From New Power Report: SuperGen’s Deborah Greaves discusses the move from fixed to floating offshore wind

Deborah Greaves is heading the new Supergen offshore renewable energy (ORE) Hub, whose stated aim is, “to bring together for mutual benefit the related research areas of wave, tidal and offshore wind in order to share skills, resources and expertise.” During an interview for New Power Report (subscribers login to download the October issue) she discussed the opportunity for floating offshore wind.

She said that the jump from fixed to floating wind is a difficult challenge for a support mechanism: “There is still a lot of opportunity for fixed offshore wind, so at what point do you need to say this now has to be floating, and we are going to have something special for it?

“We are still pushing some of the [fixed offshore] foundations to deeper water, so perhaps as an industry we don’t know fully where the limitation is on fixed turbines.”

She sees plenty of opportunity for the big players in fixed offshore wind. Might that push floating turbines onto the ‘back burner’ when we should be trying to move it forward?

She says “That is something we can’t leave to the market. it needs government support and buy-in for that vision and the elements that feed into it.”

She expects that floating wind will be required but in that case – and at increasing distance from shore – “Questions come up around the cabling and whether you are going to have those farms grid-connected in the same way.” Research is needed into other ways to transport the energy. “You could do it as electrons, or you might transport hydrogen, or methane or heat – there are all sorts of potential different ways to think about it.”

Can we take advantage of our experience in oil and gas? Greaves says, “There is lots of transferable technology from the oil and gas sector, because they know how to build large floating structures and tie them into the seabed.” But the cost structure is different. Mooring and anchoring is a large part of the cost, but oil and gas platforms are larger than would be the case for wind turbines – and their aim is to start pumping as soon as possible. “Offshore wind has multiple floating platforms and each one has to have its mooring and anchoring system, so that is a much larger proportion of the cost of the individual unit. That’s what the challenge is.” There are other challenges, including limitations in the turbine blades and tower when it is on a small platform. “You have to design on a floating platform which is stable in order to support the turbine and allow it to operate within the limits it is designed for. Then you have to moor it to the seabed.

“There are a number of designs that are out there and have been demonstrated. There is the spar, which is for very deep waters, and then there are some semi-submerged solutions. These are all transferred from the oil and gas sector, but there is quite a lot of work to do to get the costs of those platforms down.”

She says the alternative might be, “To develop a really big platform and have a number of turbines on it, or combine it with a wave energy or tidal device.”

I ask about replication, which typically cuts costs. “I think with floating offshore wind we are likely to end up with perhaps one solution.” But that may not happen yet: “There are still possibilities for maybe a different type of turbine as well. It’s definitely an opportunity for innovation and perhaps disruptive technology changes.”


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