The project also focused on improving energy efficiency and catching energy thieves along the 600 km long supply network.
“A huge amount of pumping is needed to drive all the water through the network, and electricity is a major cost,” says Pernilla Widén, head of Mälarenergi’s water treatment plant.
Previously, the pumps were either on or off. Today they are constantly in action, but at exactly the right speed. “We have a range of pump sizes, and the monitoring system, together with variable speed drives, ensures that the right pumps always work at the right speed,” she adds.
Variable speed pumps not only save electricity costs but also maintenance costs since they are subjected to less wear. Mälarenergi expects to save approximately $30,000 per pump each year, and the whole investment will pay for itself in as little as two or three years.