Precipitate

Air pollution and poor power supply can be two sides of the same coin. This is the message of the first environmental audit of electrostatic precipitators installed in thermal power plants to control pollution

 
Last Updated: Saturday 04 July 2015

albeit accidentally, a government department has prepared a review on the performance of electrostatic precipitators ( esp s) installed in thermal power stations to control air pollution, which accidentally became an environmental audit as well. It shows that the suspended particulate matter ( spm ) levels in emissions from a thermal power plants with esp s is very high -- at one plant in Bihar it reached up to 260 times the permissible limit (see table: Electrostatic farce ). Among all pollutant, spm is the biggest killer in Indian cities. High spm levels caused 52,000 premature deaths in 36 Indian cities in 1995, with Delhi recording one premature death every hour due to the pollutant, according to a 1997 study by the Centre for Science and Environment, New Delhi.

Apart from failure to check pollution, the poor performance of esp s lead to technical problems, preventing the plants from performing up to their potential for electricity generation. This is revealed in a 1999-2000 commercial report of the office of the Comptroller and Auditor General ( cag ) of India. Although the report conveys bad news, it is much better than not knowing anything about the success rate of pollution control measures adopted in India.

"It was a financial review. But, by accident, it became an environmental audit," says S Laksminarayan, additional deputy comptroller and auditor general. The cag office prepared the review for all thermal power plants under all the state electricity boards ( seb s). These were then to be presented in the legislative assemblies of the respective states. So far, the reports on seb s of Madhya Pradesh, West Bengal, Bihar, Delhi have been presented in their state legislatures.

Though the attempt is still at an experimental level, Laksminarayan says the environmental aspect should be incorporated in the audit of public sector undertakings in industries like textiles, tanneries and cement. This, he adds, depends on the feedback to the cag report. He says he will recommend that incorporation of an environmental audit should be made into a policy decision. It is common knowledge that poor power generation, apart from causing economic losses, also leads to greater use of diesel power generators in Indian cities, adding to the overwhelming pollution load.

Environmental audit is not a common practice in India, but it is gaining importance with rising concern for healthy, pollution-free environment. The origin of the term 'environmental audit' can be traced back to the mid-1970s, when a few European companies developed audit programmes on their own accord to review and evaluate environmental problems at the operating level.
In India, a March 1992 notification made it compulsory for industrial units to submit an 'environmental audit' report every year under the Environment Protection Act ( epa ), 1986.
Tosses up the losses The cag review covers the performance, maintenance and renovation/replacement of esp s in the thermal power stations between 1994-95 and 1998-99. The esp reduces levels of suspended particulate matter ( spm ) in the gases emitted from the smoke-stacks of coal-fired boilers. In Indian cities, spm is the most harmful pollutant.

The report shows that the spm emission levels in most esp s installed in power plants were much higher than the permissible limit set by the Union ministry of environment and forests of 150 milligramme per cubic nanometre (mg/cunm; nanometre is one-billionth of a metre).

The poor performance of the esp s has not only affected the ecology and the environment adversely but has also resulted in frequent breakdown of induced draft fans, leading to loss of electricity generation potential. This failure resulted in financial losses of more than Rs 121 crore in Bihar and about Rs 15 crore in Delhi in the above-mentioned period. Similarly, there was a loss of over Rs 15 crore in Madhya Pradesh and more than Rs 18 crore in West Bengal.

Electrostatic farce
SPM levels at power plants with ESPs show the mockery of pollution control
Name of the thermal
power station and unit
SPM* levels
in emissions
PERMISSIBLE LIMIT 150
Pataratu unit no 5 (Bihar) 38,963 (1998)
Pataratu unit no 1 (Bihar) 3,235 (1998)
Amarkantak Phase-II unit 4 (MP) 2,700 (1998)
Korba East Phase III unit 5 (MP) 2,648 (1995)
Korba East Phase III unit 6 (MP) 2,625 (1995)
Korba East Phase II unit 3 (MP) 1,508 (1996)
Bandal unit no 5 (WB) 1,085 (1998)
Amarkantak Phase I unit 2 (MP) 920 (1999)
Amarkantak Phase I Unit 1 (MP) 900 (1999)
Indraprastha unit no 5 (Delhi) 811 (1999)
Source: Anon 2000, Review of performance of electrostatic precipitators in thermal power stations, Report no 2 (Commercial) of 1999 and 2000, Comptroller and Auditor General of India, New Delhi
* SPM = suspended particulate matter. All figures in milligramme per cubic nanometre

Subscribe to Weekly Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.