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Energy Storage – For More Than Renewables

The views expressed are those of the author and are not necessarily those of Scientific American.

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Large-scale energy storage technologies are often hailed as a key to enabling increased use of intermittent renewable energy resources – like solar and wind – to supply the nation’s electricity demand. If one can balance out the generation dips (for example, when the wind dies down on a summer afternoon) using an energy storage technology, they can create a system that is capable of providing electricity around the clock. But, the potential for these technologies is much more broad, with applications on short and long timescales, giving them the power to increase grid reliability and defer the need new infrastructure.

In the electricity world, energy storage generally refers to electricity, thermal, or potential energy storage. Examples include batteries (electricity), molten salts (thermal), and pumped hydro projects (potential energy). Today, the vast majority of installed grid-scale energy storage is pumped hydro technology, where water is pumped to a higher elevation when electricity is cheap and then gravity moves the water downhill to produce electricity during peak (expensive) periods.

But, large (utility) scale energy storage technologies can be used to meet a variety of other functions, including assuring power quality and deferring infrastructure upgrades.

The value of these functions is hinged on the fact that the electric grid requires a constant balance of electricity supply and demand. The latter is constantly shifting, which forces grid operators to constantly make changes in order to maintain acceptable reliability and power quality.

Earlier this month, the U.S. Energy Information Administration (EIA) published a visual depicting types of energy storage technologies in terms of their discharge time and total capacity. Both are indicative of the types of applications that the system could be used for. For instance, certain types of battery technologies can not only respond quickly – providing power when needed – but also supply a large amount of total energy if needed.

It should be noted that the visual above does not include an axis for price. Many of these technologies are not widely used at this point because of their total system cost compared to their expected benefits.

Photo Credit:

  1. Pumped hydro graphic courtesy of the U.S. Geologic Survey (a part of the Department of Interior) and can be found here.
  2. Energy storage discharge time versus capacity graphic courtesy of the U.S. Energy Information Administration and can be found here.
Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. BigInScience 11:22 pm 05/14/2012

    Very interesting article Melissa! I’m intrigued as to the feasibility of charging electric (or battery) powered vehicles with renewable energy sources such as wind and solar power, and allowing vehicles to redeposit or sell electricity stored in their batteries back to an electric grid during periods of low energy production (ie at night and during low-wind conditions). I actually wrote about this in an article I posted today:

    Link to this
  2. 2. AndyChuA123 3:40 pm 05/15/2012

    This is Andy Chu, vice president with A123 Systems ( Your point about the increasing number of applications other than renewable integration for which energy storage is suitable is a good one, and as the world’s leading provider of lithium ion battery technology for grid energy storage, we are seeing growing demand for our solutions for a wide variety of applications. However, you mention price as a potentially limiting factor. It’s worth noting that we (and the industry at large) is focused on bringing the cost of these systems down, and we are making progress along our trajectory to do so. Further, there are a number of evolving policies and market developments that are favorable to energy storage, including those that assign a value to the higher performance capabilities storage can provide. For example, the major U.S. electricity market operators have all filed their final rule changes to comply with FERC Order 755, which mandates pay-for-performance compensation for frequency regulation. This model would reward the use of fast-responding resources like A123’s grid energy storage solutions that can provide frequency regulation more quickly and accurately than alternative solutions. For those interested, we talk about the potential impact of FERC Order 755:

    Link to this
  3. 3. Melissa Lott 9:03 pm 05/15/2012

    Thanks for y’alls comments. Glad that you both enjoyed the article.

    @BigInScience – There are certainly potential opportunities for using vehicle energy storage (i.e. batteries in electric and hybrid cars) as a sort of ancillary service or back-up local power resource. To avoid getting too far into the weeds, I will mention one program (out of Austin, Texas) that has that sort of idea in mind. Austin Energy’s Plug-In Parters offers economic incentives for people to buy and drive electric vehicles in their service area. If you read into the history of the program, you will find that one of their potential future benefits of a robust EV community is this back-up potential.

    @AndyChuA123 – I certainly agree with you that many companies (and the government) are investing in RDD&D projects aimed at lowering the cost of many types of energy storage technologies. And, a lot of success has already been realized. If we can get the price points to a more universally competitive place, there is a lot of potential to be found (no pun intended).

    Again, thanks for y’alls comments.

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