Much of the world’s electricity is generated thermally using non-renewable fuels. Coal is the world's most abundant fossil fuel and the fuel most often used to generate thermal electricity. Only a small portion of the world’s thermal electricity is generated using renewable fuels such as biomass.
In contrast, thermal electricity only accounts for around 15 percent of British Columbia’s total electricity generated. Much of this electricity is generated using either renewable fuel sources such as biomass, or Energy Recovery Generation (ERG) technologies.
Renewable and/or non-renewable fuels sources can be burned to generate steam to drive an electricity generation turbine. Renewable thermal generation generally burns biomass, biogas and, in some cases, municipal solid waste to generate electricity. Non-renewable thermal generation generally uses the same technology but burns fossil fuels (e.g. natural gas, diesel, coal, oil, etc.) instead. Occasionally, non-renewable fuels are used in renewable thermal facilities to increase temperatures to allow for a cleaner burning, more efficient thermal process for generating electricity.
There are two methods of producing thermal electricity in power plants: the simple cycle and combined cycle methods. A simple cycle gas turbine is a power plant engine which has no provision for waste heat recovery, resulting in low thermal efficiency. However, the simple cycle engine has an advantage in its ability to turn off and on within minutes, unlike other power plants which must be online for a set time. This cycling ability makes the simple cycle method optimum for supplying power during peak demand periods.
A combined cycle gas turbine operates on more than one thermodynamic cycle, resulting in improved overall efficiency. In a power plant or engine, a gas turbine generator generates electricity while the waste heat is used to make steam. Additional electricity is generated through a steam turbine, enhancing the efficiency of electricity generation. In order to achieve the highest efficiency, the different temperatures between the input/output heat must be extremely high.
Energy Recovery Generation (ERG) Technology
ERG thermal electricity generation involves the recovery of heat from another industrial process. Many British Columbian firms, particularly those in the forest sector, use this technology. For instance, pulp mills will often recover the hot steam from their pulping boilers and use it in a steam turbine to generate on-site energy.
Thermal power plants produce air emissions that can impact local air quality and contribute to global climate change if fossil fuel fired. More recently, exhaust from compressors on natural gas pipelines have been used to generate electricity.
Where can Thermal Generation be found?
The following major thermal, natural gas electricity generation facilities exist in the Province:
- Burrard Generating Station in Port Moody: a large conventional thermal plant fuelled by natural gas with a capacity of 950 megawatts (MW). Due to age and cost of running the facility, it is primarily used to provide transmission support and electricity security back-up for the Lower Mainland.
- Island Cogeneration Plant, Elk Falls, Vancouver Island: this facility produces both electricity and steam. Traditionally, the steam was generated and sold to local pulp mills.
- Fort Nelson Natural Gas Generation Plant: this facility is not connected to British Columbia’s integrated electricity grid. Instead, the facility is tied into the Alberta system and has 47 MW of capacity and is the primary source of electricity for the local community.
- Prince Rupert Plant: this facility is a 46 megawatt natural gas plant operates intermittedly and primarily provides electricity supply for power outages, maintenance activities and voltage support.
- McMahon Cogeneration Plant, Taylor in northeast British Columbia: provides 120 MW to British Columbia’s electric grid and steam to a gas processing plant owned by Westcoast Energy Inc.
Much of the renewable thermal biomass and ERG electrical production can be found throughout the province primarily as part of forest company facilities. Biogas, in the form of methane, is also extracted from landfills in both Victoria and Vancouver and used to generate electricity.
The Future of Thermal Generation
Through the 2007 BC Energy Plan, the provincial government is dedicated to promoting renewable energy sources and reducing our greenhouse gas emissions. Government has implemented several key policies to support these objectives:
- Carbon tax: in 2008, British Columbia became the first jurisdiction in North America to introduce a consumer-based carbon tax. The tax applies to all fossil fuels, including natural gas and coal. Revenues generated by the carbon tax will be returned to consumers by way of tax cuts and credits.
- GHG Cap and Trade system: To help achieve British Columbia’s greenhouse gas reduction targets, in 2008 the government introduced Greenhouse Gas Reduction (Cap and Trade) Act that provides the framework to establish a GHG Cap and Trade System. Under a cap and trade system, large emitters are responsible for ensuring that they have emission allowances to cover all of their emissions. British Columbia is working as a part of the Western Climate Initiative to establish a region-wide cap and trade system.
- Net Zero Emissions: Electricity generation facilities are required to have ‘net zero’ greenhouse gas emissions. This means that those facilities must acquire offsets that completely cover their GHG emissions. In 2008, the Environmental Management Act was amended to enable requirements that existing electricity generation facilities offset emissions by 2016, and new facilities offset emissions immediately.
- Zero Emission Coal: The government will allow coal as a resource for electricity generation when it can reach zero greenhouse gas emissions. Clean-coal technology is expected to become commercially available in the next decade.