Cogeneration can be thought of as the energy version of multitasking, or doing two things at once.  In technical terms, it is the production of electrical power and thermal energy simultaneously using a common source of primary energy, or fuel. The first power plant built was actually a cogeneration cycle designed by Thomas Edison in 1882. Possible fuels for a cogeneration cycle include natural gas, oil, diesel, propane, coal, wood, wood-waste, and bio-mass. Throughout the world, facilities have been implementing successful cogeneration units into universities, industry, hospitals, and various other applications. Princeton University, University of California Los Angeles, University of Iowa, and the University of Montana-Missoula are just a few university examples with thriving cogeneration systems.

The University of Montana-Missoula installed a cogeneration unit in 1997. This is a relevant comparison to the Minnesota State system because of the similarity in size of the student population and the types of boilers available. Before the cogeneration unit was installed, the Missoula boilers operated at steam pressures of 80 - 180 psig. Steam was reduced to a pressure of 30 psig before being distributed throughout campus. This drop in pressure before being distributed created an opportunity to install a steam turbine generator. The unit installed reduced 165 psig steam to 30 psig, with a mass flow rate of 24,978 lb/hr. This particular

Case Study: University of Montana-Missoula: Combined Heat and Power - 440 kWe [4]

In 1995 Minnesota State University decided to look into the idea of a cogeneration cycle for campus. Personnel on campus at this time had previous experience with cogeneration and believed a cogeneration  unit installed at Minnesota State University Mankato was a great idea. Research on the benefits of installing a cogeneration unit was done by an outside engineering firm and a report was filed which included the amount to be spent on the unit, installation, additional fuel, and the amount of money that was estimated would be saved. After approval from the University, a bid data sheet was created by the engineering firm stating the plant specifications for the unit. A bid was accepted based on a Coppus model RLHB24 single stage turbine (shown above) and a Reliance Frame E5010S generator with an expected cost of $453,000 (in 1995 dollars). This system was designed to provide an additional 434 kW of power to campus using excess heat from the boilers.

Coppus model RLHB24 single stage turbine [5]