When it came time to replace the biogas-fueled combined heat and power system at the Theresa Street Water Resource Recovery Facility in Nebraska, one number stood out: the price of utility electricity.
“Right now, power in the Midwest, certainly here, is fairly reasonable,” says Steve Crisler, superintendent of water resource recovery facilities for Lincoln Wastewater System. “It’s 5 cents per kilowatt-hour. To spend the capital, operating and maintenance costs to offset 5-cent power was a challenge.”But the CHP system that had produced about a third of the facility’s power and heated the digesters since 1991 was showing its age. The generators
