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Glascow (in NewNet on June 12, 2010): New research has suggested that larger wind turbine blades are more efficient at generating electricity in certain circumstances, such as in lower wind speeds. But wind developers at New Energy World Network’s Wind Energy Investor Forum said there is a limit to how large a blade on a wind turbine can be. ‘Are we going to continue to grow blade size?’ said Vestas Wind Systems’ senior power sector specialist, Per Holmgaard when speaking at the forum.
Researchers at the University of Glasgow in cooperation with Gaia-Wind recently found that larger blades are more efficient at generating electricity in lower wind speeds.
While giant wind farms are mostly sited on hillsides and coasts with little population, smaller wind turbines that tend to serve farms and businesses are often located in more populated areas with less wind but paradoxically the implication of the findings is that bigger turbines with larger blades are more effective in these areas. The research focused on the effects of changes in the number of rotor blades; the size of the blades; and the electrical design of the generator.
From the beginning of April, owners of small wind turbines will be able to generate income from producing their own renewable electricity. The local government also recently announced support for new testing infrastructure and related equipment to be based at East Kilbride, Scotland.
Gaia-Wind’s managing director Jonnie Andringa said, ‘The research… shows the direction for our future R&D work; innovation, which is at the heart of our company, can be tested with these modelling tools prior to starting the engineering work.’ The research presented by Dr M Sergio Campobasso at the University of Glasgow was focused on the effects of various electrical and aerodynamic design choices on the overall performance of small wind turbines. The investigation, which was carried out using blade element momentum theory and electrical models to estimate the electrical performance of induction generators and permanent magnet generators coupled to inverters, found that the geometric parameter has the strongest impact on the extracted power is the rotor diameter.
Computer simulations and examination of the power curves of installed turbines show that the effect of this parameter on the collected power is particularly strong at low wind speeds, where most small turbines work with a power co-efficient close to the maximum, the researchers said. The research also showed that other design parameters affecting the aerodynamic performance of small wind turbines are the number of blades and the choice of rotational speed control, based on which constant- or variable-speed turbines can be designed.
Holmgaard suggested that two promising future routes of development are making two-part sectional blades that would include lower construction costs and making turbines bigger offshore. ‘I think we will see new sectional, lighter blades as transportation is particularly important,’ he said. |
