The Federal Energy Regulatory Commission on Dec. 9 put out for comment until Jan. 9 an environmental assessment (EA) for the Cedar Station Upgrade Project, which was proposed by Northern Natural Gas Co. and is a key to the plan of Northern States Power-Minnesota to add new gas-fired capacity at the existing Black Dog power plant in Minnesota.
Northern is requesting authorization to construct approximately 7.86 miles of natural gas pipeline in Dakota County, Minnesota, in order to fulfill its contractual obligation with Northern States Power-Minnesota (NSP-MN) to increase the delivery pressure to NSP-MN’s existing Black Dog Generating Station from 400 pounds per square inch gauge (psig) to 650 psig. As part of NSP-MN’s process of reducing its carbon footprint, it has increased its use of natural gas-fired generation, FERC noted.
The FERC staff concludes in the EA that approval of the proposed project, with appropriate mitigating measures, would not constitute a major federal action significantly affecting the quality of the human environment.
The Cedar Station Upgrade Project includes the following facilities:
- approximately 7.86 miles of new 20-inch-diameter pipeline loop;
- a new pig launcher and takeoff valve setting at Northern’s existing Rosemount Junction facility;
- a new pig receiver, tie-in valve setting, and modification of existing regulators at Northern’s existing Cedar Meter Station; and
- various piping within the Cedar Station boundaries.
Outside of the FERC review process, in order to receive the supply of natural gas at the requested pressure, NSP-MN would construct approximately 2.1 miles of new 16-inch-diameter pipeline from the Cedar Station into its existing Black Dog Generating Station in Burnsville, Minnesota. Additionally, NSP-MN plans to install a new valve setting at the Cedar Station and a new regulator facility inside the Black Dog Generating Station. Construction of NSP-MN’s pipeline and associated facilities is expected to begin in 2017. The commission has no jurisdiction over NSP-MN’s new pipeline and associated facilities.
The Minnesota Public Utilities Commission on Sept. 26 had approved an October 2015 application from the NSP-MN subsidiary of Xcel Energy (NYSE: XEL) for a site permit for the Black Dog Unit 6 project. This is a 215-MW simple-cycle natural-gas-fired combustion turbine unit and associated facilities to be built at the existing Black Dog Generating Station. The project is expected to be operational by March 2018, and is estimated to cost approximately $100 million. The existing infrastructure at the generating station, which includes the powerhouse building and the 115-kV substation and transmission system infrastructure, will be used to the extent possible. Unit 6 will be fueled entirely by natural gas.
The existing Black Dog station was initially developed as a coal- and gas-fired generation station, with the last of the coal capacity shut earlier this decade. There is operational gas-fired capacity at the site. This project will be constructed within an existing powerhouse building for the retired Unit 4.
Unit 6 will operate as a peaking generator with an anticipated annual capacity factor of 4%-10%. Unit 6 will interconnect to the existing substation located on-site. The substation will require minor modifications that include the addition of a motor-operated 115-kV disconnect and minor buswork between the generator breaker at the substation and the high voltage transmission lines coming from the step-up transformer.