Guest essay by Eric Worrall

At €125 million per floating turbine, vs €20 million for a fixed offshore turbine, the new technology still “has a long way to go on the economics”. But people are getting excited, and EU cash is pouring into this expensive new wind power scheme.

A New Weapon Against Climate Change May Float

The wind power industry sees an opportunity in allowing windmills to be pushed into deeper water.

By Stanley Reed

This article is part of a special report on Climate Solutions.

FERROL, Spain — A strange-looking contraption that could represent a new frontier in clean energy wallowed in the water alongside a coal dock here in a bay in northwest Spain.

This floating windmill with a tower about 600 feet high was sheltering in the harbor. After waiting out the rough winter seas and the disruption from the coronavirus pandemic, it was towed in late May to join two others anchored in the Atlantic in 330 feet of water 11 miles off Viana do Castelo on the northwest coast of Portugal.

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Mr. Pinheiro’s machine floats on three partly submerged columns, each about 100 feet long. Steel catwalks bridge the gaps between the giant cylinders. Sensors signal to pumps to add or remove water from the columns to keep the platform at the right level for optimal wind generation. In a gentle sea in the bay, the vessel, which weighs thousands of tons, seemed remarkably stable.

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WindFloat, whose cost was pegged in 2018 at 125 million euros, or about $137 million today, is majority owned by EDP Renewables. About €60 million came through a loan by the European Investment Bank, a wing of the European Union, which supports what it considers to be promising renewable technologies.

By comparison, turbines of similar size installed on the sea bottom cost around €20 million each when they are used in large facilities in which the costs can be spread among scores of machines. The new technology still “has a long way to go on the economics,” said Alexander Flotre, an analyst at Rystad Energy, a market research firm.

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Mr. Metelo said that wind farms of this size would likely generate electricity at a cost of around €200 per megawatt-hour, a wholesale power measure, over their lives, which may extend to 25 years. He estimated that with far greater scale and even larger turbines expected on the market in the future costs could come down to the €50 range, which is competitive with turbines attached to the bottom.

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Read more: https://www.nytimes.com/2020/06/04/climate/floating-windmills-fight-climate-change.html

An interesting concept, but by their own admission still a long way to go until it becomes cost competitive, even with existing mainstream wind turbine technology.

From my understanding of the technology, platform sway could be a big problem.

In 2011 a senior wind engineer told me bearings are the Achilles heel of wind turbines, his words were “we need a quantum leap in bearing material technology”. As of late 2018 turbine owners were still experiencing problems with wear. The bearings wear out too fast, but if they make the bearings bigger and stronger, turbine performance plummets, because larger bearing create greater friction.

Who knows, maybe technology has advanced since 2018, or maybe the engineers who designed the floating platform have discovered new tricks to protect the bearings from damage. But a turbine platform which adds substantial sway to already overloaded turbine bearings, it will be interesting to see how long the turbine lasts.