Optimal cost analysis for 100% renewable energy integration in India: a step toward global electricity grid

The rising global environmental challenges have highlighted the crucial requirement of renewable energy (RE) adoption as a core policy worldwide. India, endowed with abundant RE resources, has emerged as a pivotal contributor to the global clean energy transition. This study examines optimal investment strategies for solar, wind, battery storage, and energy imports to meet India’s electricity demand. In this paper, three case studies are considered. The first is an isolated grid system, where Indian states or union territories operate independently. The second is an interconnected grid system, where the Indian grid is divided into nine sub-grids linked via high-voltage direct current transmission lines (HVDC TLs). For both case studies, optimal investments are determined using a novel linear optimization approach called Graph-Based Optimization Modeling
Language (GBOML). Furthermore, a global electricity grid (GEG) model is developed to connect high-RE countries through HVDC TL and assess the benefits of cross-border interconnections. The proposed work stands out by addressing key aspects of future energy systems, including sub-grid identification and HVDC TL cost analysis. Moreover, the thermal transmission line loss and the costs associated with converters and HVDC TL for both the Indian grid and the GEG are evaluated to assess its techno-economic feasibility of GEG. Finally, the Weibull distribution parameters for all locations were determined using classical methods and a metaheuristic algorithm. For the Indian isolated grid system, the total annual cost to meet the load demand is INR 22,30,671.12 crores, whereas for the interconnected grid system, it is INR 8,46,808.22 crores. In the GEG, the total cost of overhead line (OHL) is INR 110.63 crores per MW, whereas the cost of underground cables is INR 30.72 crores per MW.