Analysis of the operational characteristics and control strategies on a novel CHP system co-driven by solar, wind, and natural gas with the coordination of renewable energy priority consumption and energy storage

With the growing penetration of renewable energy, power systems are grappling with increased volatility from both generation and demand. A novel solar, wind and natural gas driven-combined heating and power system is proposed. This study investigates the performance of the system under off-design loads, response to fluctuations in wind and solar power. An optimal control strategy is proposed, which focuses on prioritizing the consumption of renewable energy, a coordinated response from the energy storage system, and the on-demand operation of the gas turbine. The energy supply characteristics and sustainability of the system in different typical days are also evaluated. The results demonstrate that as the load demand increases, the gas turbine is brought online as needed and progressively ramps up its power output, effectively supporting a high share of electric load requirements. At the rated load, the exergy efficiencies for solar, wind, and natural gas of the system are 19.3%, 50.1%, and 44.9%, respectively. Additionally, waste heat from the gas turbine can be flexibly distributed between heat supply and molten salt heating. The heating power can peak at 354.3 MW, and the mass flow rate of cold molten salt heated by the gas turbine flue gas can reach up to 2014.7 t/h. Case studies of three typical days under varying conditions of wind-solar resources and electricity-heat loads reveal that for the system, in scenarios characterized by abundant renewable resources and high energy demands, the system sustainability index can attain a value of 1.47, indicating excellent overall energy utilization efficiency and operational reliability.