A NEW tidal turbine design could “revolutionise” the renewable industry in Scotland, its creator has claimed.
Robert McAnally, a mechanical engineer who worked in the oil industry for 17 years, told the Sunday National that his proposal could open “a lot of the North Sea” to tidal stream energy, which generates power from the movement of the oceans.
The idea is to co-locate specially designed “Tide-Torrent” turbines on the sea floor alongside offshore wind farms.
Water moving past wind turbine foundations gains speed, McAnally said, suggesting smaller tidal generators could be positioned to capture that extra energy.
The engineer added that a funnel-shaped input could further increase the water flow speed over the blades.
“You're increasing the velocity, and the velocity cubed is what is the important thing,” McAnally said.
He explained that because the power you get out is proportional to the cube of the velocity, water speeds of 4m/s actually give eight times more power than 2m/s.
McAnally also said that his design was smaller than other tidal turbines, meaning it could be placed in shallower water.
“There's a lot of situations like Dogger Bank, for example, about one-third of the wind farm is in water depths that a normal tidal turbine just won't go,” he said. “They require 30-metre water depth, and this is going to work in 10.”
He claimed that two 2MW Tide-Torrent turbines could increase a single 12MW wind turbine’s output by 30%.
The engineer said that another benefit would be that the smaller tidal turbines can plug into existing offshore wind cabling, reducing the need for expensive new infrastructure work.
Asked if this could lead to increased constraint payments – which are paid to wind farms to shut down when the grid cannot handle the energy they are producing and ultimately charged to bill payers – McAnally argued that “overcreating energy” will not be a problem in the long term.
Another key benefit of co-location, McAnally said, is the cost of leasing the sea bed; if that is already being paid by a wind farm, you “get that for free, basically, and all the profit is disproportionate”.
“So it can go in shallower water, it co-locates next to the monopile, and it means that you just have a simple connection from this device straight up into the wind turbine cabin,” he added.
McAnally said that the opportunities presented by his new design would be “huge”.
“A lot of the North Sea will now come into the area of being usable for co-locating,” he said.
“I'm not saying every wind farm will be usable, but it will open up the opportunity to actually look.”
McAnally said that he is in the process of pitching the idea to energy giants because “the key to being able to produce mechanical equipment like this, to do it sustainably, you need volume”.
“This is an opportunity for the renewables industry to flourish,” he added. “It's going to revolutionise the opportunity to use tidal.”
Scotland is already home to the world’s largest tidal stream array at MeyGen in the Pentland Firth, though the sector remains relatively small-scale. Developers have long argued that tidal energy could provide predictable baseload power.
In 2021, the UK Government introduced ringfenced support for tidal in Contracts for Difference auctions to help the industry grow.
