WIND POWER:A BRITISH CONSORTIUM has unveiled two radical V-shaped wind turbine designs that are lighter, more stable, easier to maintain and generate more power than the current generation.
The concepts – the Nova vertical axis wind turbine (VAWT) and the Aerogenerator X – emerged after an 18-month feasibility study by Cranfield University, QinetiQ, Strathclyde University, Sheffield University and Wind Power Limited, funded by a group including Rolls-Royce, Shell, BP, EDF and the UK government.
V-shaped turbines operate at a lower height and do not encounter the same problems as the current generation – known as horizontal axis wind turbines (HAWTs) – because of their size and height, especially in gale force winds.
Designed for offshore deployment, VAWTs are also able to harness the wind from any direction and do not require mechanisms that ensure they’re always facing the wind.
Research carried out so far suggests the largest would have a wingspan of 275 metres (about four times that of a Boeing 747) and could generate 10MW of power, whereas most of the largest HAWTs currently installed are rated at 3MW.
Speaking at the unveiling of Aerogenerator X, John Roberts, head of energy at Arup, which was involved in its design, said: “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. There is a tremendous opportunity for new ideas to make a difference to the commercial viability and operability of offshore wind power.
Professor Feargal Brennan, head of offshore, process and energy engineering at Cranfield University, said: “Upsizing conventional onshore wind turbine technology to overcome cost barriers has significant challenges, not least the weight of the blades. As they turn, their weight pulls downwards, putting a changing stress on the structure in a cycle that repeats with every rotation – up to 20 times a minute.”
Once you reinforce a HAWT blade to cope with these stresses, mountings and other components also need reinforcing, making them heavier. The tower sections then need reinforcing because they come under additional bending stresses, amplified in very deep water.
Although it will be several years before full-scale VAWT prototypes are ready, in theory it may be possible to achieve further economies of scale with turbines that generate 20MW or more, researchers involved with the project added.
If proven, the implications of the new designs are significant for Irish companies such as Mainstream Renewable Power and for the UK, where up to £100 billion (€122 billion) of investment in offshore wind power is forecast by 2020.
They may also be significant for Ireland because, compared to the newer designs’ potential, any Irish investment in current wind technology would lock in higher electricity costs here for up to 25 years.
