Onshore, Project Development, Wind Power

Vertical Axis Challenges Offshore Wind Power Limits

Issue 1 and Volume 1.

By shifting the weight of wind turbines to their base, the UK company’s pioneering design could accelerate the achievement of the country’s wind strategy. The new design is half the height of an equivalent horizontal-axis turbine and its blades are safe from weight-induced fatigue, according to its makers.

“Upsizing conventional onshore wind turbine technology to overcome cost barriers has significant challenges, not least the weight of the blades, which experience a fully reversed fatigue cycle on each rotation,” said Professor Feargal Brennan, head of Offshore, Process and Energy Engineering at Cranfield University, speaking at the launch event on 26 July.

“As the blades turn, their weight always pulls downwards, putting a changing stress on the structure, in a cycle that repeats with every rotation – up to 20 times a minute.”

If realised, the vertical-axis Aerogenerator X would be 130 metres high with a diameter of 270 metres. But freedom from conventional loading opens up the prospect of up-scaling the device to 20 MW.

The new turbineemerged from the NOVA project, an 18-month feasibility study undertaken by Cranfield University, QinetiQ, Strathclyde University, Sheffield University and Wind Power and funded by the UK’s Energy Technologies Institute.

John Roberts, head of Energy at Arup, suggested the innovative design may also be suitable for deeper water.

“Despite the installation of a number of large wind turbines offshore, the problems of increasing capital cost for deeper water remains unsolved as does the issue of safe operability in the marine environment,” he said.

“There is a tremendous opportunity for new ideas to make a difference to the commercial viability and operability of offshore wind power.”

Wind Power Limited has announce that it is in the process of entering a memorandum of understanding with Arup to continue project development.

Theo Bird of Wind Power Limited added that the project owes much to advances in turbine design in the United States.

“Offshore is the ideal place for wind power but is also an extremely tough environment,” he said.

“The US wind researchers who worked on vertical axis projects have always regarded the technology as great to work with at sea because it can be big, tough and easily managed. We are extremely grateful to the ETI who had the vision to help us pick up from where the US left off.”