Decision on Seasonal Multiplier Factors for Gas Transmission

We have issued our decision to maintain the current seasonal multiplier factors to be applied to non-annual capacity bookings in the postalised tariff from 1 October 2023.

The annual consultation on these factors was published on 12 May 2023, as required by EU Regulation 2017/460, the Network Code on Harmonised Transmission Tariff Structures for Gas (“TAR NC”), as amended following EU Exit.

Seasonal multipliers factors apply to non-annual entry capacity products, for example monthly or daily capacity bookings, by applying a factor which either increases or decreases the relevant proportion of the annual tariff. The seasonal factors reflect the seasonality of gas flows during the year and are set to incentivise suppliers to make more use of the network in the summer and shift demand away from the winter peak. The multiplier factor incentivises the use of annual capacity. The tariff for a non-annual capacity product is calculated by multiplying the annual tariff by the appropriate seasonal multiplier factor. These have been included in the gas transmission charging regime since October 2015.

We received 10 responses to the consultation from:

  • Consumer Council NI (CCNI)
  • GNI (UK)
  • Gas Networks Ireland (GNI)
  • Mutual Energy (MEL)
  • Electricity Association of Ireland (EAI)
  • SGN Natural Gas (SGNNG)
  • Firmus energy
  • Phoenix Energy
  • ESB Generation and Trading (ESBGT)
  • Gas Market Operator Northern Ireland (GMO NI)

The respondents were supportive of the proposal to maintain the current factors and, as those factors meet the requirements of within the EU Regulation on establishing a network code on harmonised transmission tariff structures for gas, known as TAR NC, which has been amended to facilitate the UK’s exit from the EU.

Copies of all documents can be made available in large print, Braille, audio cassette and a variety of minority languages if required. Please contact John Wasson on 028 9031 6625 or email: and cc to request this.