DCP161 - Excess Availability Charges

Important Change to your electricity DUoS Availability charges 

On 1st April 2018, there was an industry-wide change which affected how your electricity is billed.

What is DUoS?

Electricity is provided to the energy network by various energy suppliers. Your local network transports the electricity from the National Grid to your premesis, which is maintained by your regional Distribution Network Operator (DNO). The Distribution Use of Systems (DUoS) charge recovers the cost of installing and maintaining that network and is based on the volume of electricity you consume through it. The cost of using this network depends on demand (i.e. time of day) and falls into 3 ‘bands’ Red, Amber and Green. The exact time of day these relate to depends on your region, so speak to your DNO for more information.

What's changed?

Previously, if your business used more than its agreed DUoS Availability, which is the value (expressed in kVA) agreed between you and your Distribution Network Operator (DNO)*, you were charged for the Excess Availability at your standard rate. This charging structure changed on 1st April 2018.

From this date, if you use more than your agreed DUoS Availability you are charged at a higher rate for the excess; this is known as agreed DUoS Excess Availability or Excess Capacity**. Please note this change only impacts half hourly (HH) metered electricity supplies with current transformer metering. Your DNO may have contacted you about this change separately.

It has been estimated that the excess charge will be up to three times higher than standard rates so may have a significant impact on your bill if your DUoS Availability is set too low. You can find out what the new DUoS Excess Availability rate is on your DNO’s website. If you’re not sure who your DNO is, refer to the ‘How to identify your DNO’ section below which also contains contact details.

Next actions we recommend you take

  1. Find your current agreed DUoS Availability
    Review your past 12 months’ bills to understand whether excess charges have been applied. This information can be found in the ‘Other Charges and Adjustments’ section of your bill.
  2. Review whether your DUoS Availability is sufficient
    If you have incurred Excess Availability charges within the past 12 months, or think that your Availability is insufficient for your current or future needs, then you should contact your DNO to adjust your agreed DUoS Availability.
  3. If necessary, contact your DNO to change your DUoS Availability
    To find your DNO, refer to the ‘How to identify your DNO’ section below.

Please note, an increase in your agreed DUoS Availability means an increase in your on-going standard DUoS Availability charge. Therefore, you should assess whether it would be more beneficial to increase the agreed DUoS Availability or to pay excess charges for the number of times you anticipate exceeding it. 

For any enquiries or changes to your DUoS Availability, please contact your DNO. For any other enquiries regarding your bill, please contact ENGIE Customer Services on 0800 130 3600 (lines open: Monday to Thursday 10:00 - 17:00, Friday 09:30 - 16:30).


*The company licensed to distribute electricity in your region
** A Capacity/Availability charge covers the peak energy requirements for each Meter Point Administration Number (MPAN). The Availability charge is expressed in pence per kVA per day where kVA is the peak allowance as agreed between you the customer and the Distribution Network Operator (DNO) in your connection agreement. An excess Capacity/Availability charge applies when the agreed DUoS Availability monthly demand is breached. DUoS Excess Availability charge may also be levied by the DNO when the monthly maximum demand exceeds the agreed DUoS Availability.

How to identify your DNO

Visit the Energy Networks Association and type in your postcode to find your DNO. The relevant contact details will be shown.


1. Find your Distribution ID on your Metering Point Administration Number (MPAN). Your MPAN can be found
at the top of your bill or on your electricity meter (Diagram below).
2. Search for your Distribution ID on the DNO look-up table below for their contact details.
In the example below the Distribution ID is 10 which means that the corresponding DNO is UK Power Networks.

MPAN Diagram

DNO Look Up Table