Originally published in http://indiatogether.org/emission-standards-for-coal-based-thermal-power-plants-environment
The draft notification specifying emission standards for coal-based thermal power plants is a welcome first step towards regulation, but needs much greater attention to detail and further calibration, writes Debadityo Sinha.
The 1500 operating hours per year translates into 62 days per year.
Compare this with similar standards in India which is densely populated
and most of the older thermal power plants are located in concentrated
pockets, operating 24x7 for 365 days.
India's Sulphur Dioxide Emission Map, 2011-12 . Pic: NASA
The draft notification specifying emission standards for coal-based thermal power plants is a welcome first step towards regulation, but needs much greater attention to detail and further calibration, writes Debadityo Sinha.
02 July 2015 - On 15 May 2015, the Government of India came out with a draft notification
on emission standards for coal based thermal power plants, opening it
up for public comments. Till the time, there had been no specific
emission standards for thermal power plants, except in respect of
Particulate Matters which was also very high when compared to global
standards.
There has been a series of publications in recent years by civil society groups like Greenpeace, Urban Emissions, Centre for Science and Environment
on thermal power plants which have made headlines in India. Some of
the country’s premier engineering institutes have also came out with an
extensive review on atmospheric pollution from coal based thermal power
plants in India, such as this from the Indian Institute of Technology, New Delhi in May 2014.
A simple Google search on the health
impact of thermal power plants in India will yield millions of results. A
recent scientific publication in a highly rated open source journal PNAS
showed how the per- hectare yield of rice and wheat have decreased over
the last decade owing to the increasing concentration of aerosols
produced as secondary pollution from thermal power plants. The problem
was grave and pressure from civil society as well as attention from
research institutes made it imperative for the Government of India to
come out with the first ever draft notification on specific emission
standards for coal-based thermal power plant.
The Centre for Science and Environment
which recently published the green ratings of thermal power plants in
India has welcomed the move of the Government and expressed satisfaction
with the new norms proposed. “We believe these lower standards are
acceptable given technical and economic limitations in installing
pollution control equipment in older units” said Priyavrat Bhati, CSE’s
Director for Green Ratings Project through the official press release.
The Narendra Modi-led government has been much criticised for diluting the environmental law
of the country in order to accelerate industrialisation and the
compliments for the draft standards make one curious to explore if it is
indeed going to be effective in reducing emissions and providing
cleaner air.
Standards Proposed by Government of India: in mg/Nm3(Milligram per Normal Cubic Meter)
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|||||
Pollutants
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Before December 31, 2003
shall meet limits within 2 years from date of notification
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After 2003 to 2006
shall meet limits within 2 years from date of notification
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From January, 2017
all units which have been accorded environmental clearance and are under construction
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||
<500 mw="" span="">
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≥500 MW
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<500 mw="" span="">
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≥500 MW
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||
PM
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100
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50
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30
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||
SO2
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600
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200
|
-
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200
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100
|
NOx
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600
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300
|
100
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||
Hg
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-
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0.03
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0.03
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0.03
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|
Will it really help?
It is admissibly difficult to understand
the concept behind selection of categories. The older units should be
classified based on the years of operation, which the proposed standards
do not mention in the categorisation.
Secondly, the category ‘After 2003 to
2006’ creates a lot of confusion, especially when the third category is
meant for units which are predicted to be operational from 2017. Does
that mean that there will be no standards for the units commissioned
between 2006 and 2017?
As per latest data
from Government of India, the total power generation in India till
April 2015 stood at 272687.17 MW, out of which 165235.88 MW came from
coal-based thermal power plants. The government’s thrust on quick clearances to projects and minimum hurdles for developmental projects makes it imperative that the strictest standards be notified without any further delay.
The draft notification is also silent on
the criteria for measurements of 24-hour average, yearly average and
calculations of temperature, pressure, correction of water vapour
content of waste gases and O2 content. All of these are very important
in specifying standards of emission.
Now let’s come to the standards
themselves. The emission standards laid down for thermal power plants
for existing and older thermal power plants are much more relaxed –
allowing for up to six times higher counts in cases of SOx (Sulphur
Oxides) and NOx (Nitrogen Oxides). Even if we go by the standards
followed in European Union which themselves are termed to be one of the
most relaxed, the Indian standard seems to be considerably more lax.
The European Union (Large Combustion
Plants) Regulations 2012 classifies thermal power units into Schedule I
(units before January, 2016) and Schedule II (later January 2016). For
the older units which were in operation before 2003, the emission
standards are relaxed up to 800 mg/Nm3 for SOx and 450 for NOx, but
with an additional condition that they do not operate more than 1,500
operating hours per year as a rolling average over a period of five
years.
India's Sulphur Dioxide Emission Map, 2011-12 . Pic: NASA
Standards of mercury: Just an eyewash!
Mercury is a deadly toxic heavy metal and it is present in coal in minor amounts. A government document
indicates that Indian coal ash has an average mercury concentration of
0.53 mg/kg, based on measurements from a few selected power plants.
Recent studies have shown how mercury from coal power plants has entered into the bloodstream of local people in India.
The proposed emission standard of 0.03 mg/Nm3 is far more than what the thermal power plants are emitting. The emissions calculated
in some thermal power plants by the Central Institute of Mining &
Fuel Research (a government funded institute) in 2014 ranged between
0.00424 mg/Nm3to 0.0148 mg/Nm3 in fact.
Also, there are no standards prescribed
for older units (before December 2003) of less than 500 MW capacity,
while the most dangerous mercury emitting thermal power plants were
built prior to 2004.
“The proposed standard (of 30ug/Nm3 ; 1 ug = 1/1000 mg) allows new
coal-fired power plants in India to emit nearly 75 times as much mercury
as applying the U S standard,” said coal activist Lauri Myllyvirta
of Greenpeace East Asia. The emission standards prescribed by the U.S.
Environmental Protection Agency are 0.003 lb/GWh (pounds per Giga Watt
Hour) which translates into 0.00041 mg/ Nm3.
Bird's
view of Vindhyachal Thermal Power Plant of National Thermal Power
Corporation, adjoining the Rihand Dam. The area surrounding Rihand dam
is also known as "Mianmata of India" for the high level of mercury
contamination. Pic: Google Earth
Water Consumption Limits
In terms of water consumption, the draft notification lays down the following standards:
- All plants with once through cooling (OTC) shall install a cooling tower (CT) and achieve specific water consumption up to a maximum of 4m3/MWh (cubic meter per Mega Watt Hour) within 2 years period from the date of notification.
- All existing CT-based plants shall reduce specific water consumption up to maximum of 3.5 m3/MWh within 2 years period from date of notification.
- New plants to be installed after January 01, 2017 shall restrict specific water consumption up to a maximum of 2.5 m3/MWh and achieve zero liquid discharge.
India is already a water-stressed
country with one of the highest growing populations. Experts have warned
that by 2025 India’s water demand may surpass supply and in the coming
decades, the nation may well become ‘water scarce’. Many of the thermal
power plants are located in water scarce regions and cooling towers
based on dry air cooling are a must.
This figure of 4 m3/MWh laid down for
plants with OTC is actually the current average specific water
consumption by the thermal power plants today. In its report
published in February (2014), the CSE had criticised thermal power
plants for consuming water at an average of 4m3/MWh which is double the
permissible limits for global counterparts in China (2.5 m3/MWh) and the
US (2 m3/MWh). In the new standards, it was expected that water
consumption limits would be reduced to 2 m3/MWh.
This as well as the guidance value of
3.5 m3/MWh for existing CT-based plants are in conflict with the
Central Electricity Authority’s (CEA) guidelines which suggest 3.0
m3/MWh for all thermal power plants with wet cooling towers. The only
relaxation as per the CEA guideline is 3.6 m3/MWh for the units which
are in their first year of operation and which use fly ash disposal in
wet slurry mode.
The strictest standard of water
consumption of 2.5 m3/MWh is to be followed only in units from January
2017, which will not make any major difference to existing scenario.
Implications for climate
Carbon dioxide emission is now a global
threat due to its impact on climate which is linked to a nation’s growth
and development as well. The CSE claims
that the average emission rate of plants was 1.08 tons CO2/MWh, which
is seven per cent higher than the global average and 14 per cent higher
than China’s.
Low efficiency of plants is directly
related to high CO2 emissions. Most of the existing thermal power plants
are based on sub-critical technology, performing at efficiencies below
33 percent. As per the report ‘The Future of Coal’
by Massachusetts Institute of Technology, the thermal efficiencies of
power plants can be increased up to 38.5 percent with supercritical
technology and more than 43 percent with ultra-supercritical
technology.
Raichur Coal based Thermal Power Plant. Pic: Tanzeel Ahad
According to a report by McKinsey
in January 2014, India’s energy demand, which was nearly 700 million
tons of oil equivalent (mtoe) in 2010, is expected to cross 1500 mtoe by
2030. Its dependence on imports is expected to increase from 30 per
cent to over 50 per cent, suggesting the need for a new way forward. In
the 2030 BAU scenario, 60 per cent of India’s power generation is
assumed to come from coal, taking coal demand up to 750 mtoe.
The draft notification surprisingly is completely silent on CO2 emission limits.
Are the proposed standards comprehensive enough?
The standards missed out specifications
on several important air emissions like Lead, Selenium, Arsenic,
Beryllium, Cadmium, Chromium, Cobalt, Lead, Manganese, Acid Gases
(Hydrogen Chloride and Hydrogen Fluoride), PAHs (Polycyclic Aromatic
Hydrocarbons) and VOCs (Volatile Organic Compounds), Dioxins and Furans.
All of these are hazardous air
pollutants emitted by coal-based power plants and are known for their
adverse impacts both on our health and the ecology.
Greater emphasis was also due on the
toxic metals such as Mercury, Cadmium, Hexavalent Chromium, Nickel,
Selenium, and other chemicals like Ammonia, Fluoride, Phenols,
Phosphorus, Sulfide, Coliform bacteria in the liquid discharge.
Pre-existing rules allow the inland
thermal power plants to discharge water at temperatures that are 10
degrees Centigrade higher than that of the receiving water body. The
World Bank guidelines suggest a maximum temperature change of 3 degrees
for thermal power plants but the proposed standards ignore this aspect
as also that of radioactivity.
It is also
noticeable that the emission standards prescribed are rather generic in
nature and may not be effective in overall reduction of pollution in
power generation hubs near coal mines where large amounts of coal are
burnt. For example, one 660-MW plant with emission at 100 mg/Nm3 may
sound quite good, but what if there are a number of thermal power plants
with cumulative capacity of thousands of megawatts?
In the final analysis, therefore, the
draft notification on emission standards is a welcome step in that it
broaches this very critical subject, but the content needs improvement
and reconsideration if it is to address the actual challenges
adequately.
Equally important would be strict
regulation by monitoring agencies since the objective of such
notification will be defeated unless there is complete compliance by the
companies. For some emissions in particular, the implementation of
technologies must be prioritized if the targeted reductions are to be
achieved. For instance, significant reduction in SO2 and heavy metals
will never be possible unless there is a clear mandate for installation
of Flue Gas Desulphurization Units. Till transparent and independent
monitoring is practised, real change may not come about.
Readings/Reference
The original representation made to Government of India on the Draft Notification.
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