Solar panels at the Boulder Municipal Water Plant next to the Walden Ponds Wildlife Habitat area. Since 2010, the one-megawatt solar electric system at the city's 75th Street Wastewater Treatment Facility has generated more than three million kilowatt-hours of energy, saving city ratepayers more than $75,000, providing approximately 15 percent of the city's largest energy consumer's annual energy needs. On a clear, sunny day, the system can provide up to 67 percent of the plant's total power requirements.