Vernon Hydroelectric Project (FERC # 1904)
Portland, Maine (June 25, 2009)–The Low Impact Hydropower Institute (LIHI) announced today that TransCanada's ("TC" or Applicant) Vernon Hydroelectric Project on the Connecticut River, in Cheshire County, New Hampshire and Windham County, Vermont, has earned LIHI's Low Impact Certification. The effective certification date is December 15, 2008. LIHI certification means that the hydropower facility has been found to meet or exceed the Institute's Certification Criteria which address eight key areas: river flows, water quality, fish passage and protection, watershed protection, threatened and endangered species protection, cultural resource protection, recreation, and facilities recommended for removal.
Certification is designed to provide consumers with assurance that a facility has avoided or reduced their environmental impacts pursuant to the Low Impact Hydropower Institute's criteria. The Board's vote to certify the project was unanimous.
• Facility location: Connecticut in, New Hampshire and Vermont.
• Installed capacity: 32.4 MW
• Average annual generation: 188 gigawatt hours
• Year FERC license issued: June 25, 1979
• Applicant: TransCanada Hydro Northeast Inc.
• Applicant contact: Cleve Kapala
• Date application was posted to website: December 15, 2008
• Date public comment period on application closed: February 15, 2009
• Effective certification date: December 15, 2008
• Certification Expiration: December 15, 2013
The project, located at river mile 142 on the Connecticut River, was originally constructed in 1909 and consists of a concrete gravity dam (a 500-foot-long overflow spillway with 10-foot high flashboards, a 100-footlong gated sill block with two 20-foot-high by 50-foot-long tainter gates, and a 336-foot-long non-overflow section) and powerhouse. The project operates as a daily cycling generating facility with limited storage and has a minimum flow requirement, set in the 1979 relicensing, of 1250 cubic feet per second (cfs). The Environmental Assessment associated with the 2006 license amendment describes the flow regime as follows:
"Flows in this reach of river are highly regulated by upstream hydroelectric projects, except under high flow conditions. Typically when flows are less than the project's hydraulic capacity, the project operates in a daily cycle run-of-river mode, where daily inflow matches daily outflow. Generation can vary in the day between the required minimum flow and full capacity if flows are available. The minimum flow at the project is 1,250 cfs or inflow, whichever is less."
The 401 Certification issued for the license amendment notes:
"The Applicant operates the Vernon Hydroelectric Project on a daily cycle, receiving inflow from upstream hydroelectric storage and un-regulated inflow. The Applicant stated that water level fluctuations greater than two feet occur infrequently in the Vernon impoundment, as the normal reservoir operating range is 218-220 ft above mean sea level."
The powerhouse structure and dam, which are 956 feet long, contain 10 Francis type turbines. Units 1 through 7 operate at 133.5 RPM and units 9 and 10 operate at 75 RPM.
The Federal Energy Regulatory Commission (FERC) relicensed the project in 1979. In a 1992 license amendment FERC authorized replacement of the circa 1909 dam's four remaining original three-wheel turbines. The new authorization would have increased the generating capacity of the project from 24.4 megawatts (MW) to 44.4 MW and raised the total hydraulic capacity of the project from 15,530 cubic feet per second (cfs) to 20,930 cfs. However, the owner at the time never installed the turbines, and the project changed ownership, eventually being acquired by the applicant in 2005. After the acquisition the applicant applied to FERC for another license amendment to replace the antiquated and inoperable turbines. Instead of installing two 14.0-MW units, as authorized in the 1992 amendment, the applicant asked to replace the four existing inoperable 2.0-MW turbines with four new 4.0-MW units.
The following agencies were consulted prior to the filing of the amendment, and none objected to the project: United States Department of Interior Fish and Wildlife Service (DOI/USFWS), New Hampshire Department of Environmental Services (NHDES), New Hampshire Fish and Game Department (NHFGD), Vermont Department of Fish and Wildlife (VDFW), Vermont Agency of Natural Resources (VANR), New Hampshire Division of Historic Resources (NHDHR), Vermont Division of Historic Preservation (VTDHP), US Army Corps of Engineers (USACE), an advisory committee to the Connecticut River Joint Commissions, and the Town of Hinsdale Conservation Commission. The following agencies provided post-filing comments expressing concerns about natural resource issues and providing recommendations: DOI/USFWS, VANR, NHDES, and the Connecticut River Watershed Council.
FERC issued a license amendment approving the change in 2006. The change decreased the project's total authorized generation capacity from 44.4 MW to about 32.4 MW. The maximum authorized hydraulic capacity decreased from 20,930 cubic feet per second (cfs) to 17,130 cfs; however, the change increased hydraulic capacity compared to the existing conditions by 1600 cfs. The added generation first generated electricity in 2008, and did not change the facility's mode of operation.
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