already been published inEnergy Reports, 6S2 (2020) 802-806, http://dx. doi. org/10.1016/j.
egyr. 2019.12. 018. The duplicate article has therefore been withdrawn. The full Elsevier
Policy on Article Withdrawal can be found at https://www. elsevier. com/about/our-
business/policies/article-withdrawal at https://www. elsevier. com/about/our-
business/policies/article-withdrawal.