Why use combined heat and power

Overview of CHP Technologies. Fuel Cells. Gas Turbines. Reciprocating Engines. Steam Turbines. Absorption Chillers. Thermal Energy Storage. It looks like a good fit as the world searches for low-cost energy by increasing efficiency while lowering carbon dioxide emissions.

The excess heat, often steam, can be used for heating—and ever more frequently cooling—and domestic hot water. Many new CHP systems can provide backup power during grid outages. This chart shows a breakdown of the fuels used to power U. CHP installations at the end of as a percentage of total capacity. Natural gas supplied the vast majority of systems. Source: U. Department of Energy. The electricity produced by a CHP system is directly related to the [cost of fuel] without any of the charges for electricity distribution that you pay for conventional utility power.

CHP can lessen the need for new transmission and distribution infrastructure and uses abundant clean domestic energy sources such as natural gas and biomass. In topping-cycle systems, the most common CHP approach today, fuel is burned to create electricity.

A portion of the heat then is converted into thermal energy for space heating, hot water, or industrial process steam. A bottoming-cycle system, more common in large industrial applications, uses fuel to make heat for an industrial process, such as a kiln or furnace, with the waste heat from that process captured and used for power production.

Combining power generation with waste heat is not new. When widespread electricity began to be produced locally in the early 20th century, power companies began selling steam to area customers for space heating or industrial use. This form of CHP was confined to localized district heating systems.

After World War II, the electric generation and distribution industry adopted a new model of large, centralized generation to serve wide regions. The electricity industry became predominantly a small number of large investor-owned monopoly utilities, regulated at the state level.

A widespread belief arose that generating power was a natural monopoly. Regulators protected the monopolies from other firms seeking to sell power. Cogeneration stalled. Some industries that need a large amount of process steam, such as paper mills, food processors, and chemical plants, used bottom-cycle CHP to turn exhaust into electricity. Some large district heating systems also remained, such as the Consolidated Edison system in Manhattan. But the potential for CHP appeared limited.

Prospects brightened after the Arab oil embargo of the early s. The resulting spike in gasoline prices, long refueling lines, odd-even purchase controls, and serious talk of rationing gasoline produced political pressure for change.

President Jimmy Carter, who took office in , advocated a national energy conservation strategy. It had major consequences. PURPA contained a provision to encourage cogeneration.

That led to a generation paradigm shift. Non-utility generators, known as NUGs, sprang up. They made money by selling to utilities that had refused to buy power from outside generators previously. This new class of merchant generators, using PURPA authority, undermined the conventional notion of how electricity could be made and sold.

It gave a boost to both competitive wholesale markets and large-scale cogeneration. The new Congress has a freshman member who brings two generations of experience with energy efficiency and combined heat and power CHP to energy debates. He has more practical experience with energy on-the-ground than any current member of the House of Representatives. He brings an extensive background in energy issues to Washington. Courtesy: Casten for Congress. The steam is then used to turn a turbine to run a generator to produce electricity.

The steam leaving the turbine can be used to produce useful thermal energy. These systems can use a variety of fuels, such as natural gas, oil, biomass, and coal. The Catalog of CHP Technologies includes a comprehensive list of CHP technologies and provides information about their cost and performance characteristics.

A number of site-specific factors will determine if CHP might be a good technical and economic fit for your facility. Answer a few simple questions to determine if your facility is a good candidate for CHP. Skip to main content. Contact Us.