Reducing Costs and Maintaining Overall Accuracy of Gas Billing – September 2017, Gas International
Ben Hanley of Northern Gas Networks and Neil Stuchbury of Orbital Gas Systems explain changes to the accuracy requirements for caloric value-determining devices in the UK in a recent issue of Gi.
Natural gas entering or moving between UK networks must be metered for volume and caloric value (CV) in order to bill appropriately for the energy transferred.
Following a proposal to Ofgem by Northern Gas Networks and a public consultation, the UK accuracy requirement for instrumentation measuring a caloric value (CV) of natural gas at directed otakes has been changed from 0.14 MJ/m3 (approximately 0.35 per cent) to 0.2
MJ/m3 (approximately 0.5 per cent) maximum permissible error. The reasoning behind this has been the development and increasing application of inferential and correlative measuring devices which have much faster response times than the traditional gas chromatograph (GC). This produces more frequent data which, in the current climate of rapid changes to gas quality, provides signicant improvements in accurately tracking CV variations.