Natural Gas – Simple/Combined Cycle Contracts

Natural Gas – Simple Cycle and Combined Cycle (SC/CC) Generation

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Simple Cycle and Combined Cycle Generation

Simple Cycle
Natural gas turbines operate by burning natural gas. Hot gasses produced during the combustion process turn the turbine and generate electricity. This type of electricity generation is typically favored for meeting peak loads, as the turbines can quickly achieve full generation capability. Plants of this type typically exhibit efficiencies as high as 35 percent.

Combined Cycle
The most efficient method of generating electricity from natural gas is a combined cycle unit. This configuration consists of one or more gas and steam turbines. The gas turbines operate as described above, except that the excess heat during the combustion of natural gas is directed to generate steam and turn a steam turbine. Therefore, both the gas and steam turbines generate electricity, achieving efficiencies of up to 55 percent.

The combined cycle unit takes advantage of the peaking capabilities of the gas turbine, in addition to the steady amount of power obtained from the steam turbine allowing a typical natural gas plant to meet peak and intermediate demand. Any excess steam that is generated may be sold to neighboring buildings for district heating to achieve even greater efficiencies.


The status of individual contracted electricity supply projects within different IESO procurement programs is now available in the IESO Active Generation Contract List.