India's fight against air pollution could increase greenhouse gas emissions

India’s fight against deadly air pollution may come with an unintended consequence: increased emissions of greenhouse gases.

Government-mandated pollution control devices for coal-fired power plants, which reduce deadly sulfur-dioxide pollution, could also boost carbon dioxide emissions at individual plants, according to a report by the US Environmental Protection Agency. 

That may impede India’s ability to meet international commitments to reduce carbon-emissions intensity.

“It’ll come down to a trade-off between local health impacts versus global warming,” said Deepak Krishnan, a Bengaluru-based associate director with World Resources Institute India.

India has committed to cutting its emissions intensity -- the amount of greenhouse gases released for each unit of economic growth -- by about a third from 2005 levels by 2030, under the Paris Agreement. A series of scientific reports that show nations aren’t doing enough to avert a devastating increase in the Earth’s temperature has triggered calls by younger activists at the United Nation’s COP25 meeting in Madrid for more extreme solutions than the actions to which nations have already committed.

Federal power and environment ministries, the two agencies involved in the implementation of the pollution control devices, were unable to respond to requests for comment.

India’s environment ministry in December 15 imposed caps on emissions of toxic gases, including SO2 and nitrogen oxides from power plant stacks, allowing the operators two years to retrofit facilities. But the deadlines have been extended by as much as five years as the distressed generators face financing challenges.

A more practical approach would be to prioritize requiring so-called flue-gas desulfurization units, or FGDs, in areas that are critically polluted with high levels of sulfur dioxide levels, said R. Srikanth, a professor for energy and natural resources at Bengaluru-based National Institute of Advanced Studies.

The most widely used SO2 reducing technology is the FGD system that uses limestone as a reagent, according to Qian Zhu, an analyst at IEA Clean Coal Centre in London. Power ministry officials confirmed that is the type of pollution devices likely to be installed at the country’s coal plants.

SO2 emissions control is important because it damages human health, farmland and infrastructure, according to Zhu. The scale of any additional CO2 emissions from the pollution devices “should be small enough not to cause any concern,” she said.

The chemical reaction in limestone-based scrubbers typically adds 1 per cent to the total CO2 emissions of plants that burn low sulfur coal, according to the US EPA report. Extra electricity consumed by the pollution units can be 1 per cent-2 per cent of the gross output of the generation unit, according to the analysis, which was published in 2010. The values in the report would still hold true for today, Enesta Jones, an official for the agency said in an email.

The FGD units “will increase CO2 emissions per unit of electricity generated and that will ultimately lead to a global outcry for closure of thermal power plants” in India, said Srikanth. “The pressure to keep CO2 emissions in check and the poor economics of installing these devices could spur the government to revise the policy.”