OPTIMIZING SOUTH SUDAN�S GREEN ENERGY TRANSITION: TARIFF DESIGN AND LOAD DISPATCH STRATEGIES

This paper explores the technical, economic, and regulatory challenges and opportunities associated with integrating multiple solar Independent Power Producers (IPPs) equipped with Battery Energy Storage Systems (BESS) into South Sudan�s national electricity system. With an electricity mix currently dominated by expensive diesel generation, the analyses aim to support the country�s green energy transition by proposing new tariff structures and load dispatch strategies that ensure both system reliability and cost efficiency. Utilising the PLEXOS Integrated Energy Model, we simulate scenarios for the gradual introduction of utility-scale solar PV plants and BESS under varying policy, grid, and market conditions. Our modelling focuses on the period 2024-2044 and evaluates the impact of these new renewable energy assets on the performance of the existing generation, system load dispatch, and financial sustainability under different Power Purchase Agreement (PPA) arrangements. Key findings show that a dual-component tariff scheme (fixed capacity + variable energy charges) enhances transparency in cost recovery, supports financial viability for investors, and reflects the true system value of flexibility and dispatchability provided by BESS. The introduction of solar PV and BESS reduces reliance on diesel generation, lowering costs and emissions, but also highlights transmission constraints requiring upgrades of 5-17 MW to avoid up to 439 GWh of unserved energy by 2030. Optimal dispatch strategies involve time-shifting of solar energy through BESS and regional load balancing. To attract private sector investment, the study advocates for standardised PPAs with clear risk-sharing mechanisms, transparent IPP tendering processes, and regulatory reforms aligned with international best practices. This research provides data-driven recommendations for South Sudan�s energy sector stakeholders, aiming to harmonise economic development, energy security, and climate resilience. The proposed strategies offer a pathway to a more sustainable and affordable electricity system while balancing investor confidence with consumer protection.