U.S. Department of Energy - Energy Efficiency and Renewable Energy
Federal Energy Management Program
Combined Heat and Power Applications
The ideal applications for combined heat and power (CHP) systems in traditional buildings use hydronic distribution systems (steam or hot water and chilled water). However, other buildings can also be candidates. Industrial processes, research and development activities, and service activities that involve heating and cooling are all candidates for CHP.
Increasing numbers of CHP applications are becoming feasible for single buildings, as manufacturers begin marketing "packaged" systems. Packaged equipment precludes the need for expensive custom design work. Buyers can then benefit from the economies of mass production. Research and development efforts are currently underway through cost-shared contracts between the Department of Energy (DOE) and private sector CHP companies. These efforts will lead to research, development, and deployment of first-generation packaged CHP systems. Fort Bragg and National Park Service (NPS) sites (discussed below) are two test sites for these advanced systems.
When should a facility or energy manager look into CHP potential? In general, sites should have balanced electrical and thermal loads; high electrical demand charges; and central boiler/chiller plants with heating and cooling distribution systems that are in good condition. More specifically, ideal sites fit the following profile:
- Electricity prices are high (more than 5¢ per kilowatt-hour (kWh))
- Average electric load is greater than 1 megawatt (MW)
- Ratio of average electric load to peak load is greater than 0.7
- Central or district heating and/or cooling system is in place (or a need for process heat
- "Spark spread" (difference in price per MBtu between gas and electricity) is greater than $12
- Annual operating hours are high (greater than 6,000 hours per year)
- Thermal demand closely matches electric load
- Energy security is mission critical
Keep in mind that CHP could work well at sites with even a few of these characteristics. Operations that require high energy-intensity in terms of both electricity and thermal loads are the ones most likely to offer energy and cost savings with CHP.
CHP systems are already being successfully demonstrated in Federal facilities.
A 12 MW advanced turbine CHP project is underway at Fort Bragg. The project will be financed through an energy savings performance contract (ESPC) with Honeywell, and FEMP will conduct an independent evaluation of system performance.
A 175 kilowatt (kW) microturbine CHP system will be installed and monitored at Floyd-Bennett Field with funding from New York State Energy Research and Development Administration (NYSERDA) and cost sharing by the National Park Service (NPS), FEMP, DOE's Office of Power Technologies (OPT), and Keyspan Energy (a gas distribution company).
The CHP Payback Estimator is a basic Web-based tool to estimate simple payback for CHP installations. This can help determine the economics from installing CHP at your facility. Keep in mind that this is a simplified analysis based on a minimum of inputs. If you have questions about results or would like to more carefully consider CHP for your facility, request a CHP screening available to Federal sites through FEMP's ADD CHP program.
FEMP assistance can also help determine if CHP is right for your facility.