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

Hydrogen production plays a vital role in mitigating the increasing greenhouse gas emissions and utilizing surplus renewable energy. Despite the growing attention towards hydrogen-integrated energy systems, the potential of utilizing hydrogen byproducts from industrial plants remains largely untapped. This paper presents an optimized hydrogen-electricity-gas integrated energy system, which incorporates a circular hydrogen economy model (CHEM) to reduce greenhouse gas emissions, increase profitability, reduce waste, and ensure sustainability. The CHEM employs carbon capture and storage (CCS) technologies to capture and store carbon emissions from thermal power plants (TPPs) in addition to hydrogen produced through electrolysis. These resources are then utilized in industrial processes to produce hydrogen byproducts such as ammonia, urea, natural gas, and methanol. Natural gas, in turn, is utilized as a fuel for TPPs, creating a closed-loop energy system. The model includes energy storage systems to enhance flexibility, and a stochastic optimal dispatch model is proposed to manage uncertainties related to renewables, demands, and energy prices. The proposed model is evaluated through a case study, and the results demonstrate that successful implementation of this approach can lead to a 36% reduction in CO2 emissions and a 7% increase in profits, while promoting a sustainable energy system.