Cogeneration / CHP Primer
Cogeneration, also known as Combined Heat and Power (CHP), is:
- The concurrent production of electricity or mechanical power and useful thermal energy (heating and/or cooling) from a single source of energy.
- A type of distributed generation, which, unlike central station generation, is located at or near the point of consumption.
- A suite of technologies that can use a variety of fuels to generate electricity or power at the point of use, allowing the heat that would normally be lost in the power generation process to be recovered to provide needed heating and/or cooling.
CHP technology can be deployed quickly, cost-effectively, and with few geographic limitations. CHP can use a variety of fuels, both fossil- and renewable-based. It has been employed for many years, mostly in industrial, large commercial, and institutional applications.
CHP may not be widely recognized outside industrial, commercial, institutional, and utility circles, but it has quietly been providing highly efficient electricity and process heat to some of the most vital industries, largest employers, urban centers, and campuses in the United States.
It is reasonable to expect CHP applications to operate at 65-75% efficiency, a large improvement over the national average of 45% for these services when separately provided.>
Cogeneration / CHP is unique among electricity-producing technologies and methods because it generates more than one output. For most industrial applications, the thermal energy produced by the systems is the most valued output; electricity is considered a secondary, yet beneficial, by-product. CHP systems can provide the following products:
- Direct mechanical drive
- Steam or hot water
- Process heating
- Cooling and refrigeration
- More information on the following technologies is described in the links below:
- Cogeneration / CHP Electric Technologies
- Cogeneration / CHP Thermal Technologies
- Waste Heat to Power Technologies
Benefits of cogeneration / chp
Cogeneration [i.e. combined heat and power (CHP)] positively impacts the health of local economies and supports national policy goals in a number of ways.
Specifically, CHP can:
- Enhance our energy security by reducing our national energy requirements and help businesses weather energy price volatility and supply disruptions
- Advance our climate change and environmental goals by reducing emissions of CO2 and other pollutants
- Improve business competitiveness by increasing energy efficiency and managing costs
- Increase resiliency of our energy infrastructure by limiting congestion and offsetting transmission losses
- Diversify energy supply by enabling further integration of domestically produced and renewable fuels
- Improve energy efficiency by capturing heat that is normally wasted
Recognizing the benefits of CHP and its current underutilization as an energy resource in the United States, the Obama Administration has a goal to achieve 40 gigawatts (GW) of new, cost-effective CHP by 2020.
As discussed in the August 2012 DOE and EPA report, Combined Heat and Power: A Clean Energy Solution, achieving this goal would:
- Increase total CHP capacity in the United States by 50% in less than a decade
- Save energy users $10 billion per year compared to current energy use
- Save 1 quadrillion Btu (Quad) of energy — the equivalent of 1% of all energy use in the United States
- Reduce emissions by 150 million metric tons of carbon dioxide (CO2) annually — equivalent to the emissions from over 25 million cars
- Result in $40-$80 billion in new capital investment in manufacturing and other U.S. facilities over the next decade
In general, the most efficient and economic Cogeneration/CHP operation is achieved when:
- the system operates at full-load most of the time
- the thermal output can be fully utilized by the site
- the recovered heat displaces fuel or electricity purchases
- More information on the following applications is described in the links below: