Antique reported that peak demand and supply both reached 258 gigawatt (GW) in August, rising 12 per cent year-on-year on a six per cent base and leaving non-solar shortages in the evening. Energy demand was 169 billion units (BU), up 13 per cent, and the evening peak reached 245 GW, up 8 per cent, with one to two GW of shortages during non-solar hours despite the monthly peak being met.

Installed capacity stood at 552 GW, including 240 GW of renewables at 44 per cent and 224 GW of thermal coal. Total generation was 177.8 BU, up 11 per cent, with thermal supplying 116.8 BU and renewables 35.3 BU; solar rose 36 per cent, wind 50 per cent and power exchange volumes grew 20 per cent to 13.9 BU.

The analysis said the system is constrained more by the flexibility of the coal fleet than by renewable additions. On high-solar days the gap between gross and net demand approaches 82 GW as coal is taken to technical minimum through midday, prompting renewable curtailment. The committee assessed retrofitting aged thermal plants as an alternative to high-cost storage, finding that converting 151 units aged 35 years or more, totalling 34.5 GW, would cost Rs 302 billion (bn) to Rs 377.5 billion (bn) and release about 24 GW of flexible power, compared with Rs 1.755 trillion (tn) for equivalent batteries.

The report calculated that for a buyer the extra tariff equated to Rs one point four six per unit of renewable energy freed by shutdown, versus Rs three point six one per unit with four-hour storage. It said two-shifting conversions could extend plant life by 12 to 15 years but that regulatory arrangements for cost absorption remain the principal impediment. NTPC registered 692 boiler tube leakages and cautioned that deep cycling can reduce plant life to between 14 and 20 years, noting neither unit for which it supplied data had run below 55 per cent load and that around 70 per cent of failures were linked to age, coal quality and operating practice.