Least-cost Paths to Energy Independence at a Midwestern University

ABSTRACT

In September of 2006, Wisconsin Governor Jim Doyle announced that four Wisconsin college campuses would be selected to participate in a pilot program to achieve energy independence by the year 2012. The University of Wisconsin River Falls campus was one of the sites selected for the program.

Energy independence was defined as being “capable of acquiring or producing renewable energy equivalent to…consumption.”

Wisconsin Public Power Incorporated contracted with the Energy Center of Wisconsin to identify and analyze the options for UW River Falls to achieve energy independence. Given the varied approaches and potential combinations of strategies and technologies for reaching the goal of energy independence, it was necessary to narrow them down to a manageable few. The narrowing process involved calculating the degree of “independence” produced by each measure and the resulting life cycle cost of implementing it. Energy independence was measured as the percent of carbon-dioxide (CO₂) reduction from the energy consumption baseline. The final result shows the net present value cost (or savings) of various paths to achieving energy independence.

The Energy Center evaluated four scenarios to energy independence for UW River Falls. For each scenario we evaluated a combination of measures, ranging from building efficiency and conservation to biomass-fueled boiler plants.

The four scenarios are:

	Standard Scenario: attempts to make full use of existing campus infrastructure with as little capital investment as possible;
	Geothermal Scenario: implements a campus-wide geothermal heat pump system to meet cooling and heating needs, produces an all electric campus;
	Cogeneration—Follow Thermal Load Scenario: produces steam using biomass fuel to meet heating and cooling demand, with electric production secondary; and
	Cogeneration—Follow Electric Load Scenario: produces steam using biomass fuel to meet all electric demand, with thermal needs secondary.

The key findings are:

	Energy independence can be achieved for as little as $19.1 million net present value over the existing baseline, or roughly $10 per gross square foot in today's dollars.
	Achieving partial independence costs much less. For example, 64% independence can be achieved at one-tenth of the 100% cost. Costs rise dramatically after this threshold.
	Life cycle costs are highly dependent on energy cost escalation assumptions. Under a high escalation scenario, energy independence actually saves money over the life cycle.