Reliable operation of an optimal self-scheduling multicarrier system with two alternatives: Multiple renewable utilities or hydrogen facilities

Multicarrier systems (MCSs) have been retrofitted with storage facilities to enhance their resilience to meet the fluctuating demands. Considering the complexity of the systems and the interactions among various carriers, optimal resource allocation is a serious challenge in the sustainable management of energy systems. This study proposes a new self-scheduling MCS to supply power, heating, cooling, and freshwater, without external cooling and nonrenewable heating facilities. Modeled based on circular integration principle, the MCS consists of various subsystems and storage facilities to treat the effluent and digest excess sludge of a wastewater treatment facility. The MCS is optimally designed and scheduled in a two-stage multi-objective optimization to satisfy the demand loads of a small community in two configurations: one with a material conversion unit (MCS-MC) to store and utilize hydrogen, and the other with weather-driven renewable energy units (MCS-RE) for a reliable operation. Accordingly, total annual cost (TAC), total exergy dissipation (nTED), and the mismatch between supply and demand (MSD) are minimized in a multi-objective optimization problem to obtain the optimal capacity of the equipment and the short-term storage facilities are scheduled in the first and second stages, respectively. The results show that the optimal MCS-MC and MCS-RE configurations reduced the TAC, nTED, and MSD by 30.2% and 12.4%, 32.9% and 23.4%, and 55.4% and 48.5%, respectively, compared to the base system. The new utility-free hydrogen-assisted multi-carrier systems are anticipated to substitute present systems with multiple renewable resources.