Cory Cogeneration Station Expects Commercial Operations on New Year's Day

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Researched by Industrialinfo.com (Industrial Information Resources Incorporated; Houston, Texas). Construction of the 228 megawatt (MW) Cory Cogeneration Station is coming to an end. Full operation is expected on January 1, 2003. The 228 million combined-cycle cogeneration is constructed at the Potash Corporation of Saskatchewan (PCS) Cory mine, west of the city of Saskatoon, and will be connected to the Saskatchewan transmission grid by an eight-kilometer long 144 KV transmission line.

The plant includes two (2) 85-megawatt natural gas-fired General Electric combustion turbines and generators, two (2) Applied Thermal Systems (ATS) Heat Recharge Steam Generators (HRSGs), and a 90 MW General Electric steam turbine. The exhaust gases from each gas turbine will be sent to a waste heat recovery boiler to produce steam. This steam will be used to power a steam turbine as well as provide all of PCS Cory's steam requirements. The plant has a natural gas fuel interconnection to TransGas system, and a water supply pipeline interconnection to SaskWater system. The plant will draw cooling water from the South Saskatchewan River.

The plant will operate mostly in cogeneration mode, a process that allows simultaneous production of electricity and steam from a single fuel source using combustion gas turbine, heat recovery steam generators, and steam turbine technology, but it is also capable of operating in a combined-cycle mode, a process that uses gas turbines, with a design based on the addition of one or more turbine cycles with a steam cycle. This type of plant uses thirty-five percent less fuel than a coal or oil plant, in which the electricity is obtained from the steam produced by heating water.

Combined-cycle plants are a cleaner way of generating electricity; they also required a third less energy than a customary power plant. They have the advantage of long term fuel price stability, fuel flexibility, low emissions, inexpensive construction, and faster start up than nuclear plants, which can take up to six years to build. A combined-cycle power plant typically can be completed in two years.

Material issues are of great importance for the reliable and cost effective operations of combined-cycle plants. Rapid degradation of materials due to high temperatures, or the inability to repair equipment result in high operating costs. The gas turbine hot section components incur the majority of the maintenance cost. Also the HRSG, steam turbine/generator, and balance of the steam plant experience problems related to transfer and concentration of water contaminants, pressure and thermal stresses, and high-temperature aging mechanism.

The Cory cogeneration station's "state of the art" design will enable it to generate electricity with minimum effect on the environment. Both the gas turbines and heat recovery steam generators will be equipped with low NOx combustors to minimize environmental impact. The plant can deliver a base load of about 80 MW constantly to the SaskPower grid, which is sufficient to meet PCS steam requirements. All electricity produced will be sold to SaskPower Corporation under a 25-year power purchase agreement (PPA). There will be about thirty-three workers needed to operate the cogeneration plant.

SaskPower and ATCO POWER CANADA LIMITED, jointly own the Cory Cogeneration Station. SaskPower is a vertically integrated electric utility, and a leader in the field of electricity generation, transmission and distribution, will work with ATCO Power, a world leader in the development of electric generation facilities, on the design, and construction of the plant.