Improving the energy efficiency of pumping systems

Many pumping stations do not operate at anywhere near optimum energy efficiency. Work in the UK and overseas has consistently indicated that improving the operation and performance of pumping plant can make reductions in energy costs of between 30-50%. These savings may be generated by: refurbishing or replacing equipment that is worn or no longer appropriate for the duty; improving the scheduling of multi-pump systems to give the minimum operating costs for any particular demand; employing appropriate technology such as high efficiency motors and efficiency enhancing coatings; more effectively matching pump performance to demand by improving pump selection, impeller trimming or the use of variable speed drives; minimising hydraulic losses and installation effects; continuous monitoring of high energy use pumping plant. Although several water companies are taking a proactive approach to the reduction of pumping costs there is still plenty of scope for improvement. This paper draws on the experience of carrying out many pumping cost reduction programmes in the UK and overseas. It examines the methodology behind these programmes, details potential energy saving areas and gives real examples of where significant savings have been made.