By: Sydney Byers
What is CHP?
Combined heat and power (CHP) is a specific type of technology that generates efficient energy.[i] CHP is also known as cogeneration and it provides both electric power and heat (thermal energy) from a singular source.[ii] CHP captures energy and the heat that would normally be lost or wasted in the generation of power and uses it to provide heating and cooling.[iii] The saved energy can then be used to provide useful thermal energy such as steam or hot water.[iv] This output can then be used in multiple different ways such as heating spaces, cooling spaces, hot water for domestic use and other industrial processes.[v] CHP plants can be smaller in size and located at individual facilities and buildings or can also be utilized to be a district energy source and a utility resource.[vi] Usually, CHP is used at facilities that require electricity and thermal energy.[vii] Some examples of facilities that use CHP technology are hospitals, multi-family buildings, restaurants, and universities.[viii]
How does CHP work?
Conventional electricity generation wastes nearly two-thirds of the energy produced in the form of discharged heat into the atmosphere.[ix] CHP captures the heat that would generally be wasted so CHP “can achieve efficiencies of over 80 percent, compared to 50 percent for typical technologies (i.e., conventional electricity generation and an on-site boiler).”[x] There are two common ways of CHP systems—combustion turbines (also known as reciprocating engines) and steam boilers or steam turbines. Combustion turbines burn fuel in the forms of natural gas, oil, and biogas.[xi] The burning of these fuels turns generators to produce electricity and then uses heat recovery devices to keep the heat produced. [xii] The heat that is saved is converted into thermal energy usually used in the form of hot water or steam.[xiii] With steam boilers and steam turbines, steam is produced in a boiler and then the steam is used to turn the turbine that runs the generator to produce the electricity.[xiv] With the leftover steam that leaves the turbine, the steam is then used for thermal energy.[xv]
Why is CHP important?
CHP technologies hold enormous potential to improve the United States energy security and resiliency.[xvi]The Department of Energy (DOE) has long supported the development and implementation of CHP technologies.[xvii] CHP systems that run every day are more reliable in emergencies than a backup generator system that only runs during said emergency.[xviii]
There are multiple examples of CHP performance during natural disasters and emergencies. Storms and natural disasters ruin local economies, infrastructures, and communities by causing damage and economic losses. Many of the effects of such storms and hurricanes result in extended power outages that can last for days and sometimes months.[xix] For example, when Hurricanes Harvey, Irma, and Maria struck, four hospitals powered by CHP were able to continue running and remained operational.[xx] There are many more examples of facilities with CHP that operated during disasters and helped mitigate the devastating damages.
During Superstorm Sandy, CHP plants and systems were crucial in continuing the operations of hospitals, schools, and residential buildings when the electricity grid stopped working in areas where the storm hit hardest.[xxi] CHP has demonstrated that it is one of the more resilient energy infrastructures, especially in the face of extreme weather events. CHP has mitigated the impacts of many natural disasters and emergencies through keeping critical facilities operating and running with minimal interruption.[xxii]
In the end, CHP could prove to be a good investment for critical infrastructure facilities to “improve resiliency, mitigate the impacts of a disaster, provide energy cost savings, greater efficiencies, and reduced overall emissions, all while providing reliability during grid outages.”[xxiii] However, for CHP to be successfully implemented into infrastructure, there needs to be engagement and teamwork with emergency management professionals, local and state policy makers, and with the CHP decision makers who operate and build these plants.[xxiv]
Image from GE
[i] Combined Heat and Power (CHP) Partnership, What is CHP?, U.S. Env’t Prot. Agency, https://www.epa.gov/chp/what-chp#:~:text=Combustion%20turbine%20or%20reciprocating%20engine,of%20steam%20or%20hot%20water (May 13, 2019) [hereinafter EPA].
[ii] Rebecca Matulka, Dep’t of Energy, Top 10 Things You Didn’t Know About Combined Heat and Power, ENERGY.GOV (Oct. 21, 2013), https://www.energy.gov/articles/top-10-things-you-didn-t-know-about-combined-heat-and-power.
[iv] EPA, supra note i.
[viii] See Energy Sols. Ctr., CHP Case Studies: How Companies are using Combined Heat and Power, Understanding CHP, https://understandingchp.com/installations/case-studies/ (last visited Mar. 10, 2021).
[ix] EPA, supra note i.
[xv] EPA, supra note i.
[xvi] U.S. Dep’t of Energy, CHP Basics & Benefits, Better Buildings, https://betterbuildingssolutioncenter.energy.gov/chp/chp-basics-benefits (last visited Mar. 9, 2021) [hereinafter CHP Basics & Benefits].
[xviii] Anne Hampson, et al., ICF Int’l, Combined Heat and Power: Enabling Resilient Energy Infrastructure for Critical Facilities 6 (2013), https://www.energy.gov/sites/prod/files/2013/11/f4/chp_critical_facilities.pdf.
[xix] All. for Indus. Efficiency, CHP Response in Natural Disaster Mitigation: Delivering Reliability, Saving Lives (Feb. 1, 2018), https://chpalliance.org/wp-content/uploads/2018/02/CHP-in-Disaster-Mitigation-Fact-Sheet.pdf.
[xxi] See CHP Basics & Benefits, supra note xvi.
[xxii] All. for Indus. Efficiency, supra note xix.
[xxiii] Hampson et al., supra note xviii, at 35.