Taiwan is facing problems such as energy shortage and environmental pollution. How to reduce the thermal power generation is considered as an effective direction. Several alternative sustainable energies, such as wind power generation, hydropower and solar energy are promising candidates. However, due to various different challenges and limits, none can become the final solution. Taiwan is surrounded by the sea and sufficient light, therefore, we have proposed a high-efficiency, low-cost dual hydrogen and electricity production system, a new green solution to reduce the problem of thermal power pollution. In the Sub-project 1, ‘‘The development of the electrode materials for the high-efficiency stable seawater photoelectrochemical (PEC) system’’, the layered double hydroxide integrated with special facet control iron oxide crystal surface will be used as the OER (oxygen evolution reaction) photo anode and combined with the nickel-based HER (hydrogen evolution reaction) electrode, which Prof. Wei-Hsuan Hung (co PI of Sub-project 1) developed together with Prof. Hongjie Dai at Stanford University in the United States. In the Sub-project 2 ‘‘The development of interdigitated back electrode solar cells with frontal floating emitter structure’, Prof. I-Chen Chen’s team will use a three-pole frontal floating emitter (FFE) structure design to develop a low-cost FFE-IBC(interdigitated back contact) solar cell process. Finally, we will integrate these two sub-projects of the PEC system and FFE-IBC solar components together to obtain an efficient, stable and low-cost dual-energy output, hydrogen and electricity, HPEV (hybrid photoelectrochemical and voltaic) system for the catalytic seawater splitting. Moreover, the carrier transmission path at interfaces and junctions will be simulated and discussed for further improvement. Again, this new HPEV system can efficiently control the output ratio of hydrogen production and electricity for different reaction conditions. It is more suitable for the regulation of the peak of the smart grid, and hopes this project can improve and provide a better solution for renewable energy development in Taiwan.