LIHI Certificate #167 - Millinocket-Dolby Project, Maine

The Penobscot Mills Project (FERC No. 2458) consists of four hydroelectric developments and a storage dam located in the general vicinity of Millinocket/East Millinocket, Maine. The four hydroelectric developments are located between river miles 2 and 15 on the West Branch of the Penobscot River. The four hydroelectric developments, listed in order from upstream to downstream, are: North Twin, Millinocket, Dolby, and East Millinocket. The project developments were originally constructed around the turn of the 20th century to meet the hydromechanical and hydroelectric demands of the Millinocket Mill, constructed in 1900, and the East Millinocket Mill, constructed in 1906. The Millinocket Lake Storage Development contains a pumping station, located on the opposite end of the lake from the Millinocket Lake Dam, that allows water to be pumped up approximately 12 ft from Millinocket Lake to Ambajejus Lake (part of the North Twin impoundment).

The Penobscot Mills Project is operated to maintain an instantaneous minimum flow of 2,000 cfs downstream of the Millinocket Development and a minimum flow of 60 cfs into Millinocket Stream. Operation of the project is managed in conjunction with the water flow and storage of upstream and downstream projects. Two of the four developments are included in the LIHI certification:

Millinocket Development:
The Millinocket Development is located in the town of Millinocket and consists of 1) Quakish Lake and Ferguson Pond, which together form the Millinocket impoundment having a full pond water surface elevation of 458.7 ft; 2) a concrete dam (Stone Dam) measuring approximately 1,262 ft in length located on the West Branch of the Penobscot River approximately 12.3 river miles above the confluence of the East and West Branches of the Penobscot River; 3) a gatehouse located at Stone Dam, containing ten gates and a sluiceway; 4) three earthen dikes located at various points around Quakish Lake and having a total length of 1,854 ft; 5) five earthen dikes (totaling 3,915 ft in length) located around Ferguson Pond, a “western” canal leading from the gatehouse to Ferguson Pond, Ferguson Pond, and an “eastern” canal that leads from Ferguson Pond to the intake structure, all of which are used to convey water from the gatehouse at Stone Dam to the intake structure located approximately 7,300 ft from Stone Dam; 6) an intake structure containing seven head gates, located at the entrance of the penstocks; 7) six 10-ft-exterior-diameter steel penstocks and one 11-ft-exterior- diameter steel penstock ranging in length from 1,007 ft to 1,024 ft; 8) seven operable hydroelectric units, of which five are located within the former Grinder Room; 9) a powerhouse commonly referred to as the Generator Room, where two of the hydroelectric units are located; and appurtenant facilities and equipment.

Dolby Development:
The Dolby Development is located on the West Branch of the Penobscot River, between Millinocket and East Millinocket, at approximately 4.2 river miles above the confluence of the East and West Branches. The Development consists of 1) an impoundment having a full pond water surface elevation of 336.2 ft; 2) a concrete and earth-filled dam measuring approximately 1,395 ft in length, including an intake structure and powerhouse integral with the dam containing five operable units and other appurtenant facilities and equipment.

Project Name Millinocket and Dolby Developments
LIHI Certificate No. 167
LIHI Certificate Term September 6, 2019 - September 5, 2024
Owner Great Lakes Hydro America, LLC (a subsidiary of Brookfield Renewable Energy Group)
State Maine
Location West Branch Penobscot River, river mile 12.3 (Millinocket) and 4.2 (Dolby)
Installed Capacity Total: 55.2 MW Millinocket: 37.4 MW Dolby: 17.8 MW
Average Annual Generation Total: 280,899 MWh Millinocket: 178,454 MWh  Dolby: 102,445 MWh
Facility Type Run of river
FERC No. P-2458 issued 1996, expires 20206 (part of the Penobscot Mills Project)

Certification History

February 7, 2020: The decision to certify the Millinocket-Dolby Project became final after the close of the appeals period on February 6, 2020 with no appeals filed.  The Certification term is from September 6, 2019 – September 5, 2024. The Certification includes two conditions:

  • Satisfied 2020. Condition 1:The facility Owner shall develop and implement a deviation reduction plan or procedure in an effort to proactively reduce future occurrence of potentially avoidable deviations. The plan or procedure shall include an implementation schedule and shall be submitted to LIHI for review and approval with the first annual compliance submittal due in September 2020. The plan or procedure should discuss, as applicable: Ways to avoid minimum flow deviations when ROR deviations are planned for flashboard repairs and installation; Ways to improve preventative maintenance programs and/or to make facility modifications to reduce equipment malfunctions and failures, which could include: Review of current preventative maintenance program to ensure maximum reliability of generating assets and ensuring that operating procedures are current and applicable staff is trained in the application.
  • Condition 2: The facility Owner shall provide annual reports to LIHI documenting all operational deviations that occurred during the year, whether unintentional or planned and whether or not they were found to violate the license by FERC. The report shall include root-cause analysis of each deviation and any facility or operational changes being made to reduce similar deviations in the future. The report will be due at the same time as the annual compliance submittals to LIHI.

January 7, 2020: The Low Impact Hydropower Institute has preliminarily approved Low Impact Recertification for the Millinocket-Dolby Hydroelectric Project, pending LIHI #167.

This decision is preliminary pending the 30-day appeal window. Only those who commented on the initial application during the 60-day comment period are eligible to file an appeal. Such appeal needs to include an explanation as to how the Project does not meet the LIHI criteria. Appeal requests can be submitted by email to with “Millinocket-Dolby Hydroelectric Project” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Ave, Suite 6, Lexington, MA 02420. All requests will be posted to the website.  The applicant will have an opportunity to respond and any response will also be posted. Requests must be received by 5 pm Eastern time on February 6, 2020.  The full application and reviewers report are available below.

If no appeal requests are received and the decision becomes final, the Certification term for the Project will be from September 6, 2019 to September 5, 2024.

September 9, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Certification of the Millinocket and Dolby Hydroelectric Projects.  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 “Millinocket-Dolby Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 329 Massachusetts Avenue, Suite 6, Lexington, MA 02420.  Comments must be received on or before 5 pm Eastern time on November 8, 2019 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.