-The engineering company Witteveen+Bos and the Water Board Aa en Maas explored the potential of a new concept combining Power-to-Gas (PtG) and sludge digestion in Wastewater Treatment Plant (WWTP) Cuijck. This project aims to tackle two topical issues at once, which are respectively the need for increase of energy storage for renewable energy production and the need for reduction of greenhouse gas emissions. The main conclusion of this study shows that Powerto-Gas systems can reduce around 20 % of the carbon dioxide (CO2) emissions and provide long term storage of 126.5 MWh/year (140 579 Nm 3 Synthetic Natural Gas/year) at the WWTP of Land van Cuijk.