Methane molecules are so full of energy that they don’t need rare earths or critical materials — they simply "relax" at 250 bar and offer up to 750% energy recovery. Here’s how.
Strategic seasonal high-pressure gas storage plant
Works similarly to a pumped storage plant. However, methane is used as the storage medium instead of water. (Note: Water cannot be compressed!)
Excess electricity from renewable energies, which would otherwise be lost due to grid congestion management, is converted into mechanical energy to compress methane (CH₄) to a high pressure of 250–300 bar.
The storage medium is taken from surrounding gas networks and stored seasonally in specially reinforced high-pressure pipe modules.
This creates a chemical battery with a very high energy density of around 2,500 kWh per cubic meter, which can be used for months.
Methane naturally contains around 10 kWh of chemical energy per cubic meter. When compressed, only a small fraction of renewable energy is needed to build up the pressure. This chemical energy remains fully available and can later be flexibly converted into electricity, heat, or CO₂-free hydrogen (via pyrolysis or ColdSpark® technology).
Storage Efficiency Comparison
Storage Type
Input Energy from RE (%)
Recovered Energy (%)
Water (Pumped)
100
75
Air (250 bar)
100
50
Methane (250 bar)
100
750
Note: Once methane is used as a storage medium, this approach is completely climate-neutral and also "saves" surplus renewable electricity. After extraction, the stored methane can be flexibly converted back into electricity, used for heating, or transformed into CO₂-free hydrogen.
👉 More details: DOI: 10.5281/zenodo.15862672
This storage solution enables a flexible, seasonal energy supply. It replaces expensive, geologically limited pumped storage plants and underground gas storage facilities — and, above all, it has no idea about rare earths or other critical raw materials.