CHP Basics

Combined heat and power (CHP) technologies produce both electricity and steam from a single fuel at a facility located near the consumer. These efficient systems recover heat that normally would be wasted in an electricity generator, and save the fuel that would otherwise be used to produce heat or steam in a separate unit.

CHP offers dramatic advantages in efficiency and much lower air pollution than conventional technologies. A wide variety of CHP technologies generate electricity and meet thermal energy needs (direct heat, hot water, steam, process heating and/or cooling) simultaneously, at the point of use. By contrast, conventional generation of electric power throws away much of the heat generated in production, and conventional thermal energy generation often misses an easy opportunity to generate power.

Due to their capture of useful energy both as electricity and thermal output (heating, cooling, steam, hot water, dehumidification, etc.), CHP systems should always be able to exceed the total fuel efficiency of even the best central power plants, dividing the energy content of the fuel inputs into the delivered energy content of the total useful output, and taking average transmission and distribution line losses into account. A state-of-the-art central plant (a combined cycle combustion turbine using natural gas) offers a maximum system fuel efficiency for delivered power in the range of 55-60%. At this efficiency level, CHP systems will effectively double the central electric system's average delivered fuel-use efficiency of about 30%. However, under common circumstances, CHP systems will achieve efficiencies regularly exceeding 60%, and where conditions of thermal load and site permit, may achieve efficiencies exceeding 80%. Some systems have been shown to reach efficiency levels in excess of 90%.

For these reasons, while USCHPA seeks policies to recognize and provide incentive for any CHP systems that can reduce energy waste compared to the current central system power production, USCHPA is willing to accept a requirement that CHP systems qualify for incentives only when they can demonstrate efficiency exceeding the best of the central-station power plants on a delivered power basis; i.e., achieve a useful energy output representing at least 60% of the gross energy input into the CHP system's prime mover.

CHP BASICS

MORE....

Learn how the National CHP Agenda came to be.

View the "Issues" page under CHP Basics for more details on barriers facing CHP.



CHP BASICS Combined heat and power (CHP) technologies produce both electricity and steam from a single fuel at a facility located near the consumer. These efficient systems recover heat that normally would be wasted in an electricity generator, and save the fuel that would otherwise be used to produce heat or steam in a separate unit. CHP offers dramatic advantages in efficiency and much lower air pollution than conventional technologies. A wide variety of CHP technologies generate electricity and meet thermal energy needs (direct heat, hot water, steam, process heating and/or cooling) simultaneously, at the point of use. By contrast, conventional generation of electric power throws away much of the heat generated in production, and conventional thermal energy generation often misses an easy opportunity to generate power. Due to their capture of useful energy both as electricity and thermal output (heating, cooling, steam, hot water, dehumidification, etc.), CHP systems should always be able to exceed the total fuel efficiency of even the best central power plants, dividing the energy content of the fuel inputs into the delivered energy content of the total useful output, and taking average transmission and distribution line losses into account. A state-of-the-art central plant (a combined cycle combustion turbine using natural gas) offers a maximum system fuel efficiency for delivered power in the range of 55-60%. At this efficiency level, CHP systems will effectively double the central electric system's average delivered fuel-use efficiency of about 30%. However, under common circumstances, CHP systems will achieve efficiencies regularly exceeding 60%, and where conditions of thermal load and site permit, may achieve efficiencies exceeding 80%. Some systems have been shown to reach efficiency levels in excess of 90%. For these reasons, while USCHPA seeks policies to recognize and provide incentive for any CHP systems that can reduce energy waste compared to the current central system power production, USCHPA is willing to accept a requirement that CHP systems qualify for incentives only when they can demonstrate efficiency exceeding the best of the central-station power plants on a delivered power basis; i.e., achieve a useful energy output representing at least 60% of the gross energy input into the CHP system's prime mover. This diagram compares the typical fuel input needed to produce 35 units of electricity and 50 units of heat using conventional separate heat and power. For typical electric and thermal efficiencies, CHP is nearly twice as efficient.			At present, CHP systems: Produce almost 8% of U.S. electric power; Still save building and industry owners over $5 billion/year in energy costs; Decrease energy use by almost 1.3 trillion BTUs/year; Reduce NOx emissions by 0.4 million tons/year; Reduce SO2 emissions by over 0.9 million tons/year; Prevent release of over 35 million metric tons of carbon equivalent into the atmosphere. MORE.... Learn how the National CHP Agenda came to be. View the "Issues" page under CHP Basics for more details on barriers facing CHP. View Exxon Mobil's "Understanding Energy" website that explains how cogeneration works and how Exxon Mobil is using cogeneration to produce energy cleaner, cheaper and more reliably. 4 Slides showing how CHP works versus a traditional power plant. Visit the USCHPA Resources page for presentations, reports, and fact sheets on CHP.