Hydrogen production from treated wastewater powered by solar-wind energy: Feasibility analysis and optimal planning

Wastewater treatment plants can provide a sustainable solution for hydrogen production by harnessing renewable energy and using treated water as feedstock as hydrogen demands in the future are expected to increase significantly. This study provides a decision-making model that enables the determination of optimal capacities of solar power, wind power, reverse osmosis, electrolyser, storage tank, and optimal hourly grid import. Such a project simultaneously provides electricity for hydrogen production and wastewater treatment, and sells hydrogen and renewable energy certificates. The planning aims to maximise the annual profits and renewable energy ratio. The case study shows that coupling a 120,000 m(3)/day plant scale with a 5 ton/day hydrogen facility shows a gross profit margin of 35.2%, a payback period of 7.2 years. This outperforms scenarios that exclude land and energy constraints in wastewater treatment plants. The influence of renewable energy ratios, hydrogen demand, and the prospective water usage for future regional scenario are further discussed.