Definition: Cogeneration

From Open Energy Information

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Cogeneration

The production of electric energy and another form of useful thermal energy through the sequential use of energy [as defined under the Public Utility Regulatory Policies Act (PURPA)].[1][2]

Wikipedia Definition

Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise-wasted heat from electricity generation is put to some productive use. Combined heat and power (CHP) plants recover otherwise wasted thermal energy for heating. This is also called combined heat and power district heating. Small CHP plants are an example of decentralized energy. By-product heat at moderate temperatures (100–180 °C, 212–356 °F) can also be used in absorption refrigerators for cooling. The supply of high-temperature heat first drives a gas or steam turbine-powered generator. The resulting low-temperature waste heat is then used for water or space heating. At smaller scales (typically below 1 MW), a gas engine or diesel engine may be used. Cogeneration was practiced in some of the earliest installations of electrical generation. Before central stations distributed power, industries generating their own power used exhaust steam for process heating. Large office and apartment buildings, hotels, and stores commonly generated their own power and used waste steam for building heat. Due to the high cost of early purchased power, these CHP operations continued for many years after utility electricity became available. The cogeneration industry says that it can help mitigate climate change., Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise-wasted heat from electricity generation is put to some productive use. Combined heat and power (CHP) plants recover otherwise wasted thermal energy for heating. This is also called combined heat and power district heating. Small CHP plants are an example of decentralized energy. By-product heat at moderate temperatures (100–180 °C, 212–356 °F) can also be used in absorption refrigerators for cooling. The supply of high-temperature heat first drives a gas or steam turbine-powered generator. The resulting low-temperature waste heat is then used for water or space heating. At smaller scales (typically below 1 MW), a gas engine or diesel engine may be used. Cogeneration was practiced in some of the earliest installations of electrical generation. Before central stations distributed power, industries generating their own power used exhaust steam for process heating. Large office and apartment buildings, hotels, and stores commonly generated their own power and used waste steam for building heat. Due to the high cost of early purchased power, these CHP operations continued for many years after utility electricity became available. The cogeneration industry says that it can help mitigate climate change.

Reegle Definition

Cogeneration power plants produce electricity but do not waste the heat this process creates. The heat is used for district heating or other purposes, and thus the overall efficiency is improved. For example could the efficiency to produce electricity be just 20%, and the overall efficiency after heat extraction could reach be 85% for a cogeneration plant. It has to be considered that there is not always use for heat., Combined heat and power, also called cogeneration, is a technology where electricity and steam or electricity and hot water are produced jointly. This increases the efficiency compared to separate electricity and heat generation. (IEA, 2014), Bioenergy cogeneration describes all technologies where heat as well as electric power are output products of a bioenery power plant.


Also Known As
CHP
Related Terms
Combined heat and powerElectricity generationheatpowerenergyelectricity generationbioenergyelectricity
References
  1. http://205.254.135.24/tools/glossary/index.cfm?id=C#
  2. http://www.unep.fr/energy/information/publications/factsheets/pdf/cogeneration.pdf