Energy, economic, and environmental (3E) performance assessment, comparison, and analysis of airport cargo terminal microgrid system under the islanded and grid-connected modes

Abstract

Microgrids, which can be grid-connected or isolated, may experience dependability issues as a result of intermittent renewable energy. The implementation of a hybrid renewable energy system (HRES) could alleviate this problem but is still a challenging task because of its interference, uncertain, and unpredictable nature. Currently, the absence of comprehensive assessment impedes large-scale applications. In this study, a novel 3E assessment method-based complete quantitative assessment is suggested and inventively integrated with a newly proposed triangle evaluation scheme. Loads of an airport cargo terminal, which are used to test the assessment approach, are classified into critical and non-critical categories according to their necessity. The microgrid system flexibility is considered by the trade-off of non-critical loads. Results show that the assessment method is more intuitive in quantifying the system's performance. The Levelized Cost of Energy (LCOE) in the islanded mode is lower than the current electricity price (from 0.5407 to 0.5439 CNY/kWh) and the annual carbon emission is reduced to one-third of that in the grid-connected mode. Its flexibility can effectively reduce dependence on backup power generation, where the daily peak shedding increases from 217.88 kW to 555.04 kW and daily hours without charging from 6.7 h to 8.9 h. The carbon emission decreases by 32 % considering the impacts of the system flexibility. Besides, the critical distance exists when the LCOE exceeds the current market electricity price.