Electronic locking cylinder

The cylinder (1) has a power supply device designed as a fuel cell (2) e.g. hybrid fuel cell and lithium ion battery, where fuel utilized by the fuel cell is selected from a group consisting of hydrogen, methanol or hydrocarbon. A fuel storage part is exchangeably arranged in or at the cylinder and comprises a refilling device for refilling the fuel into the fuel storage part. The fuel cell is arranged in or at a read module (3) and/or a knob (4). An electronic communication unit communicates with an electronic identification unit (8) in a wireless or contactless manner.