India’s largest power producer wants nitrous oxide emission norms for coal plants relaxed

The current emission limit applicable to most Indian plants is five times higher than that in China.

India’s power industry, led by its largest producer National Thermal Power Corporation or NTPC, is pushing to water down the norms for lethal nitrous oxide or NOx emissions, saying pilot projects of technologies to cut down emissions have proved ineffective in India, as per documents reviewed by IndiaSpend.

The companies involved in the pilot projects have contested NTPC’s findings saying that NTPC did not allow these companies to make some primary modifications to the plants before conducting the tests, and that the technologies on their own had produced good results during the pilot and are currently used in China, Japan and European countries to reduce NOx pollution.
The results of these pilots, and NTPC’s claims, are important for an ongoing air pollution case at the Supreme Court that will determine whether Indian power plants can and must follow new, stricter norms. The court will also decide whether norms should be relaxed. Under the new norms introduced in 2015, power plants commissioned between 2003 and 2016 – which account for 65% of India’s total 197 gigawatt coal capacity – will have to cap their NOx emissions at 300 milligram per cubic metre or mg/Nm3. New plants commissioned from 2017 onwards, which comprise 5% of total coal-based thermal power capacity, must limit NOx emissions to 100 mg/Nm3.

The government is already in the process of diluting the norms – for power plants that came up between 2003 and 2016 from 300 mg/Nm3 to 450 mg/Nm3, the Central Government affidavit to the Apex Court shows. The NTPC is now suggesting that norms for new plants commissioned after 2017 also be diluted from 100 mg/Nm3 to 450 mg/Nm3, our investigation found. In effect, the magnitude of reduction in NOx limit for new plants – from 100mg/Nm3 to 450 mg/Nm3 – is higher than that for older ones – from 300 mg/Nm3 to 450 mg/Nm3.

The 300 mg/Nm3 limit that applies to the majority of Indian plants is five times higher than that already being met by power plants in China. It is twice the norm in Germany and the European Union and more than three times that in the United States. Even the lowest Indian NOx norm of 100 mg/Nm3 is twice the world’s strictest norms of 50 mg/Nm3 set by China for its coal power plants. All of these countries are meeting their NOx norms using the same technologies rejected by NTPC, experts told IndiaSpend.

Documents that IndiaSpend has accessed show that ever since the declaration of new norms, the power industry has made multiple efforts to get the norms diluted – pleading lack of money or unavailability of technology. However, several studies – here and here – have proven that a range of technologies exist that enable Indian power plants to meet the prescribed norms. Installing NOx cutting technologies to achieve standards will cost Indian thermal plants between Rs 12,233 crore and Rs 15,430 crore, a much lower cost than the health benefits of cutting this pollutant, studies have shown.

NOx is a toxic gas that can cause respiratory infections and sicken or kill people after it takes the form of PM 2.5 – airborne particles 30 times finer than a human hair that enter the lungs. Power plants are one of the chief polluters of India’s air. Their emissions have been linked to 83,000 deaths annually in India. This number could go up to 186,500 to 229,500 deaths per year by 2030, by when India’s total coal power capacity is expected to more than double to 450 GW from the current 197 GW. The move to dilute the standards comes after the government of India has already shifted the implementation deadline for NOx norms in power plants by five years to 2022, after they missed their original deadline of December 2017 to meet the new standards. Even after the delay, over half the capacity of India’s coal power plants are expected to miss the deadline of capping their emissions.

The pilot tests

The NTPC pilot included two technologies: Selective Catalytic Reduction or SCR and Selective Non-catalytic Reduction or SNCR. These methods have been employed globally for more than 40 years to reduce NOx emissions by using ammonia or urea to break NOx into nitrogen and water.
Called secondary methods, they cut NOx from the smoke duct, known as the flue, post combustion. The cost of installing SNCR is about Rs 2 lakh per megawatt, while for SCR, it is about Rs 10 lakh-Rs 15 lakh per MW.

Cheaper primary methods which reduce the production of NOx during combustion also exist. These methods include combustion modification through installing low-NOx burners, which reduce NOx by 30%-50%, and Over Fire Air Burners, which reduce NOx by 20%-45%. Combustion modifications cost about Rs 2 lakh per MW.

A power plant would have to use both the primary and secondary methods to lower emissions.
Indian power plants are considering primary modifications to meet the lenient standard of 600 mg/Nm3 for plants that are older than 2003, known as vintage, and constitute 60 GW or 30% of India’s total installed capacity. The SNCR and SCR technologies were being considered for plants that have to achieve the new stricter targets of 300 mg/Nm3 and 100 mg/Nm3.
In 2017, the Government of India said that these two technologies were not tested for India’s coal, which has a high amount of ash. The same year, NTPC set out to test these technologies in pilots at some of its units, our reporting showed.