The mast supported double shell biogas roof (BGD) consists of an outer membrane that gives form and an inner membrane that builds the storage space. The biogas roof is supported by a central mast and withstands external forces and loads such as snow, rain and wind. The biaxial curvature of the roof surface avoids the flattering and pumping effect caused by the influence of wind. 

Both membranes are fixed to the outer wall of the steel or concrete tank. The leak-proof design protects the gas holder from gas overpressure and low pressure with safety valves. Fill level measurement systems transmit electronic signals indicating the fill level of the gas membrane. These signals can be used to control the system.  As this is a depressurised storage system, it is possible to combine it with other depressurised products like the single shell biogas roof.