Glossary
Bottom ash
Heavier ash that collects in the bottom of the boiler after the coal is burned. This ash is collected and stockpiled in approved disposal areas.
Carbon dioxide equivalent (CO2E)
Measure used to compare the emissions of various GHGs based on their global warming potential. Expressed in CO2.
Climate change
Term used to describe the view that the Earth's temperature and climate will change, in part, due to GHG emissions associated with human activities.
Chlorofluorocarbons (CFCs)
Various compounds consisting of carbon, hydrogen, chlorine and fluorine found in aerosol spray products and refrigerants. CFCs contribute to the depletion of the Earth's ozone layer and to the buildup of GHGs.
Cogeneration
Technology that simultaneously produces power and thermal energy (heat and steam) from a single fuel source such as natural gas.
Combined cycle
Technology that captures waste heat from gas-fired turbines to produce more electricity.
Decommissioning
Safe and orderly permanent shutdown of a utility plant.
Emission intensity
Amount of emissions per megawatt hour produced. Emission intensity rates measure an operation's efficiency in controlling emissions.
Emissions reduction trading
Innovative market-based approach that allows organizations to buy and sell emission reductions. In an emissions trade, one company earns credits for emissions removed or not released into the atmosphere. Companies that emit can purchase these credits to reduce their emissions impact on the atmosphere.
Environmental contraventions
Include events that contravene our company's permit conditions or environmental regulations. Examples may include releases (such as spills of engine oil), submitting late reports and exceeding emission limits for operating permits.
Fines
Amount payable as a result of an enforcement action.
Environmental enforcement actions
Include events that contravene our company's permit conditions or environmental regulations and result in fines, penalties or citations.
Fly ash
Particulate matter from coal ash that exits boilers along with hot gases. Pollution control equipment such as electrostatic precipitators remove more than 99 per cent of the fly ash before it can be released into the atmosphere.
Geothermal energy
Electricity generated by using steam from below the Earth's surface.
Global Reporting Initiative (GRI)
Guidelines setting global standards for sustainability reporting by companies.
Greenhouse gases (GHGs)
Gases that trap heat near the Earth's surface, thereby potentially moderating our global climate. They include CO2, methane and water vapour. These gases occur through natural and human-influenced processes.
Health and safety enforcement actions
Include employee and contractor events that contravene our company's permit conditions or health and safety regulations and result in fines, penalties, orders or citations.
Health and safety incidents
Include employee and contractor incidents resulting in medical aid and lost-time injuries.
Kyoto Protocol
International agreement created in December 1997 to address worldwide GHG emissions. Under Kyoto, individual countries are obligated to reduce their GHGs by a specified amount.
Megawatt (MW)
Measure of electric energy equal to one million watts.
Mercury
Trace heavy metal found in coal and emitted from oceans and land masses. Mercury emissions from human activities are about a quarter of worldwide mercury emissions.
Nitrogen oxides (NOx)
Gas released in the burning of fossil fuels and a contributor to smog.
Offset
Emission reductions produced by projects outside TransAlta and supported by our company through commercial purchase contracts. In most cases, these projects are less expensive than internal reductions, thereby permitting TransAlta to achieve more GHG reductions for the same investment. Also, these offsets often provide additional benefits in terms of local development, employment and general environmental improvement.
Opacity
Amount of light obscured by particulate levels in the air. A measure of environmental performance resulting from particulate emission control systems.
Particulate matter
Fine solid or liquid material released into the air from the burning of coal or other plant processes.
Renewable energy
Naturally occurring energy resources that are continually replenished. Examples of renewable energy sources are wind, solar and water.
Stakeholders
People that affect or are affected by company operations, including customers, employees, media, regulators, community leaders, governments, and investors and shareholders.
Sulphur dioxide (SO2)
Emission that results mainly from the burning of sulphur in fossil fuels and contributes to acid deposition.
Watershed
Area of land that catches precipitation and drains it to water bodies such as lakes, streams or rivers.