Steam Plant at University of Idaho
The University of Idaho has operated a central heating plant for over 100 years. Located where the Commons now sits, the original heating plant burned coal to heat a much smaller campus. The Steam Plant, constructed in its present location in 1927, has utilized fuel oil, coal, natural gas, and wood chips. To meet the growing demands of an ever-larger campus, the plant expanded in 1940, 1963, 1975 and again in 1986, when the wood-fired boiler was added. Currently, wood chips comprise the primary fuel, and natural gas supplies backup heat.
The Steam Plant generates steam at 150 psi in the boilers, and valves reduce the pressure to 60 psi for distribution to campus. The higher pressure at the boiler functions as a sort of heat storage to cover demand on campus, for example, 4000 dormitory residents taking morning showers. Steam is used to heat water as well as to heat buildings and class rooms. The lower 60 psi pressure provides safety in the tunnel system that connects the steam plant to 70% of the buildings on campus. A by-product of central heating is snow-free campus sidewalks that lie above steam tunnels.
Producing energy from biomass is economical. Wood creates steam at one third the cost of natural gas. If current upward trends in gas prices continue, wood could provide heat at one fourth the cost of gas. Some buildings on campus contain their own heating systems powered by electricity or natural gas. Energy price increases have made the buildings with independent heat the most expensive on campus, with heating costs running 75% higher than those buildings on the central Steam Plant.
In the 1990’s, the University installed eight water chillers to provide summer air conditioning. Steam powers five of these system chillers, and the remaining three operate on electricity. With chilling capacity, summer steam loads reach almost as high as winter heating loads. The spring and fall are the lowest demand periods.
The Steam Plant is proud of its environmental record. The plant passed emissions testing in 2005 with fewer than one half the allowable particulates. Stack gases are usually invisible. Replacing water-cooled equipment reduced waste water output. Electricity consumption in the plant fell by one third in 2005 with addition of electronic motor controls. About 90% of steam is condensed, collected, and returned to the plant for reheating, saving heat, water and chemicals. This rate of condensate return is extremely high.
Wood fuel, purchased from local mills as a by-product of lumber or fencing manufacture, is cheap, renewable, and sustainable. Burning in the boilers results in no more greenhouse gases than the same quantity of wood rotting or burning naturally in the woods. Money paid to the fuel suppliers stays in Idaho, boosting the economy and generating local taxes instead of going to west coast pipeline companies and Canadian suppliers.
Rising energy costs and increasing environmental awareness drive interest in sustainable energy sources. The University of Idaho has been a leader in biomass conversion, successfully utilizing wood chips for twenty years, and will seek ways to expand the use of clean, sustainable energy sources to provide healthful and comfortable living and working environments at the University of Idaho.