Ofgem has approved UNC 461 which will align the Gas Day definition in the UNC with EU gas codes. From 1 October 2015 the Gas Day in the UK will start at 05:00. However, not all times in the UNC will change. Any that are driven by the timing of the Gas Day will move, but unless there are operational reasons to make a change, many of the timings for physical processes remain the same. The full text of the modification, which is available here, has a table setting out which changes are required. Amendments to the UNC itself will be available in due course.

These changes to the UNC may affect contracts in both the gas and electricity markets. Depending on how contracts are drafted, there may be a need to make amendments to align contract terms with the new timings. Gas supply arrangements are an obvious area where changes may be required, but certain electricity contracts may also require review – tolling agreements and contracts relating to gas fired power generation usually contain timelines that derive from the daily gas timetable and may need to be changed accordingly.