Wind Power Battery

Storing energy is a key part of renewable energy. For example, wind power batteries are crucial to reduce the impact of variability and limited predictability of wind energy generation. Wind turbines only generate power when the wind blows, therefore they need back up.

Xcel Energy is one of the first utilities in the U.S. to install a giant wind power battery system to store wind power for later use. Batteries can allow wind power to be stored when prices for power are cheap and sold at peak-price times in the afternoons. The company says improved storage can lower the cost of electricity and remove one of the biggest hurdles for broad adoption of wind power: intermittency.

The wind power battery technology in questions consists of a series of sodium-sulfur batteries made by NGK Insulators, Ltd (Japan). They can store roughly seven megawatt-hours of power, which is enough to power 500 average American homes for seven hours.

At present, wind power battery is very expensive: it costs about $3 million per megawatt, besides all the costs involved in starting up and testing the battery. But Xcel says testing will help the company understand the value and it hopes it will become more economically attractive.