In 2015, the Union Ministry of Environment, Forest and Climate Change notified SO2 norms for coal-based thermal power plants. The establishment of flue gas desulphurisation (FGD system) for all 600-odd power plants in the country was made compulsory. The schedule for the implementation of this system was challenging. Most professionals associated with the power sector, technical experts, researchers and policymakers raised valid concerns. Since Indian coal has a low sulphur content, these experts argued that an FGD system was not necessary for most of these plants. The implementation of the system was, however, initiated in several plants. It was estimated that the capital expenditure on FGD in the old and the new plants would tax finance resources and lead to a tariff burden in the order of Rs 0.25 – 0.30 per KWhr. Power generators were worried, but more concerned were the distribution companies and consumers of power, who would have to finally bear the burden of the additional tariff.
Apart from the commercial implication in terms of heavy capital expenditure and the financial burden on consumers, the issue in question was also about the technical necessity of the system in view of the very low sulphur content of Indian coal. This needed more research. A study initiated by the Ministry of Power and carried out by IIT Delhi concluded that there was a need for more comprehensive analysis of SO2 emissions and whether FGDs are necessary for all thermal power plants in the country.
Niti Aayog initiated a comprehensive study, carried out by NEERI. The researchers studied all aspects of Indian coal and the extent of SO2 emissions vis-à-vis the norm. They prepared a comprehensive report and made recommendations. Their analysis suggests that “ambient SO2 concentration in all the monitoring stations is well below the prescribed Norms of 80 micrograms per cubic meter. This is even though most of the thermal power plants have not installed FGDs”. They also recommended that, “there is a need to revisit the stack emission norms for SO2… with the consideration of India’s latitudinal position, (being) close to the equator compared to European countries, the US… who have given guidelines for SO2 emission control. India has higher and stronger solar insolation leading to high ground level heating, vertical convection, high mixing height, high ventilation.” The FGD system utilises limestone and water as its main input materials. The mining and transport of limestone to power plants leave a large carbon footprint. The atmospheric lifetime of CO2 is significantly longer than that of SO2.
The revised notification does not mandate a complete withdrawal of FGD. It is now based on sound scientific studies and analysis, which have enabled 600-odd power plants of the country to be classified into three categories — those which are close to very large cities, the ones in heavily polluted areas, and others. An analysis of data collected reveals that about 78 per cent of the power plants do not require an FGD system. This means a saving of large capital expenditure, which can now be deployed for creating more power-generation capacities, primarily through the renewable route.
The notification has also allayed fears of tariff burden on power consumers. In India’s long-term energy transition plan, renewables will play a big role. However, the transition will need to respect energy security considerations. Domestic coal will, therefore, continue to play a meaningful role in the coming few decades. The notification not only provides relief for consumers at large, but also provides clarity on how to plan for domestic coal-based power.
The writer is former power secretary, Government of India and president, India Energy Forum
