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Combined Heat and Power Partnership

Environmental Benefits

CHP Environmental Benefits Tools and Resources

Combined heat and power (CHP) systems offer considerable environmental benefits when compared with purchased electricity and onsite-generated heat. By capturing and utilizing heat that would otherwise be wasted from the production of electricity, CHP systems require less fuel than equivalent separate heat and power systems to produce the same amount of energy.

Because less fuel is combusted, greenhouse gas emissions, such as carbon dioxide (CO2), as well as criteria air pollutants like nitrogen oxides (NOx) and sulfur dioxide (SO2), are reduced. The following diagram shows the magnitude of reduced CO2 emissions of a 5 megawatt (MW) natural gas-fired CHP system compared with separate heat and power used to produce the same energy output.

Conventional Generation vs. CHP: CO2 Emissions

This graphic shows the emission differences of separate heat and power versus combined heat and power (or CHP). The separate heat and power system emits 49 kilotons of carbon dioxide per year (13 kilotons from the boiler and 36 kilotons from the power plant), while the CHP system, with its higher efficiency, emits 23 kilotons of carbon dioxide per year.

This diagram illustrates the CO2 emissions output from power and thermal energy generation for two systems: (1) a separate heat and power system with a fossil fuel-fired power plant (emissions based on the U.S. fossil mix) and a natural gas-fired boiler; and (2) a 5 megawatt combustion-turbine CHP system powered by natural gas. The separate heat and power system emits a total of 45,000 tons of CO2 per year (13 kilotons from the boiler and 32 kilotons from the power plant), while the CHP system, with its higher efficiency, emits 23,000 kilotons of CO2 per year.


High-Resolution Image >>

To analyze the emission reductions for your own facility, please utilize the CHP Emissions Calculator, which compares the anticipated air emissions from a CHP system to those of a separate heat and power system.

Verifying Environmental Benefits

EPA's Greenhouse Gas Technology Center has developed technology verification reports that certify the emissions benefits associated with CHP technologies, including waste-to-energy technologies.

Additional Resources

The CHP Partnership collaborates with other government and nongovernmental agencies and programs that are interested in promoting the environmental benefits of CHP. The following resources provide further insights into the benefits of CHP for reducing air emissions:

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