On Feb. 23, the Federal Energy Regulatory Commission approved an October 2015 application from Grafton Hydro LLC for a preliminary permit, good for three years, covering work to study the feasibility of the proposed Lebanon-Mascoma Project, to be located on the Mascoma River in the city of Lebanon, Grafton County, New Hampshire.
The proposed project would include two developments. Development 1 would be located near the city of Lebanon and Development 2 would be located approximately five miles upstream of Development 1 at the existing Mascoma Lake dam.
- Development 1 would consist of: a new 110-foot-long, reinforced concrete dam with a 60-foot-long, bottom-hinged, operable crest spillway; a new impoundment with a surface area of less than 2 acres and a normal volume of less than 10 acre-feet; a 1,200-foot-long, 7-foot-diameter steel penstock; a new 40-foot-long, 30-foot-wide reinforced concrete powerhouse containing a new 2,000-horsepower Kaplan-type turbine and a new 1,500-kW synchronous generator; and an approximately 500-foot-long transmission line connecting the generator to a 2.0-kilovolt amp (kVA) transformer.
- Development 2 would consist of: the existing 18-foot-high, 575-foot-long concrete, gravity Mascoma Lake dam with four 6-foot-wide outlet gates, seven 35-foot-wide stop-log bays, and a 125-foot-long overflow spillway; the existing 1,158-acre Mascoma Lake impoundment; a new 40-foot-long, 30-foot-wide reinforced concrete powerhouse containing four 150-horsepower, horizontal axis, propeller-type turbines, each with a 150-kW asynchronous generator; and an approximately 500-foot-long transmission line connecting the generators to a 1.0-kVA transformer.
The purpose of a preliminary permit is to preserve the right of the permit holder to have the first priority in applying for a license for the project that is being studied. During the course of the permit, the commission expects that the permittee will carry out pre-filing consultation and study development leading to the possible development of a license application.