Complete Application Received – Mattaceunk Project, Maine

March 29, 2022: The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Mattaceunk Project. LIHI is seeking public comment on this application. Specifically, we are interested in knowing whether you think the Project meets the LIHI Low Impact Certification Criteria, as revised in the 2nd Edition Handbook. Please review the program and criteria in LIHI’s revised Handbook and then review the Project’s application materials below.

Comments that are directly tied to specific LIHI criteria (flows, water quality, fish passage, etc.) will be most helpful, but all comments will be considered. Comments may be submitted to the Institute by e-mail at with “Mattaceunk Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Avenue, Arlington, MA 02476. Comments must be received on or before 5 pm Eastern time on May 28, 2022 to be considered. All comments will be posted to the web site and the applicant will have an opportunity to respond. Any response will also be posted.

Project Name Mattaceunk
LIHI Certificate No. N/A
LIHI Certificate Term N/A
Owner Great Lakes Hydro America, LLC (a subsidiary of Brookfield Renewable Energy Group)
State Maine
Location River Mile 67 on the mainstem of the Penobscot River
Installed Capacity 19.2 MW
Average Annual Generation 123,332 MWh
Facility Type Run-of-river
FERC No. P-2520, issued February 26, 2021 and expiring January 31, 2061

The Mattaceunk Project is located on the mainstem of the Penobscot River in the towns of Medway, Woodville, Mattawamkeag, and the unorganized township of Molunkus in Aroostook and Penobscot Counties, Maine. The river is approximately 75 miles (mi) long from the confluence of the West and East Branches of the Penobscot River (to form the mainstem) downstream to the head of tide in Bangor, Maine. The Mattaceunk Project consists of a dam and integral powerhouse located on the mainstem approximately 7 miles downstream from the confluence of the West and East Branches of the Penobscot River.

The project is a run-of- river hydroelectric generating facility. The project consists of a 1,060-foot-long dam topped with a variable crest elevation, creating a 1,664-acre impoundment with a normal full pond elevation of 240 feet USGS. The powerhouse contains four generating units with a total installed capacity of 19.2 MW and a maximum hydraulic capacity of 7,438 cfs. The project also includes an approximate 9-mile-long transmission line and appurtenant facilities. Project lands and waters are available for recreation opportunities. The project is operated in run-of-river mode for the enhancement of downstream fisheries, including Atlantic salmon, and has upstream and downstream fish passage measures. The project commenced initial commercial operations in 1942.

This is now the third Project on the mainstem Penobscot River following dam removals undertaken as part of the Lower Penobscot River Multiparty Settlement Agreement, the goal of which was to restore self-sustaining populations of 11 native species of sea-run fish along the Penobscot River in Maine. The Settlement Agreement involved the purchase and removal of the lower-most dams on the Penobscot River – Veazie Dam (FERC No. 2403) and Great Works Dam (FERC No. 2312), and the decommissioning of the Howland Dam (FERC No. 2721) on the Piscataquis River, a tributary of the Penobscot River. A new license for the Mattaceunk Project was issued by the FERC on February 26, 2021.


2022 Certification