Low calorific gas (L-gas) is an important part of the natural gas market in North West Europe (NWE) and Grmany in particular. Most L-gas comes from the declining Groningen gas field. Yet, the speed of conversion of L-gas to H-gas installations is limited. Authors: Andrej Pustišek, Christoph Merkel, Michael Karasz, Iñaki Merkel de Gurtubay