Water Conservation = Energy Conservation, Examples from Colorado

In a report for the Colorado Water Conservation Board, Stacy Tellinghuisen, an Energy/Water Analyst with Western Resource Advocates, describes one of the most important reasons that Colorado's water utilities should be investing more to achieve water savings: water conservation = energy conservation.

The report, aptly titled Water Conservation = Energy Conservation (PDF) was released in June 2009. In addition to raising awareness of the energy embedded in some of Colorado’s water systems, Western Resource Advocates encourages state water and energy agencies to collaborate on water conservation programs that save energy in order to leverage their resources and “provide invaluable financial and environmental benefits to Colorado’s communities.”

After providing an introduction to the concept of embedded energy in water, the report looks at the energy intensity of specific water utilities. Two examples used in the report – Denver Water and the City of Parker – offer a good illustration of how much variation exists in the energy intensity of water supplies:

In 2007, Denver Water used just over 20,000,000 kWh to treat raw water to potable standards, and over 31,000,000 kWh to distribute this water to their customers. Denver Water supplied 222,187 AF of water to its customers; accordingly, the energy intensity of Denver’s water supplies is 232 kWh/AF. In 2005, the City of Fort Collins used slightly more than 4,000,000 kWh of electricity to treat and distribute potable water; the energy intensity of its water supply is 154 kWh/AF. Many of Colorado’s cities have gravity-fed systems and high-quality water supplies that do not require energy for extensive treatment; the energy-intensity of water supplies in cities with systems similar to Denver or Fort Collins likely will be comparable.
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The City of Parker, in the South Metro area, relies exclusively on groundwater from Denver Basin and alluvial aquifers. In 2008, Parker pumped 8,754 AF of water, and used 24,749,000 kWh of electricity. The energy intensity of the groundwater is substantial: the average energy intensity of Parker’s water is 2,827 kWh/AF. Water from deeper aquifers has higher energy intensity; pumping water from the Arapahoe Aquifer, for example, required between 3,700 and 3,950 kWh/AF. The Arapahoe aquifer is not the deepest of the Denver Basin Aquifers – it overlies the Laramie and Fox Hills Aquifers.

Even more important than the varying energy intensities of existing water supplies is the fact that some of the new water supply projects in that have been proposed in Colorado will create huge new energy demands:

Colorado Springs’ Southern Delivery System (SDS) would pump 52,900 AF/year from Pueblo Reservoir to the City of Colorado Springs – lifting the water 2,100 feet over a distance of 62 miles. Annually, the pipeline would use 245,000,000 kWh of electricity, enough energy to meet the annual needs of approximately 24,500 Coloradans. The energy intensity of water provided by the SDS would be 4,630 kWh/AF.

The Northern Integrated Supply Project (NISP), as planned, would provide water to 13 cities or water providers in Northern Water Conservancy District’s service area. The project would use energy to lift water from the Poudre River and pump it into Glade and Galeton Reservoirs. Ultimately, NISP would have an annual energy demand between 34,000,000 and 58,000,000 kWh, and the energy intensity of the water would range from 850 to 1,450 kWh/AF.

With Soft Path approaches – including water conservation, efficiency, low impact development and water reuse – Colorado has the potential to obviate the need for new supply projects and the new energy demands greenhouse gas emissions that go along with them. Investing in supply-side management and techniques to restore local water supplies offers Colorado utilities the opportunity to protect their environment, save some money and address protect future generations from water scarcity and the effects of climate change.

To download the full report: Water Conservation = Energy Conservation (PDF)