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Energy Storage Information

Historically, most energy storage facilities were pumped hydro systems.  These systems provide energy storage for the Massachusetts electricity grid (see an example), and account for over 90% of existing energy storage systems worldwide.  However, battery storage technology is on the rise.  As battery technologies increase in efficiency and decrease in cost, these energy storage systems are becoming increasingly common.  In fact, lithium ion batteries accounted for 93% of all new storage capacity added in 2020.  Other storage technologies, including flow batteries, thermal storage, and compressed air systems, are also being researched and developed.

In Massachusetts, energy storage systems are now being proposed for development either as stand-alone systems connected directly to the electricity grid, or in conjunction with energy-generating facilities, such as solar PV arrays.  In fact, as of April 2020, the state's solar incentive program (SMART) requires that most large solar PV arrays (500 kW AC or more in size) include an energy storage component.

Energy storage systems are critical for balancing electricity supply and demand, particularly as part of the transition towards a renewable energy future in which more variable sources of energy, like wind and solar power, are added to the grid.  Energy storage systems also can reduce the need for extra energy generation capacity that is only used during periods of peak demand, when electricity use is at its highest; these systems do so by storing up electricity when demand is low, and then discharging electricity into the grid when demand is high.  Reducing the maximum electricity generation capacity needed has both environmental and financial benefits.  In addition, energy storage research & development could provide job opportunities and other economic benefits to residents and businesses within Massachusetts - see CEE's report HERE.  On the other hand, energy storage systems may have safety, social, and environmental impacts.  As these systems become more common, municipalities will want to weigh these considerations during planning and permitting processes.  

Basic Information about Energy Storage

Battery Storage FAQ - Basic information about grid-scale battery storage from the National Renewable Energy Laboratory.

Energy Storage Information - Basic information about energy storage from the U.S. Office of Electricity.

Energy Storage Resources - Energy storage information, programs, and policies from the Massachusetts Clean Energy Center.

Energy Storage Technologies - Basic information about energy storage and types of storage technologies from the University of Michigan.

Battery Storage - Basic information about battery storage from National Grid.

Municipal Planning & Permitting Resources

Town of Medway - Medway officials have assembled a variety of helpful energy storage resources, including consultant reports solicited and paid for by the town, as part of review of a proposal for a new 10-acre battery storage system and substation to be built in the muncipality. 

Energy Safety & Reliability Forum - Pacific Northwest National Laboratory is hosting an Energy Storage Systems Safety & Reliability forum to be held in early May.  The two-day event will will focus on the current state of energy storage safety and reliability, and identify additional R&D efforts to advance the U.S. Department of Energy roadmap for energy storage. The forum will also examine key challenges, opportunities, and potential solutions for improving the safety and reliability of energy storage systems.

 PVPC Best Practices - Excerpts from the Pioneer Valley Planning Commission's Solar Best Practices Guide, developed in part by CEE, regarding energy storage.  The full guide can be found HERE.

Energy Storage Best Practices - New England best policy practices regarding energy storage, from the Clean Energy States Alliance.


Note:  Large battery storage facilities are still relatively new.  As additional information and resources become available, we will post them on this page.  If you have additional resources to share, please e-mail Zara Dowling (