Experimental assessment of a residential scale renewable–regenerative energy system

An experimental assessment of a hydrogen based regenerative (electrolyser-fuel cell) system is presented. The experiment was conducted on a residential scale Integrated Renewable Energy Experiment (IRENE) test-bed under conditions that are representative of the real demands that would be placed on a solar based, regenerative system, with a focus on dynamic operation under transients in both load and renewable energy supply profiles. A control algorithm employing bus voltage constraints and device current limitations is outlined. Results for a 2 week operating period indicate that the system response is very dynamic but repeatable.The overall system energy balance reveals that the energy input from the renewable source was sufficient to meet the demand load and generate a net surplus of hydrogen. The energy loss associated with the various system components as well as a breakdown of the unused renewable energy input is presented. In general, the technical challenges associated with hydrogen energy buffering can be overcome, but the round-trip efficiency for the current system is only 22%.