The article describes the technology of the “hydraulic piston”, as well as the studies that confirm the viability of this technology, implemented in various devices, designed to compress natural gas (CNG) and biomethane (bio-CNG), to accumulate CNG and bio-CNG, to deliver bio-CNG from the production site to the point of its injection into the natural gas network or to the vehicle fuelling stations to fill the Natural Gas Vehicles (NGV). The article presents prototypes of personal fuelling devices and mobile fuelling systems developed by Hygen Ltd. (Hygen), thereby showing the potential of the technology to contribute in the deployment of alternative fuel infrastructure and into the global GHG emissions reduction, mainly in the transport sector.

Natural gas, including biomethane, is a sustainable alternative fuel. Widening compressed natural gas applications by now is restricted by weakly developed infrastructure. Hygen Ltd. works on “hydraulic piston” technology for natural gas and biomethane compressing, storing, delivering and discharging the storage cylinders by means of an innovative hydraulic boosting technology. Designing of the Vehicle Fuelling Appliance (VFA) demands to take into account thermodynamics and gas dynamics properties at fluid compression and motion. The present paper deals with theoretical characteristics and their link to test measurements regarding a particular VFA HYGEN+ Alpha prototype manufactured by Hygen Ltd.