June 1, 2010

Energy Storage: Renewables’ Necessary Partner

By Angela Neville, JD

Timing is everything in the world of electric power generation. The timing of the delivery of electricity is affected by both the users’ demand and the speed with which a variety of energy sources supply power to the transmission system. Modern grids require reliable energy sources to instantly meet the needs of their users.

A big limitation of several renewable energy sources—wind, solar, wave, and tidal power—is the fact that they are available on an intermittent basis due to fluctuations in natural conditions. For example, the variable nature of wind generation poses special challenges to grid operators who must constantly balance the supply of and demand for electricity on the grid.

Fortunately, new and emerging energy storage (ES) technologies are poised to help develop renewable energy resources by increasing their efficiency and dependability in providing electrical energy to any nation’s electric grid.

“Time Machine” Technologies

The attraction of bulk ES technologies is that they can harness the power of renewables and allow the energy to be used selectively when it is needed, not just when it is generated. As such, these technologies function as “time machines” that overcome the timing issues that plague renewables.

Examples of ES technologies include, but are not limited to, these:

• Large-scale advanced electrochemical batteries, which use chemical reactions to create a flow of electrons.
• Compressed air energy storage (CAES), which involves the use of electric energy to drive compressors that compress air into a cavern at high pressures. Then, when electrical energy is needed, the compressed air is released through a modified natural gas–fired turbine to generate electric energy.
• Pumped storage hydroelectric facilities, which pump water from a lower elevation to a higher elevation during off-peak periods for release through turbines during peak periods.