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Dominion Energy Plans to Build 4 Storage Pilots and Study Them for 5 Years



Dominion Energy Plans to Build 4 Storage Pilots and Study Them for 5 Years

The Virginia utility has been under pressure from corporations like Apple and Amazon to embrace renewables and storage more quickly. By: Julian Spector, Aug. 7th, 2019


Virginia utility Dominion Energy wants to stop observing energy storage from afar.

The utility asked regulators for permission last week to build four battery storage facilities as pilots to test the technology's functionality. After expected completion in 2020, Dominion will study the operations for five years.

That’s a marked advance from Dominion’s position in its original 2018 integrated resource plan, which acknowledged the existence of battery storage but proposed no actions to take advantage of it. "The Company continues to monitor advancements in other energy storage technologies, such as batteries and flywheels,” the IRP stated, while calling for at least 3,664 megawatts of combustion turbine capacity by 2033.

Since then, Dominion has had more time to process Virginia's Grid Transformation and Security Act of 2018, which authorized up to 30 megawatts of utility storage pilots. It was not a mandate, but conveyed legislators’ belief that storage has a role to play in the future of the grid.


Unlike most electricity generators, which can be characterized by their power capacity, batteries are characterized by two metrics: power capacity and energy capacity

i. Power capacity, measured in megawatts (MW), is the maximum instantaneous amount of power that can be produced on a continuous basis. 

ii. Energy capacity, measured in megawatthours (MWh), is the total amount of energy that can be stored or discharged by the battery.

Two (2) Observations:

1. Verbatim copied: “Virginia's Grid Transformation and Security Act of 2018, which authorized up to 30 megawatts of utility storage pilots”

Observation 1: 30 MW of utility storage pilots is a very small capacity; for sure this is an experiment in studying the performance or lack thereof batteries as an energy storage.

2. There are 2 main reasons to deploy energy storage systems right now: 

i. The first is for low voltage ride-through purposes to prevent outages due to short term voltage dips.

​​​​​​​ii. The second, and more important, is for frequency regulation on transmission systems

Observation 2: The above applications is a valuable commodity since it can prevent cascading failures on transmission systems. Many grid operators, including PJM, CAISO, and ERCOT are deploying battery storage for this reason.

Battery storage as a method of leveling the output of intermittent resources is a fiction with today’s technology.  See Observation 1 above.

There are, however other types of energy storage that are promising but expensive – small scale pumped storage hydro with essentially large wells used for this purpose. The technology works great but the cost is not even close to practical.


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Geoff Thomas's picture
Geoff Thomas on Jan 28, 2020

Thanks for the article, Noam, just one point. Your criticism of observation 1, ie not practical/cost effective etc. excludes the role that a battery bank can/should play in that situation, and that includes the information that a 30m/Watt battery for such situations will have a very high 'surge' capacity, somewhat like a car battery, - of eg 25Amps, will provide 600 amps (CCA) to start the vehicle.

So, the battery may provide considerably more short term power whilst other systems come on line, eg the Hydro system I have mentioned where extra generators are added to an existing dam to allow the Hydro capacity of that dam to be used in short bursts at peak periods or at other times also, and also gas generator back-up, as they are really only cost effective as back-up, not general supply.

Also as I have mentioned, there is the kinetic energy of revolving wind turbine blades, the which can be used almost as fast as batteries, but the batteries can fill in that gap - the energy of wind turbines, can be briefly harnessed by increasing the voltage of the field, or as other more modern technology dictates.

So to use the batteries as a very high instantaneous power to immediately continue supply whilst a number of other supplyers come on line is an extremely good thing, - Cheers, Geoff Thomas, Advanced Wind Technologies, Australia.

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