Power to gas

Surplus electric power can be used for the electrolysis (electrochemical decomposition) of water (H2O) to hydrogen gas (H2) and oxygen gas (O2). The hydrogen gas is then pressurized or liquefied and stored in tanks. When electric power is needed, the hydrogen is converted back to electric power by combustion via fuel cells, gas turbines, diesel engines, or Stirling engines. Alternatively, hydrogen gas can also be stored in the natural gas network up to approximately 5 percent to 10 percent. If the share of renewable electricity grows, methane (CH4 = “natural gas”) is produced from H2 and CO2 through multistep catalytic reactions and stored in the gas network. The necessary chemistry and technology are tried and tested; in fact, even during World War II, Germany produced synthetic gasoline in a similar manner. A very efficient and extensive distribution and storage infrastructure is already available as the natural gas network and the existing large-scale natural gas stores (capacity of up to four months). The existing gas turbine power plants could now also be operated using only renewable energy sources. The hydrogen and methane production and electric power generation by gas turbines could take place at any location in the power supply grid. This flexibility means that the power supply grid doesn’t need to be expanded to such a great extent.

Fuel cell for experiments (Bild)

Chemistry; Physics; Technology

Grade 7 to 9; Grade 10 to 13

Middle/high school; Vocational training

Energy; Energy supply; Renewable energy

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