Thermal Power Generation

“Thermal generation” refers to any plant that burns fuel as a means for generating electricity.  There are two basic alternative processes used in thermal generating plants:  (1) a process that burns fuel in order to boil water so that the resulting steam drives a steam turbine, which spins a generator; and (2) a process that burns fuel in an internal combustion engine, which in turn spins generator.

Various kinds of fuel may be burned in thermal power plants, all of which release emissions into the air.  Some fuels that are well known include fossil fuels (natural gas, oil, diesel or coal), methane (produced by biomass) and wood waste.  Because the fuels are burned, all thermal plants produce emissions in the form of CO₂, water vapour and probably NOx, sulphur dioxide, waste heat and other pollutants.  The emissions can vary dramatically, depending upon the fuel being burned and the plant technology.

Cogeneration plants are thermal power plants, but they increase the efficiency of the thermal generating process by capturing some or all of the waste heat energy that is generated as a by-product in the thermal process.  Cogeneration facilities take the heat energy by-product, capture it and divert it for direct heating of an attached facility.  Cogeneration processes work particularly well for large facilities, such as universities and hospitals, which consume large quantities of both electricity and heat.

Significance of Thermal Power Generation to Watershed Protection:

Thermal power generation processes create direct and indirect impacts upon aquatic environments and watersheds.  Some of the environmental impacts which may be associated with thermal power plants include:

·         air pollution/airborne emissions, including particulates, toxics, greenhouse gases and heat

·         risk of spills of fuel on land, or contamination of water or groundwater

·         service road construction

·         construction of gas pipeline supply corridors

·         installation of gas storage facilities

·         construction of electrical transmission line corridors

·         noise pollution

Regulation of Thermal Power

Thermal power generation is primarily regulated by the provincial government.  The construction and operation of power generation facilities is generally regulated by the Utilities Commission, under the Utilities Commission Act.  However, while the Utilities Commission can consider environment concerns, the Act is primarily aimed at ensuring that consumer receive fair prices for electricity, rather than at environmental protection. 

The environmental side of thermal power generation will be more often regulated by the province’s Waste Management Act and Environmental Assessment Act.  The purpose of the Waste Management Act is to regulate the disposal of “waste” in the province, including air contaminants, various kinds of waste and discharges, refuse, litter and pollution.  Thermal power generation will inevitably produce air emissions which will be regulated by the Act.  Under the Waste Management Act the Ministry of Water, Land and Air Protection will set maximum emission criteria and standards.  The usual maximums are set in the following government policies:

·         Emission Criteria for Gas Turbines December 1992

·         Technical Memo Re: Recommended NOx Emission Limit for Natural-Gas-Fired Boilers Greater than 73 MW (250 MMBtu/h) February 1993

·         Coal-Fired Power Boiler Emission Objectives.

In addition, there are some regulations created under the Act that may be relevant to thermal power, including:

·         Oil and Gas Waste Regulation (facilities 600 kW to 3 MW in capacity).

·         Special Waste Regulation (regulating such things as handling of waste oil, gas and PCBs; handling of ignitables; and management of hydrocarbon-contaminated soil).

·         Sulphur Content of Fuel Regulation.

Finally, Many dams and hydro-electric projects will be subject to the Environmental Assessment Act, which will require a process of assessing and reviewing the environmental, economic, social, cultural, heritage and health effects of the project before it is authorized to proceed.  A power project may require an assessment if the Minister of Sustainable Resource Management orders it or if it will:

·         be a new project with a rated “nameplate capacity” of 50MW or more of electricity;

·         increase the capacity of an existing project by 50 MW or more; or

·         be a new project involving laying 40km or more distance of transmission lines over a new right of way.

Even if a project meets the above requirements, however, the executive director of the Environmental Assessment Office may decide that the assessment is not necessary.   

 

Related Guide Pages:

·         Power Generation

For more information related to Thermal Power Generation:

·         Thermal Generation System from the B.C. Hydro website.

·         Climate Change - Solutions - Electricity from the David Suzuki Foundation website.

·         What can we do about climate change? on the Environment Canada website.