While aeration is the largest consumer of electricity in wastewater treatment plants, water pumping is the biggest energy-user in drinking water systems. Representing more than 80 percent of the electricity used in water treatment plants, water pumping represents a significant opportunity for programs to achieve energy savings.
At CEE’s January Program Meeting, the CEE Municipal Water and Wastewater Committee received a briefing on Southern California Edison’s Hydraulic Services (Pump Test) Program, one of the largest and longest running pump-related, energy-efficiency programs in the country.
The presentation is part of CEE’s ongoing exploration of successful program approaches to achieve energy savings in the municipal water and wastewater sector.
Program Manager Gary Suzuki explained that SCE provides free pump tests to customers pumping potable water, such as agricultural irrigation and water agencies.
The pump test determines overall system efficiency, electrical motor performance, pump hydraulics and water well characteristics. The test compares the relationship between energy consumed (kWh) and water flow (gallons per minute) at a given pumping head (feet). The result is a computer-generated report containing the estimate of overall efficiency of the motor, pump assembly and applicable distribution systems (pumping plant).
Tests are administered by SCE and independent contractors, using a common procedural manual. After the test, facility managers receive a letter detailing the pump’s efficiency.
If a pump passes the efficiency test, it’s a congratulatory letter. If not, the letter contains a cost analysis which describes upgrades, potential savings and paybacks. Southern California Edison’s Danny Johnson noted that most of the savings opportunities are related to adjusting the bowl and impeller assembly – pump overhaul or pump replacement.
SCE does not work with customers to determine the cost of the repair work; customers are expected to follow up with their contractors for that information.
Based on the pump test results, customers are invited to participate in SCE’s Agricultural Energy Efficiency Program, where they are eligible to receive an incentive of 8 cents per kWh saved, capped at 50 percent of the project cost.
Based on program experience, approximately 20-40 percent of those getting the letter pump test report, complete the repair work and participate in the incentive program. The program, which is funded for $1.7 million per year and includes 17 full-time employees, tests about 4,400 pumps annually. The tests identify 25-33 million kWh of potential savings a year.
“It’s a very popular program,” said Suzuki. “There is a waiting list for pump tests and a shortage of qualified pump testers. It’s cost effective [for the facility] and by targeting market segments, we can realize great energy savings potential.”
CEE Program Manager Ted Jones noted that SCE’s experience with improving pump performance is of great value to CEE members.
“Later this year CEE’s Water and Wastewater Committee plans to develop a program guidance document on water-pumping efficiency measures,” said Jones. “It will be based on successful programs, such as SCE’s Pump Testing Service.”
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