Energy Efficiency Benefits of Saving Water Murky

By Published On: January 7, 2011

While 19 percent of the state’s electricity is used to pump, treat, heat, and clean up water before discharge, water-saving measures may not be ready for prime time in utility energy efficiency programs, according to an evaluation discussed Jan. 5 at the California Public Utilities Commission. In the months ahead, state utility regulators plan to weigh whether utilities can start routinely incorporating water saving measures into their massive energy efficiency programs, said Mikhail Haramati, CPUC manager. She said the commission could allow water savings in the current 2009-11 energy efficiency program cycle or wait until the next three-year cycle. Regulators could make a decision as soon as this spring on the role of water savings in energy efficiency programs. The study examined the results of nine separate pilot projects run by the state’s investor-owned utilities between mid-2008 and the end of 2009. It found that many were not cost-effective and that too little was known about water recycling to determine if the practice actually would save energy. The commission ordered the utilities to undertake the pilot projects in 2006. It then hired consultants to evaluate the results. In the report, consultants recommended further research on the potential to save energy by saving water. That’s because only three of the utility projects demonstrated proven, cost-effective energy savings, said John Borowski, a consultant with ECONorthwest, the firm that carried out the evaluation. The most clearly cost-effective way to save energy by saving water, according to Borowski, was shown in Southern California Edison’s leak detection project. In that effort, the utility hired a contractor to work with three water agencies to identify and repair leaks in water supply pipes, meters, and other places. The effort demonstrated “the greatest energy savings potential (at a relatively low cost) among all the pilot programs,” the report said. The study also found that projects by Pacific Gas & Electric and San Diego Gas & Electric to audit water use of their large customers and fund efficient toilets, urinals, and toilet flush timers generated high energy savings. However, other projects missed the mark or proved inconclusive, including utility efforts to encourage drought tolerant landscaping, install low-flush toilets in low-income households, and create water recycling facilities. Numerous problems arose in the real world in these efforts, according to Borowski. For instance, energy savings were dashed when the low-flush toilets in households developed leaks that went unrepaired. When it came to evaluating recycling projects, the consultant noted, regulators needed to know not only about how much energy is used to treat and deliver water for reuse, but also how much energy it takes to treat and deliver an equivalent amount of water from a fresh source. Without that data--which can vary widely by location--any savings that may result from recycling are unclear. The report cautioned that before incorporating water-saving measures into the state’s energy efficiency programs the CPUC should make sure it can get information from water agencies on the amount of electricity that’s embedded in their operations, such as pumping, treating, and delivering water. The study also warned that the pilot projects involved relatively small sample sizes, limiting the certainty with which the findings could be applied on a wholesale basis. Consequently, it recommended further study with larger sample sizes. It further recommended more studies aimed at determining the actual cost effectiveness of water saving measures as a way to save energy.

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