WIND POWER:A US start-up has designed a wind turbine combined with a gas-driven turbo motor that can be used to turn the turbine when the wind is not blowing, which is on average 70 per cent of the time.

Colorado-based Hybrid Turbines use a ground-level turbo compressor to compress air that then drives a turbo motor directly connected to the wind turbine.

This can be powered using either natural gas or a renewable fuel such as biofuel or biogas, and even if natural gas is used, the electricity generated still emits half the CO2 as a coal-burning power station, the company claims.

Although the technology adds about 30 per cent to the cost of a turbine, this is cheaper than existing technology – typically a gas powered back-up system – which costs at least twice as much.

In addition, providing that there is room in a wind turbine’s gearbox housing to install Hybrid Turbines’ technology, it can be retro-fitted to existing wind turbines, one at a time if needed, whereas existing backup systems have to be installed for whole farms at a time.

The company is currently targeting both onshore and offshore wind farm operators, although its current designs are only compatible with turbines of up to 4MW.