Optimal integration of a low-carbon energy system – A circular hydrogen economy perspective

•The feasibility of integrating carbon capture technologies into a circular economy is assessed.•Captured CO2 is used as a feedstock to produce hydrogen byproducts.•A sustainable closed-loop system is proposed to reduce emissions and minimize waste.•Optimization of methane, ammonia, urea, and methanol production is implemented.•Case study is evaluated in US and Australia, and sensitivity analysis to carbon tax is provided.