Business Help

Wattless charges explained

In large commercial or industrial premises, there are likely to be items of electrical equipment that require wattless energy to operate.

Wattless energy is measured separately from your general units, and if you exceed a certain limit, during the winter peak period (4pm-7pm Monday to Friday November to February) it will give rise to a separate charge.

How wattless charges work

Electric power consists of two components: active power and reactive power. Active power is recorded on your normal electricity meter, and appears on your bill as general day and night units.
Reactive power is also recorded by your normal meter, but will only affect you if you are a large industrial or commercial business user. This is because certain equipment common to industrial or other large businesses - such as motors or fluorescent lights (e.g. in an industrial premises) - need reactive power in order to operate.

Your wattless unit allowance

For each kVAarh in excess of 50% of the kWh delivered in the period stated above, a wattless charge will apply. An overall power factor of 0.95 must be maintained in order to avoid wattless charges.

How to reduce wattless charges

You should contact your electrical contractor to fit power factor correction equipment. This will reduce the amount of reactive power you consume and help to avoid wattless charges on your bills.

Cost considerations

Weigh the cost of fitting special power factor correction equipment and how it will reduce wattless charges on your bill. The rate at which the new device will pay for itself naturally varies according to the level of wattless charges you have incurred, but generally speaking, if you have had a consistent wattless charge on every bill, the payback period is less than four years.

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