In this month’s back-to-basics series, Cathryn Hickey, from the National Skills Academy for Environmental Technologies, looks at micro-wind, one of the less common forms of renewable energy.
A basic wind turbine operates on the principle that wind passing across the rotor blades causes a ‘lift’ and ‘drag’ effect, which in turn makes the hub rotate. The hub is connected by a low-speed shaft to a gearbox, which increases the speed of rotation of the shaft. The high-speed shaft is then connected to a generator that produces electricity.
Basic system categories
Although there are a number of system types, variations andconfigurations, micro-wind turbine systems fall into two basic system categories:
- On-grid systems, which allow any surplus electricity generated to be exported to the national grid.
- Off-grid systems, which use a battery bank arrangement to store the electricity generated for on-demand power. The popularity of on-grid systems has increased significantly since the introduction of the Feed-in Tariff scheme. Some micro-wind turbine systems combine both arrangements.