TNERC Proposes Amendments To Tariff Regulations To Enhance Thermal Power Plant Efficiency And Renewable Energy Integration

The Tamil Nadu Electricity Regulatory Commission (TNERC) has issued a draft notification regarding amendments to the regulations for determining tariffs, dated June 26, 2024. The proposed amendments aim to address several key issues related to the operation of thermal power stations and the integration of renewable energy sources into the power grid.

The draft regulations will be considered after 15 days following their publication on the TNERC website. During this time, stakeholders and the public can submit their objections or suggestions, which the Commission will review.

The key amendments focus on the impact of part-load operations on the performance of thermal generating stations. For coal and lignite-based thermal plants, the new regulations propose specific factors for unit heat rate degradation at various loading levels. For instance, sub-critical and super-critical units will see different rates of heat rate degradation depending on their operational load, with the degradation percentage increasing as the load decreases. Similar considerations are made for the auxiliary energy consumption, where additional energy consumption is permissible at reduced loading levels.

The regulations also address the impact on specific fuel oil consumption for coal-based thermal stations. Given the increasing capacity addition from renewable sources, additional specific oil consumption is proposed for units operating at lower average loading levels.

For gas and liquid fuel-based thermal generating stations, the amendments specify the degradation of gross heat rate for both combined cycle gas turbine mode and open cycle mode operations. The degradation rates increase as the plant loading percentage decreases, reflecting the operational challenges faced at lower load levels. Additionally, the amendments propose permissible increases in auxiliary energy consumption for these types of stations.

Transit and handling losses of coal are also addressed in the new regulations. Different norms are proposed for pit-head and non-pit-head stations, with specific percentages assigned for transit and handling losses depending on the transportation method. The regulations provide a formula for calculating these losses when multiple transportation methods are used.

The explanatory statement accompanying the draft amendments highlights the reasons behind these changes. Tamil Nadu, being rich in renewable energy resources, is focused on promoting the development of renewable power within the state. This is in line with the Renewable Energy Purchase Obligation (RPO) trajectory set by the Ministry of Power. The shift towards a higher share of renewable energy in the power generation mix necessitates frequent ramping up and down of existing thermal power plants, leading to increased operational challenges such as higher station heat rates and auxiliary consumption.

To accommodate these changes, the Central Electricity Authority (CEA) has suggested “relaxed operational parameters” for thermal power stations operating at part load. The state-owned power utility, TANGEDCO, has also requested consideration of actual operating parameters in its recent true-up petitions, indicating that the normative parameters are often exceeded.

The TNERC has proposed these draft amendments to safeguard the interests of state-owned thermal power plants and ensure their operational viability in the context of an evolving energy landscape. By considering the parameters suggested by the CEA and addressing the operational challenges posed by increased renewable energy integration, the Commission aims to create a balanced regulatory framework that supports both conventional and renewable energy sources.

The proposed amendments reflect a proactive approach to regulatory adaptation, ensuring that the power generation sector in Tamil Nadu remains robust and capable of meeting future energy demands while aligning with national and global environmental goals. The draft notification invites feedback from all interested parties, emphasizing the Commission’s commitment to transparency and stakeholder engagement in the regulatory process.