What is Power Factor?

Power Factor is a measure of how efficiently electrical power is consumed. In the ideal world Power Factor would be unity (or 1). Unfortunately in the real world Power Factor is reduced by highly inductive loads to 0.7 or less. This induction is caused by equipment such as lightly loaded electric motors, luminaire transformers and fluorescent lighting ballasts and welding sets, etc.

What does it do to my electricity bill?

In a 3 phase supply, kW consumed is (VOLTS x AMPS x 1.73 x Power Factor) / 1000. The Electricity Company supply you VOLTS x AMPS and they have to supply extra to make up for the loss caused by poor Power Factor. When the power factor falls below a set figure, the electricity supply companies charge a premium on the kW being consumed, or, charge for the whole supply as kVA.

Reactive Power Charges

Poor power factor increases electricity costs

The Reactive Power charge is one of the ways by which consumers with a poor power factor pay more for their electricity than consumers with a good power factor. From April 2010, a common charging method will be in force across all UK Electricity Supply Companies.

This will apply to ALL half-hourly metered consumers. If your electricity bill does not yet include a charge for reactive power, this will be introduced over the coming months.

The way the reactive power charge is calculated is; the consumer will be ‘allowed’ to use reactive power up to a third of the active power consumed for free; i.e. ‘allowed’ reactive power = 0.33 x total kWh.

Any reactive power which is used over this ‘allowed’ figure is considered to be ‘excess’ usage and is chargeable.

By installing power factor correction equipment and ensuring that the average power factor is better than 0.95 lagging, no ‘excess’ reactive power is consumed.

This means that ALL excess reactive power charges are avoided.

Please contact the workshop on 01435 865533 for more information.