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Grid Storage Reality

FEBRUARY 3, 2017

By Donn Dears

The only potential solution for the problems caused by wind and solar generated electricity is storage.

But are there limits to storage? Is it possible to provide sufficient storage to allow the closing of a large number of fossil fuel power plants?

The CAISO Duck Curve defines the potential problems if wind and solar are to provide 80% of the grid’s electricity. See, Wind and Solar Inflict Pain.

It’s not possible to know the exact amount of storage that would be required to allow enough fossil fuel power plants to be shut down to cut CO2 emissions from power generation by 80%.

Without the ability to shut down these fossil fuel power plants, it would require consumers to pay a capacity charge to reimburse the utilities for keeping these plants operational, or, alternatively, allow the utilities to go bankrupt and then be nationalized by the government.

While it’s not possible to know precisely how much storage is needed to replace the fossil fuel power generation capacity that must be shut down, a reasonable estimate is that approximately 400,000 MW of storage, with sufficient operational use in hours, is required to replace the electricity that’s lost with the closure of fossil fuel power plants.

This estimate is derived by calculating the amount of coal-fired and natural gas power plants that must be closed to achieve an 80% reduction in CO2 emissions. An 80% reduction in CO2 emissions from fossil fuel power plants requires shutting down 441,000 MW of coal-fired and natural gas power plants.

Unless there is adequate storage of electricity, the fossil fuel power plants must be kept operational, and be ready to go online when the sun stops shining and the wind stops blowing.

Is it possible to have 400,000 MW of storage? Or anything close to that amount of storage?

Pumped storage and Compressed Air Storage (CAES) can store large amounts of electricity, but there are insufficient locations around the United States to accommodate the approximately 400,000 MW of storage needed.


Only two CAES facilities have been built thus far. One, at Huntorf Germany, in 1978, the second at McIntosh, Alabama, in 1991. Huntorf is rated 321 MW, McIntosh is rated 110 MW. A third CAES facility is proposed for the Intermountain Power Generation site in Utah, which is to be rated around 300 MW.

Note that these amounts of storage using CAES are minuscule when compared with the amount of storage needed.

Pumped Storage

There currently is 20,000 MW of pumped storage in the United States, with the potential for an additional 31,000 MW. While substantial, it still falls far short of the storage capacity needed to eliminate a large portion of fossil fuel generating capacity.

Other Storage Alternatives

Batteries and other possible storage mediums lack the necessary size, and have other additional limitations.

Batteries, for example, have relatively short lives and would have to be replaced periodically, which adds to their cost as a storage option.

Storage, using batteries, costs at least $2,000,000 per MW. A recent trial by Pacific Gas & Electric of battery storage cost more than twice this amount.


It’s virtually impossible to build sufficient storage capacity in the United States to allow for the closure of large amounts of fossil fuel power plants.

By using wind and solar, we are not only faced with the higher cost of electricity from these sources, but also having to pay for retaining nearly all of our existing fossil fuel power plants.

Reposted from Power For USA by Donn Dears.


About SMIPP Ltd.

SMIPP Ltd is a DG Independent Power Plant Private Joint Stock Company. 25-60 MW Gas Turbines Power Generators


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