The “stunned” developer of the pioneering Icebreaker Wind project on the US Great Lakes said a consent condition added by local power officials could prove fatal to the project’s viability.

A condition added to the Ohio Power Siting Board (OPSB)’s approval of the project that turbines should be shut down overnight for most of the year “renders the project economically not viable”, said LEEDCo, which has spent years planning the six-turbine Icebreaker offshore wind farm in Lake Erie, Ohio.

LEEDCo said it had made the consequences of adding the condition “abundantly clear” and thought that the matter had been settled under a prior agreement with OPSB staff.

“We have been fully transparent with the OPSB Staff that this requirement makes the project economically unworkable and unrealistic,” said LEEDCo after the decision was published late last week.

“Today’s order is not an approval. A condition added by the Ohio Power Siting Board (OPSB) may well be fatal to the entire project. We are extremely disappointed the Board took this unfortunate step backward for clean energy in Ohio.

LEEDco president David Karpinski said: “The project had been thoroughly reviewed for many years under the strictest of environmental regulations and reviews by 13 local, state and federal agencies. In light of today’s decision, LEEDCo will need to reconvene in the coming days and examine our options on how and whether we can move forward.”

LEEDCo, a non-profit, public-private partnership, is co-developing Icebreaker Wind with Norwegian equity investor Fred Olsen Renewables.

Icebreaker plans to use MHI Vestas 3.45MW turbines, specially adapted offshore versions of Vestas’ V126-3.45 onshore machines. It is targeting start of construction in 2021 and operation in 2022.

The project is designed to act as a showcase for potential wider developer of Great Lakes wind power.

“This development is unsettling and unnecessary," said Liz Burdock, CEO of US industry business development body Business Network for Offshore Wind. We hope both parties can work past this in order to bring clean, renewable, and affordable energy to the region.”