by Scottish engineer Stephen Salter, which were meant to harvest energy at sea to artificially brighten clouds and combat climate change, or currently by French firm Farwind, which makes rotor sails to add wind propulsion to cargo ships but has also developed a design meant to store the wind energy onboard as hydrogen.
The general principle of extracting wind energy from the far offshore is reasonably sensible, McDonald says: “Wind speeds get higher as you go further from shore, but water depths become more challenging for existing wind turbine designs, and distance for cables means cost and losses. So autonomous energy harvesting vessels become the route to accessing this energy source.”
However, according to Simon Hogg, a professor at the Department of Engineering at Durham University in England, any new technology of this type needs to be sold on its advantage over other offshore renewable energy technologies, which could prove challenging because modern wind farms consist of hundreds of turbines in the 8-to-15-megawatt range with ever-increasing efficiency. Drift’s value is also dependent upon hydrogen becoming a major energy source, he adds, which is not yet certain.
He says that the challenges around scaling up the technology and integration with shipping and other sea users means it is best suited to “very specialized applications, such as hydrogen generation for remote locations.”