LIHI Certificate #52 - Penacook Upper Project, New Hampshire

The Penacook Upper Falls project is located on the lower Contoocook River in Merrimack County in the southeastern New Hampshire Village of Penacook. The Contoocook River enters the Merrimack River upstream of the fifth mainstream dam. The Village of Penacook is made up of a small part of the Town of Boscawen and the northern end of the City of Concord. The project is located on the extreme northern end of Concord, with a section of the tailrace crossing into Boscawen.

The dam is a 21‐foot high, 187‐foot long structure with a spillway built on the remains of an existing dam. It consists of a timber stoplog dam, one generating unit (2,800 kW), and appurtenant facilities. The dam is at an elevation of 306 feet MSL and it creates a pool with a surface area of approximately 11.4 acres. The facility also includes:

  • 16 gates in the spillway, 6 operable timbergates,9.5 feet wide and 15.5 feet high;
  • 8 fixed timber stopgate logs, and two operable (ice) gates, 12 feet wide and 3.5 feet high;
  • a gross reservoir volume of 70 acre feet and a net storage capacity of 0.23 billion gallons;
  • a powerhouse at the east side of the dam with one generating unit having an installed capacity of 2,800 kW;
  • a 35.0 foot long, 4.16 kV generator lead;
  • a 4.16/34.5 kV 3.6 MVA three‐phase transformer;
  • a 50‐foot long 34.5 kV overhead transmission line; and
  • a tailrace, 47 feet wide and 350 feet long.

A concrete powerhouse, 81 feet long and 44 feet wide, is located on the east river bank. The powerhouse contains one horizontal shaft tube turbine with a capacity of 2,800 kW. The riverbanks upstream and downstream of the powerhouse are contained by concrete retaining walls to bedrock. A 47‐foot wide (average) tailrace exists at the draft tube exit of the powerhouse and extends approximately 350 downstream to provide downstream fish passage. A 15‐foot long forebay with a 58‐foot (average) width begins and the powerhouse and extends upstream. From the southwest corner of the powerhouse, a concrete gated spillway extends 187 feet across the river. The project is operated as a run‐of‐river facility.

Penacook Hydro Associates (PHA) began construction of the project in 1984 and completed construction in 1986, when the project first generated power. PHA operated the facility until 1993 when FERC authorized the transfer of the project license to Briar. PHA is a general partner of Essex Hydro Associates (Essex); Essex is also a general partner of Briar. The license was transferred in 1993 from PHA to Briar (the project operator) to simplify administration of the project.

The FERC license Article 26 requires the Facility to be operated as a run‐of‐river facility with a continuous minimum flow of 338 cubic feet per second (cfs) or the inflow to the reservoir, whichever is less.

Project Name Penacook Upper
LIHI Certificate No. 52
LIHI Certificate Term September 25, 2019 - September 24, 2024
Owner Briar Hydro Associates
State New Hampshire
Location Located at river mile 1.0 on the Contoocook River in the Village of Penacook, New Hampshire.
Installed Capacity 3.02 MW
Average Annual Generation 14,967 MWh
Facility Type Run-of-river
FERC No. P-6689 issued 1984, expires 2024

Certification History

April 15, 2020: The decision to recertify the Penacook Upper Project is now final. The Certification term is from September 25, 2019 – September 24, 2024 with an option to extend the term by three years.

April 10, 2020:  LIHI sent a response letter to the appeal requestor. The letter can be found below under 2019-2020 Recertification Files.

April 3, 2020: One letter requesting an appeal of the preliminary decision were received on April 3, 2020. The letter can be found below under 2019-2020 Recertification Files.

March 5, 2020: The Low Impact Hydropower Institute has preliminarily approved Low Impact Recertification for the Penacook Upper Hydroelectric Project, LIHI #52. There is one mandatory and one option condition on the Certificate.

  • Condition 1: Since the Project is in relicensing and is likely to receive a new FERC license during the new LIHI Certification term, the facility Owner shall provide to LIHI as part of the annual compliance reports, a brief status summary of the FERC licensing progress listing significant agency interactions that have occurred in the past year that are relevant to any LIHI criteria, the results of any relicensing studies, and highlighting major topics of agreement or disagreement.  LIHI reserves the right to modify conditions and/or reassess Certification in light of new agency recommendations or if a new license changes Project operations or facilities related to the LIHI criteria.
  • Condition 2 (optional): If at any time prior to six months before the expiration of the Certification term the Facility Owner has implemented upstream eel passage at the Project in advance of a new FERC license, LIHI will review that information and determine whether or not to award a PLUS standard and extend the Certificate term for three additional years.

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 “Penacook Upper 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 April 4, 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 25, 2019 to September 24, 2024, with the option to extend the term until September 24, 2027.

November 26, 2019: The Low Impact Hydropower Institute has received a complete application for Low Impact Recertification of the Penacook Upper Falls Hydroelectric 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 “Penacook Upper Falls 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 January 25, 2020 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.

August 5, 2016: LIHI Executive Director, Michael J. Sale, using authority delegated from the LIHI Governing Board, has certified that the Penacook Upper Hydroelectric Project (FERC No. P-6689) satisfies the LIHI Certification Criteria. A Preliminary Decision was announced on June 17, 2016, and a 30-day appeal period was open through July 17, 2016. No requests for appeal were received. This Certification Decision includes two facility-specific conditions, as follows:

  • Condition satisfied 2017. Condition 1.The facility owner shall consult with NHDES to determine the most appropriate and efficient way to report on minimum flows and pond level fluctuations, then, after reaching agreement with NHDES on best methods, complete the subject summary report on or before the end of December 2016. The owner shall provide a copy of this report to LIHI along with all related correspondence.
  • Condition satisfied 2017. Condition 2.  Within 30 days after LIHI recertification, the facility owner shall complete consultation with the NHDES to finalize the details of an alternative approach for spot testing the current water quality conditions at the facility. The owner shall provide LIHI with all related correspondence pertaining to resolution of this issue and with the water quality data once testing has been completed.  The owner shall complete the water quality testing before the end of December 2016, weather permitting.

The effective certification date for the Penacook Upper Project is September 25, 2014 for a five (5) year term, which will expire on September 25, 2019.

October 30, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Penacook Upper Hydroelectric project.  The application materials can be found in the Files section below.

The public comment period for this application closed on December 30, 2015.

April 21, 2010: The Penacook Upper Hydroelectric Project has been certified as low impact for a five year term, effective September 25, 2009 and expiring September 25, 2014.

November 25, 2009: The public comment period has been closed.

September 25, 2009: Briar Hydro Associates has submitted an application for certification of the Penacook Upper Falls Hydroelectric Project. A public comment period will remain open for 60 days.