Sulphur-cleaning device in coal plants not necessary: Central scientific committee

The Hindu

2 days ago

A high-powered committee of experts, chaired by Principal Scientific Advisor (PSA) Ajay Sood, has recommended that India do away with a decade-long policy of mandating equipment, called Flu Gas Desulphurisation (FGD) units, in all coal-fired thermal power plants (TPPs), according to documents perused by The Hindu.
These FGD units are required to be retro-fitted in TPPs to cut harmful sulphur dioxide (SO2) emissions. While 92% of India's 600 TPPs have not yet installed FGD units, the recommendation would exempt about 80% of them from needing to install such equipment.
The limited number of vendors capable of installing such equipment in India, the high installation costs, the potential rise in electricity bills, and disruptions due to the COVID-19 pandemic have been some of the reasons historically cited by the Power Ministry, the overseer of India's TPPs, for plants' inability to adhere to previous deadlines. In theory, the costs of non-compliance could run to crores of rupees in fines, though these have not materialised thanks to deadline extensions.
'FGD not necessary'
However, this was the first time that multiple arms of the government congregated to deliberate on whether FGDs were required in the first place. Their verdict draws on three reports by the CSIR-NEERI, the National Institute of Advanced Studies, and the Indian Institute of Technology, Delhi. The lead scientists of these three institutions – each 'supported' by different arms of the government – were at the meeting on April 23, along with representatives from the Office of the PSA, the Union Power Ministry, and the NITI Ayog. They were all largely unanimous that FGD 'was not necessary.'
The guiding principles informing the committee's recommendation are that: SO2 levels in ambient air across the country are around 10-20 micrograms/cubic metre, well below India's air quality norms of 80; Indian coal is low in sulphur; SO2 levels in cities near plants with operational FGD units do not differ significantly from those without these units, and all of these were anyway well below permissible levels.
The committee opined that concerns about sulphates – a potential by-product when SO2 emissions reach certain atmospheric levels, thus forming particulate matter (PM) – are unfounded. They cited an analysis of 5,792 PM samples across the country, which found 'low elemental sulphur' content (max 8 micrograms/m3 after outlier removal) which was deemed 'insignificant — for considering PM removal as a benefit of FGD.'
FGDs may worsen carbon emissions
One argument mentioned in the report was that using FGDs might result in additional carbon dioxide emissions and accentuate global warming. 'Installing FGDs in all TPPs by 2030 will increase the Auxiliary Power Consumption (APC) of the TPPs, thereby adding approximately 69 million tons of CO2 emissions to the atmosphere (2025-30) while reducing SO2 emissions by —17 million tons. Adding more long-lived CO2 emissions while removing short-lived SO2 emissions by installing FGDs indiscriminately in all TPPs in India despite the low Sulphur content of Indian coal will enhance global warming.'
On the other hand, given that burning coal is India's primary source of electricity, India's annual SO2 emissions has risen from 4,000 kilotonnes in 2010 to 6,000 kilotonnes in 2022. By comparison, Indonesia, a source of imported coal to India has averaged about 2,000 kt in the same period, according to data from the Centre for Research on Energy and Clean Air (CREA), a Helsinki-based think tank. This is when India's emission standards, at 100 micrograms/m3 (thus requiring FGD), is lower than Indonesia's 800.
Environment Ministry 'studying' order
Those who attended the meeting included the Secretary, Minister of Power and three other senior officials; Secretary, Environment and Forests and two other officials; four officials of the Office of the PSA; representatives of the NITI Ayog, Central Electricity Authority (the power regulator), Central Pollution Control Board, and academicians.
A detailed questionnaire to the Power Ministry was unanswered until press time. Tanmay Kumar, Secretary, Environment Ministry, told The Hindu that his Ministry was 'studying' the order.
India has 180 coal-fired thermal power plants, each of them with multiple units. The 600 TPPs, depending on their size, age, proximity to densely populous cities, and background pollution levels, were given different timelines by the Environment Ministry to comply with the FGD installation requirements. Deadlines have been shifted three times, with the most recent extension coming on Dec 31, 2024.
Major population centres
The committee, according to the minutes of the meeting seen by The Hindu, will 'recommend' to the Power and Environment Ministers that only power plants located within a 10-km radius of the National Capital Region and other cities with a million-plus population be required to install FGDs. These are called Category A plants. There are 66 such plants, and only 14 of them have installed FGDs. Currently, all these plants are required to comply by 2027.
Plants within a 10-km radius of 'Critically Polluted Cities' or 'Non Attainment Cities', called Category B plants, would be eligible for exemption on a 'case by case' basis, on a joint review by the Central Electricity Authority or Central Pollution Control Board. There are 72 such plants, with only four having installed FGD. These plants currently have a deadline of 2028.
The remaining 462 plants all come under Category C, of which 32 have installed FGDs. These plants have been given a 2029 deadline, but the committee has now recommended that Category C plants be exempted completely, along with some units in Categories A and B which were set up at least 20 years ago.
'Will not affect public health'
'The key common point in these studies is that fitment of FGDs in all TPPs in India is not necessary to comply with the NAAQ (National Ambient Air Quality) standards whose compliance is essential to safeguard public health. While all TPPs must comply with the December 2015 stack emission standards for PM pollution and freshwater consumption, the SO2 stack emission standards can be relaxed to ensure that they are in conformance with the NAAQ standards which are notified by CPCB, keeping in mind the human health and other aspects. This way, TPPs may be able to comply with these standards without fitting FGDs. Since the existing NAAQ standards (for ambient SO2) must be complied with, this change will not affect human health in India,' the committee concludes.
Currently, State governments or affiliated companies run a majority of the Category A TPPs, whereas private authorities hold the highest share in Categories B and C.