Green hydrogen production and solar to hydrogen ratio using innovative and integrated bifacial solar photovoltaics and cool roof technologies

emissions from the energy sector and accelerating the clean energy transition. Primarily, the high cost of electricity
generation from renewable sources and the low efficiency of water electrolyzers contribute to the high
cost. To increase the efficiency of electrolyzer, decrease the price of renewable electricity, and increase the power
output of solar PV systems, new and novel energy technologies will be required in the future. A bifacial solar PV
(bPV) system that incorporates cool roof technology (high-albedo roof coatings) is the primary focus of this
research since it has the potential to significantly improve green hydrogen production and solar-to-hydrogen
(STH) ratio. Solar-to-hydrogen (STH) ratio is a system’s performance metric and refers to the ratio between
the amount of power produced by hydrogen to the amount of input solar energy. To optimize the power output
and green hydrogen production, the optimal operating conditions of the bifacial solar PV system must be found.
These conditions include albedo, height from the ground, tilt angle, and distance between the solar panels.
Albedo is the most significant factor. This study’s uniqueness and originality lie in integrating cutting-edge
technology like bifacial solar PV and creating cool roof paint to increase power generation output and green
hydrogen production. The experimental set-up is composed of bPVs, a building roof with high solar reflective
material, microinverter, electrolyzer, metal hydride hydrogen tank, and an integrated data acquisition system.
The daily performance of the bPV with different building roof coatings (green, grey, and white) and the impact
on daily green hydrogen production are presented in this study. The results reflect that bPV with green and grey
reflecting surfaces enhances the system’s STH by 13.74% and 15.77% respectively, as compared to the monofacial
PV (mPV) panel. Further, a green hydrogen production system powered through bPV having white
cardboard, white wallpaper and cool roof paint as reflecting surfaces improves the system’s STH by 22.70%,
25.26% and 26.69%, respectively. Hence it is concluded that cool roof paint as a reflecting surface for bPV
powered hydrogen generation systems not only enhance the energy generation by PVs but also improves the
solar-to-hydrogen ratio significantly resulting generation of 27.31% additional hydrogen from the same system.