Electricity supply companies must supply electricity between pre-defined limits. In Australia this level is 230V +10% -6% (216V to 253V). All equipment sold within Australia must be capable of operating within these limits. To maintain this in all areas, power is often supplied at even higher levels close to the 253V.

Why?
Fluorescent lights that use electronic ballasts are suited to voltage reduction since operating at higher than optimum voltages leads to higher energy consumption.

How?
It is possible to install a transformer unit which can reduce the voltage level delivered.
There are two types of units available:
- Units that provide a fixed voltage reduction, rather like tapping down on a transformer.
- Units that track the voltage to maintain it at a pre-programmed level.
The latter type of units is generally more expensive, but depending on the site’s voltage profile, may be more cost effective. The price of the units depends on the maximum demand of the site and the annual electricity consumption.

How did we calculate this?
Savings will depend on the amount of fluorescent lamps with magnetic ballasts that voltage reduction is applied to.  Voltage reduction does not work well with electronic ballasts and CFLs.
The following assumptions have been used to calculate this figure:
- The average Victorian SME emits 107.3 tCO2e per year (Carbon Down, 2011)
- On average, electricity accounted for 64% of emissions
- Lighting accounts for 26.5% of the electricity use
- Half of the lighting is fluorescent with magnetic ballasts
- A typical 8% saving on the fluorescent lighting with magnetic ballasts
Saving =107.3tCO2e x 1000kg/t x 64% x 26.5% x 50% x 8% = 728kgCO2e

Cost to implement
Costs vary depending on the load that the voltage reduction is being applied to. Domestic-sized single-phase units are available at 80 Amps at a cost of around $1,500 installed. A three-phase unit rated at 55kVA would cost around $6,500 installed.