Safety and Regulatory Challenges of Using Hydrogen/Natural Gas Blends in the UK

The addition of hydrogen to natural gas for heating and cooking is being considered as a route to reducing carbon emissions in the United Kingdom (UK). The HyDeploy programme (hereafter referred to as HyDeploy) aims to demonstrate that hydrogen can be added to the natural gas supply without compromising public safety or appliance performance. This paper relates to the preparatory work for hydrogen injection on a live site at Keele University closed network comprising domestic premises, multi-occupancy buildings and light commercial premises. The project is based around the injection of up to 20 %mol/mol hydrogen into mains natural gas at pressures below 2 barg. Work streams addressed during the pre-trial preparation included; assessment of material interaction with hydrogen blends for all distribution system components and appliances; understanding of gas appliance behaviour; review of: gas detection systems, fire and explosion considerations, routine and emergency procedural considerations; and the design of a new hydrogen injection grid entry unit. This paper describes the safety and regulatory challenges that were encountered during preparation of the project, including obtaining the necessary regulatory permissions to blend hydrogen gas.