Pathways for Net-Zero: How Future Electricity Demand Shapes India's Power Sector Decarbonization Strategies

India faces the dual challenge of decarbonizing its power sector while meeting rapidly growing electricity demand. Electricity consumption is projected to nearly triple by 2040, while the power sector accounted for about 54% of national energy-related CO 2 emissions in 2023. Recognizing this issue, the Indian government pledged at COP26 to achieve net-zero emissions by 2070. Transitioning to a low-carbon power system is a long-term and capital-intensive process, where assumptions about future electricity demand play a central role. This paper examines how optimal investment strategies for decarbonizing India's power sector by 2070 vary under alternative demand scenarios. To this end, a dynamic, bottom-up linear optimization model of the Indian power system has been developed, which simultaneously determines the least-cost hourly dispatch and optimizes investment in generation and storage capacities for each decade from 2023 to 2070. Three electricity demand scenarios are considered, representing distinct development pathways for India based on GDP evolution. Results indicate that while wind and solar dominate capacity growth, dispatchable thermal technologies remain essential for system flexibility and reliability. Achieving net-zero emissions requires full deployment of nuclear, hydro, while coal with carbon capture and storage (CCS) plays a critical role after 2060, especially under the high-demand scenario. However, the required deployment rates, particularly for wind, nuclear, and CCS, exceed historical levels, raising feasibility concerns without significant demand-side efficiency gains and lower transmission losses.