Can floating vertical-axis wind turbines really bring down the cost of offshore wind power at deep waters by a significant extent? We may know the answer to that question soon enough as Swedish wind turbine supplier SeaTwirl has signed an agreement with offshore energy and maritime provider Westcon that will see a construction and deployment of 1MW wind turbines in Norway no matter the preliminary cost.
Energy transformation and carbon reduction are gradually marching towards deep waters in the midst of depleting nearshore areas for the development of offshore wind power resources, and fixated horizontal-axis wind turbines that resemble offshore fans are not easy in installations at deep waters, or else an exorbitant level of construction cost must be incorporated, which is where floating vertical-axis wind turbines come in.
A vertical-axis wind turbine can capture and utilize wind from all directions, why is why it has a higher density and a smaller wake effect compared to normal horizontal-axis wind turbines. Differentiating from horizontal-axis wind turbines that place key power-generating components on the top of the tower that forms a heavy upper, vertical-axis wind turbines are able to store equipment at the bottom, which prevents wobbling from happening.
SeaTwirl was established in 2012, and installed the 30kW floating wind turbine S1 at the coast of Lysekil in Sweden during 2015 according to its prototype design and test theories back in 2007, which has been proven to withstand various hurricane and wave conditions over the past 7 years. SealTwirl’s design consists of three blades being securely installed on the floating tower, and the heavy objects at the bottom are used as the keel.
SeaTwirl is currently preparing the first 1MW variation, and has signed with a MOU with Westcon. The first commercial wind turbine S2X, regardless of the cost, will be deployed in Bokn of Norway, and is scheduled to initiate operation in 2023 that will last about 5 years.
S2x should be 30 times larger than S1, with roughly 55m of height over sea level, and 80m deep under water in order to balance the bottom part. Power will be cut off during a wind speed of more than 25m/second, though its design is able to sustain an extreme wind speed of 50m/second. S2x is estimated to have a lifespan of 25-30 years.
An analysis from third parties indicates that the LCOE of S2x may be lower than €50/MWh in the future. SeaTwirl commented that the company is also researching 6-10MW wind turbines aside from S2x, and may come to fruition by 2025. Future wind turbines may also expand to 30MW, which is almost a twofold increase in capacity compared to the largest horizontal wind turbine right now.
With that being said, a 1MW S2x wind turbine requires a 135m long backbone, which imposes transportation and deployment problems, and SeaTwirls has also commented that the company has yet to decide on the methods of installation and transportation, with no plans in using a deepwater terminal. Cost will definitely be a major factor.
(Cover photo source: SeaTwirl)