This book brings together recent research from across the world on enriched methane, and examines the production, distribution and use of this resource in internal combustion engines and gas turbines. It aims to provide readers with an extensive account of potential technological breakthroughs which have the capacity to revolutionize energy systems. Enriched methane, a gas mixture composed by methane and hydrogen (10-30%vol), constitutes the first realistic step towards the application of hydrogen as an energy vector. It provides strong benefits in terms of emissions reduction, that is -11% of CO2, eq emission with the combustion of a 30%vol H2 mixture, if hydrogen is produced from renewable energy sources. Enriched methane offers the following advantages: • it can be produced at competitive costs;  • it can be distributed by means of the medium pressure natural gas grid; • it can be stored in traditional natural gas storage systems;