Storage and regeneration of renewable energy via hydrogen - A novel power system integrating electrified methane reforming and gas-steam combined cycle

Abstract

Renewable energy is developing rapidly, while the fluctuation limits its accommodation. The power to power (PTP) system, which stores and re-generates renewable electricity, can mitigate fluctuations of renewable energy. Hydrogen can be used to realize the large-scale peak-load shifting of renewable energy as an energy carrier. However, the high cost and low efficiency of hydrogen production via electrolyzer significantly affect the performance of the PTP system. Furthermore, previous studies have not effectively integrated each part of the PTP system and optimized the parameters, resulting in unsatisfactory performance. In this study, a novel, efficient, and economical PTP system is proposed by integrating an electrified methane reforming process and a gas-steam combined cycle, through which the natural gas reacts with steam to produce hydrogen-rich syngas driven by renewable electricity. Then the syngas is blended in methane to produce electricity. The proposed system is modelled and analyzed in terms of energy and economic aspects. The optimal round-trip efficiency of the novel PTP system is 45.8%, which is 9.8% higher than that of the PTP system coupled with an electrolyzer, and the levelized cost of electricity for the novel system is 11.9% lower. The system can achieve efficient storage and utilization of renewable energy.