In 2014, Mitsubishi Heavy Industries (MHI) formed a joint venture with Vestas called MHI Vestas Offshore Wind. The strategy behind that joint venture is now substantially clearer. MHI’s decision to stop the commercialization of its 7 MW SeaAngel offshore wind turbine, to focus instead on the Vestas V164-8.0 MW turbine under MHI Vestas Offshore Wind, makes sense given Vestas’ expertise in the offshore market and the need to move forward without confusion or conflict between the two turbine platforms.
Technology-wise, the SeaAngel’s novel Digital Displacement Transmission Technology (DDT) looked like the more advanced drivetrain system. It employs a sophisticated series of hydraulic pumps, values, and motors to transfer the energy from the constantly varying rotor speed to a fixed speed generator, without the use of a gearbox. No other wind turbine employs a hydraulic drivetrain like this.
That novel technology, however, adds uncertainty to the construction and operation of offshore wind farms.
The increased construction and turbine servicing costs and associated risks for offshore wind increase the rate of return that investors expect to up to 12% compared to an onshore wind farm’s 7% to 9% in developed markets. Once you add the risk of employing a completely new transmission technology system, you likely outweigh the benefits offered by the new drivetrain design. The joint venture with Vestas provides access to a similarly sized turbine based on a proven and more conventional, medium speed geared technology, eliminating the added risk.
Although Vestas’ turbine is also new in the market, the company’s offshore turbine reliability has dramatically improved since 2004, when it had to replace the transformers and generators in all 81 of its then new V80 machines at Horns Rev offshore wind farm. Much refinement and advancement specific to offshore has been achieved by Vestas and its peers.
It’s also important to send a clear signal to the market that the Vestas V164-8.0 turbine is the primary turbine offering of the joint venture, without a separate Mitsubishi-branded product offered outside or within the joint venture. Although the SeaAngel turbine will disappear as a stand-alone brand, testing of the hydraulic technology will continue.
Onshore testing of the full-size 7 MW turbine officially began on February at a test center in the United Kingdom for validation of the drivetrain design. A similar hydraulic-powered turbine may be installed later in 2015 in Japan on a floating platform, depending on the results from the U.K. tests.
Ultimately, the aim of the effort is to focus on refinement and validation of the hydraulic drivetrain for possible future use under the MHI Vestas joint venture. The floating platform may, in coming years, become part of the joint venture’s offerings as well. For now, though, the V164-8.0 turbine using proven Vestas technology is marching out to sea, having recently landed its first order of 32 units for the 258 MW Burbo Bank Extension project on the west coast of the United Kingdom in the Irish Sea. Hiring has just begun to build the 80 meter turbine blades.
Roberto Labastida contributed to this post.