Technical feasibility of biomethane and CNG in a gas distribution network

The recast of the renewable energy directives (RED II) mandates that 32% of gross final energy consumption and 14% of energy consumption in transport in the EU must come from renewable sources [1]. Biomethane production combined with the use of compressed natural gas (CNG) is an alternative renewable fuel for heavy goods vehicles (HGVs). The EU-funded Causeway project will introduce a network of CNG filling stations and a biomethane injection facility to the Irish gas industry for the first time [2]. This presents several technical challenges to the operation of distribution (Dx) networks, including changing load-balancing patterns, and determining optimum locations for biomethane injection facilities. In this work, a representative gas Dx network, for an Irish town of 17,000 inhabitants in an area of high potential for both CNG and biomethane was chosen as a case study. The results found that by optimising the biomethane injection facility location and injection pipeline diameter, the quantity of biomethane injected into the grid as a percentage of the annual demand, could be increased from 35% to 40% with no CNG demand, 33% to 40% with low CNG demand, and 31% to 50% with high CNG demand.