U.S. Environmental Protection Agency
nmental Technoloov Verification
ET
i
Microturbine/Combined Heat and Power (CHP)
The U.S. EPA Environmental Technology Verification
(ETV) Program's Greenhouse Gas Technology (GHG) Cen-
ter, operated by Southern Research Institute under a coop-
erative agreement with EPA, has verified the performance
of six microturbine/combined heat and power (CHP) sys-
tems that generate electricity at the point of use.1 Collabora-
tors included the State of Colorado, the New York State
Energy Research and Development Authority (NYSERDA),
and the EPA CHP Partnership. Several of the verified tech-
nologies also included heat recovery systems that capture
excess thermal energy from the system and use it to heat
water and/or spaces.
Test Description and Results
Large- and medium-scale turbines have been used by elec-
tric utilities since the 1950s. Recent advances have allowed
for smaller turbines (i.e., microturbines) to be developed.
Because they are relatively new, reliable performance data
are needed. ETV has responded by verifying the perform-
ance of six microturbines, four of which included heat re-
covery (Table 1). The technologies were tested at residen-
tial, commercial, institutional, and industrial facilities.
Power production, power quality, and emission performance
were verified during each test. Carbon dioxide (CO2) and
nitrogen oxides (NOX) emissions concentrations and rates
were verified during each test and carbon monoxide (CO),
total hydrocarbon (THC), methane, and other emissions
were verified for some tests. ETV also measured heat re-
covery rates, thermal efficiency, and total system efficiency
at selected loads for systems with heat recovery. In certain
cases, ETV also estimated CO2 and NOX reductions com-
pared to emissions generated by electricity obtained from
the grid and heat obtained from a conventional technology,
either for the test site or for hypothetical sites. Table 2 lists
selected performance data for the verified microturbines/
CHP systems. More detailed performance data are available
in the verification reports for each of the technologies and
can be found at http://www.epa.gov/etv/verifications/
vcenter3-3.html
Electric Utility Emissions and
Microturbines at a Glance
EPA estimates that, in 2002, the United States
emitted almost 6.4 billion tons of CO2 and
nearly 22 million tons of NOx. Electricity gen-
eration accounted for 39% of the total CO2
emissions and 21% of the total NOX emissions.
Other pollutants are also emitted during elec-
tricity generation, including CO and THC. Each
of these emissions can have significant environ-
mental and health effects. CO2 and methane are
greenhouse gases linked to global climate
change. CO, THC, and the various compounds
in the NOx family cause a wide variety of
health and environmental impacts.
Microturbines are well suited to providing elec-
tricity at the point of use because of their small
size, flexibility in connection methods, ability to
be arrayed in parallel to serve larger loads, abil-
ity to provide reliable energy, and low-
emissions profile. By generating electricity at
the point of use, microturbines reduce the need
to generate electricity from sources such as
large electric utility plants. When coupled with
heat recovery systems that capture excess ther-
mal energy to heat water and/or spaces, micro-
turbines also reduce the need to use conven-
tional heating technologies such as boilers and
furnaces, which emit significant quantities of
CO2, NOx, and CO. When well-matched to
building or facility needs in a properly designed
combined heat and power (CHP) application,
microturbines can increase operational effi-
ciency and avoid power transmission losses,
thereby reducing overall emissions and net
fuel consumption.
Table 1 . Verified Microturbine and CHP Technologies
Technology Name
Mariah Energy Corporation Heat
PlusPower™System
Ingersoll-Rand Energy Systems IR PowerWorks™
70 kW Microturbine System
Honeywell Power Systems, Inc. Parallon®75 kW
Turbogenerator
Honeywell Power Systems, Inc. Parallon®75 kW
Turbogenerator with CO Emissions Control
Capstone Turbine Corporation 30 kW Microtur-
bine System
Capstone Turbine Corporation 60 kW Microtur-
bine CHP System
Electricity
Generating
Capacity
(kilowatts, W/V)
30
70
75
75
30
60
Includes
Heat
Recovery
for CHP?
Yes
Yes
No
No
Yes
Yes
Additional Information
Tested at a 12-unit condominium site that combines a street-
level retail or office space with basement, and a one- or two-
level residence above.
Tested at a 60,000 square-foot skilled nursing facility provid-
ing care for approximately 120 residents.
Tested at a 55,000 square-foot university office building.
Same technology as above, but with installation of optional
CO emissions control equipment.
Tested system operates on biogas recovered from animal
waste generated at a swine farm.
Tested at a 57,000 square-foot commercial supermarket.
The ETV Program operates largely as a public-private partnership through competitive cooperative agreements with non-profit research institutes. The
program provides objective quality-assured data on the performance of commercial-ready technologies. ETV does not endorse the purchase or sale of any
products and services mentioned in this document.
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Selected Outcomes of Verified
Microturbine/CHP Technologies
Available sales data indicate that a capacity of 13
megawatts (MW) of ETV-verified microturbines
(in CHP applications) have been installed in the
United States since the verifications were com-
pleted in 2001 - 2006. ETV estimates that these
systems have:
• Reduced CO2 emissions by 36,000 tons
per year and NOX emissions by approxi-
mately 120 tons per year with associated
climate change, environmental, and human
health benefits
• Reduced emissions of other green-
house gases and pollutants, with additional
environmental and human health benefits
• Reduced natural resource consumption
by utilizing renewable fuels (such as biogas)
or by increasing efficiency (and reducing
net fuel consumption) when well-matched
to building or facility needs in a properly
designed CHP application.
Assuming annual sales continue at the same rate
as in 2005, ETV estimates the total installed ca-
pacity of ETV-verified microturbine/CHP sys-
tems should reach 42 MW in the next five years,
reducing CO2 between 83,000 and 150,000 tons
per year and NOX between 490 and 530 tons per
year. The use of biogas as a fuel in one of the
verified microturbine/CHP systems can result
also in the conservation of finite natural re-
sources and potentially result in cost savings for
the user.
References
U.S. EPA, 2006. ETV Case Studies: Demonstrat-
ing Program Outcomes, Volume II. EPA/600/R-
06/082. September. (Primary source)
U.S. EPA ETV, http://www.epa.gov/etv.
Table 2. Selected Performance of Microturbines
Power Production*
Electrical efficiency
Thermal efficiency8
Total system efficiency8
20.4% -26.2%
7.2% -47.2%
33.4% -71. 8%
Emissions
C02 emissions rates
NOX emissions rates
1.34to3.9lbs/kWhc
4.67x10-5 to
4.48x10-3 |bs/kWhc
A At full load, under normal operation.
B For the four systems with heat recovery.
c Ibs/kWh = pounds per kilowatt-hour
A Verified Microturbine Technology
ETV Greenhouse Gas
Technology Center
David Kirchgessner, EPA Project Officer
kirchgessner.david@epa.gov
Tel: (919) 541-4021
Tim Hansen, Southern Research Institute
hansen@sri.org
Tel: (919) 806-3456
A Verified Microturbine Technology
EPA/600/F-06/018
October 2006
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