-Bhasker Tripathi
Contd from previous issue
NTPC had invited many international companies working with SCR and SNCR to conduct these pilots, including Doosan from South Korea, Mitsubishi from Japan, General Electric from USA and Yara from Norway, according to documents accessed by IndiaSpend.
The results of the pilot would form the basis on which NTPC would invite tenders to finally implement the two technologies in its plants to meet the 2015 NOx emission standards.
NTPC’s certificates for SCR and SNCR would also serve as a stamp of approval for the suitability of these technologies for other power plants in India.
The results are also awaited by the Supreme Court in the ongoing case on air pollution, where the court is reviewing the progress made by the power industry to abide by the new Indian emission standards of 2015, as we said.
The three-year-long tests started in April 2017. According to the timeline, NTPC should have published the results after all the plants had tried the technology for 4,400 running hours.
Many of the companies completed this run around June-July 2019, but NTPC has not yet published the results. These results will show how much NOx was cut, among other details.
“The contract of the pilot project is ending in a few months’ time [by April 2020],” an official of one of the companies involved in the pilots told IndiaSpend. “We were first told that the results will publicly come out by September-October 2019, but nothing happened. Now we have reminded the NTPC again to issue the certificates.”
The NTPC presented the results of these pilots to India’s chief environmental agency, the Central Pollution Control Board, in a meeting on November 2, 2019, where they declared that both the technologies “are not suitable for installation” in Indian power plants. The companies involved were not present at this meeting, sources told us.
IndiaSpend reached out to three companies involved in the NTPC pilot project through emails and phone calls, but they did not respond. The NTPC then suggested that the norms for the new plants be diluted from 100 mg/Nm3 to 450 mg/Nm3. The diluted level can be achieved by “carrying out combustion modification and tuning of operational parameters”, NTPC said. These are the cheaper primary methods that we explained earlier.
It is very difficult to believe that proven technology is not working for Indian plants, Vibhuti Garg, senior energy specialist at the International Institute for Sustainable Development, said. An independent analysis by a non-government organisation is required to establish the claims made by NTPC, and the government should make public NTPC and other power plant emission data for a detailed analysis, she added.
“The emission limit for existing plants [300 mg/Nm3] is eminently achievable using a variety of techniques,” said Lauri Myllyvirta, lead analyst for the advocacy, Centre for Research on Energy and Clean Air, and a former member of a European Union technical working group that revised the emission limits for thermal power plants for the EU.
“If the government walks back regulations every time a polluter complains, there is no hope of meeting the [Indian government’s] National Clean Air Programme target of reducing PM 2.5 pollution by 20-30% by 2024,” Myllyvirta said.
IndiaSpend’s emails, including detailed questions to NTPC and CPCB, went unanswered even after repeated follow-up attempts for more than a week.
NTPC’s findings
NTPC’s presentation to the CPCB, reviewed by IndiaSpend, mentioned some of the issues related to both the technologies. “NOx reduction ~23.4% to 30%. So NOx can be brought down from 450 to 345 mg/Nm3 and norms cannot be met,” the presentation said on SNCR. The presentation also cited the requirement of additional urea, coal and water as an issue.
For SCR, the NTPC presentation accepted that the NOx reduction of nearly 80% could be achieved “but not on [a] consistent basis”. SCR can only work efficiently when flue gas has a certain required temperature that plants can only achieve when they are working above 80% of their capacity, the presentation said.
The presentation also mentioned several constraints faced during the pilot use of SCR technology in power plants, including the disposal of a huge amount of catalyst used in the SCR method and abnormally high erosion of the catalyst due to the high ash content and abrasive nature of Indian coal. It also said that there were space constraints in some plants to install SCR.
Post the NTPC presentation, the CPCB met some of these companies to discuss these issues, on November 7, 2019, according to internal communications accessed by IndiaSpend. Companies in this meeting rejected NTPC’s findings of the pilot projects, according to an audio recording of the meeting accessed by IndiaSpend. Representatives of NTPC did not join this meeting.
To some of the technical issues related to efficiency of SCR and SNCR raised during the November 7 meeting, one of the companies involved in the pilot projects informed CPCB that NOx emissions from Indian power plants could be reduced to 450 mg/Nm3 just by primary measures – combustion modifications. These could be further reduced to 280 mg/Nm3 and up to 80 mg/Nm3 if the primary measures are combined with SNCR and SCR, respectively.
Problems are solvable
Many of the problems of these technologies, except for high-ash content of coal, are not exclusive to India, and countries around the world have been successfully dealing with them, said experts.
Combustion modification can reduce NOx by another 20%-30%, said Soundaram Ramanathan, deputy programme manager of environment governance–energy at the Centre for Science and Environment, a Delhi-based think-tank.
Combustion modifications are a primary step before installing SCR or SNCR, as we explained earlier. The CPCB knew from the beginning that these technologies would use additional urea, coal and water. And it is too minuscule – maybe less than 1%-2% of the total use or CO2 emissions – but the benefits are much larger as NOx has higher global warming potential, Ramanathan said.
The problem of high ash content in Indian coal can easily be dealt with some engineering choices that power plants across the world are already making, Myllyvirta of CREA said.
China, which also uses high ash and low calorific value coal, has retrofitted hundreds of gigawatts of coal-fired capacity to comply with a NOx limit of 50 mg/Nm3, half of India’s strictest limit of 100 mg/Nm3, said Myllyvirta. Old coal-fired power plants in Japan and South Korea that have undergone retrofits routinely achieve emissions below 100 mg/Nm3, he added.
“It is always possible to install dust controls before the SCR to have low dust levels in the flue gas going into the SCR and avoid the issues NTPC is describing,” he said, adding that it cannot be a reason to not comply with the NOx standard. “They [NTPC] have already retrofitted SCR systems to conduct the pilot in existing power stations,” Ramanathan of CSE said. “Currently denying that it is not possible to retrofit SCR is ambiguous. If space is unavailable, then technical diagrams and other valid evidence should be included for further assessments,” she added, referring to the NTPC’s claim of not having space in the plants to install new technologies.
“The company [NTPC] could view this as an opportunity to improve the operation of the plants, but unfortunately its response so far has been to oppose any and all measures that would address the tremendous damage to air quality and public health its facilities are causing,” Myllyvirta said.
The lobbying
This is not the first time NTPC and the Indian power ministry have tried to dilute pollution norms for power plants. In the Supreme Court case on air pollution, the government of India informed the Supreme Court that the level of 450 mg/Nm3 can be achieved through “combustion modification”, and hence that, for the plants that came up between 2003 and 2016, NOx norms will be relaxed from 300 mg/Nm3 to 450 mg/Nm3.
The government’s argument in the affidavit was based on a joint monitoring study conducted by the Central Electricity Authority of India or CEA and CPCB between February 2019 and April 2019. For this study, both the authorities monitored emissions from seven units of four power plants that had combustion modifications – two plants of NTPC and two from a private generator, Adani Power.
Even though the study’s findings stated that emission standards with combustion modifications were achieved by five out of seven units monitored, representatives of India’s power and environment ministries, along with CEA, CPCB and NTPC officials, agreed to dilute the standards for plants that came up between 2003 and 2016 to 450 mg/Nm3, on May 7, 2019, the affidavit said.
“Out of seven monitored units, only five units were found complying with the NOx emission standards of 300 mg/Nm3 at full load only,” said the government’s affidavit submitted to the Supreme Court and reviewed by IndiaSpend.
The two units that could not comply with the 300 mg/Nm3 NOx norm belonged to Adani Power, that ran on “approximately full load”, as per the affidavit.
(To be contd)