In pump engines, the practice of controlling the rate of flow by varying the positions of valves and crimpers has now been superseded. These conventional mechanical controls have been replaced by frequency converters, which enable the rotation speed of electric motors and of the pumps powered by them to be continuously regulated. This variable control of voltage makes for a high level of performance in engines and pumps, even at low speeds. The intelligent electronic components reduce electricity consumption by just under 3 million KWh per year, representing an annual 2 000-tonne saving of CO2.