It is predicted that the future shift of gas supply sources will drive the requirement to reconsider the basis of the current GS(M)R specifications so that the UK gas market is able to operate efficiently and continue to attract these alternative sources of supply. In addition there are a number of other factors that make a review of the GS(M)R prudent at this time being:-
European gas quality harmonisation.
The European Commission has asked ENTSOG (European Network of Transmission System Operators for Gas) to develop a draft amendment, following a detailed impact assessment, to the EU Network Code on interoperability to codify the CEN standard EN 16726 (Gas Infrastructure – Quality of Natural Gas – Group H.) by the end of June 2017. At present the standard does not include a Wobbe Index component but there are detailed differences in other areas from the current GS(M)R specification.
The European Commission is continuing the process over the next few years of finding a consensus on the Wobbe Index range for the next version of the CEN standard. One key option for this is the adoption of the EASEE “H-gas” Wobbe range
UK Wobbe Range
Currently the UK Wobbe range is narrower than in most other EU gas markets. Maintaining this narrower range could affect the attractiveness of the UK market to upstream parties if such parties would incur additional gas processing costs for entry into the UK compared to other markets.
The output of the programme will provide an assessment of equipment, processes and specifications that would be impacted if a change to gas quality specification is required to meet a maximum / minimum limit from across the selected specifications of GS(M)R, CEN and EASEE ‘H’ Gas. The assessment must provide sufficient information that NGGT will be able to communicate to an external audience a clear understanding of the type of NTS assets impacted by a widening of the Wobbe within UK and an estimate of the further work required and options available to mitigate the risks identified. This further work, if required, will be accompanied by associated estimates of the costs and timescale to achieve this work as necessary.
This evaluation could then be used as a common process baseline for the NTS assets from which any future changes in gas quality can be related.