Pumps and Blowers as Program Measures

Q: We are trying to figure out if and why we should look at pumps and blowers as a part of our energy efficiency program offering. What potential do you see for pumps and blowers in a program? A: Extensive research of existing water pumping inventory in CA indicate that an average irrigation pump efficiency is about 53% rather than 75-78% as in the original design condition. Agricultural/irrigation customers account for 7% of total statewide electricity use. Out of this total of 7%, 80% is used by pumping systems. If you consider that the average irrigation pump size of 75 hp (varying between 15 hp to 750hp) and the number of pumps within a water utility, a municipal distribution system, or agricultural irrigation pumps, your utility’s potential in energy savings could be substantial. From the technical perspective, efficiency losses may come from motors, bearing and electrical losses (9%), column and shaft losses (5%), and impeller and bowl assembly losses (31%). As per the CA study, average energy savings per pump is about 34,000 kWh per year. In addition to the pump efficiency improvements, a utility program may evaluate the use of variable speed drives (VSD) if the flow is or may be made variable based on the water demand.Please note that VSD applications are more complex and should be evaluated based on operating parameters. Energy savings for properly commissioned VSDs should be about 20-30%. From the program design perspective, you need three main ingredients such as 1) selection and training of pump testers, 2) pre-qualification of pumps based on certain factors that will help you reach a benefit cost ratio of greater than 1.0, and 3) marketing and outreach campaign to ensure that your program will reach its savings and demand reduction goals. By the way, pumps are a great source for demand response as well, if you have a demand response program or if you are thinking about starting one. Similar opportunities are also available for blower systems used in wastewater treatment. At Lincus, we have designed and currently implementing pump and blower testing programs for three investor owned utilities and if you need further information on program details please contact us.