CitiPower Powercor Jemena move to kVA network tariff

In October 2013 Genesis Now wrote about Victoria network providers moving from demand charges based on real power (kW) to apparent power (kVA) for large energy users (here’s the link).

At that time, Ausnet and United Energy had made the switch; Citipower / Powercor will do so from 1st July 2016 and Jemena from 1st January 2017.

This means that businesses will be charged not only for the actual real power used but for the overall power used to deliver this, which includes reactive power (kVAr).

Due to this change in tariff structure, reducing demand cost requires not only reducing real power but also reducing the reactive power.

In order to reduce reactive power businesses need to improve the ‘power factor’.

This can be achieved by installing power factor correction devices on individual items of equipment or at the main switchboard.

However, replacing inefficient plant equipment or lighting can improve power factor and also reduce demand.

For example, if present demand is 200 kW and power factor is 0.7, the associated apparent power is 285 kVA. Improving power factor to 0.98 would reduce apparent power to 204 kVA, a reduction of 81 kVA or 28%.

However reducing demand instead to 143kW would also reduce apparent power to 204 kVA with no change in original power factor.

Thus it is important to assess both energy efficiency (demand reduction) opportunities and power factor correction actions in order to determine the most cost effective solutions.

Both of these actions would also increase existing capacity meaning that extra equipment could be operated simultaneously or that additional equipment could be installed without the need to undertake costly and disruptive upgrading of electrical infrastructure (e.g. customer transformers, wiring, switchboards).

If you would like to reduce both your electricity demand and improve your power factor, Genesis Now is here to assist you.

Definitions

• Real power: makes loads, such as motors and lighting, operate.
• Reactive Power: enables the real power to circulate within inductive loads such as motors.
• Apparent power: combination of both real and reactive power.
• Power Factor: a measure between 0 and 1 of the proportion of real compared to apparent power.
  A power factor of 1 means that all the energy supplied is able to be converted into real power meaning it is fully utilised.

Emilia Iacovino
Senior Electrical Engineer,
Energy Efficiency and Renewable Energy
Genesis Now.