Biogas is a key renewable energy source that provides an alternative for the future.

Upgrading biogas to biomethane, which can be fed into the public natural gas grid, offers additional potential.

UBE CO₂ separation membrane modules (CO₂ separator) have polyimide hollow fibre membranes originated from UBE. The modules that carbon dioxide (CO₂) permeates preferentially than methane (CH₄) can generate biomethane by separating CO₂ efficiently from biogas. Biogas is a mixture gas of CO₂ and CH₄ mixed gas obtained from fermentation or digestion of livestock waste, landfill waste, sewage sludge, and so on.

Biomethane has attracted much attention as renewable natural gas (RNG) and is a high purity CH₄ concentrated from biogas. UBE modules are applied to several hundreds of biomethane plants all over the world from 1980's. The modules also can be applied to He or H₂ recovery at low pressure operation up to 2.4 MPaG.