Rise of renewable energy impacts RTPP fortunes

The 1,650-MW Rayalaseema Thermal Power Plant (RTPP) at Kadapa bore the brunt of the State’s Renewable Energy (RE) capacities overshooting the Renewable Power Purchase Obligation (RPPO). RTPP had consistently operated at 70% to 80% Plant Load Factor (PLF) till 2015 when the share of wind and solar power in the total energy mix started increasing rapidly.

All thermal power plants have since been adversely affected by the rising RE generation, especially the RTPP which has certain other factors also that pushed it into the red. Still, it (RTPP) can be revived by taking some remedial measures.

This was the opinion which the APSEB Engineers’ and Assistant Electrical Engineers’ Associations conveyed to the four-member expert committee constituted by the State government in early January to examine the problems being faced by RTPP and suggest steps to overcome them.

Associations’ president M. Vedavyasa Rao and Vamsi Srinivas stated in their communication to the committee that the thermal units’ heat rate, auxiliary consumption, specific coal and oil consumption and wear and tear have increased as a consequence of their (plants’) operation at low loads in the wake of injection of a large quantity of RE into the grid.

This had its impact on the RTPP, whose PLF stood at just 46% in 2018-19 and plummeted to 21% in 2019. They cited the sudden addition of RE power beyond the RPPO, procurement of premium coal at a high cost and poor quality of the coal as the three major reasons for the increase in the RTPP’s cost of generation.

The APSEB engineers have suggested that with 100% materialisation of fuel supply from Mahanadi Coalfields and Singareni Collieries, the RTPP could be operated at 90% PLF and that the diversion of 1.88 million tonnes per annum under the flexible raw coal scheme should be discontinued from 2020-21.

They also advised that the Singareni Collieries Company Limited should be asked to supply only G-12 to G-15 grades to the RTPP to reduce the cost and variations in quality.

Long-term contracts

Besides, long-term imported contracts should be made with foreign suppliers directly without the involvement of middlemen to ensure proper quantity and quality at affordable prices.

As per a Central Electricity Authority recommendation, the RTPP was best suited for flexible thermal energy generation and that was probably the reason for NTPC showing interest in taking it (RTPP) over because its small size generators (210-MW) were advantageous for flexible generation, the engineers observed.


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