The basic idea behind the Power to Gas (P2G) concept is to use electrochemical processes to convert surplus electrical energy from renewable sources into methane and store or distribute it in the gas grid.
Electrolysis is first used to split water using electrical energy. In a further process step, carbon dioxide is then used to produce methane with the electrolytic hydrogen.
In this way, surplus electricity can be stored permanently. If this electricity comes from wind turbines, the synthesis gas is referred to as Wingas, while electricity from photovoltaic systems is referred to as solar gas.The P2G principle is based on the idea that more renewable energy will be available in the future, but that this will have to be absorbed into the power grid irregularly or to a certain extent unpredictably.Another aspect is to relieve the load on the transport lines for electrical energy, as the P2G concept makes use of the gas grid.
However, the conversion losses during electrolysis and downstream during synthesis are relatively high. With losses of around 30%, hydrogen production is still comparable to pumped storage plants. The synthesis of methane currently results in further losses of around 15%.
The first plants for converting electricity from renewable sources into synthetic methane are already in operation.Commissioning of the first plants:
2011 by Greenpeace Energy in Sunderburg
2012 by E.ON in Falkenhagen
2013 by AUDI AG in Wertle