430F98080
oEPA
United States
Environmental Protection Agency
Air and Radiation
6202J
Draft
July 1998
EPA Coalbed Methane Outreach Program Technical Options Series
COAL MINE METHANE USE IN FUEL CELLS
200 kW Phosphoric-acid fuel cell (PAFC) with a thermal output of 700,000 Btu/hr
Unit dimensions = 1 Oft x 1 Oft x 18ft. (Photo courtesy of International Fuel Cells)
COAL MINE METHANE POWERED FUEL CELLS CAN. ..
+ Operate on methane from mine pre-drainage and medium quality gob gas
« Use methane at near atmospheric pressure, avoiding compression costs
* Use methane diluted with air and/or carbon dioxide
4 Generate electricity for distributed power generation systems
+ Lower NOX and SO2 emissions, and virtually eliminate particulate emissions
* Reduce emissions of methane (a greenhouse gas)
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Coal mine methane
can be used in fuel
cells to generate low
cost power for mining
operations, trimming
overhead costs
Powering fuel cells
with coal mine
methane provides
economic benefits, as
well as the
environmental
benefits already
associated with
fuel cells
WHY CONSIDER COAL MINE METHANE POWERED FUEL CELLS?
At present, tuel cells are economically competitive with conventional forms of
electricity generation only in certain cases. Fuel cells are, however, making steady
progress toward the goal of widespread commercial use. Use of methane in fuel
cells, recovered from gassy coal mines, may be an economical approach to on-site
power generation or local use.
Gob areas (collapsed rock over mined-out areas) release large volumes of gas and
subsequently vent it to the atmosphere. Much of this gas is of medium quality and
unsuitable for pipeline injection. However, fuel cells can operate on medium-quality
gas, reducing methane emissions to the atmosphere while producing electrical
power for on-site use. Because of their high efficiency, the use of fuel cells for power
generation emits less carbon dioxide per kilowatt-hour of electricity produced than
conventional turbine and internal combustion power generation methods. Sulfur and
NOX emissions are also low, making permitting easier and less expensive.
Several hundred phosphoric-acid fuel cells (PAFCs) are now in use worldwide. In the
United States, several small commercial and light industrial operations have begun
using PAFCs during the past five years. PAFCs are reliable and can operate on
conventional natural gas as well as coal mine methane. PAFCs that produce from
200 kW to 11 MW at 40 percent efficiency are now commercially available from
International Fuel Cells.
Molten-carbonate fuel cells (MCFCs) are smaller than PAFCs, and testing indicates
that they are more efficient. The US Department of Energy, in conjunction with the City
of Santa Clara, has successfully tested MCFCs with a capacity of 200 kW to 2 MW.
The U.S. Department of Energy plans to test MCFCs using gas produced from coal
gasification, and coal mine gob gas. Commercial versions of these fuel cells should
be available by 2001,
SOME FACTS ABOUT POWER GENERATION USING FUEL CELLS. .
Coal mine methane
lacks heavy
hydrocarbons,
making it better
suited to fuel cell
power production
than natural gas
4 Modular design allows for custom power generation and generation close to
the load, reducing transmission and distribution losses
* Better efficiency than turbine generated power (efficiencies between 40-60%)
* A typical gassy mine can drain at least 1 mmcf of methane per day. A 200 kW
PAFC unit would require about 80 mcf per day of medium heating value (50%
methane) gas; a MCFC would require about 62 mcf per day
* Ideal power for industries located near coal mines producing medium to high
heating value coal mine gas
* Short permitting and licensing schedules due to clean, quiet, safe operation
* Capable of using thermal output for heating (cogeneration), raising potential
efficiency to over 80 percent
* Main by-product is purified water
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COMPARISON OF PHOSPHORIC ACID AND MOLTEN CARBONATE FUEL CELLS
Parameter
Phosphoric-acid Fuel
Cells JPAFC}
Molten-carbonate Fuel
Cells (MCFC)
Typical operating costs ($US)
Typical capital costs ($US)
Estimated total costs/kWh ($US)2
Typical efficiency
Operating temperature (°C)
Thermal output (Btu/kWh)
Oxidant requirements
Can use coal mine methane4
Fuel processor required
Commercial availability
$0.0017/kWh
$2,250-3,750/kW
$0.0527-0.0873/kWh
40-45%
200
7,000-8,300
Oxygen
Yes
Yes
Now
$9.8/kW/yr + $0,0017/kWh1
$1,000-1,500/kW
$0.0256-0.0370/kWh
50-60%
650
6,000-6,800
Oxygen & Carbon dioxide3
Yes
No
2001
1 Estimated for commercial operation when available.
2Based on a 200 kW unit over a five year operation period at maximum capacity. Five years is the minimum
expected life for the cell stacks. Technology is evolving rapidly and prices are expected to decrease.
3Fuel cells can use air as an oxygen source. Product gas can be a source of carbon dioxide.
4Either coal mining operations or "stand-alone" wells can provide coalbed methane for the process. Utilization of
methane produced during coal mining operations is especially attractive because in most cases, mines vent the
methane to the atmosphere, which contributes to global warming. Because mines would otherwise waste coal
mine methane, it is typically less expensive than conventional natural gas.
USING COAL MINE METHANE IN FUEL CELL-POWERED VEHICLES
Proton exchange membrane (PEM) fuel cell technology has been refined during the
past few years and used in a wide range of stationary and transportation applications.
Since 1997, several urban transit buses in Vancouver, British Columbia and Chicago,
Illinois have been powered by 275 HP Bollard Fuel Cell engines. These zero-emission
engines use hydrogen reformed from natural gas or methanol to create electricity with-
out combustion. The Fuelcell Propulsion Institute is currently developing fuel cells pow-
^ .." . ..."... .. • .. ered by hydrogen produced
from coal mine methane for
use in underground mine
vehicles. Coal mine methane
can play a key role in the
production of hydrogen to
fuel both stationary fuel cell
power plants and fuel cell
engines for vehicles.
m.:
El
How A Proton Exchange
Membrane Fuel Cell Works
The underlying principle of the
fuel cell is similar to that of a
battery. Operating with a solid
electrolyte at low temperature
of approximately 80°C, hydro-
gen (H2) and oxygen (O2) are
fed into the cell and an elec-
trochemical reaction generates
direct current. The only reaction
product is water (H2O).
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For More Information.
Recent developments in fuel cell technol-
ogy are expanding the options for coal
mine methane use. Use of coal mine
methane in fuel cells can increase mine
profits while reducing methane emissions to
the atmosphere.
To obtain more information about using
coalbed methane in fuel cells for power
generation, contact:
Eric Simpkins
Energy Research Corporation
1634 Eye Street Northwest
Washington, DC 20006
(202)737-1372
e-mail: ercc@erols.com
Fred S. Kemp
International Fuel Cells
P.O. Box 739
South Windsor, CT 06074
(860)727-2212
Fax: (860) 727-2399
e-mail: kempfs@icf.hsd.utc.com
Arnold R. Miller Ph.D.
President
Fuel Cell Propulsion Institute
PO Box 260130
Denver, CO 80226
(303) 986-0530
Fax: (303)986-2184
e-mail: fuelcell@mines.edu
Or contact U.S. EPA's Coalbed Methane Outreach Program for information about this and
other profitable uses for coal mine methane:
Coalbed Methane Outreach Program
U.S. EPA (6202J)
401 M Street, SW (6202-J)
Washington, DC 20460 USA
(202) 564-9468 or (202) 564-9481
Fax: (202) 565-2077
e-mail: fernandez.roger@epa.gov
schultz.karl@epa.gov
http://www.epa .gov/coalbed
C O A
M E T H A N E
OUTREACH
PROGRAM
The mention of products or services in this case study does not constitute an endorsement by EPA.
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