(The opinions expressed here are those of the author, a columnist for Reuters.)

LITTLETON, Colorado - California and Texas lead the national charge on grid-scale power sector battery systems, accounting for 72% of the battery networks currently in operation and around 65% of the battery development pipeline.

California has the largest footprint of currently deployed utility batteries, with roughly 9,920 megawatts (MW), according to the United States Energy Information Administration (EIA). Texas has the next largest power battery system, with 4,832 MW.

In total, 29 states currently deploy 20,521 MW of battery systems within their power networks, and an additional 28,600 MW is in development and expected online by mid-2026, according to energy data platform Cleanview.

FULLY CHARGED

Grid-connected utility batteries allow for state energy suppliers to store surplus power during times of high output, such as when solar output peaks and pushes total generation levels above system demand needs.

Power firms can then discharge the batteries during peak consumption periods, which ensures that utilities can make full use of renewable power output and meet system demand peaks with power that was partially generated at other times of the day.

Utilities with extensive battery systems can also use them to displace power from fossil fuels, thereby helping to reduce power pollution even as they lift overall power supplies.

The California Independent System Operator - the state's main electricity provider - currently supplies around 17% of its electricity from batteries during the evening peak demand period, according to energy data platform gridstatus.io.

That share of electricity supply exceeds the share of California's wind farms and hydro dams over the same period, and has allowed utilities to reduce power imports.

CONCENTRATED POWER

Once the planned battery systems are completed in 2026, the national battery network will more than double from its current scale to around 49,110 MW.

Texas will overtake California as the top battery state once its pipeline of 12,425 MW is brought online, bringing the state's total to 17,257 MW.

California's 6,071 MW of planned capacity will lift its total battery network to 16,000 MW, ensuring those two states retain a roughly 70% share of the total battery network after the development pipeline is finished.

GROWTH MARKETS

Arizona, Nevada and Florida are the next largest states in terms of currently deployed power battery systems, boasting around 1,813 MW, 1,125 MW and 561 MW of capacity, respectively.

Arizona also has one of the largest battery pipelines, of 2,616 MW, which will lift the state's total capacity to 4,430 MW when complete and ensure the state remains the third-largest power battery user.

South Carolina and New York have the next largest battery development pipelines, of 1,881 MW and 1,178 MW, respectively.

Idaho, New Mexico, Utah and Nevada all have planned capacity additions of over 400 MW, EIA data shows.

An additional nine states have 100 MW or more in development, and five states have between 50 MW and 99 MW planned.

Altogether, 31 states have some battery capacity planned for their power networks within the next two years.

NO SHOWS

Currently, 19 states have no planned battery systems in development, including Pennsylvania, Nebraska, Kansas, Iowa and Kentucky.

Some of those power systems are overwhelmingly powered by fossil fuels, such as Kentucky's, and so generate little to none renewable power that requires storage.

Others, such as Iowa, source over half their total electricity from renewable sources, and have a growing network of gas "peaker" plants that supply power whenever there's a supply-demand mismatch.

Overall, however, battery systems look set to become increasingly popular across a majority of states, especially as costs continue to trend lower while overall electricity and power demand increases.

The cost of a 20-foot direct current (DC) battery container that can store around 3.7 megawatt hours (MWh) of power for 4 hours has nearly halved between 2022 and 2024, according to consultancy Clean Energy Associates (CEA).

Grid-scale battery systems are priced by the kilowatt hour (kWh), or the amount of power or electricity that can be discharged over an hour.

In 2024, the average price for U.S. utilities is around $148/KWh for a 20-foot container system. That compares to around $270/kWh for the same unit in 2022, according to CEA.

If prices continue to rapidly decline in the coming years, that will make them affordable at scale for a growing number of utilities, and likely make them commonplace within large power systems within the next decade.

The opinions expressed here are those of the author, a columnist for Reuters.

(Reporting by Gavin Maguire; Editing by Christian Schmollinger)