University of Missouri Energy System Capabilities
MU’s CHP plant allows the university to meet its electrical needs reliably while optimizing
its participation in the wholesale energy markets. MU participates in the Midwest
Independent System Operation (MISO), buying low-cost wholesale electricity when
prices are less than its marginal cost to generate. MU typically produces 75 percent of
its electricity requirements annually, buying the balance in the MISO market.
about the biomass fuels and to confirm the
plant’s stoker boilers and material-handling
system were able to effectively co-fire biomass
with coal.
A balanced mix of electric and steam chillers in its district cooling operation enables
MU to optimize its satellite chiller plant and CHP plant to achieve the lowest-cost energy
at any given time. About half the chillers are steam absorption units, mostly dual-effect,
with the balance electric variable-speed centrifugals.
Plant Capacity Equipment
Combined Heat
and Power Plant
Steam
1. 1 Mlb/hr
4 stoker boilers
1 circulating fluidized bed boiler
1 gas/oil boiler
2 heat recovery steam generators
Corn Cobs
Cobs were the first biomass fuel tested in
fall 2005. Testing demonstrated that 10 percent or more of the coal could be replaced
with corn cobs with minimal impact on plant
operation. The cobs are low-ash fuel with
about 7,800 Btu/lb heat value – about 75
percent of the heat value of MU’s coal. The
challenge with cobs was availability: While
plentiful in Missouri, most corn today is harvested using combines that shell the grain in
the combine and reject the cob back to the
field. Most major farm implement companies
are currently developing equipment to add to
their combines to allow cost-effective co-har-vest of corn and cobs.
Electric
66 MW
District Cooling
Plant
24,042 tons
Paul’s urban wood waste plant and the University
of Iowa’s co-firing of oat hulls, the MU power
plant staff assembled a team in 2005 to explore
viable biomass fuel options. This biomass
development team included representatives
from plant operations, MU’s Agriculture
Engineering Department, MU Extension, other
MU engineering departments and Missouri’s
Department of Natural Resources.
Encouraged by the success of other IDEA members, the MU power plant staff assembled a team to explore biomass fuel options.
The group’s goals were to identify viable
biomass fuels for the plant, sources where
they may be obtained, areas where research
support could help and potential benefits. The
group recommended four possible biomass
fuels for additional consideration: corn cobs;
4 auto-extraction steam turbines
2 combustion turbines
1 blackstart/peaking diesel generator
43 chillers: 13,488 tons electric
centrifugals; 10,554 tons steam
absorption
waste wood; waste paper; and grasses, such
as switch grass. These potential fuels were
short-listed due to their availability in Missouri,
long-term economic value, environmental
benefit and suitability for use in MU power
plant boilers.
The group recognized that using biomass
in the plant would help prepare MU for potential
future climate regulation and benefit the state
economically. Because biomass has low energy
density, transporting it more than 100 miles is
generally not cost-effective; therefore it is usually
purchased from local sources. By shifting a portion
of its fuel budget from out-of-state coal and
gas to locally supplied biomass, MU would be
able to keep more of its fuel dollars in Missouri.
Biomass Fuels Tested
Following suggestions from MU’s biomass
development team, the power plant staff prepared to test three biomass fuels: chopped
corn cobs, loose-cut switch grass and wood
waste. Plant staff obtained authorization from
the Missouri Department Natural Resources
Air Quality Program to test biomass in the
plant. The test’s purpose was to learn more
Switch Grass
As a natural prairie grass, switch grass
grows well in many portions of Missouri, with
a fairly good heat value of 8,100 Btu/lb and a
moderate ash content of about 7 percent. The
challenge with switch grass is that it has very
low energy density, in Btu per cubic foot of
material. For a test, the grass was chopped to
4 inches or less; however, it was extremely
difficult to handle and blend. When a single 3
percent blend test was conducted in one of
the boilers, the switch grass combusted well.
However, plant staff recognized that grasses
would have to be either densified to blend or
fine-chopped to blow into the boiler. A concern for further study is that switch grass is
fairly high in chlorine content, which could
“There’s Only One Mizzou!”
The University of Missouri (MU) is a land
grant university established in 1839 in
Columbia, Mo. Commonly referred to as
“Mizzou,” MU was the first public university
west of the Mississippi River and the first
state public university in the Louisiana
Purchase Territory. MU is a major research
university and a member in the American
Association of Universities. MU offers more
than 286 degree programs with a diverse
population of more than 30,200 students
from every county in Missouri, every state
in the nation and 100 different countries.
