Study: Wind energy needs controls to minimize risk of instability on the grid

The problem of intermittency, or fluctuating availability depending on the weather, has long been cited as a hurdle for getting renewable energy onto the power grid. Researchers at North Carolina State University and Johns Hopkins University have identified a new dimension to this problem:

They say that the variability of wind power might actually worsen instability when there are disturbances on the grid, increasing the risk of power outages, depending on where the wind turbines are located, among other factors. (See related quiz: “What You Don’t Know About Wind Energy.”)

The paper’s authors detail a technique employing controllers to moderate the flow of wind power coming onto the grid by diverting it to battery storage when necessary. “If the power output for the wind farm increases, the surplus can be siphoned off to charge batteries at the storage facility, instead of being dumped directly onto the power grid,” said a release announcing the paper. “Similarly, if the power output at a wind farm declines, the batteries can compensate for the loss and provide power to the grid.” (See related story: “New ‘Flexible’ Power Plants Sway to Keep Up With Renewables.”)

The researchers point out that their system can be put to use regardless of where the turbines and batteries are located, making it applicable in decentralized systems over large geographical areas.

Though wind energy accounts for just a small percentage of U.S. electricity generation as a whole (3.4 percent in 2012), it is growing by leaps and bounds: the added electricity generation capacity for wind in 2012 was larger than for any other source, and is expected to grow by nearly 50 percent between 2015 and 2040, according to the Energy Information Administration.

Meanwhile, creative minds around the world are exploring ways to store surplus wind energy when the breeze generates more than the grid can handle. Ideas for storage vessels range from rock reservoirs to frozen fish. (See related stories: “Too Much Wind Energy? Save It in Underground Volcanic Rock Reservoirs” and “Frozen Fish Help Reel In Germany’s Wind Power.”)

http://theenergycollective.com/cnunez/323441/wind-energy-needs-controls-minimize-risk-instability-grid-study-says