Skip to content

Grid Storage Reality

February 3, 2017

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.

Diagram of pumped storage, courtesy Energy Storage Association

Diagram of pumped storage, courtesy Energy Storage Association

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.

* * * * * *

Nothing to Fear, Chapter 12, explains why carbon capture and sequestration will not work.

Nothing to Fear is available from Amazon and some independent book sellers.

Link to Amazon:

Book Cover, Nothing to Fear

Book Cover, Nothing to Fear

* * * * * *


It’s easy to subscribe to articles by Donn Dears.

Go to the photo on the right side of the article where it says email subscription. Click and enter your email address. You can unsubscribe at any time.

If you know people who would be interested in these articles please send them a link to the article and suggest they also subscribe.

© Power For USA, 2010 – 2017. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author, Donn Dears LLC, is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Power For USA with appropriate and specific direction to the original content.

12 Comments leave one →
  1. February 3, 2017 9:03 am


    And there are environmental problems with storage batteries-

    Study: Batteries For Wind And Solar Do ‘More Harm Than Good’ For Environment

    Texas has been evaluating this form of storage.

    • February 3, 2017 9:29 am

      Yes. Thanks for pointing that out and for the link.

  2. Tom Clegg permalink
    February 3, 2017 5:19 pm

    Donn batteries have their own potential and you can only recharge them. When they reach their potential you are only wasting electric trying to put more power in them. Just like your cell phone once it is 100% charged leaving it plugged in is a waste of electric.

  3. February 4, 2017 3:05 am

    Thanks for this post Donn. I tried to read the PG&E study, but the jargon was too dense for me. Do I have these numbers right? 100% battery backup would cost between $800 billion to $1.6 trillion and the batteries would need to be replaced periodically. How often would they need to be replaced? Is this DC storage? If DC, does that include the cost of transformers to convert 400,000 MW to AC? And the real estate to locate millions of large banks of DC batteries and transformers? And the specialized grid to move DC from millions of solar panels or turbines to millions of storage batteries? Or, has someone invented an AC battery? How many acres would be required for 400,000 MW of solar panels or wind turbines and the banks of batteries, transformers and grids required to bring this on line? Is this physical space within the realm of possibility?

    • February 4, 2017 7:57 am

      Great questions. I have done a number of calculations as to the amount of space needed or the availability of resources for alternatives such as biofuels. They take a lot of time to get it right. But, I have never tried to calculate the space require by batteries. I should mention that there are different tyes of batteries besides the Litium-ion that has everyone’s attention. Flow batteries, for example, are probably better suited for this purpose. Battery costs would be at least that amount, and probably more based on actual experience such as mentioned above.

  4. Bill Palmer permalink
    February 4, 2017 7:24 am

    Discussion of energy storage must be in terms of MWh, not MW.

    A 100 MW pumped storage facility means only that it can absorb or supply 100 MW, but does not say for how long.

    Storage to replace solar or wind needs to be able to shift not just for a few hours but for seasons. Wind is strong in spring typically but low in summer. The problem is far bigger than this article suggests.

    • February 4, 2017 7:49 am

      I agree. My article focused on what most people could understand. In keeping it simple, I understated the problem. As you point out, storage must be long enough to meet needs for a period of time. The length of time varies from a few minutes to days. A battery can handle storg=age for relatively short periods of time, while pumped storage can handle longer periods of time. Thanks for your comments.

  5. Tom Clegg permalink
    February 4, 2017 11:10 am

    Donn I should have made myself clearer on my previous post. You can not store electric on a battery. Batteries have their own potential. The only thing you are doing is recharging their potential.

  6. March 10, 2017 10:59 am

    I just saw an article (on real science? Eew) about a German foundation that is studying using submerged spheres with a turbine/generator, pump the water out with wind power electricity, let the water in to generate electricity when the wind drops. Sounds like a too good to be true situation

    • March 10, 2017 11:08 am

      Haven’t seen it, but sounds too good to be true.


  1. Weekly Climate and Energy News Roundup #257 | Watts Up With That?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s