Advancing Commonwealth Energy Storage (ACES)

The Challenge: Accelerate Commercialization and Deployment of Storage Technologies

The electric grid will require greater flexibility in order to integrate new renewables and electrify cost effectively. Energy storage performs a variety of functions that benefit both ratepayers and the grid. Systems can be used to reduce peak demand, defer transmission and distribution investments, reduce GHG emissions, reduce cost of renewables integration, defer new capacity investments, and increase grid flexibility, reliability, and resiliency.

Still nascent in 2017, the energy storage market was in need of replicable projects demonstrating how to optimize the benefits of energy storage for different use cases and how to monetize multiple value streams.

About ACES

The ACES program is part of the Energy Storage Initiative, which builds on the insights from the State of Charge report to advance energy storage in Massachusetts. 

To prime Massachusetts for increased commercialization and deployment of storage technologies, ACES piloted energy storage demonstration projects with the goal of creating innovative, broadly replicable energy storage use cases/business models with multiple value streams. Many of the projects integrate storage with other technologies, such as solar PV and demand management.

Program Accomplishments

  • By analyzing existing energy storage systems and different use models, the Commonwealth determined how to optimize the benefits of energy storage for different cases and provided funding to demonstrate these use cases.
  • Through public presentations and aggregated reports, ACES has educated customers, utilities, consumers, policy makers and a variety of industry stakeholders on the benefits and successful business models of energy storage
  • ACES also helped de-risk future investments in energy storage projects by demonstrating replicable financial models and use cases, enabling storage developers to confidently grow their businesses.
  • The energy storage market is now growing rapidly thanks in part to early support from the Commonwealth.


Program Area
Net Zero Grid
Program Duration

2017 - 2024

Activities Supported

Demonstration projects

Total Funds Awarded
Total Number of Awards
Questions? Contact

ACES by the Numbers

Open book

9 Use Cases

8 from State of Charge, plus one new use case


32 MW / 83 MWh

Total energy storage proposed

Two people reaching for dollar sign

$20MM / $31MM

Grant funding requested / Cost-share leveraged

Finance icon

14 Unique Business Models

Varied approaches to stacking value from diverse grid services

Awardee Host Sites and Facility Types

Map of ACES projects by facility type

Key Findings

Project Cost

Final project costs are often higher than originally budgeted, and external factors such as import tariffs can affect project costs. However, it is possible to negotiate additional revenue streams by collaborating with either demand aggregators or local utilities.

Permitting and Approval Process

Host sites and developers should budget significant time for the permitting process for large energy storage systems; project planning and approvals usually took longer than project construction.

Safety Concerns

Energy storage projects present unique safety concerns that must be addressed in a site-specific way. Projects should include safety plans, use industry-certified equipment, and engage their local fire department.


The interconnection process can burden projects and create long timelines due to the application process, interconnection impact studies, utility review, engineering screening, and a lack of transparency between the EDC and developers. Municipal Light Plant projects typically have more streamlined interconnection processes.


The complexity and scope of commissioning can vary by energy storage system project. Issues during commissioning may result in delays in early project activities and should be planned early in the project development process.

Energy Storage System (ESS) Technology

Lithium-ion batteries are the market leader in battery storage due to their commercial availability, market reputation, and familiarity with the technology, but risks are still associated with their deployment. Alternative technologies are available for use but are generally not mature enough in the market for widespread application.

Regional Network Service (RNS) Dispatch

ESS dispatch strategy influences estimated discharge effectiveness, which can range significantly, and is also affected by unexpected or unseasonal weather.

ACES Initial Findings

Program Outputs and Reports

Aggregated Reports and Associated Time Series Data

Aggregated Reports

Time Series Data (Excel)

First Report (including memo on financing, siting, and permitting), Sep 2020

First report data

Second Report (including memo on safety and interconnection), Dec 2020

Second report data

Third Report (including memo on commissioning and reporting), March 2021

Third report data

Fourth Report (including memo on ESS technology and co-location), Feb 2022

Fourth report data

Fifth Report (including memo on discharge effectiveness), July 2022

Fifth report data

Sixth Report (including memo on O&M and supply chain challenges), December 2022 

Sixth Report Data

Seventh Report (including memo on grantee lessons learned), July 2023

Seventh Report Data

Technology Providers and Integrators

Logos of energy storage companies

Program Details

Notable Program Features

The ACES Request for Project Proposals (RFP) was released Spring 2017. The RFP design was based on recommendations from the State of Charge study. Selection considerations included project use cases and benefits, business models, and geographic diversity. Staff favored projects with many diverse benefits and value streams, both monetizable and non-monetizable, that would benefit ratepayers, utilities, and/or bulk power systems. Successful projects showcased examples of future storage deployment, helped to grow the energy storage economy, and contributed to Massachusetts' leadership in clean energy innovation.


To assist in managing the ACES program, MassCEC engaged a program consultant to provide expertise in energy storage projects and energy analytics. The program consultant helped evaluate and verify the value of the storage systems' realized and non-monetizable benefits. The consultant also provided assistance in evaluating technical and business models, pro-formas, and energy data, and performed related program management tasks.