During the winter months, renewable energy is in short supply throughout Europe. An international project is now considering an unconventional solution: Renewable hydrogen and carbon dioxide are pumped into the ground together, where naturally occurring microorganisms convert the two substances into methane, the main component of natural gas.During the winter months, renewable energy is in short supply throughout Europe. An international project is now considering an unconventional solution: Renewable hydrogen and carbon dioxide are pumped into the ground together, where naturally occurring microorganisms convert the two substances into methane, the main component of natural gas.