The power-to-gas (PtG) method converts electricity into hydrogen or, in a further process step, into methane, to enable the energy to be stored easily and cost-effectively. Liquid fuels can also be produced (power-to-liquid, PtL) using this conversion method. Due to the wide range of options, the term power-to-x (PtX) technologies is generally used. Where renewable electricity is used, the resulting energy carriers are virtually emission-free.

Ludwig-Bölkow-Systemtechnik GmbH has been maintaining a database of PtG plants since 2011. While initially only smaller research facilities with capacities in the kilowatt range were in operation, today there are 25 installations with a total capacity of 26 MW in Germany alone, the majority of which use PEM electrolyzers . The number of plants in operation is expected to increase to over 35 by 2022; more than 50 plants with a total capacity of 55 MW are planned for the future, some of which are already under construction. Noteworthy is the focus in Germany on the generation and use of hydrogen as an energy carrier, without any further processing of this into other energy carriers. This is predominately attributable to the increasing use of green hydrogen as a feedstock in refineries or as a fuel in the mobility sector.