Integrating Demand Response and Solar PV in Indian Coal Power Plants: A Hippopotamus Optimization Approach to Emission Mitigation

Coal-fired electricity generation remains a dominant global source of greenhouse gas emissions, contributing approximately 15.22 billion metric tons of CO₂ in 2022. This study addresses the urgent need for decarbonization within the Indian coal-based power sector by examining the coordinated use of demand response (DR) strategies and optimally integrated solar photovoltaic (PV) systems. Solar PV is considered as a strategic complementary resource capable of reducing the dependence on conventional coal-fired units while enhancing clean distributed generation. The optimal siting and sizing of PV installations are determined using the Hippopotamus Optimization (HO) algorithm, which incorporates solar irradiance availability, temporal load patterns, and the emission intensity of coal-based supply. The proposed framework aims to increase renewable energy penetration, reduce technical losses, and achieve significant CO₂ mitigation while addressing solar intermittency and dynamic demand variations. Simulation results obtained on the IEEE 33-bus distribution system indicate that coordinated DR–PV integration leads to substantial reductions in peak demand, system losses, and up to 30.79 % reduction in CO₂ emissions compared to the base case. These findings highlight the effectiveness of combining renewable deployment with demand-side measures in achieving a sustainable, efficient, and environmentally responsible energy transition, offering valuable guidance for policymakers and utility planners engaged in coal-sector decarbonization.