SEPA Energy Storage Snapshot Highlights Accelerating Deployments and Increased Range of Applications | SEPA Skip to content

SEPA Energy Storage Snapshot Highlights Accelerating Deployments and Increased Range of Applications

Residential and Public Power Utility markets pacing growth under favorable policies and falling costs

WASHINGTON, D.C. — The release of 2019 Utility Energy Storage Market Snapshot, a new Smart Electric Power Alliance (SEPA) report, finds the U.S. energy storage market is healthy and primed for continued growth, with interconnected capacity growing 44.9% in 2018.

The release of the Snapshot report also marks the announcement of the SEPA 2019 Top 10 Rankings, recognizing the utilities with the most overall energy storage capacity interconnected in the year 2018 by each of two measurements, total megawatt-hours (MWh) and watt-hours per customer account (Wh/C).

“Energy storage deployments are accelerating, driven by increasingly compelling economics, favorable state policies, and residential programs in California, Hawaii, and Vermont,” said Mac Keller, co-lead author and Research Associate at SEPA. “Beyond traditional back-up generation, battery storage is able to provide ancillary services, ramping, smoothing, and peaking services to meet the demands of an increasingly diversified and distributed electrical system. Based on these expanded applications, coupled with the emergence of long-duration technologies, the energy storage market is primed for continued growth.”

The report shows that in 2018, a total of 760.3 MWh of energy storage were interconnected, a 44.9% increase over 2017, bringing the cumulative energy storage total capacity to 1,966.6 MWh nationwide. Residential storage deployments grew 500.1% in 2018, non-residential storage showed strong growth of 34.9% while utility-supply storage remained the largest segment at 394.8 MWh and grew by 11.3%.

Now in its 3rd year, the Utility Energy Storage Market Snapshot relies on interconnection data and market insights obtained directly from 211 electric utilities, representing approximately 56% of all customer accounts in the U.S.

Key takeaways from the report include: 

  • Investor-owned utilities (IOUs) deployed the most storage of any utility type, accounting for 64.3% of the total market in 2018, with public power utilities and electric cooperatives also experiencing strong growth at 1435.5% and 154.4% respectively over 2017.
  • Of the 211 utilities that responded to our survey, 94 had at least one energy storage installation in their service territory as of the end of 2018. One-quarter of those deployed their first storage project in 2018.
  • The business case for certain lithium-ion battery storage applications has become more attractive as the price of lithium-ion storage assets has declined by 72.9% since 2013.

On the Top 10 Utility Energy Storage Rankings by Annual Megawatts list, Southern California Edison maintained the top spot with 154.3 MWh capacity interconnected, while Kauai Island Utility Cooperative was second with 102 MWh and Pacific Gas & Electric ranked third with 73.2 MWh.

Kauai Island Utility Cooperative also held the top spot on the Annual Watt-Hours Per Customer (Wh/C) rankings, interconnecting an impressive 3,037.6 Wh/C in 2018. Massachusetts based Sterling Municipal Light Department and the City of Holyoke ranked 2nd and 3rd respectively with 523.1 and 341.6 Wh/C.

The 2019 Utility Energy Storage Market Snapshot is the second of three Snapshot reports based on data from SEPA’s 2018 Utility Survey. The 2019 Utility Solar Market Snapshot can be downloaded here. The 2019 Utility Demand Response Market Snapshot will be released in the fall.

Download the free 2019 Utility Energy Storage Snapshot report here.

View the full 2019 Top 10 rankings here.

To receive alerts on the Demand Response Snapshot, email [email protected]

For media requests, please contact Jordan Nachbar, j[email protected] or 202-559-2034

About SEPA

The Smart Electric Power Alliance (SEPA) is dedicated to helping electric power stakeholders address the most pressing issues they encounter as they pursue the transition to a clean and modern electric future and a carbon-free energy system by 2050. We are a trusted partner providing education, research, standards, and collaboration to help utilities, electric customers, and other industry players across four pathways: Transportation Electrification, Grid Integration, Regulatory Innovation and Utility Business Models. Through educational activities, working groups, peer-to-peer engagements and advisory services, SEPA convenes interested parties to facilitate information exchange and knowledge transfer to offer the highest value for our members and partner organizations. For more information, visit

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