Avijit Mondal, Scientist, NTPC Energy Technology Research Alliance (NETRA), highlights the crucial role of stainless steel in enhancing power plant efficiency, durability and sustainability, particularly in high-temperature supercritical zones.
Avijit Mondal, Scientist, NTPC Energy Technology Research Alliance (NETRA), in an exclusive Stainless steel interview with Stainless Today, gave insights into NTPC’s innovative efforts in carbon capture and renewable energy to underscore its commitment to a greener future.
NTPC Limited, formerly known as National Thermal Power Corporation, is an Indian central Public Sector Undertaking (PSU) under the ownership of the Ministry of Power and the Government of India. NTPC is one of India’s leading power generation companies.
Here is an excerpt from his interview.
What role does stainless steel play in power plants, particularly in enhancing the efficiency and durability of critical equipment?
In thermal power plants, materials like carbon steel or alloy steel were predominantly used in the earlier subcritical technology phase, where operating temperatures and pressures were relatively lower. Subcritical plants typically operated at around 540°C and 190 kg/cm² pressure, resulting in low efficiencies of around 32 percent, sometimes even as low as 29 percent in practice.
With environmental norms and the global push to reduce carbon footprints, India began adopting supercritical technology around 2008. These plants operate at temperatures of 595–610°C and higher pressures, leading to significantly improved efficiencies. For these conditions, stainless steel became the preferred material for the highest temperature zones, especially in superheater and reheater areas. Two specific grades, Super 304H and SS 347, are now widely used due to their superior corrosion resistance and durability under extreme conditions.
As India plans to implement advanced ultra-supercritical technology, stainless steel consumption will rise further, along with the use of superalloys. Although stainless steel has limitations such as lower thermal conductivity compared to alloy steel, its other properties like oxidation and corrosion resistance make it indispensable for modern power plant operations. Since its introduction in 2008, stainless steel has delivered excellent results and become a critical material for thermal power plants.
How does stainless steel contribute to minimising maintenance and extending the life cycle of power generation infrastructure?
Stainless steel offers excellent corrosion resistance, making it an ideal choice for harsh environments like those near seashores or in marine conditions. In wind and solar power plants, where support structures are constantly exposed to corrosive elements, stainless steel significantly reduces maintenance requirements and enhances the lifespan of equipment.
While initial costs may be higher compared to other materials, the long-term benefits of reduced maintenance and replacement make stainless steel a cost-effective choice. For thermal power plants near coastal areas, stainless steel ensures the durability of critical components, mitigating issues that inferior materials would face. Its ability to withstand such environments without frequent repairs makes stainless steel a superior material for power generation infrastructure.
How does stainless steel contribute to sustainability initiatives in power generation?
Sustainability in power generation involves optimizing resources, reducing emissions, and minimizing maintenance. Stainless steel contributes to these goals by increasing plant efficiency and durability, as already discussed. Additionally, the recyclability of stainless steel aligns with the principles of a circular economy, making it an environmentally friendly material.
At NTPC, sustainability is a core objective. The organisation has expanded its portfolio beyond thermal power to include renewables like solar, wind, and hydro, and even nuclear energy in collaboration with the Nuclear Corporation of India Limited. Materials like stainless steel play a crucial role in optimising resources and supporting these sustainable energy initiatives. Despite its higher initial cost, stainless steel’s longevity and recyclability make it a key material in NTPC’s strategy to produce energy sustainably.
How is NTPC positioning itself to meet the growing energy demands while maintaining efficient operations?
India’s per capita energy consumption is rising steadily, and NTPC is positioning itself to meet this growing demand through a diversified energy portfolio. While coal-based plants still play a role, NTPC is heavily investing in renewable energy sources like solar, wind, and hydro. It is also exploring green hydrogen, methanol, ethanol production, and carbon capture technologies to reduce emissions and create valuable by-products.
NTPC is also working on advanced ultra-supercritical technology, which could achieve efficiencies of up to 46–47 per cent, significantly higher than current technologies. This would drastically reduce carbon emissions. Additionally, NTPC is implementing flue gas desulfurisation (FGD) systems to minimise pollutants like SOx and NOx, with plans to use the by-products in industries such as cement manufacturing.
By combining innovation, sustainable practices, and a focus on operational excellence, NTPC is leading the way in meeting India’s energy needs while aligning with environmental goals.
What technological advancements are being adopted to improve the efficiency of power generation?
NTPC has been at the forefront of adopting advanced technologies, including the advanced ultra-supercritical (AUSC) technology, which promises a significant leap in efficiency with operating parameters of 710°C and 310 kg/cm² pressure. AUSC technology could improve efficiency to 46–47 per cent and drastically reduce emissions.
Another major focus is on carbon capture and utilisation (CCU). NTPC has set up plants to convert CO2 emissions into useful products like methanol, ethanol, and aviation fuel. Energy storage is another critical area, with NTPC exploring large-scale battery solutions and small hydro storage to address renewable energy intermittency. The company is also utilising waste heat for desalination plants and leveraging fly ash to create construction materials like bricks, tiles, and pipes. Through these innovations, NTPC is addressing both efficiency and sustainability challenges, ensuring that it remains a leader in power generation technology.
How is stainless steel used in power generation beyond thermal power plants?
Stainless steel finds extensive applications across different types of power generation. In hydroelectric plants, it is used in valves and piping due to its corrosion and fatigue resistance. In solar and wind energy, stainless steel ensures the durability of support structures exposed to harsh environmental conditions.
In thermal power plants, duplex stainless steel, with its superior oxidation and erosion resistance, is increasingly being used. While cost considerations sometimes favour alternative materials, stainless steel remains a preferred choice for applications requiring high reliability and longevity. As power generation evolves towards more efficient and sustainable methods, the role of stainless steel is only expected to grow.
Any final thoughts on the role of stainless steel in power generation?
Stainless steel has proven to be a vital material in the power generation industry, offering durability, corrosion resistance, and adaptability to high-temperature and high-pressure environments. With the push for efficiency and sustainability, its applications are expanding across various power generation methods. Although cost remains a consideration, the long-term benefits of stainless steel make it an irreplaceable component in modern energy infrastructure.
As NTPC and the industry adopt advanced technologies, stainless steel will continue to play a significant role in shaping the future of power generation. Its versatility and performance ensure it remains at the core of innovation and sustainability efforts.
