As global energy demand rises, it has become crucial to ensure the efficiency and reliability of thermal power plants (TPPs). To achieve optimal performance, reduce downtime and extend asset lifespans, effective operations and maintenance (O&M) strategies are crucial. Given the high thermal and mechanical stresses on critical components like boilers, turbines and generators, continuous monitoring and upkeep are essential. Utilities are also partnering with third-party service providers to leverage economies of scale, advanced remote operations and best practices, enhancing performance and cost efficiency across energy assets.
O&M in TPPs focuses on the regular maintenance of essential equipment. Preventive maintenance helps reduce unexpected breakdowns through routine checks, cleaning, lubrication and part replacements. Predictive maintenance, using advanced data analytics and sensors, forecasts potential failures before they occur. This proactive approach minimises disruptions and avoids the high costs associated with reactive repairs. By employing condition monitoring tools and artificial intelligence (AI)-powered analytics, operators gain real-time insights into the health of critical components, enabling early detection and resolution of issues before they escalate into major failures.
Best practices
The upkeep of the boiler is critical as it is subjected to extreme thermal stresses. Boilers must undergo regular inspections to check for corrosion, leaks and scaling, which can reduce their efficiency and lead to potential failures. Turbine maintenance is also of utmost importance, as turbines convert heat energy into mechanical power. The blades, lubrication systems and the overall structure of turbines need frequent monitoring to ensure smooth operation and prevent costly downtimes. Similarly, generator maintenance is essential for reliable operation. This includes inspecting the electrical connections, insulation and cooling systems to ensure the generator operates without disruption.
Further, the regular monitoring of fuel quality and combustion efficiency is critical for reducing emissions and preventing inefficient burning that could lead to increased operational costs. Heat rate optimisation is also a crucial factor in fuel management, as it measures the amount of fuel required to generate a unit of electricity. A lower heat rate indicates better fuel efficiency, which translates into reduced costs and lower emissions, thus contributing to more sustainable plant operations.
Indian coal’s high ash content leads to substantial fly ash generation in coal-based power plants, which, if improperly handled, can harm the health of the population and contribute to air and water pollution. Therefore, it is essential to manage fly ash disposal and repurposing scientifically. Fly ash can be effectively utilised in the construction industry to make bricks, blocks, tiles, cement, concrete and plaster. It can also be used for land reclamation, filling low-lying areas, raising ground levels and filling mines. Fly ash is used in projects such as roads, embankments, ash dykes and roadblocks, as well as in agricultural development and wasteland reclamation.
In recent years, TPPs have turned to remote monitoring and automation to enhance the efficiency of their O&M activities. Remote monitoring systems allow operators to track the plant’s health from a centralised location, facilitating early detection of potential issues. Supervisory control and data acquisition systems provide real-time data on critical operational parameters such as temperature, pressure and energy output, enabling quick decision-making and intervention. Automated control systems further reduce the need for manual operations, ensuring that the plant remains within safe operational limits and operates at its peak efficiency with minimal human intervention.
Recent trends in O&M
Emerging practices such as furnace mapping are being utilised to improve boiler combustion, ensuring more effective and efficient burning processes. Equipment changeover is increasingly managed through SAP systems, streamlining scheduling and coordination. Further, air preheater intake is being cross-checked using portable gas analysers to ensure optimal performance, while advanced techniques such as boiler tube leakage management, smart soot blowing, and insulation surveys for critical piping and furnaces are being employed to prevent breakdowns and optimise maintenance.
The use of gamma rays is becoming increasingly popular for monitoring emissions, assessing the emptiness of electrostatic precipitator hoppers and scheduling maintenance accordingly. Exfoliation meters are utilised to track oxide layer build-up on coils, while small oil igniting systems and phased array ultrasonic testing are employed to detect metallurgical flaws. Implementing an oxygenated treatment cycle chemistry programme helps reduce corrosion and iron carryover.
To boost water efficiency, power plants are adopting air-cooled condensers, particularly in regions facing water scarcity. These condensers reduce the need for cooling water by using dry cooling to condense steam, alleviating the strain on local water resources. Moreover, power plants are enhancing their cooling systems by increasing cycles of concentration (CoCs), which helps minimise water waste. While most systems currently operate with two to four CoCs, achieving six or more is becoming a feasible goal. Additionally, many TPPs are advancing towards zero liquid discharge by employing cutting-edge wastewater treatment technologies. These systems purify, recycle and reuse water, effectively closing the water cycle within the plant and reducing environmental impact.
Challenges
TPPs face several challenges that impact their O&M strategies. Ageing infrastructure remains a significant issue, as many plants were constructed decades ago and now require more frequent maintenance or costly upgrades to remain competitive. As older plants struggle to maintain optimal performance, plant owners and operators are often faced with the financial burden of undertaking modernisation works. Additionally, stricter environmental regulations are placing more pressure on TPPs to reduce emissions and comply with increasingly stringent standards. This has led to a rise in the adoption of cleaner technologies, such as carbon capture, utilisation and storage, and enhanced emission control systems. However, these solutions often come with high capital and operational costs, further complicating O&M planning.
The volatility of fuel prices also presents a significant challenge for TPPs. The cost of fuel, particularly coal, can fluctuate significantly, depending on market conditions, geopolitical factors and regulatory changes. This volatility makes it challenging for plant operators to manage their costs effectively, requiring them to adopt O&M strategies that prioritise fuel efficiency and cost reduction while ensuring that the plant meets energy output demands.
The demand for a skilled workforce is another critical consideration for O&M in TPPs. As plants incorporate more advanced technologies and systems, the need for highly trained personnel capable of managing and maintaining these complex systems becomes even more urgent. Ensuring that the workforce is equipped with the necessary skills through ongoing training programmes is essential for maintaining plant performance and responding promptly to emergencies.
Outlook
Utilities must incorporate standard operating procedures, such as generating a daily heat rate deviation report and tracking key parameters such as main steam pressure, reheat steam temperature, superheater and reheater spray flow, and condenser vacuum. For combustion optimisation, regular checks on air preheater intake for oxygen and carbon monoxide with a portable gas analyser, along with monitoring APH and duct in-leakage, are essential. Closely monitoring oxygen levels in flue gas, unburnt carbon in fly ash and bottom ash, feed water temperature, make-up water flow and auxiliary power consumption is crucial. Comparing these metrics with historical data helps identify controllable factors that affect energy efficiency. Insulation surveys should also be conducted periodically to further improve efficiency. Optimising cooling tower fans, cleaning condenser tubes and checking the terminal temperature differential of heaters are vital practices. Helium gas testing can detect air ingress into the condenser, while insulation studies on critical pipes and furnace areas minimise radiation loss.
Monthly (and as needed) tasks should include conducting efficiency tests, performance tests (such as clean air and dirty air flow tests), and evaluating the performance of the condenser, air preheater and high-pressure heaters. Additionally, fire-fighting mock drills should be performed to ensure safety preparedness.
The best practices in O&M for TPPs emphasise the importance of continuous employee training, the integration of advanced technologies such as internet of things sensors and AI analytics, and the establishment of robust systems for spare parts management. Keeping an inventory of critical spare parts and working closely with reliable suppliers can significantly reduce downtime during equipment failure. Additionally, optimising water usage, which is essential for cooling, can help reduce operational costs and lessen environmental impact, as water conservation becomes an increasingly important issue in power plant operations.
Looking ahead, the future of O&M in TPPs will be shaped by ongoing advancements in technology and a growing emphasis on sustainability. As the world moves towards a cleaner energy future, the role of TPPs will evolve, with increasing pressure to lower emissions and adopt greener technologies.
Aastha Sharma