Coal is the dirtiest source of fossil fuel. When burned it produces emissions that cause global warming, create acid rain and pollute water and farm land. Coal burning produces many pollutants. These are sulphur dioxide, nitrogen oxides, particulate matter (PM), heavy metals and radioisotopes. Pollution from coal – fired power plants lead to numerous respiratory, cardiovascular, and cerebrovascular effects. Coal dust released during coal transport can cause severe and potentially deadly respiratory problems.
Coal combustion waste in USA is the second largest waste stream after municipal solid waste. It is disposed of in landfills or surface impoundments. As rain filters through the toxic ash pits year after year, the toxic metals are leached out into the local environment.
Pollution from particulate matter
The particulate matter emitted from coal plant (PM) has a very grave effect on public health. The main contributor to the particulate matter is coal fly ash, and minor are sulphate and nitrate Coal fly ash is the incombustible materials that is 20% of the collected coal – ash. Particulate matter causes irritation and obstructions on fine airways of the lungs. This leads to asthma and chronic bronchitis. Every four tons of coal burned produce one ton of ash. It is further estimated that one ton of ash can spread over up to 150,000 square km (60,000 square miles). Fly ash can travel up to 40 - 50 km in the down wind direction. It settles down subsequently causing land degradation, severe air and water pollution and diseases in plants and animals, including humans.
Under this coverage area the harmful substances have been detected even in the milk of cows. According to WHO, exposure to PM increases the risk of death from heart disease, respiratory diseases and lung cancer. A study conducted in USA found that the underground dumped ash (produced by coal – fired power plants) has contaminated ground water. The toxic contaminants include Arsenic and lead. Arsenic causes skin, bladder and lung cancer and leads damage to the nervous system. Local aquatic life is also disrupted due to the coal ash life cycle because coal ash also transmits various types of toxic contaminants into the local atmosphere which travels to other sites with air. The carried over coal ash is dropped and dissolved in ponds, lakes and rivers. A research conducted by Stuttgart University estimates that the air pollution caused by coal – fired power plants was responsible for 22,300 premature deaths in the EU in 2010.
Pollution from nitrogen, sulphur oxides
Modern day coal power plants pollute less than older designs due to new technologies that filter the exhaust air in smoke stacks. However emission levels of various pollutants are greater than the emissions from natural gas power plants. Pollution from coal – fired power plants comes from the emission of gases such as nitrogen oxides and sulphur oxides into the atmosphere. These gases react with the atmospheric air to create acidic compounds, which precipitate as rain leading to acid rain.
Pollution from heavy metals
Coal contains many heavy metals. Many of the heavy metals released in the burning of coal are environmentally and biologically toxic elements, such as lead, mercury, cadmium and arsenic, as well as radio isotopes.
A research conducted by University of Stuttgart under commission from Greenpeace found that coal-burnt power plants were the largest source of mercury air emissions in the EU. It is stated that 200,000 babies are born each year in the EU with mercury levels harmful to their mental and neurological development. A 500 MW coal power plant produces 170 pounds of mercury per a year. A teaspoon of mercury added to a 25-acre lake will make the fish in that lake unsafe for consumption. Lead and Cadmium are toxic metals that accumulate in human and animal tissues leading to mental retardation, development disorders and damage to the nervous system.
A 500 MW coal powered plan produces 225 pounds of arsenic per year. In people who drink water which contain 50 parts per billion of arsenic, the chance of developing cancer is 1 in 100.
Radioactivity and coal
Coal contains minor amounts of the radioactive elements, uranium and thorium. When coal is burned, the fly ash contains uranium and thorium “at up to 10 times their original levels.”It has been estimated that concentration of radioactive material is increased from 0.03% to 0.12% annually in the upper 30 cm. layer of soil in a radius of 20 km of coal power plants.
Retirement of coal-power plants
USA has retired 175 coal fired power plants up to 2016. Britain has built 30 gas fired power plants to replace coal powered plants. France only produces 4% of its electricity needs from coal fired plants and even then has closed down 7 coal – fired units. Germany is moving towards renewable energy sources and has announced that the coal power plant opened in 2017 would be the last such plant in Germany.Canadian coal consumption has been reduced to 42% since 2005. The decrease is because Canada is gradually stopping power generation from coal – fired power plants. China is moving away from coal and at present has the highest wind power capacity in the world. China will soon overtake Germany for installed solar power capacity.
"A 500 MW coal power plant produces 170 pounds of mercury per year
Particulate matter emitted from coal plant has grave effects on public health
A ton of fly ash can spread over up to 150,000 sq. km (60,000 sq. miles)
Burning coal contains hazardous biological toxic elements such as lead, mercury, cadmium and arsenic"
Norochcholai power plant
No detailed study of pollution from Norochcholai power plant is available. The silence from Universities and environmental agencies is quite surprising. We know that pollution in Kandy and Colombo and various water bodies are frequently studied and communications are submitted. However a report from an activist about the Norochcholai power plant shows the importance given to environmental protection. He states that the cooling towers ocean intakes have a screen that is intended to stop large fish and shellfish going through the pipe. However, a large quantity of shellfish and large fish are also getting caught and killed. There is a mountain of dead marine life stacked in the ash dump. If we are unable to maintain a filtering screen, there is no point in talking about preventing pollution control.
The future of coal power in SL
There is no future for coal power in Sri Lanka. People who have seen the effects of Norochcolai power plant will not allow a power plant to be established in their areas. If the government tries to impose this project by force, it will lead to riots. The government will be forced to close the project after large financial losses and irreparable political damage.
Author is an Emeritus professor, University of Colombo and past President of SLAAS (2015)