MITIGATING EMISSIONS from Coal-based Power Plants

In India around 60% of electricity is generated from fossil fuels. Out of that coal-based thermal power plants have a share of almost 52%. The obvious result is tremendous increase in pollution that leads to several diseases and death. Consequently, the Government of India has set to achieve 450 GW of renewable energy installed capacity by 2030. Till then other measures have been in force… - P. K. Chatterjee (PK)

The World Health Organization (WHO) has recently pointed out that – “Ambient (outdoor) air pollution in both cities and rural areas was estimated to cause 4.2 million premature deaths worldwide per year in 2016; this mortality is due to exposure to fine particulate matters of 2.5 microns or less in diameter (PM2.5), which cause cardiovascular and respiratory disease, and cancers. People living in low- and middle-income countries disproportionately experience the burden of outdoor air pollution with 91% (of the 4.2 million premature deaths) occurring in low- and middle-income countries, and the greatest burden in the WHO South-East Asia and Western Pacific regions. The latest burden estimates reflect the very significant role air pollution plays in cardiovascular illness and death. More and more, evidence demonstrating the linkages between ambient air pollution and the cardiovascular disease risk is becoming available, including studies from highly polluted areas,” –  there cannot be  a second thought on the fact that today measuring, and arresting PM2.5 and mitigating its ill effects on human bodies is a matter of global concern.

WHO estimates that in 2016, some 58% of outdoor air pollution-related premature deaths were due to ischaemic heart disease and stroke, while 18% of deaths were due to chronic obstructive pulmonary disease and acute lower respiratory infections respectively, and 6% of deaths were due to lung cancer.

With this backdrop, at present, we cannot expect a dramatic change overnight, however, action at a highly accelerated pace could be taken to eliminate the root causes behind spread of these highly dangerous particles. This has not happened in one day. As the harmful trend was realised much earlier, ultimately the Paris Agreement (COP 21) in 2015 came into force. It was an international treaty through legal binding, which was adopted by 196 Parties at COP 21 in Paris, on December 12, 2015 and entered into force on November 4, 2016.

Air quality and climate change

It often stands as a query to many of us what the relation really is between air quality and climate change. EPA (United States Environmental Protection Agency) has very simply put it as: “Climate change can impact air quality and, conversely, air quality can impact climate change.”

What does that mean? EPA only gives the answer too. It states, “Changes in climate can result in impacts to local air quality. Atmospheric warming associated with climate change has the potential to increase ground-level ozone in many regions, which may present challenges for compliance with the ozone standards in the future. The impact of climate change on other air pollutants, such as Particulate Matter (PM), is less certain, but research is underway to address these uncertainties.

Emissions of pollutants into the air can result in changes to the climate. Ozone in the atmosphere warms the climate, while different components of Particulate Matter (PM) can have either warming or cooling effects on the climate. For example, black carbon, a particulate pollutant from combustion, contributes to the warming of the earth, while particulate sulfates cool the earth’s atmosphere.”

Goals of Paris Agreement

Its goal is to limit global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre-industrial levels.

To achieve this long-term temperature goal, countries aim to reach global peaking of greenhouse gas emissions as soon as possible to achieve a climate neutral world by mid-century.

The Paris Agreement is a landmark in the multilateral climate change process, because, for the first time, a binding agreement brings all nations into a common cause to undertake ambitious efforts to combat climate change and adapt to its effects.

Researchers at work

As per EPA, considering the present situation, researchers across the globe are all focusing on works related to:

  • Developing methods to apply possible global-scale changes in air temperature and precipitation patterns to local-scale conditions that affect
    air quality.
  • Understanding the influence of climate change on fine particulate matter and other air pollutions.
  • Identifying co-benefits of reducing air pollutants that also reduce the impacts of climate change.
  • Understanding how mitigation options to reduce carbon dioxide, a greenhouse gas, can affect emissions of particulate matter, ozone, precursors and other air pollutants.

Effect of the steps taken so far

A recent survey report from UNEP (United Nations Environment Program) and IVL Swedish Environmental Research Institute states that efforts to tackle air pollution have stepped up in recent years and are bringing dividends in many European countries, but extreme hotspots remain in Central Asia and the Balkans. Dangerous air quality levels continue to be recorded throughout Europe and Central Asia, and ammonia emissions are rising in all sub-regions.

It also states that “Air pollution is the world’s biggest environmental killer, responsible for around seven million premature deaths each year through diseases such as lung cancer, acute respiratory infections and heart disease. Meanwhile, the main sources of air pollution and greenhouse gases are often the same. Most actions to improve air quality also therefore help to fight climate change”.

Between 2010 and 2017, emissions of most monitored air pollutants decreased in Western, Central, Eastern and South Eastern Europe, the study finds.

For example, in Western and Central Europe, emissions linked to electricity, heat production and industry – a major source of air pollution – were found to have fallen by up to 20% in some countries. This is due to a greater uptake of renewable energy, improvements in energy efficiency and the use of environmental impact assessments.

Road transport emissions in Western and Central Europe were found to have fallen by 20-30% over the same period, partly due to enhanced efforts on vehicle inspections and the promotion of electric mobility. Meanwhile, stricter vehicle standards saw traffic emissions in South Eastern Europe plummet by 40%.

In Western and Central Europe, emissions linked to residential heating dropped by roughly 15%, thanks to an increased focus on energy efficiency and green technologies. Thirty-eight European countries now also ban the open burning of waste, up from 32
in 2016.

Such actions are being shown to benefit people’s health. For example, in 2018, around 417,000 people are estimated to have died prematurely in the European Union due to exposure to fine particles (directly emitted as particles or formed from gaseous pollutants in the atmosphere, PM2.5), which affects more people than any other air pollutant. By 2020, this figure had dropped to 240,000, and by 2030 the toll is expected to fall to 170,000.

However, PM2.5 levels still exceed World Health Organization guidelines at 70% of the stations located in all countries surveyed, the report underlines. Furthermore, unlike for much of Europe, emissions are found to be on the rise in Central Asian countries. For example, PM2.5 emissions increased by 21% between 2010 and 2017 in Kazakhstan, while carbon monoxide emissions in the country jumped 34%, and road traffic emissions rose by 20%.

Meanwhile, emissions of ammonia increased across Europe and Central Asia during 2010-2017, with the biggest increase recorded in South Eastern Europe. Once emitted, almost entirely from farming, much of the ammonia forms into PM2.5 and can cause respiratory diseases. The rise in emissions occurred despite 75% of countries promoting sustainable agricultural practices.

Pollutants from power plants

As per EIA (US Energy Information Administration), in the United States, about 65% of total electricity generation in 2018 was produced from fossil fuels (coal, natural gas, and petroleum), materials that come from plants (biomass), and municipal and industrial wastes. The substances that occur in combustion gases when these fuels are burned include:

  • Carbon dioxide (CO2)
  • Carbon monoxide (CO)
  • Sulfur dioxide (SO2)
  • Nitrogen oxides (NOx)
  • Particulate matter (PM)
  • Heavy metals such as mercury

Nearly all combustion by-products have negative effects on the environment and human health:

  • CO2 is a greenhouse gas, which contributes to the greenhouse effect.
  • SO2 causes acid rain, which is harmful to plants and to animals that live in water. It also worsens respiratory illnesses and heart diseases, particularly in children and the elderly.
  • NOx contribute to ground-level ozone, which irritates and damages the lungs.
  • PM results in hazy conditions in cities and scenic areas and coupled with ozone, contributes to asthma and chronic bronchitis, especially in children and the elderly. Very small or fine PM, is also believed to cause emphysema and lung cancer.
  • Heavy metals such as mercury are hazardous to human and animal health.

Mitigation measures taken in Indian thermal power segment

We must be proud of our progress in harnessing Renewable Energy (RE), the total installed renewable energy capacity in India, excluding large hydro, has crossed the mile-stone of 100 GW. Today India stands at 4th position in the world in terms of installed RE capacity, 5th in solar and 4th in wind in terms of installed capacity. While 100 GW has been installed, 50 GW is under installation and more are under tendering.

Recently, to fight out the chronic winter smog, India has temporarily shut down five coal-fired power plants around the capital New Delhi, which is one among the world’s most polluted capital cities.  There are other such instances.

In India, supercritical technology has already been adopted for thermal power generation. The design efficiency of supercritical units is about 5% higher than typical 500 MW subcritical units. They have comparatively low fuel consumption and CO2 emissions in ambient air. All future projects (if at all) will have supercritical technology.

By now, we all are aware that the Perform, Achieve, Trade (PAT) scheme was introduced by the National Mission for Enhanced Energy Efficiency. It is a regulatory instrument to reduce specific energy consumption in energy intensive industries, with an associated market-based mechanism to enhance the cost effectiveness through certification of excess energy saving that can be traded. The first cycle of the PAT Scheme (2012-2015) managed to reduce the energy consumption of more than 400 energy-intensive enterprises (known as Designated Consumers -DCs) by 5.3%, above the initial target of 4.1%.

High efficiency Electrostatic Precipitators (ESPs) have been installed to capture Particulate Matters (Fly ash) from Flue gases.

Low NOx burners have been installed for reducing NOx emission from flue gases.

SO2 emission control is achieved through dispersion of flue gases through tall stacks (275 metres) to reduce the concentration of polluting gases at ground level.


By P. K. Chatterjee (PK)

Electrical India needs informative articles from working professionals.

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