Coal has been a sought-after source of energy for centuries. It was used not only in homes, but also in coal-fired power plants to generate electricity. The mining and use of brown coal formed an important part of the Slovak economy. Now the situation is changing. Although some countries returned to the use of coal in 2022, in Slovakia it is becoming a thing of the past.
Coal, an energy source that played a major role in the Industrial Revolution and the boom of industry in the 20th century, is dying, especially in Europe.
The reason is simple – the negative impacts of using coal as an energy source far outweigh its benefits in the long term. When coal is burned, toxic fumes are released into the air, which suffocate and kill the planet.
That's why 196 countries on the climate at the UN conference in Glasgow (November 2021) agreed on a gradual shift away from coal. At that time, Slovakia committed to ending coal-fired electricity generation by 2023.
Why is coal dirty?
Coal is non-renewable, fossil energy sourceIt is a brown to black combustible rock with a banded structure that was formed from dead plants and animals under the influence of time, pressure, and temperature.
The remains of living organisms deposited in water did not decompose (rot), but turned into coal due to the minimal, almost zero amount of oxygen (anaerobic environment).
The deeper and longer the peat (the first stage of carbonization) was without access to oxygen and under pressure, the greater part of the volume of the matter changed from organic to inorganic with an increasingly higher proportion of carbon (from 60 to 90%), until it turned into graphite, i.e. pure carbon.
Brown coal (lignin) has less energy use than "older" black coal (anthracite).
Burning coal produces carbon dioxide, sulfur dioxide, and nitrogen oxides. Sulfur dioxide reacts with water vapor in the atmosphere to form sulfurous acid (acid rain).
Coal can also contain other toxic substances such as arsenic, mercury, and uranium. Although these elements are only present in trace amounts, the levels of radiation around some coal-fired power plants (such as in China) are higher than around nuclear power plants.
Coal mining also has negative environmental consequences.
Source of heat and light
Coal can be used in ways other than combustion through chemical reactions. In the past, coal was used to produce natural gas, which was piped into homes for lighting, heating, and cooking. Later, natural gas, produced by gasification of coal, was replaced by natural gas.
In times of crisis with resource shortages (such as during World War II), coal was liquefied and used to produce diesel, gasoline, and ethanol.
By removing volatile components, coke is produced from coal - an energy-efficient fuel. Coal powder pressed into small balls or cylinders is called eco-peas. It is also a fuel used in pellet boilers. It has a higher calorific value than conventional coal, but also a high proportion of water, sulfur and ash, which makes it an unecological fuel.
Coal in Slovakia
For decades, coal has been the primary fuel used in thermal power plants to generate electricity, accounting for the majority (40%) of global electricity production.
Several countries that had intended to end coal as an energy source returned to its extraction and use during 2022 due to the energy crisis and natural gas shortage.
This is no longer possible in Slovakia. The end of coal mining in the Hornonitrianske mines is in the final phase. Mining is only being carried out in the Nováky and Čáry mines.
There are still plenty of brown coal reserves in Slovakia. The Nováky mine should have enough to mine for ten years (6 to 9 million tons of coal reserves) and the Gbely deposit should have 26 million tons of coal.
In addition to being unecological, generating electricity from coal is also uneconomical in Slovakia. Consumers (all of us) pay approximately 120 million euros annually for the burning of lignite (brown coal) at the Nováky Power Plant.
The end of coal-fired power plants
Subsidies for electricity production from coal mined in our country will end in 2023. Electricity production from this source will also end in two coal-fired power plants in Vojany and Nováky.
In Vojany in eastern Slovakia, they plan to use solid secondary fuel to produce electricity. The power plant in Nováky is technologically outdated, and since the announcement of the end of subsidies, no significant funds have been invested in its reconstruction to extend its lifespan beyond 2023, so its future use is questionable.
Of course, many Slovak households still use coal for heating, and will continue to do so. Although it can be assumed that they will gradually use other types of solid fuel.
The main reason is the price of coal, which has soared to dizzying heights in 2022. Never before in history has coal been more expensive than wood or wood briquettes. Furthermore, they have a higher calorific value and lower ash content than coal, which means they are more efficient for heating.
These economic reasons may thus convince end users to switch to a different, more environmentally friendly fuel than coal.
Coal substitutes
Finding another source of electricity generation instead of coal will certainly be more difficult than switching from coal to another fuel source in households.
"Replacing coal as a cheap energy source will not be easy. Green sources do not have the same parameters as we are used to with coal," stated Vladimír Lásik from PPA CONTROLL.
Biomass appears to be a realistic replacement, specifically the burning of dendromass, i.e. biofuels from wood waste, and the burning of treated municipal waste, which is to take place at the Vojany Power Plant.
"Our experience confirms our belief that waste incineration in modern incinerators is an effective and ecological solution. Instead of accumulating in landfills and polluting the air and water, waste can be used to generate heat and electricity," continues V. Lasik.
The loss of electricity generated in Slovakia in coal-fired power plants should be replaced by energy from testicles, i.e. the electricity produced in the third unit of the Mochovce Nuclear Power Plant.
The current energy crisis is complicating the transition from coal to other, greener energy sources. The ambitious plan to achieve carbon neutrality in Europe by 2050 will be even more expensive than previously thought.
Nevertheless, it makes sense to replace coal – a fossil fuel with exhaustible resources – with other sources. The current state of the energy sector also suggests that the ideal path is an energy mix consisting of nuclear, wind, solar, water, geothermal, dendromass and sorted waste.
However, it will not be enough to stop global warming if it happens in the European Union countries. The biggest air polluters such as China, but also many other Asian and African countries, are not yet interested in limiting the use of coal for energy purposes. Economic interests still outweigh environmental ones.
However, the longer the transition from non-renewable to renewable sources is delayed, the more expensive it will ultimately be.
