More warm weather in February should translate to smaller utility bills for units around campus again this month. It's a trend we've enjoyed all winter, according to director of utilities Jeff Witt, and is a result of a drop in both campus coal use and market prices for electricity.
He said that during December, January and February, the university used about 4,100 fewer tons of coal – 10 percent less than average for this period – and sold 87 million fewer pounds of steam (heat) to campus units. This represents more than $1.6 million in savings for colleges and other campus customers.
Witt noted that in a typical year, steam sales through January are 61 percent of budget for the fiscal year. Using the same annual average, steam sales were at 41 percent of budget through January 2012.
But he also noted that an unusually humid and warm July and August last summer created a greater demand for chilled water (building cooling). That tends to be a smaller piece of energy use, so units' utility budgets still may be in better shape than a year ago.
To cogenerate or not
The Iowa State power plant's capability for cogeneration means that coal produces multiple sources of energy, in this case steam for heat and hot water, chilled water for cooling, and electricity.
With warmer-than-average winter temperatures lowering the demand for building heat, the opportunity to cogenerate also drops. Cogeneration normally is the lowest cost method for generating electricity. The university took advantage of electricity market prices that are down 25 percent from last winter.
"When the steam demand is down, we cogenerate less and, in this case, we purchased electricity rather than generated it ourselves," Witt said.