Coal affects the environment at every stage: mining, transport, storage and, above all, combustion. Burning coal releases carbon dioxide, sulphur dioxide (SO2), nitrogen oxides (NOx), particulates and mercury. Coal has the highest CO2 emissions per unit of energy of the major fossil fuels. Industrial users cannot remove every impact, but proven technologies and better coal choices cut local pollution sharply.
This guide sets out the main impacts and the practical ways plants reduce them.
The main impacts
| Stage | Impact |
|---|---|
| Mining | Land disturbance, loss of vegetation, water pollution, dust, methane release |
| Transport and storage | Dust from stockpiles, conveyors and loading; runoff from stockpiles |
| Combustion | CO2, SO2, NOx, particulates, mercury |
| Waste | Fly ash and bottom ash that must be stored or reused |
Air pollution
- SO2 comes from sulphur in the coal and causes acid rain and respiratory problems.
- NOx forms during combustion and contributes to smog and acid rain.
- Particulates (fine dust) affect health and visibility.
- Mercury and other trace metals can build up in the environment.
Climate
Burning coal releases more CO2 per unit of energy than oil or natural gas. Coal mining also releases methane, a powerful greenhouse gas.
Water and land
Mining can disturb landscapes and, without proper management, pollute rivers and groundwater. Ash ponds must be managed to prevent leaks.
How industrial users reduce the impact
1. Choose cleaner coal
The simplest step is buying coal with lower sulphur and ash. Many Indonesian coals are naturally low in sulphur and ash, which reduces SO2 and particulate emissions before any equipment is involved. See the benefits of low-sulphur coal.
2. Capture pollutants
| Pollutant | Common control technology |
|---|---|
| Particulates | Electrostatic precipitators or fabric filters (baghouses), which capture the great majority of fly ash |
| SO2 | Flue gas desulphurisation (scrubbers), typically removing most of the SO2 |
| NOx | Low-NOx burners and selective catalytic reduction (SCR) |
| Mercury | Activated carbon injection, plus co-benefits from scrubbers and filters |
3. Burn less coal for the same output
Higher efficiency means less coal per unit of energy, and so lower emissions of every kind. See improving efficiency in coal-fired power plants.
4. Reuse ash
Fly ash can replace part of the cement in concrete, and ash can be used in bricks and road construction, reducing waste and the need for new materials.
5. Control dust in handling
Covered conveyors, water sprays, wind fences and enclosed storage reduce dust at ports and plants.
6. Reduce CO2
Options include efficiency upgrades, co-firing with biomass, and, at a larger scale, carbon capture. Many companies also report their emissions and set reduction targets as part of their wider energy transition.
What buyers can ask suppliers
- Full coal analysis, including sulphur, ash and trace elements
- Information about the mine and its environmental permits
- Independent inspection at loading
- Consistency between cargoes, so emission controls work as designed
See how to assess coal quality.
Buying Indonesian coal through Agromer
Agromer holds mandates for Indonesian thermal coal for power plants and industrial buyers. Send us your specification, including sulphur and ash limits, monthly quantity, contract length and discharge port. We work with an end-buyer LOI, payment by 100% DLC or SBLC, and SGS inspection at loading. See our Indonesian coal supply page.
Frequently asked questions
What is the environmental impact of coal?
Coal mining disturbs land and water. Burning coal releases CO2, SO2, NOx, particulates and mercury, which affect health and the climate.
How can coal pollution be reduced?
By using lower-sulphur, lower-ash coal, installing filters and scrubbers, controlling NOx, improving efficiency and reusing ash.
What does a scrubber do?
A flue gas desulphurisation unit, or scrubber, removes most of the SO2 from the exhaust gases before they leave the chimney.
Why is low-sulphur coal better for the environment?
Less sulphur in the coal means less SO2 formed during combustion, which reduces acid rain and the load on scrubbers.
Is coal worse than natural gas?
For CO2, yes. Coal releases more CO2 per unit of energy than natural gas, and usually more local air pollutants.
What happens to coal ash?
It is stored in managed sites or reused, for example in cement, concrete, bricks and road building.