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Are thermal plants resource inefficient?

Are thermal plants resource inefficient?
In a study which spanned over two years beginning early 2012, non-profit Centre for Science and Environment (CSE) assessed the environmental performance of coal-based power sector—one of the most critical sectors of the Indian economy. The findings, released in February 2015, revealed a grim picture. Coal-fired power sector was found to be one of the most resource wasteful and polluting sectors in the world. Our pollution norms are significantly weaker than other major economies, including China, where the particulate matter (PM) norms are 30mg/Nm3 compared to India’s range of 150-350 mg/Nm3.

What is more worrying is that two-thirds of the power plants failed to comply with even these lenient standards, the study found. One of the reasons could be that the plants could afford to ignore regulatory penalties since electricity is an essential service and shutting down even flagrantly violating plants was not an option.

Power plants consumed 530 million tonnes of coal in 2014-15, which amounts to three-fourths of the total coal used in the country. India’s coal is of poor quality with almost 40 percent ash, which means the plants burn 0.74 Kg/KWh of power generation, which is 41 percent higher than the global average. Poor coal also means more pollution. As a result, coal- based power plants are a significant contributor to total pollutants such as PM, NOX and SO2 in the country.

Domestic power plants were also found to be inefficient in using fresh water. Their average fresh water consumption is around twice that of the US and Chinese plants. Thermal power sector cumulatively withdraws around 22 billion cubic metres (BCM) annually, a significant usage considering that the country’s total domestic needs are estimated at 43 BCM.

Given the pace of growth of coal-based power generation (capacity is expected to reach 260 GW by 2022, up from 170 GW as of September 2015), pollution will worsen if emission regulations are left unchanged. Based on its findings and study of best practices in the sector globally, CSE suggested several policies and regulations—ranging from tighter air pollution standards and efficient technology to developing a policy framework for managing waste products—to improve the sector. The results of CSE’s study and its recommendations spurred a wide public debate and, over the last few months, the government announced a series of draft regulations and policies to help improve the sector’s performance.

New Developments
Air pollution standards: In December 2015, the Ministry of Environment, Forests and Climate Change announced new regulations on air pollution standards that are in line with emission norms of leading economies such as the USA, the EU and China. While the existing standards governed only PM emissions, the new regulations will impose stringent standards for all major pollutants—PM, SO2, NOx and mercury emissions.

Under these regulations, plants installed in and after 2017 would need to meet PM emission standards of 30 mg/Nm3—an 80 percent reduction over the current norms. New plants would also need to install pollution-control equipment such as Flue Gas Desulphurization and low NOx burners to meet the standards. Older plants would need to meet looser standards, based on their age, due to both economic considerations and technical challenge.

Water use: The new norms can have a remarkable reduction in freshwater withdrawal by thermal power plants—cumulative freshwater withdrawal could decrease by 80 percent from around 22 BCM in 2011-12 to around 4.5 BCM in 2016-17. The norms will require all freshwater based once-through-cooling (OTC) system plants to install water-efficient cooling towers that consume up to four cubic metres per watt hour (m3/MWh). Furthermore, existing cooling-tower-based plants will need to restrict water consumption to 3.5 m3/MWh and plants that will be set up after January 2017 have to achieve 2.5 m3/MWh.

Fly ash: Since the utilisation of fly ash from power plants has been far below the 100 percent target that was supposed to be achieved by 2014, the government introduced draft amendments in March 2015 to push fly ash use. The proposed notification mandates construction activities (buildings, roads and flyovers, reclamation and embankments) within 500 km of power plants to use only fly ash. It also requires power plants to provide fly ash for free to construction agencies and to transport it at their own cost up to 100 km for private users and up to 500 km for government projects.

Supercritical technology: The Ministry of Power announced its plans to mandate supercritical technology for Ultra Mega Power Projects (UMPPS) as well power projects during the 13th Five Year Plan period. However, almost 40 GW of the 87 GW capacity under construction is subcritical. The power ministry has also announced plans to shut down around 36 GW of old capacity that is inefficient. 

(The views expressed are strictly those of Centre for Science and Environment)
Priyavrat Bhati

Priyavrat Bhati

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