Sundara Kavidass, Managing Partner, SP Energy Tek.
How will implementation of this technology increase efficiency?
Supercritical technology utilises higher steam temperature and higher pressure. The heat rate of the thermodynamic process is the heat energy fed into the Rankine cycle divided by the electrical energy output. If the energy input to the cycle is kept constant, the electrical output can be increased by selecting higher pressures and higher temperatures. This is why efficiency (or reduced heat rate) of the power plant increases due to supercritical technology or ultra-supercritical technology.
Is India ready to adopt ultra-super critical technology?
The Indian power sector is ready for ultra-supercritical power plants. The power sector has witnessed significant GDP growth. To meet demand-supply gap, large size is inevitable. Also, power plant performance can be achieved by raising inlet steam condition to 31 MPa and temperature above 600°C.
Ultra-supercritical plants operate at higher steam conditions, with temperatures ranging from 600°C to 620°C and pressures over 30 MPa, result in design efficiency of 45-46 per cent. Unit capacity for such plants can be reached up to 1,200 MW. Ultra-supercritical capital cost is around 15-20 per cent higher than the supercritical technology cost. Worldwide, more than 50 projects have been executed. In India, eight ultra-supercritical projects are identified and two are executed.
What policies would make this technology commercially viable?
For a country like India, where major generation (nearly 70 per cent) is based on thermal power, withe coal being used as a fuel source, the need to control the emissions and reduce the cost of power supply to the consumer is necessary for future generations on a sustainable basis (24x7), unless larger size nuclear power implementation is in place.
As such, abandoned, older, lower capacity units can be substituted with higher size supercritical units.
Therefore, supercritical and ultra-supercritical technologies are required. With the advancement in metallurgy, India has progressed from subcritical to supercritical technology and now to ultra-super critical technology. This gain in technology would help in achieving cleaner generation and commercially viable proposition.
How will implementation of super critical technology fulfil our promise towards climate change?
Supercritical technology will reduce the fuel cost anywhere 5-7 per cent and improve the cycle efficiency from 39-42 per cent by operating the power plant above the Rankine Cycle critical pressure of 22.1 MPa in the boiler. The station heat rate is lower compared with subcritical technology. This technology provides an opportunity to reduce CO2 emission to the tune of 5-7 per cent that will reduce the impact of the environment. In the past four years, supercritical technology share may be around 25-30 per cent and will continue to increase its technology share in India.
Since supercritical technology increases the power plant cycle efficiency associated with the reduced heat rate, implementation of supercritical technology uses less coal and has lower emissions per table and thus reduces the cost of generation. This technology provides an opportunity to implement larger size units to meet the power demand-supply gap. Therefore, the power sector outlook improves and promises to reduce CO2 emission. Increasing renewable energy may be impact supercritical technology implementation.