Licence modifications to gas licences under section 23 of the Gas Act 1986 to ensure Great Britain’s (GB’s) compliance with the European Union legislative definition of gas day

Publication date
12th June 2015
Information types
Policy areas

This is our decision to modify certain licence conditions relating to the definition of “gas day” (the daily period over which gas transmission system operators work) to align them with the European Union (EU) legislative definition. Further details on the provisions of that EU legislation, the background to it and Ofgem’s powers and duties in respect of it, are contained in our open letter dated 28 July 2014 and our statutory consultation letter dated 14 April 2015. The July open letter consulted on consequential changes to relevant UK law and licence conditions to comply with these EU requirements.

We consider that these licence modifications are necessary to facilitate the implementation of certain aspects of two EU Network Codes.  EU Network Codes are detailed binding EU laws and so take priority over domestic legislation. Two EU Network Codes require a harmonised start time for the “gas day”, namely 05:00 GB local time.

Having taken account of the responses made to our statutory consultation, we are modifying the Standard Licence Conditions (‘SLCs’) of the Gas Shipper Licence and the Gas Transporter Licence and the Standard Special Conditions (‘SSCs’) and Special Conditions of certain Gas Transporter Licences. The detail of these licence modifications are set out in full in the modification notices published alongside this decision letter.

In summary, the changes are:

  • Gas shipper licence: amend the definition of “day” to align with the EU definition of “gas day”; and
  • Gas transporter licences: amend the starting time of “Formula Year”/ “formula year” and associated time periods (“Formula Month”) in relevant licences to align with the EU definition of “gas day”. Where those definitions refer to a 1 April start date, the first affected time period would commence on 1 April 2016.

We consider that these changes are necessary to implement the EU requirement for a harmonised start to the gas day as mandated by the relevant EU Network Codes.

Subject to any appeal of our decision to modify the licences mentioned in this letter, the licence changes will take effect on 1 October 2015. If you have any questions regarding the content of this letter, please contact Dora Ianora by email at or on 0207 901 1854.