A method and apparatus for energy-optimized data transmission by OPC UA protocol in radio networks is disclosed. When OPC UA communication is operated in a mobile device, e.g. as mobile access to part of a plant for maintenance, monitoring, parameterization, transmission is frequently implemented by the OPC UA's own request-response based communication behavior. Since the device is rarely able to switch off the transmitter, the battery of the device is very quickly discharged. This poses a problem, particularly in the case of devices that are intended to respond promptly to infrequent warnings or events. However, when a client device is intended to provide notification in relation to one event only, the previous polling, i.e. the periodic interrogation is dispensed with and an alternative notification through means inherent in the mobile network is used. This method uses, for example, a mobile push service supplied by the network provider.