Upwards to 19 percent of California’s electric energy is used for the conveyance and delivery of water. As energy usage is a major cost driver for water utility rates, the water - energy nexus for water utilities means reducing energy usage in the delivery and treatment of water. In 2008, the CPUC authorized an RD&D program to identify potential energy and water savings at this critical nexus. Known as the Operational Energy Efficiency Program, or OEEP, this program entails the operation of well pump and motor combinations at optimal efficiency levels using specialized software.
While initial preliminary results from the pilots showed promising energy efficiency gains, the final results showed that at a majority of the sites, the OEEP did not produce efficiency savings sufficient to offset the additional losses of 2-5 percent associated with the additional variable frequency drive hardware (VFD).
The OEEP program, however, did provide useful information on peak demand reduction and the benefits of real-time energy efficiency modeling for operators. An Application Guide was prepared to guide operators considering OEEP programs at their well sites.
OEEP Application Guide
Embedded Energy in Water
In December 2007, the Commission approved Pilot Programs in D. 07-12-050 through which the four largest IOUs would develop partnerships with water agencies, undertake specific water conservation and efficiency programs, and measure the results to inform the Commission in determining whether water conservation programs and/or measures should be added to the utilities’ energy efficiency portfolio in 2009 – 2011 and beyond. Cumulatively, the utilities were anticipated to spend approximately $6.4 million on this effort.
In general, most of the program evaluations provided useful information about embedded energy savings to inform future analyses of cost-effectiveness and program continuation. However, notable data limitations were found in the evaluation of the programs.
Energy in Water Pilot EMV Report
Energy Recovery through use of Flow Control Valves
In its 2010 WAP, the CPUC set forth its intent to encourage the self-generation of energy using renewable sources. To this end, the CPUC approved six RD&D projects for our four largest water utilities to replace pressure-reducing valves (PRV) with modern electrical regenerative Flow Control Valves (FCV). An electrical regenerative FCV uses the excess pressure embedded in the water to spin a turbine, coupled to a generator, to recover the energy. We seek to determine whether replacing a mechanical PRV with an electrical regenerative FCV presents an opportunity to recover wasted energy as electric power. These projects are underway now and are expected to be completed in 2012/13.
The CPUC continues to investigate promising energy efficiency programs and policies to reduce energy used in the delivery and treatment of water utility service.