Small-scale turbine is ‘very efficient’ at lower wind speeds

The creators of a vertical-axis wind turbine say their new design could at least double the energy it captures at lower speeds.

Pembrokeshire-based Quiet Revolution has found a way to make small changes to the size, aerodynamics and electrical conversion and control systems of its small-scale turbines that yield substantial increases in the amount of energy produced.

Initial tests suggest the new design is particularly effective at lower wind speeds, meaning it could open up locations that were not previously cost effective as turbine sites.

‘The challenge in general for small wind is that there is a vast range of power outputs that we need to deal with but also the rate at which it changes,’ Richard Cochrane, chief technical officer at Quiet Revolution, told The Engineer.

‘The vertical axis gives us an inherent advantage in turbulent wind conditions as we don’t need to turn to face the wind. But direction is just one aspect of it. It’s also about maintaining your efficiency in rapidly changing wind velocities.

‘You need a broad, well-rounded aerodynamic design combined with an active control system that can speed up and follow those gusts to capture that energy very efficiently.’

He added: ‘We’ve also done a number of things within the structure to simplify the mechanical design to make it much quicker and easier to manufacture and therefore cheaper as well.’

The company collected data from a number of its QR5 wind turbines already in the field, as well as from lab testing, in order to make the adjustments.

Further tests are needed to confirm the exact increase in power output. ‘The relative improvement is not so good on a high-wind-speed site where the current generator was more optimal anyway,’ said Cochrane.