While the quest for pulling more megawatts from wind turbines has generally led to bigger and bigger rotors on turbines of conventional design – like this monster 22-MW number in China – Norway’s Wind Catching Systems (WCS) has taken a different path. It claims its mega-array of smaller rotors arranged in a grid would achieve up to 126 MW, or five times the energy of a 15-MW single-rotor turbine, in North Sea conditions – and even more in some other locations around the world.
In addition to the superior energy output, WCS says the Windcatcher design would allow for simpler installation compared to conventional wind turbines, greater ease of access for maintenance, simpler scalability, and a longer service life of 50 years, as opposed to 30 years for large single-turbine units.
The idea is to share the floating supports between a whole lot of small, relatively lightweight turbines, trussed up in enormous arrays of structural scaffolding, distributing both the weight of the turbine fans and generators, as well as the force supplied by the wind, across a broad area.
The scaffolding provides a perfect foundation for small installation/maintenance elevators, which run up and down behind the generators; once the main structure's up, all the working parts can be installed and maintained with relative ease. And since the system doesn't require massive generators and enormous blades, it promises to be much less logistically challenging to manufacture and move the parts around.
When we first wrote about the Windcatcher floating wind turbine array in 2021, there were a number of commenters who voiced some doubts about the design. And who can blame them? At over 1,000 ft (324 m) high and roughly just as wide, these massive grids of wind turbines would appear to stretch the bounds of feasibility. Just look at the potential scale of these things:
But in the past three years, WCS has made significant progress towards realizing its vision. In June, 2022 it announced it had secured up to US$10 million is a Series A investment round from GM Ventures, the venture capital arm of General Motors, and entered into a strategic agreement with GM to collaborate on “technology development, project execution, offshore wind policy, and the advancement of sustainable technology applications.”
This was followed in September 2022 and February 2023 by grants of NOK22 million (US$2.1 million) and NOK9.3 million (US$0.9 Million), respectively. These grants came from Enova SF, a Norwegian government enterprise devoted to reducing greenhouse gas emissions and exploring new clean energy technologies.
And now the design has received a major stamp of approval that, while probably not silencing the doubters, may give them pause. It comes from DNV (Det Norske Veritas), an international accredited registrar and classification society that provides services for various industries, including maritime, oil and gas and renewable energy. Many standards devised by DNV have served as the basis for international standards, so they’re a heavy hitter in the field.
DNV has awarded an Approval of Principle to WCS for its design for a 40-MW system that WCS says will be the first of four expected units for a demonstrator project off the coast of Øygarden, Norway.
“This is an important milestone towards the construction our first commercial demonstrator unit,” says Ole Heggheim, CEO of WCS.
WCS is yet to come forward with a specific Levelized Cost of Energy (LCoE) for this design – and the price of energy is fundamental to the success of all renewables projects. But if this upcoming demonstrator project proves the feasibility of the unique Windcatcher concept, the offshore wind farms of tomorrow may look very different to what we’ve become accustomed to.
It's extremely rare to see numbers as high as 40 MW – much less 126 MW – bandied about for a single offshore wind installation, so the potential here is incredibly exciting. We look forward to learning more about this demonstration installation as it comes together.
Source: WCS
