The Alberta Utilities Commission on March 4 went out for public comment until March 28 on an application by Capital Power Generation Services to construct and operate two natural gas-fired generation units with a total capacity of 1,050 MW.
The planned Genesee Units 4 and 5 would be located on a brownfield site adjacent to the existing, coal-fired Genesee station located approximately 30 kilometers southwest of Stony Plain, Alberta. In the fourth quarter of 2013, Capital Power and ENMAX Corp. announced their letter of intent to pursue joint arrangement agreements to develop, construct, own and operate the Genesee 4 and 5 facility (formerly called the Capital Power Energy Centre).
Capital Power filed the application with the AUC on Dec. 20, 2013, requesting approval to construct and operate Genesee Units 4 and 5. The project will use natural gas combined-cycle technology and each unit consists of a single natural gas turbine paired with a heat recovery steam generator and a single steam turbine.
The project is being developed to meet expected increases in Alberta’s power requirements in the 2017-2020 timeframe, arising from continued economic growth and from the expected retirements of existing coal-fired generating units.
The project will make effective use of the existing Genesee plant infrastructure, specifically, utilization of the existing river water intake, pumphouse, cooling pond, point of discharge to the North Saskatchewan River, settling pond, sewage lagoon, access roads, and transmission interconnection.
Gross output of the existing Genesee Unit 1, 2, and 3 is 430 MW, 430 MW, and 516 MW respectively, for a combined total of 1,376 MW. The gas-fired project would increase the electrical output of the existing Genesee facility by approximately 76% (up to an additional 1,050 MW gross) for a combined total gross nameplate capacity of up to 2,426 MW at the site.
Each new unit will be equipped with advanced Selective Catalytic Reactor (SCR) for NOx control and a minimum stack height of 80 meters to facilitate flue gas dispersion. The SCR will utilize aqueous ammonia as a reagent with an ammonia storage and handling facility being built for ammonia injection into the SCR.
Electricity generated by the project will be transmitted to the Genesee switchyard owned by EPCOR via an approximately 200-meter-long overhead 500-kV power line.
The December 2013 application does not include interconnection to the Alberta Interconnected Electric System. Capital Power will submit a facilities application for the interconnection facilities application separately.
Project will use once-through cooling, take gas off of a TransCanada pipeline
Genesee Units 4 and Unit 5 heat rates are estimated at 6112 kJ/KWh (Lower Heating Value) each, with an efficiency of 58.8% based on LHV at an ambient temperature of 15°C. The project will utilize a once-through cooling process for the steam turbine condenser taking water from the Genesee cooling pond through the extended intake canal. Water for equipment cooling and other process needs will also utilize cooling water from the cooling pond. All of the cooling water discharge from the steam turbine condenser and other equipment will be returned back to the Genesee cooling pond through the existing discharge canal.
Nominal summer ratings of each unit are expected to be up to 460 MW (540 MVA) gross capacity with supplementary firing. Nominal winter ratings of each unit are expected to be up to 525 MW (620 MVA) gross capacity with supplementary firing.
The project will require approximately 170,000 GJ/day of natural gas operating at full load during winter months. Natural gas for the project will come from TransCanada’s mainline located east of Drayton Valley. An underground pipeline of approximately 78 kilometers will be developed for the project.
Capital Power estimates that annual energy production of the project will be up to 7,750 GWh/yr at average ambient temperature without duct firing at 100% capacity.
The earliest in service date for the interconnection is the third quarter of 2017 for Unit 4. Commissioning of Unit 4 is expected to be complete by the fourth quarter of 2017 at the earliest. The earliest interconnection and commissioning dates for Unit 5 are third quarter 2018 and fourth 2018, respectively.