Cogeneration power systems
Cogeneration power systems, also known as Combined Heat and Power (CHP), are energy systems that simultaneously produce useful electricity and heat from a single fuel source, typically natural gas, wood, or fossil fuels. This process enhances energy efficiency significantly, utilizing nearly 90% of the energy input, compared to conventional power generation methods, which often lose about 75% of energy as waste heat. Historically, cogeneration dates back to the original electrical power plants designed by Thomas Edison, but its adoption has surged since the energy crises of the 1970s, driven by the need for cost-effective and efficient energy solutions.
Cogeneration systems are especially beneficial for industrial facilities and some commercial buildings, such as hospitals and universities, as they can produce electricity on-site and utilize the byproduct heat for space heating and water heating. While the use of fossil fuels in cogeneration raises concerns about air and water pollution, many environmental organizations support its implementation as it offers a more sustainable alternative to traditional energy production methods. In Europe, cogeneration is more widely established, delivering a significant portion of the continent's electricity, while in the United States, the number of operational cogeneration facilities has been growing. Overall, cogeneration presents a viable option for enhancing energy efficiency and sustainability in various sectors.
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Cogeneration power systems
DEFINITION: Power generation that produces useful electricity and heat simultaneously
Since the mid-twentieth century cogeneration power systems have become increasingly attractive for the on-site industrial production of energy because of their cost-effectiveness and their efficiency.
Cogeneration is an energy process. The process puts to work the heat produced by the generation of electricity, energy which when produced off-site at conventional power stations is routinely lost, vented into the atmosphere largely through cooling towers. In conventional energy production, public utilities produce electricity at power plants and transmit thermal energy through miles of insulated piping to distant industrial and commercial complexes, most often factories, a process that routinely works at a tremendous inefficiency, roughly 25 percent (that is, nearly 75 percent of the energy is lost). Factories that rely on that energy must thus pay high rates for electricity that reflect the inefficiency of the system. In contrast, when a factory opts for a cogeneration plant on-site, a primary fuel source (most often natural gas, wood, or fossil fuel) is used to generate electricity, in this case a secondary fuel, and the heat that is naturally and simultaneously produced in that process is retained and used on-site, most prominently in space heating (and cooling) and in heating water. In utilizing the heat that is a of electricity production, cogeneration (also known as CHP, for “combined heat and power”) offers a nearly 90 percent efficiency. Because it uses significantly lower amounts of fuel to produce usable energy, cogeneration production is often cited for its potential to save industry jobs.
Cogeneration, although attractive in an era of energy conservation, is hardly new—in fact, the original commercial electrical power plant designed by Thomas Edison more than a century ago was a cogeneration plant, largely for practical reasons: No network grid existed to move energy across distances. As power networks became established and government regulations sought to protect public utilities from unlicensed competition, public utilities gradually became the dominant providers of energy in return for government control of pricing and rates. When fuel prices were relatively stable and low, industries had little incentive to develop cogeneration technology. Since the major energy crisis of the mid-1970’s, however, industries have increasingly looked toward cogeneration. In addition, in light of emerging scientific knowledge regarding global warming, a process that increases energy efficiency and recycles heat offers an environmentally friendly alternative to traditional power generation.
Given that the cogeneration process involves the burning of fossil fuels, it has the potential to contribute to air and water pollution, but most established environmental groups, most prominently the Sierra Club, have long backed cogeneration as part of any responsible comprehensive domestic energy agenda. Cogeneration is far better established in Europe than in the United States; in 2024 more than 4,400 cogeneration facilities were active in the United States. In Europe, cogen plants provided about 11 percent of the European Union's electricity in 2020. The kinds of facilities that most often use cogeneration are those in various process industries (breweries, food-processing plants, paper mills, brick and cement factories, textile plants, refineries); some commercial and public buildings (hospitals, hotels, large universities, airports, military facilities) also use cogeneration. Given its potential to secure at least some short-term constraints on carbon dioxide emissions and its ability to maintain power supplies despite whatever interruption might affect the larger power grid, cogeneration has emerged as a significant element of environmentally conscious energy production.
Bibliography
"Cogeneration at the Capitol Power Plant." Architect of the Capitol, www.aoc.gov/what-we-do/projects/cogeneration-capitol-power-plant. Accessed 16 July 2024.
Flin, David. Cogeneration: A User’s Guide. Stevenage, Hertfordshire, England: Institution of Engineering and Technology, 2009.
Jonnes, Jill. Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World. New York: Random House, 2003.
Kolanowski, Bernard F. Small-Scale Cogeneration Handbook. Lilburn, Ga.: Fairmont Press, 2008.
Kutz, Myer. Environmentally Conscious Alternative Energy Production. Hoboken, N.J.: John Wiley & Sons, 2007.