主題
Providing the energy of 25 regular wind turbines at half the price.
Oct 21, 2021
The Windcatcher.
Norwegian company Wind Catching Systems developed a floating offshore wind power system that generates energy at a much more affordable rate than traditional wind turbines, thanks to efficiency gains built-in through clever engineering.
The system, dubbed the Windcatcher, can truly "unleash the power of offshore wind," Daniel Engelhart-Willoch, VP of Industry and Government Affairs at Wind Catching tells us over an email exchange.
Describing the benefits of the Windcatcher, Engelhart-Willoch says "the main highlights are that we aim to dramatically slash costs for floating wind, and that we use about 20 percent of the ocean acreage for the same electricity generation as a single-turbine 15 MW floater."
Slashing the cost of offshore wind
The floating Windcatcher, which stacks 126 small rotors vertically on a 1,000-foot-high (324 m) framework, is capable of producing energy for 80,000 homes, according to Wind Catching's website. Five Windcatcher units, the company explains, are able to produce the equivalent energy of 25 traditional wind turbines at approximately half the price. According to the company, the system's Levelized Cost of Energy (LCOE) is comparable to the price of the power grid — which in Norway and the U.S. is approximately $105 per megawatt-hour. All going as planned then, it is a system that could unlock the potential of offshore wind, helping global governments reach their net-zero goals.
The way Wind Catching achieves this impressive efficiency, Engelhart-Willoch tells us, can be simplified into three main points: firstly, it is achieved by "lowering maintenance and operations costs through incorporating autonomous service systems and using simpler turbines." Secondly, "having shorter blades [allows] for higher-rated wind speed," and lets the firm "take advantage of the exponential growth in wind's power content with increasing wind speed." Lastly, it is achieved via "a modular system that allows for a much longer design life than what makes sense for single-turbine technology."
A side-by-side comparison of the number of Windcatchers and traditional wind turbines needed to produce the same amount of energy. Source: Wind Catching Systems
Traditional floating wind turbines, whose large blades can go up to 377 feet (115 meters) in length, typically max out at speeds of approximately 11 meters per second. By comparison, the Windcatcher relies on many smaller turbines with 15-meter-long blades that perform more rotations per minute and max out at approximately 18 meters per second. Placing many smaller rotors side by side also allows operators to reap the benefits of the multirotor effect, which means that several rotors together generate more energy than the sum of their individual parts as they feed off of the extra wind turbulence that is generated.
Wind Catching's system mounts 126 of these smaller turbines — a previous model used 117 — onto a steel framework that is erected on a semi-submersible hull. At the center of this structure is a rotating turret that allows the entire framework to move like a sail and "catch" the wind. Another great benefit of the stacked rotor system is that it uses an elevator-based turbine installation system, meaning maintenance is easier and no specialized vessels or cranes are required.
The Windcatcher can also be set up near the shore before being towed out to tap the potential of deep-sea winds. Traditional turbines, on the other hand, require complex installation procedures using specialized vessels.
Dramatic innovation is required as humanity faces 'code red'
Wind Catching explains that its units could produce up to 400 gigawatt-hours of energy per year, and that they have a 50-year lifespan, which is roughly 30 years longer than the average offshore wind farm. This means that not only will the system produce more energy, it will also produce less waste and will require a smaller footprint as each unit will operate for longer periods, reducing the number of installation operations required. The company has yet to set any location or dates in stone, though says that a pilot operation may set sail at some point in 2024.
Wind Catching isn't the only firm aiming to provide alternative solutions to traditional wind turbines. German firm Kitefraft, for example, is developing 100kW flying wind turbines that require 10 times fewer materials to develop than traditional wind turbines. These machines are also more adaptable than regular wind turbines as they can be reigned in via their tethers to avoid damage during hurricanes or strong wind conditions.
According to a recent report by the Energy Information Administration (EIA), with current technologies, offshore wind is 2.6 times more expensive than wind farms on land and it is 3.4 times more expensive than power produced at natural gas combined cycle plants.
So, with the IPCC's latest report — described as "code red for humanity" by UN Secretary-General António Guterres — calling for dramatic action from governments and organizations to combat climate change, the innovation of companies such as Wind Catching is desperately required.
"If we can bring floating wind power down to the costs that bottom-fixed offshore wind is currently producing at within a few years, we have come a long way in making one of the last major untapped renewable resources available to the world," Engelhart-Willoch says. "Most of the wind energy available out there is found in areas unavailable to the only technologies that are commercially valid today, and so what we aim to do is essentially to unleash the power of offshore wind."
