AK Jha, Director - Technical, NTPC
How is supercritical technology likely to bring down the fuel cost and its usage?
Supercritical technology is an efficient technology as higher steam parameters lead to better efficiencies, which in turn means lesser fuel consumption. The percentage in fuel saving is proportionate to improvement in efficiency level of a supercritical unit, vis-+á-vis a contemporary power unit, based on subcritical steam parameters. We have witnessed an increase of 5 per cent in efficiency from supercritical units installed initially over the most recent subcritical units. This leads to reduction in fuel consumption by about 5 per cent. In addition, units being ordered recently will have further efficiency improvement of 3-4 per cent over and above initial super critical, units hence the fuel cost is likely to be further reduced for a supercritical unit.
What policies will make it commercially viable?
There are lots of positive initiatives from GoI to install large chunks of units based on supercritical technology in 12th and 13th plans. Significant weightage is given to supercritical based project for granting coal linkage. Further, there is provision of automatic transfer and enhanced coal linkage of scrapping old, inefficient units and installing new units of supercritical technology. As a testimony to the success of this initiative, most IPPs are also putting up power plants based on supercritical technology.
Does supercritical technology need to be of a certain size?
Based on the international status of the power equipment technologies and also their costs, NTPC has taken a decision to go for supercritical units with capacities 660 MW and above, based on various factors including techno-economics involving land availability, coal quality and cost of our funds etc.
I cannot talk for other utilities as they do have their own techno-economic evaluation factors to go for supercritical units.
Is India ready to adopt this technology as it comes with a high cost?
It is not correct to say now that supercritical technology comes with high capital cost. Initially, it was true, but with high economies of scale and indigenisation of manufacturing process cost is showing significant downtrend w.r.t. overall project cost.
NTPC has already inducted ultra-supercritical technology and have started construction at various locations like 660 MW units at North Karanpura (3 nos.), Khargone (2 nos.) based on higher steam parameters. We have also invited bids for Barethi (4x660 MW), Telengana (2x800 MW) and Pudimaddaka (4x1,000 MW) which are based on ultra-supercritical parameters with steam temperatures in the range of 593-600 C.
What innovation and improvements has your company done in these technologies?
Our unit efficiencies have improved over the years since NTPC´s inception. NTPC, as a responsible corporate citizen, continuously endeavors to improve generation efficiencies and has already implemented/is implementing various projects with supercritical/ultra-supercritical steam parameters.
Furthermore, I would like to add here that NTPC along with BHEL and IGCAR is participating in ´Mission 2017-Development of Adv-USC technology´. The Mission envisages development of indigenous capabilities in the field of Adv-USC technology with steam parameters of about 310 Kg/cm2/710 deg C/720 deg C and is expected to deliver an indigenous advanced ultra-supercritical plant with expected efficiency of 46 per cent as against 38 per cent for the conventional 500 MW subcritical units being installed, leading to approx. 20 per cent less CO2 emission compared to a typical subcritical plant. I believe that it is only because of NTPC´s achievements in this sector, GoI has reposed faith in us along with BHEL and IGCAR for indigenous development of advanced ultra-supercritical technology in India.
What are your views on possible technology development for carbon capture and its commercial viability in present scenario?
There are many issues involved with Carbon Capture and Storage/Sequestration (CCS) before its implementation on Indian soil can be considered. These include major reservations on the provenness/ technical viability of the technology, high energy penalties (i.e. high auxiliary power consumption), safety, logistics, etc. Apart from this the high costs of CO2 capture technologies available today, high transportation/logistical costs and storage costs also impinge on its commercial viability. However, we encourage participation in R&D on this subject, including in international research ventures for the development of a reliable and affordable CCS technology. India is already a member of Global Carbon Capture and Storage Institute in Australia (GCCSI) which is engaged in research in this field.