LIHI Certificate #66 - Orono Hydroelectric Project, Maine

The Orono Project is located on the Stillwater Branch of the Penobscot River ("River) in Orono, Penobscot County, Maine. The Penobscot River Basin ("Basin") is New England's second largest river system with a drainage area of 8,570 square miles. The Basin includes the East and West Branches of the Penobscot River, the Piscataquis River, the Sebec River, the Pleasant River, the Mattawamkeag River, the Passadumkeag River, the Stillwater Branch and the main stem of the Penobscot River. These are illustrated on the following page. The Orono Project is located on the Stillwater Branch less than 1,000 feet upstream where the Branch enters the main stem of the Penobscot River, and approximately one mile downstream of the Stillwater Project. With removal of the Veazie Dam in November 2013, there are no longer any dams on the Penobscot River downstream of the Orono Project. Removal of the Veazie and Great Works dams was key feature part of the Settlement Agreement, and the nationally recognized restoration of the Penobscot River.

The Orono site was first developed for hydropower in 1898, and in the ensuing decades went in and out of operation. The project stopped operating in 1996 due to catastrophic failure of the facility’s wood-staved penstocks which caused the project to be shut down. After FERC issued a new license for the Project on December 8, 2005, the Project was refurbished and began commercial operation of the four units in the original powerhouse in the first quarter of 2009.

The Project's impoundment is approximately 2.3 miles long, with a surface area of 180 acres at the normal full pond of 73.0 feet above mean sea level (msl) and an estimated gross storage capacity of 1,405 acre-feet. An increase of the headpond full elevation by 0.6 inches was part of the Settlement Agreement, and amended FERC license and Water Quality Certification (WQC). The impoundment raise increased the gross storage capacity by about 105 acre-feet and inundates about 4.4 additional acres. The current project boundary encloses the dam, the reservoir up to the 73.0-foot msl elevation, the powerhouse, and the penstocks except for a short section that traverse beneath the Maine Central railroad bridge. Land area occupied by the non-reservoir features described above is estimated at 1.2 acres. The application states that approximately 95 acres of land is contained in a 200-foot zone extending around the impoundment. BBHP owns a very small portion of this area.

The Orono Project consists of a 1,178-foot-long by 15-foot-high concrete gravity dam with a 320-foot-long spillway topped with 2.4-foot-high flashboards; three 10-foot-diameter penstocks; a 40-foot-wide, 94-foot-long and 27-foot-high surge tank; and an original powerhouse with four existing generating units. The second powerhouse was constructed in 2012-2013 and began operation on November 22, 2013. The new powerhouse (Powerhouse B) is located within the existing bypassed reach about 420 feet downstream of the dam and is supplied by a 292-foot-long, 25-foot-wide, 12-foot-high concrete penstock and surge chamber just upstream of the powerhouse. A new 84-foot-wide, 20- foot-high intake is integrated into the existing intake and shares a single trashrack having with 1 inch clear spacing.

The new upstream anadromous fish trapping facility is adjacent to and integral with the new downstream fish passage facility. Of the 150 cfs downstream attraction flow entering the screen chamber, approximately 130 cfs passed through the floor screen and is used for upstream attraction flow for the trapping facility, controlled by two submerged gates. The upstream trapping facility consists of a fixed rail system, a blocking screen and an elevating hopper to retrieve the trapped fish. BBHP provides trucking of trapped fish to a location upstream of the Milford Dam on the main stem Penobscot River, and not to the Stillwater Branch at the Orono Dam. Upstream eel passage is provided through a concrete structure with a sloped steel ramp near the junction of the non-overflow section of the dam and the spillway.

The Orono Project is operated as a run-of-river development with discharge from the project turbines and spillway equivalent to inflow. Flows are reallocated between the main stem of the Penobscot River and the Stillwater Branch through operation of its Milford Project (No. 2534).

New downstream diadromous fish passage facilities at the Orono Project include an 8-foot-wide entrance into a 20-foot-long by 12-foot-wide floor screen chamber with a 3-foot wide exit at the downstream end. The fish exit the screen chamber into a steel sluice and are conveyed to a plunge pool which discharges into the bypass reach below the dam. Passage is also provided via a lower level entrance, which consists of a 4-foot-square opening at the base of the trashrack. The downstream fish passage facility is designed to pass a combined flow of approximately 150 cfs through the surface entrance and lower orifice.

The Orono Project includes a downstream minimum flow bypass that discharges to the tailrace. The Project provides a minimum flow to the bypass reach of 200 cfs via 153 cfs through the fish passage facility and approximately 47 cfs through the flashboards.

The Orono project is owned by Black Bear Hydro Partners (BBHP), an indirect subsidiary of Brookfield Renewable Energy Group (Brookfield). The Orono was originally licensed to Bangor Hydro Electric Company in 1997. Ownership of the facility changed in 2000 to Penobscot Hydro LLC, which later became PPL Maine, LLC, and was subsequently purchased by BBHP with the license transfer on September 17, 2009. Brookfield Renewable Energy Group purchased BBHP and assumed operational control in January 2014. The Project is licensed by the Federal Energy Regulatory Commission (FERC) as Project Number 2710.  The current license expires on March 31, 2048.

Project Name Orono
LIHI Certificate No. 66
LIHI Certificate Term June 1, 2015 - June 1, 2020, extended to March 15, 2021
Owner Black Bear Hydro Partners, LLC
State Maine
Location Located at river mile 0.0 on the Stillwater Branch of the Penobscot River in Orono, Maine.
Installed Capacity 6.85 MW
Average Annual Generation 50,800 MWh
Facility Type Run-of-river
FERC No. P-2710 issued 2005, expires 2048

Certification History

December 1, 2020: The Low Impact Hydropower Institute has received a complete application for Low Impact recertification of the Orono Project. The complete application can be found below.

LIHI is seeking public comment on the application. 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 “Orono 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 January 30, 2021 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.

March 24, 2017: On March 13, 2017, LIHI issued a Preliminary Certification Decision that the Orono Hydroelectric Project (FERC No. 2710) continues to satisfy the LIHI Certification Criteria. The Orono certification includes the following conditions:

Condition satisfied 2018. Condition 1. The Owner shall notify LIHI within 30 days of receipt of USFWS certification of the upstream and downstream anadromous fish and eel passage facilities as required by the Lower Penobscot River Multiparty Settlement Agreement. This certification requires affirmation that: a) the facilities were designed and installed as prescribed, b) the facilities are ready for routine operation as evidenced by approved Operating Manuals and electronic data collection systems, and c) one year of testing and any required “fine tuning” has been completed. It is assumed that certification of the fish lift indicates that the capacity concerns have been resolved. If such USFWS certification is not received by the end of 2017, the Owner shall provide LIHI documentation as to why the certification has not been received and the plan and schedule to remedy deficiencies identified by USFWS preventing such certification.

Condition 2. If the requirement for re-initiation of quantitative studies of downstream passage of juvenile and adult alosine species occurs within this LIHI certification period, the Owner shall notify LIHI within 60 days of receipt of such study re-initiation. This notification shall include the study schedule including the expected report issuance date. A copy of the final report, along with agency statement as to whether the testing results prove that safe downstream passage has been demonstrated, shall be provided to LIHI within 60 days of issuance of the final report.

Condition 3. The Owner shall notify LIHI within 60 days of receipt of USFWS, NMFS and MDMR acknowledgement that the standards specified in the Biological Opinion for safe downstream passage of Atlantic salmon have been met. Currently, effectiveness testing could be completed by 2018 based on the three-year testing requirement, unless advancement to a higher enhancement sequence is found to be necessary. Should this occur, the Owner shall notify LIHI in the annual compliance report as to the new date by which such continuing testing to meet passage standards is expected to be completed.

Condition 4. The Owner shall provide LIHI with a summary of the results of the 2016 quantitative downstream effectiveness study for American eel, along with any comments received from USFWS, NMFS and Maine Department of Marine Resources (MDMR) as to whether the testing results prove that safe downstream passage for American eel has been demonstrated. Also, the Owner shall provide a summary of the annual American eel upstream passage results, along with confirmation that any changes to the passage facilities recommended by the resource agencies have been, or are scheduled for implementation. The noted upstream and downstream passage results shall be provided within 60 days of report finalization.

Condition satisfied 2018. Condition 5. The Owner shall provide LIHI a summary of the results the 2017 survey for Hyssopleaved fleabane, a state-listed species of Special Concern, as required by the Sensitive Species Protection Plan. This summary shall be provided within 60 days of its finalization, following review and comment by the Maine Natural Areas Program and New England Wild Flower Society.

This application was processed under the 2014 edition of the LIHI Handbook because the application materials were received prior to 2016. As provided for in Section 2.14 of the LIHI 2014 Edition Handbook, the Preliminary Certification Decision, along with the Application Reviewer’s report and (if prepared) report of the Executive Director, will be posted on the Institute’s web page for 30 days. Notice of the posting will be provided to all individuals or organizations that commented on the initial Application Package.

Any Commenter may submit a letter to the Executive Director requesting an appeal within the 30-day period.  The appeal request must state specific reasons why the hydropower facility should have failed one or more criteria.  If an individual or organization did not comment on the initial Application Package, they may not file an appeal.  Further information about the LIHI appeal process is available in the LIHI Handbook, available HERE.

If no appeal is requested within the 30-day period, the Executive Director will issue LIHI Certification for the facility and post a notification of certification on the Institute’s website.  Once final, the effective certification date for the Orono Project is June 1, 2015 for a five (5) year term, which will expire on June 1, 2020.

December 11, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Orono Hydroelectric project.  The application materials can be found in the Files section below.

The public comment period for this application closed on February 12, 2016.

January 28, 2011: The Orono Hydroelectric Project has been certified as low impact for a five year term, effective June 1, 2010 and expiring June 1, 2015.

August 2, 2010: Public comment period for the application for certification has been closed.

June 2, 2010: Black Bear Hydro Partners has submitted an application for certification of the Orono Hydroelectric Project. Public comment period on the application will be open for 60 days.


2020 Recertification