TransAlta is Canada’s largest power generation and wholesale marketing company, and largest publicly traded provider of renewable energy.
TransAlta’s portfolio of assets includes coal, gas, hydro, wind, geothermal and biomass. TransAlta will continue to use coal as an affordable, reliable energy source, and is investigating environmental mitigation technologies such as carbon capture and storage, along with emission reduction technologies.
Our longer term strategy is to increase the amount of renewable power generation sources in our portfolio, such as wind, geothermal and hydro. Coal will continue to be a key source of electrical power because it is affordable, plentiful and reliable. There are no comparable alternatives to coal in the short term to meet society’s growing needs for reliable, affordable electricity.
Our growth strategy is focused upon greening our portfolio to reduce our carbon footprint and develop long-term, sustainable power generation. We’ve delivered on this plan in 2009 by acquiring Canadian Hydro Developers, expanding our wind portfolio, and improving efficiency at our coal plants. We continue to develop opportunities for future sustainable power projects.
TransAlta has six coal-fired power plants located in Canada and the U.S. Coal that is used for power generation is mined either in close proximity to plants, or shipped to power plants. Within the plant it is crushed in pulverizers and blown into a furnace where it burns. This heats a series of boiler tubes filled with pressurized water, converting the water to steam. The steam then travels through a turbine, spinning a generator to produce electricity.
TransAlta has 13 cogeneration gas power plants in Canada, the U.S. and Australia. Cogeneration involves natural gas being combusted to propel a gas turbine which generates electricity. Excess heat produced during combustion is used to create steam, which turns a steam turbine generating additional electricity.
Hydropower plants are run-of-river, meaning they are built on large rivers that have a natural drop in elevation, such as a waterfall or rapids. Alternatively, a dam is built across a river to raise the water level and provide the drop that is needed. As the water behind the dam is released, it passes through a hydraulic turbine causing it to turn and generate electricity. TransAlta has hydro operations in Alberta, British Columbia, Ontario and the United States.
TransAlta has wind power operations across Canada. The turbines used by TransAlta are of the horizontal axis variety, meaning the design typically has three rotor blades that are aerodynamically designed to move when the wind passes over them. The blades are connected to a generator, which produces electricity.
TransAlta holds 50 per cent ownership of 10 geothermal facilities in Imperial Valley, California, with a net ownership capacity of 164 MW. Geothermal power plants capture the energy from the Earth by tapping into naturally occurring hydrothermal convection systems. When water seeps into the Earth’s crust it naturally heats and rises to the surface as steam. Geothermal captures this super-heated fluid to drive electric generators.
TransAlta has one biomass facility in Canada, acquired in 2009. This cogeneration plant uses wood waste from a nearby saw mill. The bark and sawdust are burned to create both steam and electricity. The resulting ash is then sold to nearby organic farmers. This facility is Ecologo certified by the Environmental Choice Program.