Revised design for Grant Lake hydro|
FERC seeks public comments prior to preparing environmental impact statement for project near Moose Pass on the Kenai Peninsula
The Federal Energy Regulatory Commission is requesting comments on a revised design for a proposed hydroelectric project at Grant Lake on the Kenai Peninsula. FERC is going to prepare an environmental impact statement for the project and anticipates publishing a draft EIS in October and a final EIS in April 2019.
Kenai Hydro LLC, a subsidiary of the Alaska Electric and Energy Cooperative, the business entity that operates power generation and transmission facilities as a part of Homer Electric Association, is proposing to build the hydropower system to help meet Homer Electric’s goal for the use of renewable energy in the utility’s power generation mix.
Near Moose PassGrant Lake is an L-shaped water body in the hills above and to the east of the Seward Highway, where the highway runs through the valley of Moose Pass, with Grant Creek flowing from Grant Lake into Lower Trail Lake, just south of the southern end of Upper Trail Lake. Construction of the five-megawatt hydro facility would involve diverting water from Grant Lake through a tunnel to a powerhouse near the outlet of Grant Creek canyon, a natural rock canyon.
The project has raised numerous concerns about possible impacts on the Kenai River watershed. The historic Iditarod Trail from Seward to Nome also passes through the project area, a situation that has required discussions over any conflicts with the trail route.
Although Kenai Hydro had at one time considered the possibility of constructing a concrete dam at the outlet end of Grant Lake, the company eventually settled on a design which eliminates the need for a dam and places a water intake below the level of the lake’s natural water surface, to the east of the lake’s outlet into Grant Creek. A bypass pipe to Grant Creek would enable the required minimum flow rate in Grant Creek to be maintained.
The maximum drawdown of the lake, to feed the hydropower system, would take place in the winter, with the spring runoff subsequently replenishing the lake.
Kenai Hydro filed a license application for the project with FERC in April 2016 and FERC subsequently conducted scoping meetings and prepared scoping documents for an environmental impact statement.
Agency requestFERC says that in October 2016 the National Marine Fisheries Service and the U.S. Fish and Wildlife Service asked Kenai Hydro if it would be feasible to move the bypass flow into Grant Creek to a point close to the outlet of the creek from Grant Lake. The agencies said that this bypass relocation would facilitate downstream ecological processes with little impact on the project economics or power generation capabilities.
During the winter of 2016-17 Kenai Hydro conducted engineering and economic feasibility assessments for the agencies’ request. The company ultimately determined that the relocation of the bypass flow would be viable and proposed this option as the preferred design for the hydropower facility. The company subsequently filed an amendment to its original FERC license application, to incorporate the altered design. The new design involves a pump system and a weir structure at the outlet from the lake and eliminates the bypass pipe in the earlier design.
FERC is now seeking comments on the amended design.