How a cogeneration station works
Cogeneration is the simultaneous production of electricity and steam from a single fuel source using combustion gas turbines, heat-recovery steam generators and steam turbine technology.
In traditional gas turbines, most of the energy potential of fuel is wasted when hot exhaust gases are released into the atmosphere. In cogeneration facilities, the exhaust gases from each gas turbine are captured and redirected into a waste-heat recovery boiler to produce steam. This steam is used to power a steam turbine, which generates additional electricity.
Additional steam is also available for adjacent mining and other applications.
In a cogeneration facility, significantly more potential energy of natural gas is converted into electricity and steam than what is achieved by conventional power stations. Greenhouse gas emissions are also significantly lower than a similarly sized coal-fired power station.
Cory Cogeneration Station
The Cory Cogeneration Station, a 228-megawatt (MW) natural gas-fired cogeneration facility, is located at Potash Corporation of Saskatchewan Inc.'s (PCS) Cory mine site, near Saskatoon.
The Cory Cogeneration Station is a 50-50 joint venture between SaskPower and ATCO Power.
The plant operates mostly in cogeneration mode, which is the simultaneous production of electricity and steam from a single fuel source using combustion gas turbines, heat-recovery steam generators and steam turbine technology. The facility is also convertible to operate in a straight combined-cycle mode, a process that combines a natural gas turbine and a steam turbine to generate electricity only. In this mode, the facility can produce 260 MW of electricity.
The plant consists of two natural gas-fuelled combustion turbines and generators. The exhaust gases from each gas turbine are sent through a waste-heat recovery boiler to produce steam. This steam is used to power a steam turbine as well as provide all of PCS-Cory's steam requirements.
The Cory Cogeneration Station's design enables it to generate electricity with minimal effect on the environment. Both of the gas turbines are equipped with low nitrogen oxide combustors to minimize the environmental impacts of generating electricity. The Cory Cogeneration Station turns approximately 60 per cent of the natural gas' potential energy into electricity and steam, compared to an average of 33 per cent achieved by conventional power stations, while emissions of greenhouse gases are only about one third of a similarly sized coal-fired power station.
Capacity
- 260 megawatts—combined-cycle mode
- 228 megawatts—cogeneration mode
Equipment
- Two General Electric PG 7121EA gas turbines rated at 85 MW
- Two heat-recovery steam generators rated at 140 tonnes per hour
- One 90 MW General Electric Steam Turbine
Highlights
- Natural gas fuel interconnection to TransGas system
- Water supply pipeline interconnection to SaskWater system
- Connection to the Saskatchewan transmission grid
Commercial operations
- January 2003
Meridian Cogeneration Station
The Meridian Cogeneration Facility, owned by Meridian Limited Partnership, a wholly owned entity of Stanley Energy Inc., is a 210 megawatt (MW) natural gas-fired cogeneration plant located at Husky's heavy oil upgrader site in Lloydminster, Saskatchewan.
Capacity
- 210 MW
Equipment
- Two natural gas generating units
- A steam turbine generator
Highlights
- This was SaskPower's first large-scale cogeneration energy purchase
- The plant also produces steam for Husky's Lloydminster heavy oil upgrader operations
Commercial operations
- December 1999
MRM Cogeneration Station
The MRM Cogeneration Station is a 172-megawatt (MW) cogeneration facility located at the Muskeg River Mine, 75 kilometres north of Fort McMurray and is part of the Athabasca Oil Sands Project (AOSP), which is owned by Shell Canada Limited (60 per cent), Chevron Canada Limited (20 per cent), and Marathon Oil Sands L.P. (20 per cent).
The MRM Cogeneration Station is owned 30 per cent by SaskPower and 70 per cent by ATCO Power.
The plant operates in a highly efficient cogeneration mode, which is the simultaneous production of electricity and steam from a single fuel source using combustion gas turbines and heat-recovery steam generators.
The plant consists of two natural gas-fuelled combustion turbines and generators. The exhaust gases from each gas turbine are sent through a waste-heat recovery boiler to produce steam that is used in the mine's bitumen extraction process. The Muskeg River Mine uses all the steam output from the cogeneration facility and currently uses about 60 per cent of the power output, with the remaining power being sold into the Alberta power grid.
The MRM Cogeneration Station's design enables it to generate electricity with minimal effect on the environment. Both of the gas turbines are equipped with low nitrogen oxide combustors to minimize the environmental impact of generating electricity. The MRM Cogeneration Station turns approximately 84 per cent of the natural gas' potential energy into electricity and steam, compared to an average of 33 per cent achieved by conventional power stations, while emissions of greenhouse gases are only about one third of a similarly sized coal-fired power station.
Capacity
- 172 megawatts
Equipment
- Two GE 7EA gas-fired turbines and generator sets with low nitrous oxide burners
- Two heat-recovery steam generators with supplemental heat injection
- Two standby auxiliary gas-fired boilers
- Associated control equipment
Highlights
- Muskeg River Mine currently uses about 60 per cent of electric energy generated. The remaining balance of electricity is sold into the Alberta power pool
Commercial operations
- January 2003
