A novel planning method for design and dispatch of hybrid energy systems

Abstract

The hybrid energy systems that integrate renewable technologies with natural gas combined cooling, heating and power technologies are an excellent way to provide low-carbon energy and promote sustainable development. Simultaneously, the hybridization of two technologies necessitates more advanced management strategy. Thus, this paper proposes a novel planning method to optimally design and dispatch the hybrid energy system that consists of power generation unit, absorption chiller/heater, ground source heat pump, photovoltaic panel, solar thermal collector, water storage tank and battery. According to the operation status of power generation unit and energy storage units, six dispatching strategies are designed, which consider the efficiency fluctuation of power generation unit and the electricity price variation of the utility grid. At the same time, in addition to the economy, energy and environment performance, the grid integration level for assessing the electrical matching performance and the thermal energy waste level for evaluating the thermal matching performance are introduced as two additional indicators. Then, the modified non-dominated sorting genetic algorithm with adaptive simulated binary crossover is utilized to solve the multi-objective optimization model that considers economic, energy and environmental performance with and without the matching performances as objective functions. The best solution is selected from Pareto frontier solutions through TOPSIS method. The results of the studied case demonstrate that the combination of power generation unit under daily change strategy and energy storage technologies under full-time mode is the best operational strategy. The optimal economy, energy and environment indicators are respectively 359373.37 $, 2914623.42 kWh and 720663.80 kg. As for the optimal equipment capacity, more than half of the available solar area is used for photovoltaic panel installation; the capacity of water storage tank is almost 3 times that of battery. Besides, when matching performances are considered, the capacity of uncontrollable equipment is decreased. The capacity of photovoltaic panel is reduced from 465 kW to 357 kW to improve the electrical matching performance. For the purpose of better thermal matching performance, solar thermal collector is not adopted. In addition, the power generation unit as a controllable component plays an important role in adjusting the matching performances.