Natural Gas Fired Power

Of the total electricity generated in Canada, approximately 5% (31 million megawatt hours) can be attributed to the combustion of natural gas. Natural gas-fired steam electric plants (boilers), combustion turbines (gas turbines) and internal combustion engines account for about 9,500 megawatts of electricity. Boilers account for less than 20% of this capacity whereas gas turbines slightly more than 75%. The remaining capacity results from the operation of internal combustion engines.

Courtesy of TransAlta Corp. This natural gas cogeneration plant is located in Ottawa, Ontario. It provides electricity, heating, steam, and chilled water to a hospital complex.Gas turbine plants fuelled by natural gas are considered one of the cleanest fossil fuel-fired options available for electric power generation. Since natural gas contains no ash and practically no sulphur or metals, emissions of these substances are virtually zero. As is the case with coal and oil-fired plants, the combustion of natural gas leads to emissions of nitrogen oxides (NOx) and carbon dioxide (CO2), albeit in smaller amounts. Major environmental issues related to these pollutants include smog and climate change. Dry low NOx combustion, and system efficiency through cogeneration, are the most effective solutions to these issues.

Natural gas-fired combustion turbines are especially efficient when used in combined heat and power (CHP) systems (also called cogeneration systems) since by-product heat, which would otherwise be wasted, is used for heating and/or cooling purposes. As a result, natural gas combined cycle co-generation yields an overall efficiency of more than 80%, whereas conventional coal-fired power plants achieve approximately 33% efficiency.

In January 2003, Environment Canada released the New Source Emission Guidelines for Thermal Electricity Generation under the Canadian Environmental Protection Act. The Guidelines provide limits for emissions of sulphur dioxide (SO2), nitrogen oxides (NOx) and particulate matter (PM) for fossil-fuel fired steam combustion units (boilers). Environment Canada also has Codes of Practice for steam electric power generation.

Environment Canada led the development of the National Emission Guideline for Stationary Combustion Turbines, published by the Canadian Council of Ministers of the Environment in December 1992. This Guideline is used today by many provincial permitting agencies.

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