The purchased power is the amount of power that is purchased from others each hour. The amount of purchased power varies according to a schedule developed by the operators each day.
Iowa State has the capability to generate all the electricity for the campus with its own generators or can choose to purchase electricity. The primary goal for the plant operators is to provide utility services to the campus in a safe, reliable and efficient manner, at the lowest possible cost each day. One of the methods to achieve this goal is to balance electricity produced by our own generators and electricity purchased from others.
The operators always maximize the "Combined Heat and Power" process which produces the lowest cost electricity. However, the university requires more electricity than can be produced through this process. The operators then evaluate the lowest cost method of providing the additional electricity and either by producing with our generators or purchasing it from others.
Iowa State purchases electricity on the Midwest Independent System Operator (MISO) open market. MISO manages and operates the electrical grid in the upper Midwest. Iowa State purchases electricity on the Day Ahead market and schedules power a day in advance for each hour of the following day. Operators at the Iowa State power plant work closely with operators at the City of Ames power plant to coordinate power purchases from MISO whenever it is more economical.
Iowa State also purchases electricity from a wind farm located approximately 15 miles northeast of Ames. The quantity of the power available from the wind farm varies continuously with the wind speed.