Long Term Planning for Indian Power Sector with Integration of Renewable Energy Sources

India being a developing country has the need of both addition in generation and replacing the old ones commensurate with ever-increasing demand in the domestic, agricultural, commercial, and industrial sectors. With Demand Side Management (DSM) resorted to effectively, however, there exists potential of shaving peak, and consequently to some extent energy in this important infrastructure of economy. Having an installed capacity of about 81 GW from Renewable Energy Sources (RES) out of a total of 360 GW by July 2019 it has an ambitious plan for significant addition of renewables reaching the level of 175 GW (100 GW from solar including 40 GW of rooftop, 60 GW from wind, 10 GW from bio-mass, and 5 from small hydro), and 275 GW respectively by the end of country’s 13
^th
(March 2022) and 14
^th
five-year plan (March 2027). Thus, as estimated, by 2030 it may be in a position to contribute about 48% from renewables only. This is based on detailed studies on load forecasting in different sectors geographically over pan-India in different time-frame followed by estimation of potential from RES. The latter consist of development from solar, wind, biomass, waste, etc. both off-grid and on-grid. Finally planning has been carried out simulating likely scenario at different point of time with system having sizeable penetration of renewables in the overall requirement of generation to meet the electricity demand. Technological developments, standardization, and regulatory measures have paved the way for large-scale integration of renewables to the Extra High Voltage (EHV) grid by pooling the surplus from one region for haulage to other regions for distribution of electricity. In the process gradually conventional fossil-fuel based generating plants are being phased out, though it continues with still addition of the backlog in the system. However, in the process Plant Load Factor (PLF) of such type of generation is coming down enabling lessening pollution too. With economy of scale and more accuracy achieved in predicting intermittent generation from renewables, it has already been possible to achieve much reduction in per unit charges of electricity from RES, notably from both, solar and wind.In the paper based on Long-Term Load Forecasting, results of studies to find out optimal mix of existing conventional fossil-fuel based generation integrated with renewables from various sources have been depicted based on computation. While carrying out studies specifically for the two periods ending on March 2022 and March 2027, development envisaged in respect of renewables has been taken into account, and so the reduction in demand due to DSM. Corresponding peak demands projected to be met appear to be about 226 GW and 299 GW with annual energy requirement to the tune of 1,566 and 2,047 Billion Units (BU) of electricity. Reduction in peak demand of 9 GW and 12 GW and energy requirement of 206 and 273 BU too is expected on account of DSM.As per studies projected renewables would be accounting for 175 GW out of a total of 479 GW by March 2022, while 275 GW out of 619 GW by March 2027. Consequently, in terms of installed capacity overall percentage of non-fossil-fuel based generation would rise to 49.3% and 57.4% respectively. However, considering additional coal-based capacity requirement vis-à-vis under construction as well as retirement of old ones, overall contribution of energy from this segment would remain significant, although with reduced average Plant Load Factor (PLF). Considering the transition period of 10-12 years from now, Long-Term studies have been carried out corresponding to the time-frame 2029-30 to find out the optimal mix of primarily RES and fossil-fuel based Thermal plants. Thereafter for the year 2029-30 corresponding to the various critical days how such planned system meets the peak load as well as fulfil energy requirement has been studied. From the results it is observed that 48% of energy is expected to come from RES with installed capacity touching about 65% of the total installed capacity of 831 GW by 2030, predominantly with Solar. The latter has significant role in meeting the daily load demand vis-à-vis energy out of different types of generation. But in the studies with projection of data, at the time of actual peak of the day, occurring typically in the evening, there is almost no contribution from Solar. So, though installed its presence could not been considered at the time of peak demand. This is indeed a big constraint with further growth in load due to economic development or otherwise and desirability of phasing out fossil-fuel based power plants. Under such circumstances flattening of load curve by the extensive use of Pumped-Storage Hydro (PSH) plants, BESS, etc. are definitely the viable option as alternatives, as considered.