AUTHOR=Wang Ying , Zhao Jing , Zheng Tao , Fan Kai , Zhang Kaifeng 

TITLE=Optimal Planning of Integrated Energy System Considering Convertibility Index

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.855312

DOI=10.3389/fenrg.2022.855312

ISSN=2296-598X

ABSTRACT=Nowadays, developing the Integrated Energy System (IES) is considered an effective pattern to improve energy efficiency and reduce energy supply costs. For the IES, flexibility assessment and planning are pressing problems to solve. This paper proposes a new index - Convertibility Index (CI) - to quantitatively assess the flexibility of the IES regarding the energy conversion processes between different energy flow types. Then a planning problem for IES with CI constraints is built up, and it is modeled as a bi-level optimization problem. A hybrid Genetic Algorithm (GA) – MILP algorithm in Matlab/GAMS is developed to solve this problem. A case study is carried out to verify the effectiveness of the proposed method. The results show that with CI constraint, the planning results will be impacted by both the cost coefficients and the flexibility requirement, and the total cost of the IES will increase.  For a given case study, the total cost increases by 26.2% when CI decreases to 0.7, increases by 3.7% from when CI increases to 1.6. Sensitivity analysis shows that with the increase of the CIs, the total numbers and capacities of conversion devices show an overall increase trend. The total cost at first decreases quickly, and then slightly increases, which in a whole shows a "Nike" shape. With different CI constraints, the IES MW per CI ranges from 31.8 MW to 37.5MW, and the average increase in cost is 2.229 Million Yuan (2.1%/0.1CI).