How voltage optimisation works
		Effects of reducing and controlling voltage on an electrical system: 1. Before reducing and controlling the voltage The voltage entering the facility is high and variable. Many loads are using more electricity than they need and are subject to stress through: • Overheating because they are operating at higher than their design voltage, and • Fluctuations in the delivered voltage   2. After reducing and controlling the voltage Incoming voltage is reduced to an optimum voltage for the facility. This creates a beneficial operating environment for electrical equipment and enables certain loads to use less electricity. In a stable electrical environment, equipment works better, lasts longer and needs less maintenance.
		Basic diagram showing the impact of reducing and controlling voltage on kWh consumption and incoming voltage at a typical facility.
		Additional information Virtually all sites can benefit from reducing and controlling their voltage, but the size of the benefit will vary as conditions and loads differ from site to site. One important fact to remember: it is the loads that make the savings. The higher the ratio of inductive or 'fixed impedance' loads to resistive loads on a site, the larger the potential savings. Fixed impedance loads that will benefit from a stable 220 volt supply include motors, compressors, refrigerators, fluorescent lighting etc., but not controlled heating processes. An example: a 3kW kettle rated 230v will require the same energy input for the water to reach the desired temperature, therefore any reduction in voltage will require the kettle to be on for longer. However, operate that kettle at 240v and it then consumes 3.27kW and the life of the element is reduced.		Other loads that cannot achieve a saving are variable speed drives, electronic ballast lighting and devices fitted with 'Switch Mode Power Supplies' that are typically found in office equipment, PBX etc. For constant power devices that have a wide input voltage range (typically 100V - 260V) reducing the voltage will only increase the current. In this instance, the savings if any, are negligible. However, in all cases equipment life is extended. Even after taking into account the loads that do not make a saving (discarded loads) it is usually cost effective to install voltage control at a facility. For more background on voltage optimisation, click here.		The Carbon Trust and Voltage Management The Carbon Trust have produced an introduction to voltage management. To download it, click here.