Operation of UK gas appliances with hydrogen blended natural gas

The HyDeploy project has undertaken a programme of work to assess the effect of hydrogen addition on the safety and performance of gas appliances and installations. A representative set of eight appliances have been assessed in laboratory experiments with a range of test gases that explored high and low Wobbe Number and hydrogen concentrations up to 28.4 % mol/mol. Tests have demonstrated that the addition of hydrogen does not affect the key hazard areas of CO production, light back, flame out or the operation of flame failure devices. It was identified that for some designs of gas fire appliances the operation of the oxygen depletion sensors may be affected by the addition of hydrogen and further studies in this area are planned. A laboratory based study was supported by an onsite testing programme where 133 installations were assessed for gas tightness, appliance combustion safety and operation against normal line natural gas, G20 reference gas and two hydrogen blended gases. Where installations were gas tight for natural gas, analysis showed that no additional leakage occurred with hydrogen blended gases. There were also no issues identified with the combustion performance of appliances and onsite results were in line with those obtained in the laboratory testing programme.