The RENERG2 project was started officially in July 2013 and finished in September 2017. This final scientific report summarizes the results over the whole project duration. The project was divided into the 5 work packages Electrolysis (WP1), Methanation (WP2), Combustion fundamentals (WP3), HCNG field test (WP4) and Markets and Grids (WP5).