POWER-TO-GAS
Power-to-gas is a technology that converts electrical energy (power) into chemical energy (gas). The gas produced can be hydrogen or methane – the processes are called power-to-hydrogen or power-to-methane. The existing infrastructure makes it possible to store large quantities of electrical energy in the form of gas. Since renewable energy sources are very volatile in their availability, storage is of great importance. Power-to-gas makes it possible to bind renewable electrical energy in chemical energy and store it seasonally. Both hydrogen and methane can be used as fuels to generate heat and electricity and as fuels for mobility.
In order to declare the gas produced as renewable gas, the raw materials used must come from renewable sources.
The synthetic gas produced by power-to-gas replaces gas from fossil sources and can also help to stabilize the electricity grid.
Power-to-gas production paths
Power-to-methane is a two-stage process. In the first stage, electricity is used to split water into hydrogen and oxygen, known as water electrolysis. The electrical energy is chemically bound in the hydrogen. In the second stage, carbon dioxide is added to the hydrogen in a ratio of one to four. In a reactor, these two gases react with each other to form methane and water. The electrical energy is now chemically bound in the methane.
The stored energy from the power-to-hydrogen process can be converted into the desired form of energy by a fuel cell or gas engine if required.
The advantages of power-to-methane over power-to-hydrogen lie in the higher energy density of the product in its gaseous state, the existing storage options and the existing gas grid infrastructure. The methane produced with power-to-methane can be fed into the existing natural gas grid without restriction if the methane content is greater than or equal to 96% by volume (hydrogen content up to 2% by volume).
Sustainable use of available resources
Reduction of fossil fuels
CO2 emissions through substitution of fossil fuels
