True carbon costs of offshore wind are not being declared in order to make the solution seem more environmentally acceptable than it actually is, according to a leading academic.

Cambridge University senior teaching associate Jim Platts is a former partner at Gifford [now Ramboll] and has focused his academic career on manufacturing issues.

He told NCE: “The concept of offshore wind is being sold as being environmentally friendly but the reality is that it is ferociously costly and has a big carbon footprint.”

Platts believes that the energy companies developing offshore wind farms are hiding full details about their carbon footprints and is calling on the sector to be more transparent about them.

NCE also understands that a number of people in the industry have raised concerns about the issue but have been silenced by their employers. NCE has approached industry leaders in the offshore wind energy sector for comment.

“People are becoming concerned with climate change but there is a need to focus on the numbers to make a difference,” he said. “Offshore wind turbines stick out of the water but there is lots of under the water too that people seem unaware of – there’s lots of steel and cable connections.

“Working out the carbon footprint is not simple but it is currently an invisible issue to the public.

“An analysis process is needed to look at the carbon footprint of offshore wind but all the energy companies need to use the same approach.

"Just looking at the wind turbine and the foundations will give you one number but adding in the grid connection will give you another number. We need to be able to accurately compare like with like.”

According to Platts, driving down the cost of such developments does not always create a positive result for the carbon footprint.

Projects such as the Oxford University-led Pile Soil Analysis (Pisa) project has helped refine design of monopile foundations, which are commonly used for UK offshore wind farms, and – along with other innovations – has resulted in the cost of new offshore wind developments falling by 50% since 2015.

Nonetheless, Platts said that the market five years ago was very unstable with each scheme treated as an individual project.

“The lack of continuity between projects resulted in high risks and increased costs as a result,” he said. Platts believes that the falling costs since 2015 are more to do with de-risking in the market than with design improvements.

Platts has called for a re-think of the support structures used for offshore wind turbines with a view to cutting the carbon cost.

“An average designer will tweak the design rather than rethink it completely,” he said. “The current monopile or suction jacket foundations are not an efficient way of taking bending moments into the ground.”

According to Platts, spreading loads is key. He suggested that Eiffel Tower or radio mast style structures with anchoring would create more robust solutions that have a lower carbon footprint.

He described the monopile solution as a “brute force approach”.

Platts said that floating foundations have huge potential, especially as offshore wind farms move into deeper water, but said that development is 10 years behind that of seabed mounted turbines. “They have good potential in the long term but they have yet to be put into commercial operation,” he added.

“Nonetheless, we need to have better carbon footprint analysis of the current designs in order to be able to accurately compare new solutions in terms of environmental performance.”

Platts also called for the industry to focus on longer service life for offshore wind turbines. “The current turbines and foundations have a 20 year design life,” he said.

“The power stations they are replacing had service lives in excess of 40 years – why aren’t people asking why offshore wind farms are only being designed for 20 years? We should be doing better.

“In my opinion, anything that is only designed for a 20 year life span should not be called infrastructure. Infrastructure is what you design to meet the needs of future generations.”

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