LIHI Certificate #64 - Penacook Lower Project, New Hampshire

The project is located along the Penacook Lower Falls on the Contoocook River in the Village of Penacook, New Hampshire. The Contoocook River enters the Merrimack River upstream of the fifth mainstream dam. The Village of Penacook is made up of a small portion of the Town of Boscawen and the northern end of the city of Concord. The Penacook Lower Falls hydroelectric project presently is owned and operated by BHA, a New Hampshire limited partnership.

Originally, on September 10, 1981 the Federal Energy Regulatory Commission (“FERC”) issued an Order Granting Exemption from Licensing of a Small Hydroelectric Project of 5 Megawatts of Less, FERC Project 3342-001, to New Hampshire Hydro Associates (“NHA”) authorizing the construction, operation and maintenance of the PLF project. The Exemption specifically limited the project to operating with a maximum surface impoundment of 272 feet m.s.l. and contemplated a net operating head of 28 feet. This development was based upon reconstructing the project based upon the height of the dam that existed in 1981.

During development it was recognized that the project capacity could be increased by raising the impoundment level to with only a minimal effect on resources. The NH Department of Fish and game and the U.S. Fish and Wildlife Service found that the increase in elevation of six feet would inundate 2.9 acres of land, none of which was developed or developable. Construction of the project began in 1982 and on November 17, 1982, NHA relinquished its exemption and received a 40-year license issued by the FERC authorizing the construction operation and maintenance of the PLF project with a maximum surface elevation of 278 feet m.s.l. Construction was completed in 1983 when first power was generated.

The project is operated as a run-of-river facility. The estimated average net head is 34 feet. Revised Exhibits F and G were submitted to the FERC in 1982 showing as-built diagrams with an approved operating head of 34 feet (Appendix 3-2). The project is required to maintain a continuous minimum flow of 338 cubic feet per second (ABF .5 cfs) or the inflow to the reservoir, whichever is less. Project works consist of: (a) a reservoir with an 8.4-acre surface area, and a useable storage capacity of 54 acre-feet; (b) a concrete diversion spillway with three 9.5 foot by 10.0 foot high timber gates and seven timber stoplog gates; (c) a concrete gravity auxiliary spillway, 316 feet long and a main concrete spillway, gated, and 106 feet long; (d) a forebay, 70 feet long; (e) a concrete powerhouse containing a single generating unit with an installed capacity of 4,110 kW; (f) a tailrace excavated in rock, 700 feet long; (g) transmission equipment and electrical facilities consisting of (1) generator leads; (2) one 4.16/34.5 kV, 7.5 MVA step-up transformer; (3) 200 feet of 34.5-kV line and facilities necessary to connect the project to Concord Electric Company’s system; and (4) appurtenant facilities. A concrete powerhouse is constructed to bedrock on the same alignment as the centerline of the river profile. The overall length of the powerhouse is 97.5 feet and the width perpendicular to the profile is 35 feet. A 55-foot wide rock filled access area connects the north face of the powerhouse to the north river bank. Upstream and downstream sides of the access area are contained by concrete retaining walls to bedrock. The powerhouse contains one horizontal tube-type 3-meter turbine encased in concrete.

The project is located downstream of the Penacook Upper Falls project (LIHI Certification #52). The project utilizes a previously existing impoundment and the plant is unmanned, but operation is monitored on a 24/7 basis.

Project Name Penacook Lower
LIHI Certificate No. 64
LIHI Certificate Term August 13, 2015 - August 13, 2020, extended to October 31, 2021
Owner Briar Hydro Associates
State New Hampshire
Location Located at river mile 0.3 on the Contoocook River in the Village of Penacook, New Hampshire.
Installed Capacity 4.6 MW
Average Annual Generation 20,092 MWh
Facility Type Run-of-river
FERC No. P-3342 issued 1982, expires 2024

Certification History

July 16, 2021: The Low Impact Hydropower Institute (LIHI) has received a complete recertification application from Briar Hydro Associates for the Penacook Lower Falls Project located on the Contoocook River in New Hampshire.

LIHI is seeking comment on this 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 LIHI by e-mail at with "Penacook Lower Falls Project Comments” in the subject line, or by mail addressed to the Low Impact Hydropower Institute, 1167 Massachusetts Avenue, Office 407, Arlington, MA 02476. Comments must be received at the Institute on or before 5 pm Eastern time on September 14, 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.

The project description and complete application can be found below.

August 5, 2016: LIHI Executive Director, Michael J. Sale, using authority delegated from the LIHI Governing Board, has certified that the Penacook Lower Hydroelectric Project (FERC No. P-3342) 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 2018. 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 Lower Project is August 13, 2015 for a five (5) year term, which will expire on August 13, 2020.

October 30, 2015: The Low Impact Hydropower Institute has received a complete application for a new term of Low Impact Certification for the Penacook Lower 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.

June 19, 2015: The Penacook Lower Hydroelectric project has been granted an extension of the current certificate term. The new expiration date is December 31, 2015. See ExtensionLetter_2015Recert for explanation below.

January 29, 2011: The Penacook Lower Hydroelectric project has been certified as low impact for a five year term, effective August 13, 2010 and expiring August 13, 2015.

October 13, 2010: Public comment period on the application for certification has been closed.

August 13, 2010: Briar Hydro Associates has submitted an application for certification of the Penacook Lower Hydroelectric Project. A public comment period will remain open for 60 days.