Grid-connected Energy Storage Taking off

Michael Giberson

Yesterday’s announcement by General Compression, Inc. and ConocoPhillips that the companies would cooperate in developing compressed air energy storage systems (CAES) in Texas is yet another indication that grid-connected energy storage is beginning to take-off.

For more background on CAES see the recent article by Alexis Madrigal in WIRED, “Bottled wind could be as constant as coal.” From WIRED:

The nation’s largest energy storage option right now is pumped hydroelectricity. When excess electricity is present in a system, it can be used to pump water up to a reservoir. Then, when that power is needed, the water is sent through a turbine to generate electricity. The U.S. electric system has 2.5 gigawatts of pumped hydro storage capacity, but most of the good, cheap sites are already occupied, and creating new reservoirs is not environmentally benign.

While wind farmers say storage isn’t technically necessary until the amount of wind power on the grid exceeds 20 or 30 percent of the electrical load, private analysts, the Electric Power Research Institute, and the Department of Energy have identified grid-scale storage as a key need for the rapidly diversifying electricity system.

And going forward, compressed-air energy storage looks like the cheapest option available. Independent analysts have come to similar conclusions.

No specific projects or development dates were included in the General Compression/ConocoPhillips announcement.

On March 31 of this year Electric Transmission Texas, LLC, energized a 4-MW NaS battery near Presidio, Texas. While a few other such systems are in use – AEP first installed such a system in Ohio in 2002 – the ETT project is the largest grid-connected battery system in the United States.  National Geographic Daily News provides more details on the ETT battery project, “Texas pioneers energy storage in giant battery.”  ETT is owned in part by AEP.

I believe I’ve mentioned before in this space that cheap energy storage will revolutionize the electric power business.  We are not quite to the revolutionary stage yet, but these are signals that the day is coming nearer.

3 thoughts on “Grid-connected Energy Storage Taking off

  1. It won’t happen. CAES is just boosted natural gas generation. And the batteries are more expensive than nuclear.

  2. General Compression’s CAES technology doesn’t work in conjunction with natural gas combustion (not that there’s anything wrong with that), but rather apparently drives a turbine directly from the compressed air. (Based on somewhat general descriptions on their website.)

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