DST – NIAS Stakeholder Consultation workshop to discuss the NIAS Transition Plan for an Integrated Approach to Development and Environment in the Power Sector (Workshop Report No. NIAS/NSE/EEP/U/WR/03/2021)

Publication Type:



NIAS, Bangalore, p.39 + iv pages, 11 tables and 8 figures (2021)


Optimal Electricity Mix, peak demand, Power Flow analysis, Thermal Power Plants, Transition Plan


India’s power sector is undergoing a “green energy” transition in which the Southern Region (SR) is leading the way. While SR contains 50 percent of India’s Variable Renewable Energy (VRE) capacity, the region is facing challenges in VRE integration since the SR Grid also draws power from forty-seven +25-year-old, below 500 MW, Thermal Power Plants (TPPs) with obsolete technology working at low-efficiency levels. As part of a DST-sponsored Project, NIAS has formulated a “End-of-Life” policy for TPPs as an integral part of a journey towards an “Optimal Electricity Mix” for SR. This policy involves the progressive retirement of such TPPs by December 2022 coupled with the integration of High-Efficiency-Low-Emission (HELE) TPPs and Nuclear Power Plants (NPPs) that are already at an advanced stage of construction. By implementing this transition plan, the four State-owned power generation companies in SR can save approximately Rs.3500 crores required to retrofit imported Flue-Gas Desulfurizers (FGDs) associated with significant environmental and economic impacts. Power flow studies conducted to validate the SR Grid operations during the evening peak demand indicate that the power flow through each transmission element is largely within prescribed limits up to March 2023. However, certain transmission elements of the SR Grid must be reinforced by 2026 to meet the peak demand in SR during 2027 and 2030 by importing power from the power-surplus Western and Eastern regions of the country through the National Grid after retiring five more obsolete and inefficient sub-250 MW TPPs by 2027. The optimal utilization of existing and under-construction HELE TPPs with faster-ramping capabilities and lower technical minimums also facilitates VRE integration. The proposed transition plan has operational, economic, and environmental benefits with savings in retrofit and life extension costs in the obsolete TPPs, reduced energy charges, lower CO2 emissions and pollution levels, reduction in specific coal consumption and water requirement as well as smoother VRE integration, and efficient Grid operations.