Missouri’s Cogeneration Powers Biomass Production
The power station that got its start in 1892 now provides cooling, heating and energy for a 13 million-square-foot area that includes three hospitals and several research facilities. The University of Missouri-Columbia's (UM) plant produces 66 megawatts of electricity and 1.1 million pounds of steam per hour using gas, coal, tire-derived fuel and biomass, which most often is plant matter used specifically for the generation of electricity and heat.
This type of power is known as combined heat and power or cogeneration. Cogeneration uses a power station or heat engine to simultaneously produce electricity and useful heat. Initially this type of electricity was deemed impractical, because it had to be located close to a load and therefore lost great amounts of voltage.
Instead, alternating current caught on and became the electricity of choice for more than 100 years. This type of power centered on the transformer and its effective transmission of electricity. But as environmental concerns continue to grow, combined heat and power is taking center stage once again.
Universities are popular settings to house combined-heat-and-power plants. More than 150 universities in the United States and Canada that have some form of a cogeneration facility on campus. In Missouri, both MU and Southeast Missouri State (SEMO) have tapped into the technology. Built in 1972, SEMO’s combined-heat-and-power plant has the capacity to produce 6.2 megawatts per hour.
Cleaning Up the Air
And the power from these university plants is clean. MU’s plant uses 38 percent less fuel than a conventional plant of comparable size, because it mixes on-site thermal generation with purchased electricity. But the real benefit is in the emissions. MU has lowered emissions of carbon dioxide by 107,000 tons, the equivalent of almost 18,000 passenger vehicles. Further, it has reduced energy use by 10 percent and greenhouse emissions by 12 percent since 1990, which translates into a savings of $6.6 million a year for the university.
While MU uses a steam turbine, other cogeneration plants in Missouri, including SEMO, Anheuser-Busch, Missouri State Hospital and Laclede Gas, contain an array of different sources. These sources include combined cycle, combustion turbine and reciprocating engine. The total capacity of cogeneration plants in the state is 226,000 kilowatts of power. Steam turbines, which extract thermal energy from pressurized steam, make up the majority of this power with nearly 140,000 kilowatts.
Missouri’s contributions to the cogeneration movement are substantial. In the past five years, the state’s combined-heat-and-power plants have received Energy Star CHP Awards from the U.S. EPA. These facilities include: MU, the Missouri Joint Municipal Electric Utility Commission cogeneration system (on behalf of an ethanol plant in Laddonia, Mo.) and Macon Energy Center combined-heat-and-power project (Macon, Mo.).
The MU plant currently uses 10 percent woody biomass—trees and woody plants such as limbs, tops, needles and leaves—but it plans to replace one of its coal-burning boilers with one that uses 100 percent biomass by next year. The new boiler will use 100,000 tons of biomass from in-state sources including woody biomass, grasses, waste papers and agriculture residue. MU will be able to use these sources through bubbling fluidized bed technology.
This measure undertaken by the university is partially in response to the city of Columbia’s self-imposed mandate to increase use of renewables to 15 percent by 2022. Columbia’s renewable portfolio standard is one of just a few initiatives in the country imposed at a local level.
Columbia’s message is not lost on surrounding communities and companies. MFA Oil, a Missouri oil company, launched a new division in February: MFA Oil Biomass. This division, which is expected to create up to 2,700 jobs, will use farmer-grown crops to produce renewable energy. As part of the venture—one of the largest in the country—more than 200 farmers will grow a perennial grass hybrid called Miscanthus giganteus. The farmers will receive root stock used to grow the crop at the outset of the project along with information about the crop from those who have studied it.
Miscanthus giganteus is an ideal biomass crop because it’s noninvasive, drought resistant (requiring only 24 inches of rain per year) and pest resistant. It’s also hardy, requiring less fertilizer than food crops. Miscanthus giganteus is a stabilizing plant, returning water and nutrients to the soil. Once harvested, it is converted into pellets for electrical generation and for use in other energy products, such as ethanol.
The growing of Miscanthus giganteus does not interfere with normal yields of corn and soybeans. Further, it can be planted on marginal grounds, such as hillsides and/or pasture lands. Another benefit to farmers is the effect on their bottom line—those participating in the project will earn additional dollars on the land they farm.
But beyond its business benefits, Miscanthus giganteus promises to do wonders for Missouri’s carbon footprint. The plant sequesters 55 times the amount of carbon it takes to plant and harvest, so at its worst, it is a carbon-neutral fuel. It also produces three times more gallons of ethanol per acre of corn, thus meeting the renewable fuels standard requirement. The MFA Oil Biomass division will help meet the energy needs of participating farmers, power companies and even the new MU power plant by processing 600,000 tons of biomass per year.
The launch of this project is being embraced by a state that is ready for change. Missouri clearly wants clean energy. Voters approved the state’s RPS by a comfortable margin in 2008, requiring that 15 percent of all power must come from renewable sources by the year 2021.
Thomas Edison’s cogeneration, asleep for decades, will be a big part of the push to fulfill that requirement. And biomass will keep the fire burning.
Author: Christopher Chung
Chief Executive Officer, Missouri Partnership