Impacts of changes in commercial non-coking coal grading system and other coal policies towards estimation of CO2 emission in Indian power sector

Abstract

In India, coal-based electricity is a leading cause for greenhouse gas emissions. However, many uncertainties prevail in the emissions estimation from coal-fired plants due to the dynamics of varying net calorific values (NCV) and carbon emission factors (CEF) associated with different grades of coal coupled with the coal oxidation factors (COF) of power plants. After 2012, a major change in the Indian non-coking coal grading system along with other developments like (a) rising efficiencies of thermal power plants, (b) changes in coal quality due to mining at deeper seams, (c) coal mining and distribution strategy have affected the NCVs, CEFs and COF associated with coal combustion in Indian power plants. These changes are expected to impact the CO2 emissions from coal-based power plants. Our findings suggest that implementation of the newly revised, power sector specific, NCV-CEF-COF-2015 have resulted in reduction of CO2 emission estimates from coal-based electricity generation by about 139 Tera grams (Tg) (12%) and 73 Tg (7%) for the year 2015 as compared to the corresponding emissions calculated using NCV-CEF-COF-1994 and NCV-CEF-COF-2007, respectively. Going forward, these newly estimated factors will provide greater accuracy in emissions estimation from coal-fired power plants in India.