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Comments on Turnagain Arm tidal power EPA recommends analysis of potential environmental impacts while DOI says Tony Knowles Coastal Trail may be impacted Alan Bailey for Petroleum News
The Environmental Protection Agency and the Department of the Interior have both filed comments with the Federal Energy Regulatory Commission in response to an application for a preliminary FERC permit for a tidal energy facility at the mouth of Turnagain Arm. Both agencies pointed out some issues that need to be considered as part of any permitting for the proposed project.
As previously reported in Petroleum News, in March Turnagain Arm Tidal Energy Corp. applied for a preliminary permit for the Turnagain Arm Tidal Electric Generation Project, or TATEG, for the generation of electric power from Cook Inlet tides. The permit would enable Turnagain Arm Tidal Energy to proceed with the investigations and analysis required to potentially apply for a license to construct the system.
The tides create powerful currents in and out of Turnagain Arm. The project, as envisaged, would involve the construction of two 8-mile tidal fences across the arm, to enable the operation of tidal turbines. One fence would run from near Fire Island to Point Possession on the Kenai Peninsula, with a service road along the top to allow access from the Kenai Peninsula for servicing the turbines. The second fence would be 7.5 miles in length and would be located 5-7 miles south of Fire Island and at least 5 miles from the other fence.
Installed capacity of 2,200 megawatts Tidal energy benefits from the advantage of predictability in its renewable power output but from the disadvantage of varying in output as the tidal currents wax and wane. The proposed system, with a total of 220 10-megawatt turbines, would have a total installed capacity of 2,200 megawatts and a baseline average output of 1,200 megawatts. Turnagain Arm Tidal Energy says that this power capacity would be sufficient to meet the entirety of the Alaska Railbelt electricity demand. The company has proposed a number of studies, including a study into the potential use of industrial batteries to mitigate the loss of power output during periods of slack tides.
The company says that the two fences, with their associated turbines, could harness a large portion of the kinetic energy associated with the water flow in and out of the Turnagain Arm. The company also says that the relatively slow rotation of the turbine blades, together with their large scale, will enable fish, whales and other sea mammals to swim though the fences without difficulty.
NEPA review required In a June 30 FERC filing the EPA commented on the need to review the project under the terms of the National Environmental Policy Act.
“This proposed tidal energy project is unprecedented in Alaska,” the filing says, commenting that an alternatives analysis under NEPA must include appropriate management and mitigation measures, including measures to reduce the impacts of construction, operations and decommissioning, and to minimize impacts on traditional and cultural uses and resources.
The EPA also expressed particular concern about potential impacts on Cook Inlet beluga whales, with a need for analysis of the effects on the whales of factors including the noise generated by power stations and the physical barriers associated with the power stations that may impact the whales’ transits between “foraging, nursing and/or birthing areas.” More clarity will be needed over the ability of fish, whales and other sea mammals to swim through the turbines, the EPA said. The beluga whales, with their population in significant decline, are listed as endangered under the Endangered Species Act.
In a mid-June filing the Center for Biological Diversity, while commenting that it did not yet have sufficient information to take a position on whether the project should proceed, had expressed particular caution about potential impacts on the beluga whales.
Among other factors listed by the EPA are the need evaluate the impacts of any dredging operations carried out in association with the project, and the possible impacts on subsistence resources. The Cook Inlet is rich in resources used for subsistence fishing, hunting and gathering, the EPA said.
The EPA also recommends that the NEPA analysis of the project should consider the “reasonably foreseeable” impacts of climate change on the project and its infrastructure, as well as the potential greenhouse gas emissions from construction, operations and decommissioning activities. Climate change will alter water flow rates, temperatures, wind fields and coastal water current patterns, the EPA said.
Potential recreational impacts The DOI, in a June 25 filing, particularly focused on the potential impact of the tidal energy project on the Tony Knowles Coastal Trail that runs along the Cook Inlet coast, connecting Anchorage with the Kincaid Park. The trail, which is popular with walkers, skiers, cyclists and other recreational users, includes 7.71 miles of trail supported by the Land and Water Conservation Fund, or LWCF. The National Park Service is seeking the appropriate records that define the boundaries of the LWCF area, to determine whether the project would impact the area, DOI said.
Any conversion of land within a LWCF area would require compliance with federal laws, including NEPA and the National Historic Preservation Act, DOI cautioned. Potential impacts to the recreational and conservational purposes of the area, including impacts of the design of the tidal power system on the “viewshed” of the area, need to be understood, DOI said.
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