Document Library
Every public project document in one place, searchable, categorized, and written in plain language. Every document includes a "Why this matters to you" summary.
Project Site Plan
This engineering plan shows where the battery units, access roads, setbacks, fencing, stormwater features, and landscaping sit within the 15-acre project area.
Critical Issues Analysis
This early study checks the site for environmental, structural, and regulatory problems that could stop the project before design work goes further.
Site Elevation Map
This map shows the elevation changes, natural contours, and grading needs across the Carpenter Hill site.
Preliminary Wetlands Index
This early map identifies the wetland areas on the property and next to it.
Site Aerial Map
This high-resolution aerial photo shows the project footprint next to surrounding properties, roads, and vegetation.
Detailed Project Location Map (1-Mile Landmark Map)
This two-sheet map meets the state pre-filing rule 980 CMR 16.09(1)(a)3. Sheet 1 shows the project boundary, the battery equipment area, the access road, the interconnection route to the Carpenter Hill substation, and the schools, parks, library, medical facilities, and other community landmarks within one mile of the project boundary. Sheet 2 lists every landmark with its address, coordinates, distance, and the sources we used to verify it. Component locations reflect the current preliminary design.
Tesla Megablock / Megapack 3 Technical Specifications
This data sheet lists the dimensions, capacity, safety features, and performance figures for the Tesla Megablock / Megapack 3 battery unit.
NFPA 855: Plain Language Summary
This page summarizes NFPA 855, the national fire protection standard for battery storage. It covers siting, fire suppression, ventilation, and emergency response requirements.
UL 9540A Testing: What It Means
This explainer describes the UL 9540A fire safety test, what the test measures, and what the results mean for the Carpenter Hill project.
State Guidance on Battery Storage and EV Charger Safety (August 2025)
This is the guidance MassDEP wrote in consultation with the Board of Fire Prevention Regulations and the Department of Energy Resources, as ordered by the 2024 Climate Act. It explains the fire codes and UL certifications that apply to battery storage, when a fire department safety review is required, and the environmental rules covering wetlands, stormwater, drinking water, noise, spill response, and decommissioning.
Emergency Response Planning Framework
This framework outlines the site-specific emergency response plan we are developing with Charlton Fire Chief Rob Barton. It covers incident command, notification, and mutual aid.
2024 Climate Act (Chapter 239): Summary
This summary explains the 2024 Climate Act's rules for siting energy facilities, including the consolidated permit process the EFSB now runs.
Intervenor Support Grant Program
This official Mass.gov page describes the state's Intervenor Support Grant Program. The 2024 Climate Act created the program, and the Department of Public Utilities runs it. It pays community groups up to $150,000 per proceeding for attorneys, expert witnesses, and other costs of taking part in EFSB and DPU cases that begin on or after July 1, 2026.
980 CMR 16.00: Consolidated Permit Regulations Overview
This overview explains the EFSB regulations for the consolidated permit process, including pre-filing requirements and community engagement obligations.
How We Follow the Siting Rules (Live Tracker)
This page lists every pre-filing requirement in 980 CMR 16.00 that applies to this website and our engagement process, with links to where each item lives on this site and a status for the items that come later in the process.
Community Engagement Plan (July 2026 Update)
This plan explains how we engage the Charlton community during the state pre-filing period under 980 CMR 16.00. It lists the stakeholders we are reaching, the state and local agencies we consult, every meeting held and planned through the fall, and the regulatory milestones ahead. This July 2026 update builds on the April plan and adds the items the OEJE asked for.
OEJE / DPP Pre-Filing Engagement Meeting Minutes
These are the official minutes from our kick-off meeting with the Office of Environmental Justice and Equity and the Department of Public Utilities to review compliance under 980 CMR 16.00.
Medway Grid Battery Project (Approved Reference Project)
This is the official EFSB docket page for the Medway Grid battery project, a facility the state has already approved.
Cranberry Point Energy Storage (Approved Reference Project)
This is the official EFSB docket page for the Cranberry Point energy storage facility, another approved project.
Inaugural Citizen Advisory Committee (CAC) Meeting Minutes
These are the official minutes from the first Citizen Advisory Committee meeting, held on June 3, 2026. The committee discussed community identity, expectations, safety concerns, and benefit plan priorities.
Second Citizen Advisory Committee (CAC) Meeting Minutes
These are the official minutes from the second Citizen Advisory Committee meeting, held virtually on August 4, 2026. The committee discussed private well and groundwater protection, fire department readiness, long-term financial accountability, and priorities for the Community Benefits Plan.
Public Meeting #1 Station Posters (July 8, 2026)
These are the four posters we displayed at the July 8 public meeting: the project location map, the grid reasons this site works, the Megapack safety layers, and what we know about the land, water, and trees on this parcel.
Public Meeting #1 Dot Boards & Comment Cards (July 8, 2026)
This file shows the input residents gave at the July 8 public meeting: the dot board where attendees marked what a Community Benefits Plan should focus on, the topic list our team logged at the record table, and the anonymous exit cards from the box by the door.
US Grid-Scale BESS Incident Briefing Binder
This binder compiles 15 grid-scale battery fire and thermal runaway incidents in the United States between 2018 and July 2026, with root causes and safety outcomes.
EPRI BESS Failure Incident Database (Live)
This is the Electric Power Research Institute's public database of battery storage failure events worldwide. It lists each incident with its date, location, system details, and sources, and EPRI updates it as new events occur.
EPRI White Paper: Root Causes of BESS Failures (May 2024)
In this white paper, EPRI analyzes 26 classified battery storage failure incidents from its failure database. It sorts each incident by root cause and by the part of the system that failed. Most failures traced back to how systems were integrated, assembled, or operated. Only about 11 percent traced directly to the battery cells. EPRI also reports that the global failure rate for grid-scale battery systems dropped 97 percent between 2018 and 2023.
ACP BESS Fire Impacts Report (2025)
This American Clean Power report analyzes battery storage fire incidents across the industry, including safety statistics and environmental testing results.
Tesla Megapack 2/2XL Fire Protection Engineering (FPE) Report
This Fisher Engineering report analyzes fire protection for the Tesla Megapack 2 and 2XL energy storage systems.
Medway Host Community Agreement with Medway Grid (Executed 2022)
This is the signed Host Community Agreement between the Town of Medway and Medway Grid, a 250 MW / 500 MWh battery project that went online in February 2026. It includes yearly emergency preparedness funding, fire department training from the battery supplier, money for the town's independent consultants, property value protection for homes within 300 feet, and a $15 million decommissioning bond that names the town as beneficiary. This copy is a scan of the fully executed agreement from November 2, 2022, posted publicly by the Town of Medway.
Medway PILOT Agreement with Medway Grid (Final Text, 2024)
This is the final payment in lieu of taxes agreement between the Town of Medway and Medway Grid. The town receives $2,237,714 per year for 20 years, plus a 3 percent addition each year that makes up the Community Preservation Act surcharge the town would otherwise lose. Medway Town Meeting authorized it in May 2024. The town posts this final text without signatures.
Medway PILOT: The Town's Independent Financial Review (2024)
This short letter is the independent financial review the Town of Medway commissioned before authorizing its PILOT agreement. A municipal valuation consultant laid out the assessed value and tax rate behind the proposed yearly payment, so the town could judge the number against standard taxation.
Tewksbury Host Community Agreement with Hillman Energy Center (2026)
This is the negotiated Host Community Agreement between the Town of Tewksbury and Hillman Energy Center, a 125 MW battery project the state approved in June 2026 with more than 100 conditions. It sets a tax agreement floor of $2 million per year plus a 1 percent Community Preservation Act addition, caps town permit fees at $1.35 million, funds a property value protection reserve for homes within 650 feet, and spells out fire safety requirements in unusual detail, including a perimeter fire access road, an incident command post location, and hazard and plume analysis before construction. The town posted this copy as a redline that shows the final edits, with some portions redacted.
Revere Host Community Agreement with Revolution Storage (Approved June 2026)
This is the Host Community Agreement between the City of Revere and Revolution Storage, a proposed 200 MW battery project. The city council approved it 10 to 0 on June 22, 2026. It pays the city $600,000 in year one, rising to about $646,000 by year 20, for a total of about $12.5 million, with the first year directed to fire suppression apparatus. We extracted these pages from the public city council packet. The city expected minor wording changes before final signatures.
Revere PILOT Agreement with Revolution Storage (Approved June 2026)
This is the payment in lieu of taxes agreement between the City of Revere and Revolution Storage, approved by the city council on June 22, 2026 alongside the Host Community Agreement. The city receives $1.5 million per year at the start, rising to about $1.62 million, for a 20-year total of about $31.3 million. The first year funds fire apparatus and equipment. We extracted these pages from the public city council packet.
Chelsea City Council Order Authorizing the Energizar PILOT (2024)
This city council agenda contains the order that authorized Chelsea's 20-year PILOT, worth just over $31 million, for the 250 MW / 1,000 MWh Energizar battery project. The council approved it on July 1, 2024. Chelsea negotiated its Host Community Agreement separately, and that agreement pays $584,000 per year for workforce development. The city has not posted the signed agreement texts publicly, so this order is the best public record of the deal.
Carver PILOT Agreement with Cranberry Point Energy Storage (Executed 2025)
This is the signed payment in lieu of taxes agreement between the Town of Carver and Cranberry Point Energy Storage, a 150 megawatt battery project that began operating in 2025. Carver receives $1,690,000 a year for 20 years, from fiscal year 2026 through fiscal year 2045, for a total of $33,800,000. The agreement builds that figure from a rate of $10,000 per megawatt plus a yearly increase, then levels the whole term into equal annual payments. It covers the batteries and equipment only, and the town still assesses and bills real estate taxes on the land separately. The developer also posts $1,690,000 in security, gives up its right to ask for a reduction in the payments, and files a yearly affidavit reporting the project's capacity and how much energy it discharged. Carver did not negotiate a separate community benefits agreement, so this one document is the whole deal. This copy is the fully executed agreement, carrying the signatures and notary acknowledgments of the Carver Select Board, Board of Assessors, and Town Administrator.