Electricity Generation Choices
I’ve heard the term Cogeneration, but what exactly does the process entail?
Cogeneration, or combined heat and power (CHP), is the simultaneous production of electrical and thermal energy. The waste heat from electricity generation is recovered and used for applications, such as space heating and cooling, water heating, and industrial process heat. By making use of the waste from one process in the production of the other, substantial gains in energy efficiency can be realized.
- According to the Canadian Industrial Energy End-Use Data and Analysis Centre, in 2012 there were 200 cogeneration systems in Canada with an operating capacity of 6.5 GW. Alberta has 2.3 GW of cogeneration capacity, which is the largest in Canada. Ontario is second to Alberta, with 2.1 GW. These two provinces account for 67 per cent of the cogeneration capacity in Canada. Canadian utilities account for the most cogeneration capacity, at 45 per cent when classified by systems operator. This is followed by paper manufacturing, at 23 per cent.
- A cogeneration facility is comprised of four components: the power plant, the heat recovery and distribution system, an optional system for satisfying heating and / or cooling loads, and a control system. A range of technologies can be used to achieve cogeneration, including steam turbines, gas turbines, reciprocating engines, microturbines, fuel cells, and Sterling engines. Cogeneration can be implemented at a range of scales, from large scale systems serving communities or large industrial complexes, to independent energy supplies for hospitals or universities. Since heat is not easily transported, facilities must be located near their “thermal hosts” or users of thermal energy.
- Most of the world’s electricity is generated by rotating machinery that is driven by the combustion of fuels. As a result, cogeneration systems have enormous potential for growth. The adoption of cogeneration in the Alberta Oil Sands has improved environmental, economic and emissions results.
- Siting of cogeneration facilities can sometimes be challenging, as facilities must be located near their thermal hosts. In addition, integrating distributed energy sources into the electricity grid may require transmission and distribution system upgrades. Many players must work together in the development and operation of a cogeneration facility, including the electricity generator, the utility that distributes the electricity, and the thermal host. The distribution utility must be willing to purchase power from the generator, and may put some conditions restrictions or costs on connecting to the grid to ensure system reliability.
- Canadian Industrial Energy End‐use Data and Analysis Centre, “A Review of Existing Cogeneration Facilities in Canada,” Canadian Industrial Energy End‐use Data and Analysis Centre website, http://www2.cieedac.sfu.ca/media/publications/Cogeneration_Report_2012_Final.pdf, accessed October 17, 2012.
- Natural Resources Canada, “Combined heat & power (Cogeneration),” Natural Resources Canada website, http://www.retscreen.net/ang/g_combine.php, accessed October 17, 2012.