Abstract
Energy availability and long term operation are key challenges for wireless sensor networks and the applications where embedded devices are battery-operated and they should operate unattended for tens of years. For this reason energy harvesting (EH) is becoming very important for powering ubiquitously deployed sensor networks and mobile electronics. In this paper we introduce a Smart Power Unit (SPU) for embedded systems which integrates energy harvesters from the sun and wind with hydrogen fuel cells especially designed for outdoor applications. The power unit can work as a standard battery or providing serial communication to exchange power information to achieve power management.Experimental results show the high efficiency (up to 90%) of the power conversion subsystem and the perpetual work. Deployment in a structural health monitoring in Switzerland demonstrates that perpetual energy sustainability is achievable in real-life conditions.