Maximum Demand Tariffs (NMD)

The Maximum Demand Tariff (NMD) applies to all new loads that are 3 phases and greater than 100 Ampere (70 kVA).

The tariff codes of N4 or N5 are also used for this capacity but no new connections are being made to these tariff groups.

For tariffs N1 to N4 the price is based on the assumption that the demand of the installation is in the band as set at the time of connection. No demand metering is in place for these customers with the demand taken by the installation restricted only by the size of the supply fuse.

The N5 tariff is based on an assessment of the capacity requirement, although no ongoing monitoring of the demand need is undertaken.

The price components that make up the NMD tariff consist of a Capacity Charge, a Demand Charge and a variable kWh charge.

The Capacity Charge is based on either:

  • the size of the transformer for single customers fed directly from a dedicated transformer (in kVA) or,
  • where a customer is fed from a transformer that is shared with other customers, on the kVA equivalent of their service fuse or isolation device.

The Demand Charge (generally assessed but unknown when the customer first connects) is based on the higher of:

  • either 60% of the Capacity Charge (in kW) or,
  • the highest peak demand incurred in the preceding year (in kW). If monthly demands incurred indicate a 'significant' upward variation on the demand taken from the system it may be adjusted upwards for the following months.

Worked examples

Transformer of 200kVA supplying a single customer

  • Monthly Capacity Charge is based on 200 kVA.
  • If no demand history available the monthly Demand Charge is 60% of 200 kVA = 120 kW.
  • Variable component applied to all kWh's.

Transformer shared by more than one customer

  • Service main fuse installed = 160 Amp.
  • Monthly Capacity Charge is based on kVA equivalent of 160 Amps being 111 kVA.
  • If no demand history available the monthly Demand Charge is 60% of 111 kVA = 67 kW.
  • Variable component applied to all kWh's.

The Demand is measured as the average off-take in kilowatts for any half hour period.

It is advisable for customers to manage their demand by ensuring that plant and equipment, wherever possible, is cycled to ensure non-concurrent operation.