Abstract Ultimate goal of the sustainable energy system is to support our current without compromising the need of future generation. Limitless and continuous energy from Sun offers the potential to realize solar-powered photovoltaics (PVs) and concomitant hydrogen production by water-splitting. We propose the use of transparent PVs (TPVs) and transparent photo-electro-chemical (TPEC) cells to combine the generation of electric power and energy storage of hydrogen fuel. Transparent metal-oxide ZnO/NiO heterojunction was applied for TPV-TPEC module with high transparency (64%) to generate high photovoltage (0.546 V), photocurrent (2.28 mA/cm2) with power-conversion-efficiency (1.47%). This electric power is directly used and applied for the hydrogen production (Power-to-Gas, P2G). This onsite hydrogen production is effective to resolve the burden of hydrogen delivery and storage. Proton exchange membrane fuel cell (PEMFC) unit is linked to TPV-TPEC module to convert hydrogen to electric power (Gas-to-Power, G2P). This G2P mode is efficiently reduce the PV dependence on intermittent nature of sunlight and complete the closed-loop energy supply chain. We demonstrated TPV-TPEC-PEMFC energy system for the continuous energy production, supply and conversion for the transparent energy platform. In the future, it will be possible to obtain the continuous green energy from the window without losing vision.