Harnessing the Wind
Conventional energy sources, such as coal and nuclear energy, have serious downsides. Man is constantly searching for alternative, less harmful energy sources. Wind is a renewable energy source with promise. However, there are some obstacles that need to be overcome. Wind is an intermittent (i.e. not constant) energy source. Energy production varies as the strength of the wind changes and goes to zero when the wind dies. Power grids require constant availability of electricity. Engineers must develop techniques to store energy produced while the wind is blowing for use when there is no wind. The flywheel energy storage system (FESS) is one such technique. The wind energy is stored as kinetic energy by turning a steel flywheel connected by gears to the wind turbine. British scientists undertook a research project to develop and test two new FESS configurations: a mechanical Continuously Variable Transmission (CVT) drive and a power electronic (PE) drive. The drives were built by two industrial partners. The British researchers developed the accompanying sensors and controllers. The two systems were installed and evaluated at a test site in the UK. Both drives achieved success, but for different types of application. The PE drive is appropriate for grid-connected systems producing between 10 kW and 2 MW of power. The mechanical CVT drive more suitable for smaller applications, up to 300 kW, such as autonomous (diesel genset) applications. The results can be applied to supplement weak power grids or to provide small, uninterruptible power supplies. This work is helping to pave the way for harnessing the wind as a viable energy source.
