Water companies that use groundwater to produce drinking water can save from 5 to 10 percent of their total energy costs essentially by replacing pumps with an excessively high capacity or discharge head. This was shown by research carried out by KWR within the joint research programme for the water companies.
Analysis of 22 pumping stations
The same research led to the recommendation that, when pumping stations were due for renovation, a study should be done of the economic feasibility of equipping the well field with frequency-driven submersible pumps, or with booster pumps in the raw water pipe. Such boosters produce greater yields than the submersible pumps traditionally used in abstraction wells: 80 percent versus 60 percent for the traditional pumps.
These were the conclusions of an analysis of data from 22 pumping stations. It showed that groundwater abstraction accounted for 32 percent (0.18 kWh/m3 ) of the total energy consumption of (groundwater) water companies. Average energy savings of 25 percent in the abstraction process are economically realistic, with a payback period of zero to five years. This was the outcome of the energy scans done by Vitens at ten sites.
The biggest avoidable energy loss therefore occurs when water companies install excessively large pumps to abstract the groundwater; the pumps are ‘pinched’ for a lower capacity and thus become less energy-efficient.