Maintenance and overhaul help AP-Genco increase generation at major thermal power units

The AP-Genco did maintenance overhauls of the bigger units at Narla Tatarao, Sri Damodaram Sanjeevaiah and Rayalaseema thermal power plants in recent months after quite a long gap, and it contributed to a significant increase in the overall generation, which hit a record 6,009 MW on January 4, 2026.

The overhaul of each of these units (the 800 MW facility at NTTPS, two 800-MW units at SDSTPS and the 600-MW unit of Rayalaseema thermal plant), which was done in a staggered manner, took up to 30 days.

The result was a reduction in forced outages, which caused increased plant availability, a top official told The Hindu, while pointing out that the NTPC overhauls its units every year to keep them in good condition. One of the 800-MW units at SDSTPS was not overhauled due to some operational reasons.

As per the source, a capital overhaul of one of the units at Srisailam hydel power plant was planned a few years ago, but was kept on hold due to multiple issues, mainly the complexity of taking out every part and repairing / replacing it.

Meanwhile, the AP-Genco is able to keep the emissions at old thermal units under check through alternative methods, including by using a judicious mix of domestic and imported coal, which has high calorific value, instead of installing Flue Gas Desulphurisation (FGD) systems, which are very expensive.

As per the existing classification done on the basis of populations in the vicinity of thermal plants, only the old units of Dr. Narla Tatarao Thermal Power Station (NTTPS) attract the FGD norms.

The revised guidelines say that if a thermal unit is located within a 10-km distance of a city with million-plus population, the FGD systems need not be set up if such a unit is going to be retired. Therefore, the AP-Genco has some leeway as far as the installation of FGD systems is concerned. It also depends on stack height and certain other factors.

Nevertheless, the AP-Genco is basically not in a position to rush through big investments in the current situation as cost-benefit analysis has to be worked out carefully and fund-raising is subject to a whole lot of factors.