United States Environmental Office of Air and Radiation EPA430-F-02-012 Development Potential gas and low flow, to smaller, more Wheeless, Sanitation Districts of Los Protection Agency (6202J) October 2002 rural landfills where larger generation Angeles County, California, and At present, principal hurdles in the technology is not usually feasible. George Wiltsee, Capstone development of LFG microturbine tech- While the future of microturbines that Corporation, 24th Annual Landfill nology are the lack of information on run on LFG is uncertain, additional Gas Symposium, March 19-22, 2001, Dallas, TX. (Contact SWANA at 800- long-term reliability, unclear estimates research is essential to gain a better GO-SWANA.) P OWERING M ICROTURBINES of operation and maintenance costs aris- understanding of the long-term viability ing from extensive LFG cleanup of this technology. requirements, and high capital costs. 3) “Microturbine Using Conventional and WITH LANDFILL G AS The microturbine projects that are cur- Waste Fuel,” Jeff Pierce, SCS rently in operation or under Sources of Additional Engineers, The National Defense icroturbines are an emerging group these units into larger sets, development are attempting to address Information Industrial Association’s 28th landfill gas (LFG) energy microturbines can fill an important these concerns by: Environmental and Energy While limited research has been con- recovery technology option, niche. They can be used at landfills Symposium and Exhibition, M especially at smaller landfills where where the gas output is too low for larger • Obtaining extended-term operation ducted to date on powering Charleston, South Carolina, March larger electric generation plants are not engines and conventional or and maintenance cost guarantees microturbines with LFG, some sources 25-28, 2002. (Contact Mr. Pierce at from equipment manufacturers, based of information include: 562-427-0805.) generally feasible due to economic where excess gas or onsite energy needs on agreed upon fuel specifications. factors and lower amounts of LFG. exist. (As an example, microturbines 1) “Landfill Gas Fueled Microturbines 4) U.S. Department of Energy, Office of Several LFG microturbine projects have could be used to power blowers in a gas • Applying aggressive LFG pretreat- Are Here,” George Wiltsee, Capstone Distributed Energy Resources, come on line recently, demonstrating collection system.) ment (e.g., refrigeration, activated Turbine Corporation, and Paul Microturbines Program. (Visit both the risks and benefits of these carbon treatment). Wintheiser, EMCON-IT Group, 5th www.eren.doe.gov/der/microtur- small-scale applications. Microturbines To date, most microturbines on the Annual LMOP Conference and bines/microturbines.html.) may play an important role in future market are powered using . • Emphasizing projects with relatively Project Expo, December 13-14, 2001, LFG project development, if the technical However, they can also be operated using rapid projected paybacks. Washington, DC. (Contact LMOP at and economic hurdles facing them can LFG or other waste fuels, such as oilfield 888-STAR-YES or visit be overcome. flare gas and wastewater treatment plant Microturbines offer another option to www.epa.gov/lmop.) generate electricity at sites ranging from This fact sheet provides an overview older closed landfills with low-methane 2) “Demonstration Test of the Capstone of microturbine technology and its Microturbine on Landfill Gas,” Ed applications, as well as the economic Several LFG microturbine projects have considerations and benefits of powering come on line recently, demonstrating microturbines with LFG. both the risks and benefits of these he Landfill Methane Outreach Program (LMOP) is a small-scale applications. Microturbines voluntary program that assists project developers, utili- Overview ties, landfill owner/operators, energy users, and Microturbines are a recently commer­ offer another option to generate T cialized distributed generation (DG) communities to encourage new landfill gas use projects. The technology. Like other DG technologies, electricity at sites ranging from older U.S. Environmental Protection Agency has developed a vari- such as fuel cells, wind turbines, and closed landfills with low-methane gas ety of tools (e.g., profiles, fact sheets, project development photovoltaic cells, microturbines are generally best suited to relatively small and low flow, to smaller, more rural manuals, and software) to facilitate the development of LFG applications (i.e., less than 1 megawatt use projects. For more information, please contact LMOP at: [MW]) and are designed to produce landfills where larger generation electricity for onsite energy needs and for technology is not usually feasible. end users in close proximity to the gener­ U.S. Environmental Protection Agency ation site. As a point of reference, the Landfill Methane Outreach Program output of a 30 kilowatt (kW) microtur­ Climate Protection Partnerships Division bine can power a 40 horsepower motor digester gas. At the time of publication 1200 Pennsylvania Avenue, NW (6202J) or satisfy the electricity needs of about of this fact sheet, several companies are manufacturing and distributing Washington, DC 20460-0001 20 homes. microturbines or are expected to do so in www.epa.gov/lmop Internal combustion engines have the near future. These include: Bowman Phone: 888-782-7937 traditionally been the choice for LFG Power (Southampton, England); Fax: 202-775-6680 projects 800 kW and larger, and conven­ Capstone Turbine Company (Chatsworth, tional turbines are generally considered California); Elliott Energy Systems only for projects 3 MW and larger. (Jennette, Pennsylvania); Ingersoll-Rand However, with individual unit sizes in (Portsmouth, New Hampshire); and the 30 to 100 kW range and the ability to Turbec (Malmo, Sweden). Nearly 100 microturbine projects The extent of fuel pretreatment steps the cost to generate electricity with needed to heat water in colder operating on waste fuels are already Exhaust required depends on the characteristics microturbines will be higher than the climates to meet space-heating operational, and additional projects are of the LFG and varies by microturbine price for which it can be sold to utilities. requirements. The sale or use of expected to be operational soon. In the manufacturer. In some instances, the microturbine waste heat can signifi- Heat To Users past two years, microturbines operating gas is chilled to remove moisture and cantly enhance project economics. on LFG have come on line at at least condensable impurities and is then Benefits three landfills in the United States, and reheated to supply fuel above dew Recuperator LFG microturbines offer the following Concerns with LFG additional LFG projects are in the plan­ point temperature to the microturbine. advantages when compared to other Microturbines ning or construction stages. In addition to moisture removal, types of LFG utilization technologies: Reciprocating engines are a widely Potential some manufacturers recommend an proven, mature technology in the LFG Waste-Heat adsorption step using activated carbon • Portable and easily sized. Recovery Microturbine to remove virtually all impurities. Microturbines are modular and power generation industry, especially for Fuel To Plant Utility 800 kW and larger units. In contrast, the Technology or Grid available in incremental capacities for long-term reliability and operating costs Microturbine technology is based on multiple-unit stacks, so that single or multiple microturbines can be of microturbines have yet to be con- the design of much larger combustion Applicability configured to adapt to gas flow and firmed. Disadvantages of microturbines turbines employed in the electric power Microturbines provide unique advan- satisfy onsite power requirements. tages over other electrical generation as a LFG utilization option include: and aviation industries. Microturbines They can then be moved to another generally work as follows: Turbine technologies for landfills in cases where: project site when gas production • Microturbines have a lower efficiency Air Inlet ceases. than reciprocating engines and • LFG flow is low (or excess flow from • Fuel is supplied to the combustor other types of turbines, and they an existing project is available). section of the microturbine under • Flexibility. Microturbines may be a consume about 35 percent more fuel 70 to 80 pounds per square inch more viable option at smaller and Microturbine process schematic. per kWh produced. gauge (psig) of pressure. • LFG has low methane content. older landfills where LFG quality and quantity would not support more • Microturbines are sensitive to • Air emissions, especially nitrogen • Air and fuel are burned in the traditional LFG electric power siloxane contamination, and LFG oxide (NO ), are of concern (e.g., in combustor, releasing heat that causes Exhaust Outlet X generation technologies. They may supplied to microturbines is NO nonattainment areas where the the combustion gas to expand. X also be feasible at larger LFG projects generally expected to require more Recuperator use of reciprocating engines might be Generator Cooling Fins that have excess unutilized gas. pretreatment than LFG used to precluded). • The expanding gas powers the gas power conventional turbines or other turbine that in turn operates the gen­ • Compact and fewer moving parts. electric generation sources. • Electricity produced will be used erator; the generator then produces Combustion Chamber Microturbines are approximately the for onsite facilities rather than for electricity. size of a large refrigerator and require • Currently, few low-flow, high- exporting power. minimal operation and maintenance. pressure are available • To increase overall efficiency, micro- The use of air bearings coupled with that meet the needs of microturbines • Electricity supply is unreliable and turbines are typically equipped with an air-cooled generator eliminates without high equipment modification electricity prices are high. a recuperator that preheats the Generator the need for lubrication and liquid costs; a suitable solution would need combustion air using turbine exhaust cooling systems. to be identified to permit cost-effective gas. A microturbine can also be fitted • Hot water is needed on site or nearby. delivery of LFG to microturbines with a waste heat recovery unit to • Lower pollutant emissions. without significantly increasing the heat water. Microturbines burn cleaner than parasitic load. Compressor Economic comparable reciprocating engines. A general schematic of the microtur­ For example, NO emissions levels Considerations X • Information needs to be gathered bine process (illustration at upper right) from microturbines are typically less about the long-term reliability and Microturbine heat rates are generally as well as a cross-section of one Recuperator Housing than one-tenth those of the best per- operation and maintenance costs of 14,000 to 16,000 Btu/kWh. The total forming reciprocating engines and microturbine that is currently available Air Bearings LFG microturbines. for LFG application (lower illustration) installed cost for a LFG microturbine lower than those from a LFG flare. are shown to illustrate how a microtur­ Turbine project is estimated to be $4,000 to To learn more about the potential bine operates. $5,000 per kW for smaller systems • Capable of combusting lower-methane- concerns of running microturbines on (30 kW), decreasing to $2,000 to $2,500 content LFG. Microturbines can LFG, a pilot test of a 30 kW unit was Cross-section of a microturbine. Courtesy of Capstone Microturbines operate on LFG with 35 percent Microturbines differ from traditional per kW for larger systems (200 kW and conducted at the Puente Hills Landfill in methane content and perhaps as low combustion turbines in that they spin at above). Non-fuel operation and mainte- Los Angeles County, California. as 30 percent. much faster speeds. Those currently on nance costs are about 1.5 to 2 cents Microturbines that were operated for • LFG compressor(s) • Motor control center per kWh. the market are equipped with air bear­ • Ability to generate heat and hot water. over 2,000 hours on LFG developed ings rather than traditional mechanical some wear and tear, potentially from • LFG pretreatment equipment (for • Switchgear Most microturbine manufacturers bearings in order to reduce wear. A typi­ LFG microturbine projects are most abrasives (such as siloxanes) in the LFG. moisture, siloxanes, and particulates offer a hot water generator as a cal LFG-fired microturbine installation economical under a retail deferral standard option to produce hot water A second pilot project was launched removal) • Step-up transformer has the following components: scenario. (Retail deferral is the replace- (up to 200°F) from waste heat in the in June 2001 to learn more about and ment of purchased electric power by exhaust. This option can replace rela- • Microturbine(s) eliminate these problems. self-generated power.) In many cases, tively expensive fuel, such as , Nearly 100 microturbine projects The extent of fuel pretreatment steps the cost to generate electricity with needed to heat water in colder operating on waste fuels are already Exhaust required depends on the characteristics microturbines will be higher than the climates to meet space-heating operational, and additional projects are of the LFG and varies by microturbine price for which it can be sold to utilities. requirements. The sale or use of expected to be operational soon. In the manufacturer. In some instances, the microturbine waste heat can signifi­ Heat To Users past two years, microturbines operating gas is chilled to remove moisture and cantly enhance project economics. on LFG have come on line at at least condensable impurities and is then Benefits three landfills in the United States, and reheated to supply fuel above dew Recuperator LFG microturbines offer the following Concerns with LFG additional LFG projects are in the plan- point temperature to the microturbine. advantages when compared to other Microturbines ning or construction stages. In addition to moisture removal, types of LFG utilization technologies: Reciprocating engines are a widely Potential some manufacturers recommend an proven, mature technology in the LFG Waste-Heat adsorption step using activated carbon • Portable and easily sized. Recovery Microturbine to remove virtually all impurities. Microturbines are modular and power generation industry, especially for Fuel To Plant Utility 800 kW and larger units. In contrast, the Technology or Grid available in incremental capacities for Combustor long-term reliability and operating costs Microturbine technology is based on multiple-unit stacks, so that single or multiple microturbines can be of microturbines have yet to be con­ the design of much larger combustion Applicability configured to adapt to gas flow and firmed. Disadvantages of microturbines turbines employed in the electric power Compressor Microturbines provide unique advan­ satisfy onsite power requirements. tages over other electrical generation as a LFG utilization option include: and aviation industries. Microturbines They can then be moved to another generally work as follows: Turbine technologies for landfills in cases where: project site when gas production • Microturbines have a lower efficiency Air Inlet ceases. than reciprocating engines and • LFG flow is low (or excess flow from • Fuel is supplied to the combustor other types of turbines, and they an existing project is available). section of the microturbine under • Flexibility. Microturbines may be a consume about 35 percent more fuel 70 to 80 pounds per square inch more viable option at smaller and Microturbine process schematic. per kWh produced. gauge (psig) of pressure. • LFG has low methane content. older landfills where LFG quality and quantity would not support more • Microturbines are sensitive to • Air emissions, especially nitrogen • Air and fuel are burned in the traditional LFG electric power siloxane contamination, and LFG oxide (NO ), are of concern (e.g., in combustor, releasing heat that causes Exhaust Outlet X generation technologies. They may supplied to microturbines is NO nonattainment areas where the the combustion gas to expand. X also be feasible at larger LFG projects generally expected to require more Recuperator use of reciprocating engines might be Generator Cooling Fins that have excess unutilized gas. pretreatment than LFG used to precluded). • The expanding gas powers the gas power conventional turbines or other turbine that in turn operates the gen- • Compact and fewer moving parts. electric generation sources. • Electricity produced will be used erator; the generator then produces Combustion Chamber Microturbines are approximately the for onsite facilities rather than for electricity. size of a large refrigerator and require • Currently, few low-flow, high- exporting power. minimal operation and maintenance. pressure compressors are available • To increase overall efficiency, micro- The use of air bearings coupled with that meet the needs of microturbines • Electricity supply is unreliable and turbines are typically equipped with an air-cooled generator eliminates without high equipment modification electricity prices are high. a recuperator that preheats the Generator the need for lubrication and liquid costs; a suitable solution would need combustion air using turbine exhaust cooling systems. to be identified to permit cost-effective gas. A microturbine can also be fitted • Hot water is needed on site or nearby. delivery of LFG to microturbines with a waste heat recovery unit to • Lower pollutant emissions. without significantly increasing the heat water. Microturbines burn cleaner than parasitic load. Compressor Economic comparable reciprocating engines. A general schematic of the microtur- For example, NO emissions levels Considerations X • Information needs to be gathered bine process (illustration at upper right) from microturbines are typically less about the long-term reliability and Microturbine heat rates are generally as well as a cross-section of one Recuperator Housing than one-tenth those of the best per­ operation and maintenance costs of 14,000 to 16,000 Btu/kWh. The total forming reciprocating engines and microturbine that is currently available Air Bearings LFG microturbines. for LFG application (lower illustration) installed cost for a LFG microturbine lower than those from a LFG flare. are shown to illustrate how a microtur- Turbine project is estimated to be $4,000 to To learn more about the potential bine operates. $5,000 per kW for smaller systems • Capable of combusting lower-methane­ concerns of running microturbines on (30 kW), decreasing to $2,000 to $2,500 content LFG. Microturbines can LFG, a pilot test of a 30 kW unit was Cross-section of a microturbine. Courtesy of Capstone Microturbines operate on LFG with 35 percent Microturbines differ from traditional per kW for larger systems (200 kW and conducted at the Puente Hills Landfill in methane content and perhaps as low combustion turbines in that they spin at above). Non-fuel operation and mainte­ Los Angeles County, California. as 30 percent. much faster speeds. Those currently on nance costs are about 1.5 to 2 cents Microturbines that were operated for • LFG compressor(s) • Motor control center per kWh. the market are equipped with air bear- • Ability to generate heat and hot water. over 2,000 hours on LFG developed ings rather than traditional mechanical some wear and tear, potentially from • LFG pretreatment equipment (for • Switchgear Most microturbine manufacturers bearings in order to reduce wear. A typi- LFG microturbine projects are most abrasives (such as siloxanes) in the LFG. moisture, siloxanes, and particulates offer a hot water generator as a cal LFG-fired microturbine installation economical under a retail deferral A second pilot project was launched removal) • Step-up transformer standard option to produce hot water has the following components: scenario. (Retail deferral is the replace­ (up to 200°F) from waste heat in the in June 2001 to learn more about and ment of purchased electric power by • Microturbine(s) exhaust. This option can replace rela­ eliminate these problems. self-generated power.) In many cases, tively expensive fuel, such as propane, United States Environmental Office of Air and Radiation EPA430-F-02-012 Development Potential gas and low flow, to smaller, more Wheeless, Sanitation Districts of Los Protection Agency (6202J) October 2002 rural landfills where larger generation Angeles County, California, and At present, principal hurdles in the technology is not usually feasible. George Wiltsee, Capstone Turbine development of LFG microturbine tech­ While the future of microturbines that Corporation, 24th Annual Landfill nology are the lack of information on run on LFG is uncertain, additional Gas Symposium, March 19-22, 2001, Dallas, TX. (Contact SWANA at 800­ long-term reliability, unclear estimates research is essential to gain a better GO-SWANA.) P OWERING M ICROTURBINES of operation and maintenance costs aris­ understanding of the long-term viability ing from extensive LFG cleanup of this technology. requirements, and high capital costs. 3) “Microturbine Distributed Generation Using Conventional and WITH LANDFILL G AS The microturbine projects that are cur­ Waste Fuel,” Jeff Pierce, SCS rently in operation or under Sources of Additional Engineers, The National Defense icroturbines are an emerging group these units into larger sets, development are attempting to address Information Industrial Association’s 28th landfill gas (LFG) energy microturbines can fill an important these concerns by: Environmental and Energy While limited research has been con­ recovery technology option, niche. They can be used at landfills Symposium and Exhibition, M especially at smaller landfills where where the gas output is too low for larger • Obtaining extended-term operation ducted to date on powering Charleston, South Carolina, March larger electric generation plants are not engines and conventional turbines or and maintenance cost guarantees microturbines with LFG, some sources 25-28, 2002. (Contact Mr. Pierce at from equipment manufacturers, based of information include: 562-427-0805.) generally feasible due to economic where excess gas or onsite energy needs on agreed upon fuel specifications. factors and lower amounts of LFG. exist. (As an example, microturbines 1) “Landfill Gas Fueled Microturbines 4) U.S. Department of Energy, Office of Several LFG microturbine projects have could be used to power blowers in a gas • Applying aggressive LFG pretreat­ Are Here,” George Wiltsee, Capstone Distributed Energy Resources, come on line recently, demonstrating collection system.) ment (e.g., refrigeration, activated Turbine Corporation, and Paul Microturbines Program. (Visit both the risks and benefits of these carbon treatment). Wintheiser, EMCON-IT Group, 5th www.eren.doe.gov/der/microtur­ small-scale applications. Microturbines To date, most microturbines on the Annual LMOP Conference and bines/microturbines.html.) may play an important role in future market are powered using natural gas. • Emphasizing projects with relatively Project Expo, December 13-14, 2001, LFG project development, if the technical However, they can also be operated using rapid projected paybacks. Washington, DC. (Contact LMOP at and economic hurdles facing them can LFG or other waste fuels, such as oilfield 888-STAR-YES or visit be overcome. flare gas and wastewater treatment plant Microturbines offer another option to www.epa.gov/lmop.) generate electricity at sites ranging from This fact sheet provides an overview older closed landfills with low-methane 2) “Demonstration Test of the Capstone of microturbine technology and its Microturbine on Landfill Gas,” Ed applications, as well as the economic Several LFG microturbine projects have considerations and benefits of powering come on line recently, demonstrating microturbines with LFG. both the risks and benefits of these he Landfill Methane Outreach Program (LMOP) is a small-scale applications. Microturbines voluntary program that assists project developers, utili­ Overview ties, landfill owner/operators, energy users, and Microturbines are a recently commer- offer another option to generate T cialized distributed generation (DG) communities to encourage new landfill gas use projects. The technology. Like other DG technologies, electricity at sites ranging from older U.S. Environmental Protection Agency has developed a vari­ such as fuel cells, wind turbines, and closed landfills with low-methane gas ety of tools (e.g., profiles, fact sheets, project development photovoltaic cells, microturbines are generally best suited to relatively small and low flow, to smaller, more rural manuals, and software) to facilitate the development of LFG applications (i.e., less than 1 megawatt use projects. For more information, please contact LMOP at: [MW]) and are designed to produce landfills where larger generation electricity for onsite energy needs and for technology is not usually feasible. end users in close proximity to the gener- U.S. Environmental Protection Agency ation site. As a point of reference, the Landfill Methane Outreach Program output of a 30 kilowatt (kW) microtur- Climate Protection Partnerships Division bine can power a 40 horsepower motor digester gas. At the time of publication 1200 Pennsylvania Avenue, NW (6202J) or satisfy the electricity needs of about of this fact sheet, several companies are manufacturing and distributing Washington, DC 20460-0001 20 homes. microturbines or are expected to do so in www.epa.gov/lmop Internal combustion engines have the near future. These include: Bowman Phone: 888-782-7937 traditionally been the choice for LFG Power (Southampton, England); Fax: 202-775-6680 projects 800 kW and larger, and conven- Capstone Turbine Company (Chatsworth, tional turbines are generally considered California); Elliott Energy Systems only for projects 3 MW and larger. (Jennette, Pennsylvania); Ingersoll-Rand However, with individual unit sizes in (Portsmouth, New Hampshire); and the 30 to 100 kW range and the ability to Turbec (Malmo, Sweden).