§ CHP Combined Heat and Power
A EPA COMBINED HEAT AND
POWER PARTNERSHIP
An Energy-Efficient Choice for the
Ethanol Industry
Cmbined heat and power (CHP), also known as
cogeneration, can be an excellent solution for
the energy needs of your ethanol plant. With CHP,
your plant can:
Generate electricity and steam reliably on site.
Reduce energy and operating costs.
Reduce greenhouse gas emissions and other
environmental impacts.
Optimize the use of alternative fuels.
CHP Now on Line
at U.S. Ethanol Plants
Ethanol plants have a continuous power and steam
demand, which makes CHP cost effective in many
locations. In addition, the size of the electricity
and steam loads at ethanol plants closely matches
the size of commonly available CHP technologies.
As a result, CHP is currently providing economic
and operational benefits for a number of dry mill
ethanol facilities in the United States, including:
Adkins Energy, LLC. Lena, Illinois—
5 megawatt (MW) gas turbine.
• U.S. Energy Partners, LLC. Russell, Kansas
—two 7.5 MW gas turbines.
• Northeast Missouri Grain, LLC. Macon,
Missouri—10 MW gas turbine.
• Otter Creek Ethanol. Ashton, Iowa—7 MW
gas turbine.
• East Kansas Agri Ethanol. Garnett, Kansas—
1 MW recuperative thermal oxidizer/steam
turbine.
By using CHP, these facilities are gaining a
competitive advantage in the marketplace.
Together, they have saved millions of dollars in
annual energy costs and are reducing greenhouse
gas emissions by approximately 227,000 tons each
year. Additional CHP capacity is planned for
ethanol plants in Minnesota, Missouri, Illinois,
Nebraska, and Colorado using a variety of fuels
(natural gas, coal, and biomass).
Improved Economic and
Business Performance
CHP can provide you with a competitive
advantage in the market:
• CHP can improve the economics of ethanol
production, yielding energy savings of 10 to
25 percent, and provide a hedge against
future energy cost volatility.
• CHP can ensure that a plant keeps
operating, even when the surrounding
electric grid is down.
• CHP can offer the opportunity to partner
with your municipal utility or rural
cooperative to leverage resources.
CHP systems can be designed to operate on
any fuel, ensuring that your plant optimizes
the use of available energy resources,
improving its overall efficiency and
competitive position in the marketplace.
• CHP can help meet corporate environmental
goals and enhance a company's image.
Compared to conventional systems, CHP
greatly reduces total energy use and the
resulting emissions of carbon dioxide (CO2),
a contributor to global climate change.
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Improved Energy and
Environmental Efficiency
CHP is an efficient, clean, and reliable approach
to generating power and thermal energy from
onsite facilities. It uses heat that is otherwise
discarded from conventional power generation to
produce thermal energy. By providing electricity
and steam from the same source, CHP signifi-
cantly reduces the total fuel used to supply
energy to your plant, along with the
corresponding emissions of CO2 and other
pollutants.
The figure below compares the typical efficiency
and fuel use of a CHP facility (this one, using a
natural gas-fired turbine) to the typical efficiency
and fuel use of a conventional system that pro-
vides the same amount of energy.
In conventional systems, ethanol plants purchase
electricity from the central grid and produce
steam for their plant using an onsite boiler.
Together, the two systems would typically use
154 units of fuel to produce 30 units of electricity
and 45 units of steam at an overall efficiency of
49 percent. With CHP, one system could provide
the same amount of electricity and steam using
only 100 units of fuel. This system offers an
overall efficiency of 75 percent. Because the
CHP system uses nearly 35 percent less fuel, it
produces much lower emissions than the
conventional system. The CHP system shown
here would produce about half the CO2 emissions
of conventional separate heat and power. When
CHP systems replace aging conventional systems,
the emission reductions can be even greater.
Conventional
Generation
Power
Station Fuel
98 Units Fuel
K
154 Units Fuel\
V
56 Units Fuel
^-
Boiler Fuel
49%
/Hi
Power Plant
EFFICIENCY:
31%
EFFICIENCY:
80%
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Boiler
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^M
t
Heat
-
OVERALL
EFFICIENCY
Combined
Heat & Power
5 MW Natural Gas
Einano| Combustion Turbine
Process
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~^
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Units
Electricity
45
Units
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<100 Units Fuel
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How Is CHP Used in
Ethanol Plants?
CHP technologies are flexible, providing many
ways to apply CHP to the dry milling ethanol
process,
1. The most common CHP technology used in
ethanol plants today consists of a gas turbine-
electric generator unit, placed in tandem with a
waste heat boiler. The turbine-driven generator
provides electricity for the facility and the
turbine exhaust is used in a waste heat boiler to
produce process steam,
2. Interest in biomass and coal CHP is growing,
Biomass can be an option for ethanol plants
located near sources of agricultural or forest waste
or for plants looking to use the ethanol process
byproducts as a fuel source. Several technical
approaches are being implemented for coal and
biomass, including fluidized-bed boilers or
gasifiers that integrate volatile organic compound
(VOC) destruction directly into the system and
generate power through a steam turbine,
3. Ethanol plants with large thermal oxidizer
loads can use a waste-heat boiler to produce
steam from the oxidizer exhaust. High-pressure
steam from the waste-heat boiler is used in a
steam turbine-generator unit to produce
electricity. Low-pressure steam from the back end
of the turbine is used to meet process heat
requirements,
4. Other CHP options are also being explored for
ethanol plants, including the integration of dryer
exhaust VOC destruction into gas-fired turbine-
generator systems. This approach entails ducting
the dryer exhaust into the gas turbine waste heat
generator and then using a secondary
supplemental burner to oxidize the VOCs and
efficiently generate additional steam for the
plant.
An Innovative Solution
Fuel ethanol is one of the fastest growing business
segments in the United States, with domestic ethanol
production estimated to double between 2005 and
2012. This expansive growth in ethanol supply, in
conjunction with the rising demand for electricity and
the high cost of natural gas, creates unique oppor-
tunities to utilize CHP for cost-effective "win-win"
partnerships between ethanol plants and rural electric
utilities.
An example of this kind of partnership is located near
the city of Macon, Missouri, where a CHP system was
built in conjunction with an ethanol facility in 2003. A
partnership was forged between the Macon Municipal
Utilities, which purchased a natural gas-fired 10 MW
combustion turbine, and Northeast Missouri Grain LLC,
which built the CHP system's housing and control
building.
Each organization pays for half of the cost of the
natural gas that powers the turbine. Of benefit to the
utility, this project supplies an additional 10 MW of elec-
tricity to the local power pool at 50 percent lower
natural gas costs than traditional generation capacity.
Of benefit to the ethanol plant, the project provides
nearly 60 percent of the plant's steam needs (51,000
pounds per hour) for ethanol production, which reduces
the plant's natural gas costs by 20 percent per year. In
addition, when the electricity grid experiences a power
outage, the CHP system provides full backup power to
the ethanol plant: a system that worked successfully in
four blackouts during the first year of operation. By
reducing fuel use and increasing reliability, this shared
CHP system is an effective low-cost operating model for
the ethanol plant.
This CHP project requires approximately 25 percent
less fuel than the typical system of onsite boilers and
purchased electricity, and based on this comparison,
reduces C02 emissions by an estimated 30,200 tons
per year.
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Is My Facility a Good
Candidate for CHP?
Do you use more than 20,000 pounds per
hour of steam?
Do you pay more than 6 cents per kilowatt-
hour for electricity?
Is reliable high-quality power important?
Is it important to reduce energy costs and
increase the overall energy efficiency of
your ethanol process?
Are biomass or alternative fuels readily
available near your site?
Do you want to increase your plant's
environmental performance?
If the answer is "yes" to two or more of these
questions, CHP can benefit your facility.
Interested? What's the
Next Step?
EPA staff are available to answer your questions
and provide specific support for your project.
For information about how EPA can support the
evaluation and implementation of your CHP
project or if your facility already uses CHP and
you wish to apply for an ENERGY STAR CHP
Award, contact EPA's CHP Team at
(202) 343-9553 or e-mail Neeharika Naik-Dhungel
atnaik'dhungel.neeharika@epa.gov.
EPA CHP Partnership
The CHP Partnership is a voluntary program
designed to foster cost-effective CHP projects.
Through the Partnership, EPA engages energy
users, the CHP industry, state and local
governments, and other stakeholders in
cooperative relationships to expand the use of CHP. Information about
our services and program offerings is available on our Web site:
www.epa.gov/chp.
p CHP
&EPA COMBINED HEAT AND
POWER PARTNERSHIP
Last updated April 23, 2007
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