Every energy sector has different needs and operational characteristics, so selecting coal based on price alone is not sufficient. The type and quality of coal used need to be adjusted to the system requirements so that the combustion process can run optimally.
One important thing to also understand is that selecting the wrong type of coal can affect process efficiency, operational costs, system reliability, and equipment lifespan. For this reason, understanding the characteristics of each type of coal is important before determining the right fuel for industrial needs.
What Are the Types of Coal?
Coal is classified based on coal rank or its level of maturity, ranging from lignite, sub-bituminous, and bituminous through to anthracite.
In general, the higher the coal rank, the higher its calorific value and carbon content, while moisture content tends to decrease. These differences in characteristics affect combustion properties and suitability for various energy needs.
Table of coal types and their characteristics.
| Coal Type | Calorific Value | Moisture Content | Key Characteristics |
| Lignite | 6,300–8,300 Btu/lb | ±45% | Lowest rank, low calorific value, and high moisture content |
| Sub-bituminous | 8,300–11,500 Btu/lb | 20–30% | Higher calorific value than lignite and widely used for power generation |
| Bituminous | 10,500–14,000+ Btu/lb | <20% | High calorific value and available in various grades |
| Anthracite | >14,000 Btu/lb | <15% | Highest rank, high carbon content, and low volatile matter |
A higher coal rank does not necessarily mean it is more suitable for all energy needs. Lignite has a lower calorific value and higher moisture content, while bituminous and anthracite have higher calorific values.
However, coal selection still needs to be adjusted to the boiler or combustion system design, energy needs, efficiency targets, and the fuel characteristics that the system can accept.
As such, calorific value is not the only basis for determining the right coal. Characteristics such as moisture content, volatile matter, ash, and sulfur also need to be considered because they can affect the combustion process and equipment performance.
Read More: How Much Does Fuel Choice Impact Boiler Efficiency?
How Do Coal Characteristics Affect Energy System Performance?
Coal characteristics have a direct effect on the efficiency and combustion process inside a boiler.
Calorific value determines the thermal energy that can be generated, so coal with a higher calorific value generally requires less fuel to produce the same amount of energy.
Conversely, high moisture content means a greater fuel requirement because some of the heat from combustion is used not only to generate energy for the boiler, but also to heat and evaporate the water contained in the coal.
As a result, the higher the moisture content, the greater the heat loss and the lower the combustion efficiency. High ash content can also cause slagging and fouling, which inhibit heat transfer and increase boiler cleaning requirements.
Other characteristics such as sulfur content also affect operations because sulfur combustion produces SO2 that needs to be controlled to meet emission standards. For this reason, coal selection needs to be adjusted to the energy system specifications so that equipment performance remains stable and operational costs can be controlled.
Read More: The Ideal Fuel for Ferry Vessels in the Age of Emission Regulations
Which Type of Coal Is Suitable for Various Energy Sectors?
Every energy sector has different operational needs, from energy capacity and boiler or furnace design to process characteristics and efficiency targets. For this reason, the type of coal used can differ even when it serves the same function as an energy source.
Below are some types of coal commonly used in several industrial sectors.
| Energy Sector | Commonly Used Coal Types | Reasons for Selection |
| Coal-Fired Power Plants | Sub-bituminous, Bituminous |
|
| Industrial Boilers | Sub-bituminous, Bituminous |
|
| Cement Industry | Bituminous |
|
| Smelters & Metal Processing Industries | Bituminous, Anthracite |
|
| Mine-Mouth Power Plants | Lignite |
|
The type of coal used can differ between companies because it is influenced by equipment design, process specifications, coal quality, emission regulations, supply availability, and operational costs.
For this reason, coal with a higher calorific value is not necessarily the best choice if its characteristics do not match the boiler, furnace, or production process being used. Conversely, coal with a lower calorific value can remain an economical choice if it matches the equipment design and is available from a nearby source.
Read More: Fuel for Captive Power Plants
What Factors Need to Be Considered When Choosing a Type of Coal?
The selection of coal type needs to be adjusted to process requirements and equipment specifications. Calorific value, moisture content, ash content, and sulfur need to be considered because they can affect combustion efficiency, emission control requirements, and ash handling costs.
Coal must also be compatible with the characteristics of the boiler or furnace so that combustion can proceed stably and equipment can operate optimally.
Beyond technical characteristics, companies need to consider supply reliability and consistency as well as the total cost of use. The purchase price per ton does not always reflect the actual cost because fuel consumption, logistics, maintenance, ash management, and emission control requirements all contribute to operational costs.
For this reason, companies need to evaluate coal based on total operating cost and its suitability for long-term needs.
These considerations are also pushing companies to start evaluating energy source diversification. One option that can be considered is LNG, which has different combustion characteristics and advantages compared to coal.
Read More: Why Industries Are Being Pushed to Ditch LPG and Switch to CNG?
Why Is LNG Becoming a Fuel Choice for Industry?
LNG (Liquefied Natural Gas) is becoming one of the fuel choices for industry because it is capable of providing reliable energy with cleaner combustion compared to coal.
LNG combustion produces lower CO2 emissions compared to coal, and generates very little SOx and particulates because it does not produce combustion ash. These characteristics help industries meet their energy needs while supporting emission reduction efforts and compliance with environmental standards.
LNG has also been used across various industrial sectors, including as fuel for boilers and processes that require thermal energy. Its application can be tailored to the energy needs, process characteristics, and infrastructure of each facility.
To support this implementation, companies need to choose an LNG supply scheme that matches their operational needs and facility location. For this reason, PGN LNG Indonesia is present to provide LNG to support industrial energy needs while also encouraging emission reduction efforts.
What energy solutions do we provide for your industry? Find out more here: LNG Partner Provider in Indonesia.
References
- USGS. Accessed 2026. What are the types of coal?
- USGS. Accessed 2026. Coal Resource Classification System of the U.S. Geological Survey
- ScienceDirect. Accessed 2026. Coal Rank
- EIA. Accessed 2026. Coal explained
