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The Renewable Energy Institute
Heat and Power" or "CHP"
is another term for "Cogeneration"
Heating and Power" and
"Cooling, Heating and Power for Buildings"
are terms for "trigeneration."
Cogeneration Technologies, based in
Houston, Texas, provides "turnkey" cogeneration,
trigeneration and distributed generation development services.
Cleaner, Greener Power & Energy Solutions™ project
development services are one of our specialties. These projects are Kyoto
Protocol compliant and generate clean energy and significantly fewer
greenhouse gas emissions. Unlike most companies, we are equipment
supplier/vendor neutral. This means we help our clients select the best
equipment for their specific application. This approach provides our
customers with superior performance, decreased operating expenses and
increased return on investment.
Technologies, located in Houston, Texas, provides
project development services that generate clean energy and significantly
reduce greenhouse gas emissions and
carbon dioxide emissions.
Included in this are our
products and services which includes renewable
energy technologies, waste to energy,
waste to watts™ and waste
heat recovery solutions. Other project development
technologies include; Anaerobic Digester,
Anaerobic Lagoon, Biogas
Recovery, BioMethane, Biomass
Gasification, and Landfill Gas To
Energy, project development services.
services provided by Cogeneration Technologies includes the following
power and energy project development services:
Engineering Feasibility & Economic Analysis Studies
Procurement and Construction
Engineering & Permitting
Funding & Financing Options; including Equity Investment, Debt
Financing, Lease and Municipal Lease
Savings Program with No Capital Investment from Qualified Clients
Party Ownership and Project Development
Tag (Renewable Energy Credit, Carbon Dioxide Credits, Emission
Reduction Credits) Brokerage Services; Application and Permitting
more information: call us at: 832-758-0027
are Renewable Energy
Technologies specialists and develop clean power and energy projects
that will generate a "Renewable
Energy Credit," Carbon
Dioxide Credits and Emission
is Distributed Generation?
Distributed Generation is
also known as "onsite power
generation." Distributed Generation is a "Cooler, Cleaner, Greener" Power and Energy that:
Ends: Power Problems, Electric Grid Problems & Black-Outs
Increases: Profits Through Decreased Energy Expenses
Improves: Air Quality Through Significantly Reduced Emissions
Conserves: Natural Resources
Reduces: Dependence on Foreign Oil
Green Power and Energy Systems for the New Millennium
A confluence of utility restructuring, technology evolution, public environmental policy, and an expanding electricity market are providing the impetus for distributed generation to become an important energy option in the new millennium.
Utility restructuring opens energy markets, allowing the customer to choose the energy provider, method of delivery, and attendant services. The market forces favor small, modular power technologies that can be installed quickly in response to market signals.
This restructuring comes at a time when:
* Demand for electricity is escalating domestically and internationally;
* Impressive gains have been made in the cost and performance of small, modular
distributed generation technologies;
* Regional and global environmental concerns have placed a premium on efficiency and
* Concerns have grown regarding the reliability and quality of electric power.
Emerging on the scene is a portfolio of small, modular gas-fueled power systems that have the potential to revolutionize the power market. Their size and extremely clean performance allow them to be sited at or near customer sites in what are called distributed generation applications.
These distributed generation systems also afford fuel flexibility by operating on natural gas, propane, or fuel gas derived from any hydrocarbon, including coal, biomass, and wastes from refineries, municipalities, and the forestry and agricultural industries.
Technologies such as gas turbines and reciprocating engines are already making a contribution and they have more to offer through focused development efforts. Fuel cells are beginning to enter the market, but require additional research and development to realize widespread deployment.
Lastly, fuel cell/turbine hybrid systems and 21st century fuel cells, currently in the embryonic stage, offer even greater potential.
While addressing distributed generation potential in general, this document focuses on stationary energy gas-based distributed generation technologies and the Federal Energy Technology Center’s efforts to bring them into fruition.
More about Distributed Generation
Distributed generation strategically applies relatively small generating units (typically less than 30 MWe) at or near consumer sites to meet specific customer needs, to support economic operation of the existing power distribution grid, or both. Reliability of service and power quality are enhanced by proximity to the customer, and efficiency is improved in on-site applications by using the heat from power generation. also referred to as "cogeneration."
Significant technological advances through decades of intensive research have yielded major improvements in the economic, operational, and environmental performance of small, modular gas-fueled power generation options.
These distributed generation systems, capable of operating on a broad range of gas fuels, offer clean, efficient, reliable, and flexible on-site power alternatives. This emerging portfolio of distributed generation options being offered by energy service companies and independent power producers is changing the way customers view energy.
While central power systems remain critical to the nation’s energy supply, their flexibility to adjust to changing energy needs is limited. Central power is composed of large capital-intensive plants and a transmission and distribution (T&D) grid to disperse electricity. Both require significant investments of time and money to increase capacity.
Distributed generation complements central power by (1) providing a relatively low capital cost response to incremental increases in power demand, (2) avoiding T&D capacity upgrades by locating power where it is most needed, and (3) having the flexibility to put power back into the grid at user sites.
A New View on Energy Use Applications
There are a number of basic applications, outlined below, that represent typical patterns of services and benefits derived from distributed generation.
* Standby Power - Standby power is used for customers that cannot tolerate
interruption of service for either public health and safety reasons, or where outage
costs are unacceptably high. Since most outages occur as a result of storm or accident related T&D system breakdown, on–site standby generators are installed at locations such as hospitals, water pumping stations, and electronic-dependent manufacturing facilities.
* Cogeneration, Trigeneration and
"Combined Heat and Power." Power generation
technologies create a large amount of heat in converting fuel to electricity. If located at or near a customer’s site, heat from the power generator can be used by the customer in what are called combined heat and power (CHP) or cogeneration
applications. CHP significantly increases system efficiency when applied to
mid-to-high-thermal use customers such as process industries, large office buildings, and hospitals.
* Peak Shaving - Power costs fluctuate hour by hour depending upon demand and
generation availability. These hourly variations are converted into seasonal and
daily time-of-use rate categories such as on-peak, off-peak, or shoulder rates. Customer use of distributed generation during relatively high-cost on-peak periods is called peak shaving. Peak shaving benefits the energy supplier as well, when energy costs approach energy prices.
* Grid Support - The power grid is an integrated network of generation, high voltage transmission, substations, and local distribution. Strategic placement of distributed generation can provide system benefits and precludes the need for expensive upgrades.
* Stand Alone - Stand alone distributed generation isolates the user from the grid either by choice or circumstance, as in remote applications. Such applications include users requiring tight control on the quality of the electric power delivered, as in computer chip manufacturing.
CUSTOMER BENEFITS OF DISTRIBUTED GENERATION
* Ensures reliability of energy supply, increasingly critical to business and industry in general, and essential to some where interruption of service is unacceptable economically or where health and safety is impacted;
* Provides the right energy solution at the right location;
* Provides the power quality needed in many industrial applications dependent upon sensitive electronic instrumentation and controls;
* Offers efficiency gains for on-site applications by avoiding line losses, and using both electricity and the heat produced in power generation for processes or heating and air conditioning;
* Enables savings on electricity rates by self generating during high-cost peak power periods and adopting relatively low-cost interruptible power rates;
* Provides a stand-alone power option for areas where transmission and distribution infrastructure does not exist or is too expensive to build;
* Allows power to be delivered in environmentally sensitive and pristine areas by
having characteristically high efficiency and near-zero pollutant emissions;
* Affords customers a choice in satisfying their particular energy needs;
* Provides siting flexibility by virtue of the small size, superior environmental
performance, and fuel flexibility.
SUPPLIER BENEFITS OF DISTRIBUTED GENERATION
* Limits capital exposure and risk because of the size, siting flexibility, and rapid
installation time afforded by the small, modularly constructed, environmentally
friendly, and fuel flexible systems;
* Avoids unnecessary capital expenditure by closely matching capacity increases to
growth in demand;
* Avoids major investments in transmission and distribution system upgrades by siting new generation near the customer;
* Offers a relatively low-cost entry point into a competitive market
* Opens markets in remote areas without transmission and distribution systems, and areas without power because of environmental concerns.
NATIONAL BENEFITS OF DISTRIBUTED GENERATION
* Reduces greenhouse gas emissions through efficiency gains and potential renewable resource use;
* Responds to increasing energy demands and pollutant emission concerns while
providing low-cost, reliable energy essential to maintaining competitiveness in the
* Positions the United States to export distributed generation in a rapidly growing
world energy market, the largest portion of which is devoid of a transmission and
* Establishes a new industry worth billions of dollars in sales and hundreds of
thousands of jobs;
* Enhances productivity through improved reliability and quality of power delivered, valued at billions of dollars per year.
THE DISTRIBUTED GENERATION OPPORTUNITY
The importance of distributed generation is reflected in the size of the estimated market. Domestically, new demand combined with plant retirements is projected to require as much as 1.7 trillion kilowatt-hours of additional electric power by 2020, almost twice the growth of the last 20 years. Over the next decade, the domestic distributed generation market, in terms of installed capacity to meet the demand, is estimated to be 5–6 gigawatts per year. Worldwide forecasts show electricity consumption increasing from 12 trillion kilowatt hours in 1996 to 22 trillion kilowatt hours in 2020, largely due to growth in developing countries without nationwide power grids.
The projected distributed generation capacity increase associated with the global market is conservatively estimated at 20 gigawatts per year over the next decade.
The projected surge in the distributed generation market is attributable to a number of factors.
Under utility restructuring, energy suppliers, not the customer, must shoulder the financial risk of the capital investments associated with capacity additions. This favors less capital-intensive projects and shorter construction schedules. Also, while opening up the energy market, utility restructuring places pressure on reserve margins, as energy suppliers increase capacity factors on existing plants to meet growing demand rather than install new capacity. This also increases the probability of forced outages. As a result, customer concerns over reliability have escalated, particularly those in the manufacturing industry.
With the increased use of sensitive electronic components, the need for reliable, high-quality power supplies is paramount for most industries. The cost of power outages, or poor quality power, can be ruinous to industries with continuous processing and pinpoint-quality specifications. Studies indicate that nationwide, power fluctuations cause annual losses of $12–26 billion.
As the power market opens up, the pressure for enhanced environmental performance increases. In many regions in the U.S. there is near-zero tolerance for additional pollutant emissions as the regions strive to bring existing capacity into compliance. Public policy, reflecting concerns over global climate change, is providing incentives for capacity additions that offer high efficiency and use of renewables.
Overseas, the utility sector is undergoing change as well, with market forces displacing government controls and public pressure forcing more stringent environmental standards.
Electricity demand worldwide is forecasted to nearly double. Moreover, there is an increasing effort to bring commercial power to an estimated 2 billion people in rural areas currently without access to a power grid.
Robotic fabrication, as shown here, is becoming commonplace in the manufacturing industry and is mandating high-quality power for the associated electronic components
Although growing, distributed generation is still in its infancy. Ultimately, the market will be shaped by crucial product development and economic, institutional, and regulatory issues.
Market penetration will depend on how well manufacturers of distributed generation systems do in meeting product pricing and performance targets. Many of the more promising technologies have not yet achieved market entry pricing or risk levels, while others simply have not reached their market potential.
Customers—utilities, energy service companies, and end users—have yet to define and quantify distributed generation attributes such as transmission and distribution upgrade cost avoidance, improved grid stability, or enhanced power reliability.
A major institutional issue, regarding customer inter- connection with the distribution grid, currently stands in the way of distributed generation. Utility specifications for connection with the grid are complex and lack clarity and consistency. The results are high costs and project delays, or termination. Clearly, interconnect requirements are needed for safety, reliability, and power quality purposes. This strongly suggests the development of transparent national interconnect standards. Also needing to be addressed are the historical use charges, back-up charges, insurance charges, and other utility fees associated with those choosing to self-generate while remaining connected to the grid. Moreover, there is the matter of high liability insurance coverage for mis-operations of the distributed generator, needed to protect the utility.
Regulatory issues arise as well. For example, unless changes are made, distributed generation units may not get credit for avoided pollutant emissions. These emission credits are normally dealt with during the utility resource planning process, not during operation.
To realize the potential of distributed generation, the technical, economic, institutional, and regulatory issues must be dealt with effectively. This task will require cooperation between the public and private sectors. In doing so, a new industry can emerge benefiting the economy through jobs and revenues.
THE DOE'S GOALS FOR DISTRIBUTED GENERATION
The Department of Energy is fostering the establishment of a strong national distributed generation capability through a program supporting:
* Research, development, and demonstration to optimize the cost and performance and to accelerate the readiness of a portfolio of advance gas-fueled distributed generation systems for both domestic and foreign markets;
* Policy development necessary to remove barriers to widespread distributed
THE DOE PROGRAM PROGRAM
The Department is carrying out the Program by:
* Working in partnership with other federal agencies, state governments, technology suppliers, industry research organizations, academia, power generators, energy service companies, and end users;
* Sharing in the cost and risk of technology development;
* Providing forums for discussion of issues and Program content;
* Ensuring that customers and stakeholders have needed Program information;
* Nurturing partnerships that support Program goals.
TECHNOLOGIES USED IN DISTRIBUTED GENERATION SYSTEMS
A gas turbine produces a high-temperature, high pressure gas working fluid through combustion, to induce shaft rotation by impingement of the gas upon a series of specially designed blades. The shaft rotation drives an electric generator and a compressor for the air used by the gas turbine. Many turbines also use a heat exchanger called a recuperator to impart turbine exhaust heat into the combustor’s air/fuel mixture.
As for capacity, recently emerging microturbines, evolved from automotive turbochargers, are about to enter the market with outputs as low as 25 kW. Next generation utility-scale turbines are rated at nearly 400 MW in combined-cycle applications.
Gas turbines produce high quality heat that can be used to generate steam for CHP and combined-cycle applications, significantly enhancing efficiency. They accommodate a variety of gases including those derived from gasification of coal, biomass, and hydrocarbon wastes. However, pollutant emissions, primarily nitrogen oxides, are a concern particularly as turbine inlet temperatures are increased to improve efficiency.
Reciprocating engines, or piston-driven internal combustion engines, are a widespread and well-known technology. These engines offer low capital cost, easy start-up, proven reliability, good load-following characteristics, and heat recovery potential.
Incorporation of exhaust catalysts and better combustion design and control significantly reduced pollutant emissions over the past several years.
With the greatest distributed generation growth occurring in the under-5-MW market, reciprocating engines have become the fastest selling distributed generation technology in the world today.
Of the reciprocating engines, spark ignition natural gas-fired units have increased their percent of market share by over 150 percent from 1995 to 1997. The reason for increased popularity stems from low initial installed costs, low operating costs, and low environmental impact.
Natural gas-fired reciprocating engine capacities typically range from 0.5–5 MW. The highest efficiencies achieved for these engines, which occur in the mid-range of 1–2 MW, are 38–40 percent for domestic engines and as high as 44% for some European engines.
The impetus for continuing growth in engine use is the anticipated rapid expansion of distributed generation domestically and internationally and the preference for reciprocating engines in the less-than-5-MW market.
Domestically, realizing performance goals will alleviate potential strain on natural gas supplies and essentially eliminate pollutant emission concerns.
Internationally, improved cost and performance will provide U.S. engine manufacturers a strong market position. As with the other gas-based distributed generation systems, reciprocating engines technology is adaptable to other gases such as landfill gas, propane, and gases derived from gasification of coal, biomass, and municipal, forestry, and
Cogeneration, also known as combined heat and power (cogeneration)
or CHP, and
total energy, is an efficient, clean, and reliable approach to generating
power and thermal energy from a single fuel source. That is, cogeneration
uses heat that is otherwise discarded from conventional power generation
to produce thermal energy. This energy is used to provide cooling or
heating for industrial facilities, district energy systems, and commercial
buildings. By recycling this waste heat, cogeneration systems achieve
typical effective electric efficiencies of 50% to 70% — a dramatic
improvement over the average 33% efficiency of conventional fossil-fueled
power plants. Cogenerations' higher efficiencies reduce air emissions of
nitrous oxides, sulfur dioxide, mercury, particulate matter, and carbon
dioxide, the leading greenhouse gas associated with climate change.
More About Cogeneration
Cogeneration now produces almost 10% of our nation's electricity, saves its customers up to 40% on their energy expenses, and provides even greater savings to our environment.
Cogeneration, as previously described above, is also known as “combined heat and power” (CHP), cogen, district energy, total energy, and combined cycle, is the simultaneous production of heat (usually in the form of hot water and/or steam) and power, utilizing one primary fuel.
Cogeneration technology is not the latest industry buzz-word being touted as the solution to our nation's energy woes. Cogeneration is a proven technology that has been around for over 100 years. Our nation's first commercial power plant was a cogeneration plant that was designed and built by Thomas Edison in 1882 in New
York. Primary fuels commonly used in cogeneration include natural gas, oil, diesel fuel, propane, coal, wood, wood-waste and bio-mass. These "primary" fuels are used to make electricity, a "secondary" fuel. This is why electricity, when compared on a btu to btu basis, is typically
3-5 times more expensive than primary fuels such as natural gas.
An example of a cogeneration process would be the automobile in which the primary fuel (gasoline) is burned in an internal combustion engine - this produces both mechanical and electrical energy (cogeneration). These combined energies, derived from the combustion process of the car's engine, operate the various systems of the automobile, including the drive-train or transmission (mechanical power), lights (electrical power), air conditioning (mechanical and electrical power), and heating of the car's interior when heat is required to keep the car's occupants warm. This heat, which is manufactured by the engine during the combustion process, was “captured” from the engine and then re-directed to the passenger
Due to competitive pressures to cut costs and reduce emissions of air pollutants and greenhouse gasses, owners and operators of industrial and commercial facilities are actively looking for ways to use energy more efficiently. One option is cogeneration, also known as combined heat and power (CHP). Cogeneration/CHP is the simultaneous production of electricity and useful heat from the same fuel or energy. Facilities with cogeneration systems use them to produce their own electricity, and use the unused excess (waste) heat for process steam, hot water heating, space heating, and other thermal needs. They may also use excess process heat to produce steam for electricity production. Cogeneration currently coexists with a regulated industry that is going through major structural changes that may limit or expand its application.
The concept of cogeneration is not new. Early in this century, before there was an extensive network of power lines, many industries had cogeneration plants. As utilities became established and grew, most states began to regulate them in order to limit their pricing power.
The Public Utilities Holding Act of 1935 (PUHCA), together with amendments to the Federal Power Act (also in 1935), were the final steps in protecting utility companies from competition. These laws created vertically integrated utilities with responsibility for the production, transmission, and distribution of power. In exchange for their exclusive franchises (territories) and guaranteed revenues, utilities agreed to government regulation of rates and service. Under these rules, more investments in infrastructure and more sales meant more profits. As the network of power lines grew and electricity from utilities became more economical, industrial facilities bought more of their electricity from utilities. However, many industries still had to generate process heat on-site. The economies of scale that the utilities were able to obtain at that time, as well as the availability of low-priced process heat from cheap oil and gas, removed incentives to retain cogeneration equipment.
In the past three decades, however, the long-term trend of energy prices generally moved upward. Building more and more large power plants no longer provided economies of scale. This was a major factor in the increasing use of cogeneration by commercial and industrial facilities.
The Public Utilities Regulatory Policies Act of 1978 (PURPA) provided further encouragement for developers of cogeneration plants. Section 210
requires utilities to purchase excess electricity generated by "qualifying
facilities" (QFs) and to provide backup power at a reasonable cost. QFs included plants that used renewable resources and/or cogeneration technologies to produce electricity. PURPA cogenerators must use at least 5% of their thermal output for process or space heating (10% for facilities that burn oil or natural gas). In many cases, this forced independent cogenerators to accept very low rates for their steam production in order to become a
qualifying facility under PURPA. Another problem is the rate at which utilities purchase a cogenerator’s excess power production.
Most states set the price at "avoided cost," or the cost to the utility of producing that extra power. Utilities with excess power generation capacity are often allowed to have extremely low avoided costs. This practice has created artificial barriers to cogeneration as well as to independent power generators.
The Energy Policy Act of 1992 (EPAct) tried to create a more competitive marketplace for electricity generation. It created a new class of power generators known as Exempt Wholesale Generators (EWGs). These are exempt from PUHCA regulation and can sell power competitively to wholesale customers. A cogeneration facility can be (but does not have to be) a QF under PURPA and an EWG under EPAct. This happens when the facility is in the exclusive business of wholesale power sales, and makes no retail power sales to its "steam host" (customer).
A typical cogeneration system consists of an engine, steam turbine, or combustion turbine that drives an electrical generator. A waste heat exchanger recovers waste heat from the engine and/or exhaust gas to produce hot water or steam. Cogeneration produces a given amount of electric power and process heat with 10% to 30% less fuel than it takes to produce the electricity and process heat separately.
There are two main types of cogeneration techniques: "Topping Cycle" plants, and "Bottoming Cycle" plants.
A topping cycle plant generates electricity or mechanical power first. Facilities that generate electrical power may produce the electricity for their own use, and then sell any excess power to a utility. There are four types of topping cycle cogeneration systems. The first type burns fuel in a gas turbine or diesel engine to produce electrical or mechanical power. The exhaust provides process heat, or goes to a heat recovery boiler to create steam to drive a secondary steam turbine. This is a combined-cycle topping system. The second type of system burns fuel (any type) to produce high-pressure steam that then passes through a steam turbine to produce power. The exhaust provides low-pressure process steam. This is a steam-turbine topping system. A third type burns a fuel such as natural gas, diesel, wood, gasified coal, or landfill gas. The hot water from the engine jacket cooling system flows to a heat recovery boiler, where it is converted to process steam and hot water for space heating. The fourth type is a gas-turbine topping system. A natural gas turbine drives a generator. The exhaust gas goes to a heat recovery boiler that makes process steam and process heat. A topping cycle cogeneration plant always uses some additional fuel, beyond what is needed for manufacturing, so there is an operating cost associated with the power production.
Bottoming cycle plants are much less common than topping cycle plants. These plants exist in heavy industries such as glass or metals manufacturing where very high temperature furnaces are used. A waste heat recovery boiler recaptures waste heat from a manufacturing heating process. This waste heat is then used to produce steam that drives a steam turbine to produce electricity. Since fuel is burned first in the production process, no extra fuel is required to produce electricity.
An emerging technology that has cogeneration possibilities is the fuel cell. A fuel cell is a device that converts hydrogen to electricity without combustion. Heat is also produced. Most fuel cells use natural gas (composed mainly of methane) as the source of hydrogen. The first commercial availability of fuel cell technology was the phosphoric acid fuel cell, which has been on the market for a few years. There are about 50 installed and operating in the United States. Other fuel cell technologies (molten carbonate and solid oxide) are in early stages of development. Solid oxide fuel cells (SOFCs) may be potential source for cogeneration, due to the high temperature heat generated by their operation.
Cogeneration systems have been designed and built for many different applications. Large-scale systems can be built on-site at a plant, or off-site. Off-site plants need to be close enough to a steam customer (or municipal steam loop) to cover the cost of a steam pipeline. Industrial or commercial facility owners can operate the plants, or a utility or a non-utility generator (NUG) may own and operate them. Manufacturers use 90% of all cogeneration systems. Some industries and waste incinerator operators who own their own equipment realize sizable profits with cogeneration.
Another large-scale application of cogeneration is for district heating and cooling. Many colleges, hospitals, office buildings and even cities, that have extensive district heating and cooling systems, have at their core, a cogeneration or trigeneration power plant. The University of Florida has a 42 Megawatt (MW) gas turbine cogeneration plant, built in partnership with the Florida Power Corporation. Some large cogeneration facilities were built primarily to produce power. They produce only enough steam to meet the requirements for qualified facilities under PURPA. If no steam host is nearby, one can be built. For example, there are large (80 MW) plants operating under PURPA that have large greenhouses as "steam hosts." The greenhouses operate without losing money only because their steam heat is virtually free of charge. These types of plants are candidates to become EWGs in the new regulatory environment.
Many utilities have formed subsidiaries to own and operate cogeneration plants. These subsidiaries are successful due to the operation and maintenance experience that the utilities bring to them. They also usually have a long-term sales contract lined up before the plant is built. One example is a 300 MW plant that is owned and operated by a subsidiary co-owned by a utility and an oil company. The utility feeds the power directly into its grid. The oil company uses the steam to increase production from its nearby oil wells.
Cogeneration systems are also available to small-scale users of electricity. Small-scale packaged or "modular" systems are being manufactured for commercial and light industrial applications. Modular cogeneration systems are compact, and can be manufactured economically. These systems, ranging in size from 20 kilowatts (kW) to 650 kW produce electricity and hot water from engine waste heat. It is usually best to size the systems to meet the hot water needs of a building. Thus, the best applications are for buildings such as hospitals or restaurants that have a year-round need for hot water or steam. They can be operated continuously or only during peak load hours to reduce peak demand charges, although continuous operation usually has the quickest payback period.
Several companies also attempted to develop systems that burn natural gas and fuel oil for private residences. These home-sized cogeneration packages had a capacity of up to 10 kW, and were capable of providing most of the heating and electrical needs for a home. As of May 2000, none of the companies that developed these systems are selling these units. Several fuel call manufacturers are targeting residential and small commercial applications.
While cogeneration provides several environmental benefits by making use of waste heat and waste products, air pollution is a concern any time fossil fuels or biomass are burned. The major regulated pollutants include particulates, sulfur dioxide (SO2), and nitrous oxides (NOx). Water quality, while a lesser concern, can also be a problem. New cogeneration plants are subject to an Environmental Protection Agency (EPA) permit process designed to meet National Ambient Air Quality Standards (NAAQS). Many states have stricter regulations than the EPA. This can add significantly to the initial cost of some cogeneration facilities located in urban areas.
Some cogeneration systems, such as diesel engines, do not capture as much waste heat as other systems. Others may not be able to use all the thermal energy that they produce because of their location. They are therefore less efficient, and the corresponding environmental benefits are less than they could be. The environmental impacts of air and water pollution and waste disposal are very site-specific for cogeneration. This is a problem for some cogeneration plants because the special equipment (water treatment, air scrubbers, etc.) required to meet environmental regulations adds to the cost of the project. If, on the other hand, pollution control equipment is required for the primary industrial or commercial process anyway, cogeneration can be economically attractive.
Even the environmental groups are on the cogeneration bandwagon. Since its' founding, the Sierra Club has supported total energy (cogeneration). See the Sierra Club's statement on energy policy.
Future Market Development
Several factors will affect the growth of cogeneration activities. They include the initial cost of buying and bringing a cogeneration system on-line, maintenance costs, and environmental control requirements. Some electric utilities do not need additional electricity. They may have excess generation capacity or a stable customer base. This leads to lower "avoided cost" rates, which reduces the viability of cogeneration projects that rely heavily on power sales to utilities.
The restructuring of the electric power generation and distribution industry that is currently underway in many states, makes it more attractive for developers to become independent power producers and to build "electricity only" power plants, instead of cogeneration plants. There has also been a great deal of pressure from utility and industrial special interests to repeal or amend PURPA. If they are successful, it could be difficult for new cogeneration projects to get off the ground. Barring that development, improved technology and cooperation among industries, businesses, utilities, and financiers should provide impetus to the continued development of both cogeneration projects and independent power production projects.
One significant impetus for cogeneration is the issue of global climate change from global warming caused by the greenhouse effect, of which fossil fuel combustion is a major contributor.
Cogeneration is the environmentally-friendly, economically-sensible way to produce power, simultaneously saving significant amounts of money and also dramatically reducing total greenhouse gas emissions.
Cogeneration technologies are conventional power generation systems with
the means to make use of the energy remaining in exhaust gases, cooling
systems, or other energy waste stream. Typical cogeneration prime movers
Boilers with steam turbines
Cogeneration offers energy, environmental, and economic benefits,
By improving efficiency, cogeneration systems can reduce fuel costs
associated with providing heat and electricity to a facility.
Improving power reliability
Cogeneration systems are located at the point of energy use. They provide
high-quality and reliable power and heat locally to the energy user, and
they also help reduce congestion on the electric grid by removing or
reducing load. In this way, cogeneration systems effectively assist or
support the electric grid, providing enhanced reliability in electricity
transmission and distribution.
Reducing environmental impact
Because of its improved efficiency in fuel conversion, cogeneration
reduces the amount of fuel burned for a given energy output and reduces
the corresponding emissions of pollutants and greenhouse gases.
Conserving limited resources of fossil fuels
Because cogeneration requires less fuel for a given energy output, the use
of cogeneration reduces the demand on our limited natural
resources—including coal, natural gas, and oil—and improves our nation's
Where Can cogeneration Be Used?
Cogeneration installations are most likely to be economically viable at
locations where the following characteristics exist:
* Coincident demand for electricity and thermal energy (i.e., steam,
heating, or cooling) during most of the year.
* Access to fuels, including natural gas, biomass, and/or by-product
The following are typical markets for cogeneration:
Energy-intensive industries, including the chemical, refining, forest
products, food, and pharmaceutical sectors.
District energy systems that distribute heat or chilled water to a network
of buildings. Such systems show the greatest promise in downtown areas,
industrial parks, college campuses, military bases, and other large
High power reliability/quality applications, such as Internet or
telecommunications data centers requiring high-quality, reliable power and
substantial cooling capacity.
Institutional markets, including hospitals, hotels, and convention centers
where large year-round demands exist for electricity, heating, and
Abandoned industrial sites, or brownfields, where cogeneration-based
systems can provide the energy infrastructure for "power parks,"
facilitating economic redevelopment of underutilized properties.
Commercial buildings—as building-scale cogeneration technologies become
better integrated and increasingly cost-effective, this market offers
large potential for new applications.
A small sample of successful businesses now using cogeneration
Agriculture, apartment buildings,
auto/car dealerships, casinos, cold storage facilities, communications
sites, convenience stores, credit card processing facilities, customer
service centers, dairies, fabrication plants, feed yards, foundries, golf
courses, government buildings, commercial greenhouses and nurseries, grocery stores, hospitals, hotels, ice
skating rinks, industrial parks, ISP's, landfills, laundries/laundromats,
malls, manufacturing plants, military bases and installations, motels,
nursing homes, oil & gas leases, office buildings, paper & pulp, parking
garages, printing companies, processing plants, radio stations, resorts,
restaurants, retail stores, retirement homes, schools, server farms,
shopping centers, sports complexes, steel manufacturing, supermarkets,
television stations, universities, warehouses, waste treatment facilities,
The U.S. Department of Energy (DOE) and the U.S.
Environmental Protection Agency Supports Cogeneration.....
Because the average efficiency of the fossil-fueled power plants in the
U.S. is around 30-33% and has remained virtually unchanged since the
1930's. This means that two-thirds of the energy in the fuel is lost as
heat. Cogeneration systems recycle this waste heat and convert it to
useful energy and achieve effective electrical efficiencies of 50% to 70%.
This improvement reduces emissions of sulfur dioxide, nitrous oxide,
mercury, particulate matter, and carbon dioxide, the leading greenhouse
gas associated with climate change. In addition to reducing air pollution,
cogeneration conserves our limited fossil fuel resources, thereby
increasing our nation's energy self-sufficiency.