Dynamic characteristics and load regulation strategies of a novel combined system based on solar‑hydrogen complementary utilization

In this paper, a novel combined system based on solar energy‑hydrogen complementary utilization technology is developed, which first integrates hydrogen gas turbine, thermoelectric generator and proton exchange membrane electrolyzer into the solar power tower-supercritical CO2 Brayton cycle system. The concept of replacing the thermal storage system in conventional solar power tower system with a hydrogen gas turbine is first proposed. Three flexible operating modes include pure hydrogen mode, solar energy‑hydrogen complementary mode and pure solar mode are proposed to address solar intermittency. An integrated dynamic model of the proposed system is established. The detailed annual performance analysis and sensitivity analysis are carried out. A comprehensive evaluation method for the proposed system dynamic performance under three operating modes is proposed. And the load regulation strategies are carried out. Results present that the hydrogen production rate of the proposed system is the highest in July, and the hydrogen consumption rate is the lowest in December. The proposed system has the fastest response speed in pure hydrogen mode, with a minimum response time of 45 s. The solar energy‑hydrogen complementary mode has the maximum response time with 330 s. Prioritizing the adjustment of air mass flow rate (for the pure hydrogen mode) and direct normal irradiance (for the solar energy‑hydrogen complementary mode and pure solar mode) can make the proposed system have a larger load adjustment range. This work lays the theoretical foundation for the research of combined system dynamic characteristics and load regulation strategies based on the complementary utilization of solar energy and hydrogen.