Coal 101

Summary

Coal is a combustible rock primarily composed of carbon, formed millions of years ago from plant material in swamps. It is classified into four main types based on carbon and heat content: lignite, sub-bituminous, bituminous, and anthracite. Coal can be extracted through underground or surface mining, with underground mining currently dominating global production. It serves as a key energy resource, providing 40% of the world's electricity. However, coal has significant environmental and health impacts, including CO2 emissions, sulfur and nitrogen pollutants, and health risks from particulates. Clean coal technologies are being developed to address these concerns.

Takeaways

• 😀 Coal is a combustible rock primarily made of carbon, formed millions of years ago from decayed plant matter.
• 😀 The four main types of coal are lignite, sub-bituminous, bituminous, and anthracite, classified by their carbon and heat content.
• 😀 Higher-grade coal burns cleaner and is more versatile in use, making it a more efficient energy source.
• 😀 Coal is extracted through underground mining or surface mining, with underground mining currently accounting for a larger share of global production.
• 😀 Coal is commonly used for electricity generation by converting thermal energy into steam to power turbines and generators.
• 😀 Coal is also a raw material for industries, such as being converted into coke for steelmaking and processed into liquid fuels and synthetic gases.
• 😀 Despite being abundant and inexpensive, coal is the most CO2-intensive fossil fuel and contributes significantly to climate change.
• 😀 Coal combustion also releases harmful pollutants like sulfur, nitrogen, mercury, and heavy metals, causing air pollution and acid rain.
• 😀 Particulates from coal combustion pose health risks, and mining practices raise concerns about worker safety and environmental impacts.
• 😀 The development of clean coal technologies, such as carbon capture and storage (CCS), aims to reduce coal's environmental impact, though these technologies are costly.

Q & A

What is coal primarily made of?

Coal is primarily made of carbon, with other elements such as sulfur, nitrogen, and mercury also present.

How was coal formed?

Coal was formed millions of years ago when plants and trees died and fell into swamps. The swamp conditions prevented the organisms from decaying completely, and over millions of years of heat and pressure, coal was formed.

What are the four main types or ranks of coal?

The four main types or ranks of coal are lignite, sub-bituminous, bituminous, and anthracite. These are classified based on their carbon content and heat generation capacity.

What determines the method of coal mining?

The method of coal mining—underground or surface mining—is largely determined by the geology of the coal deposit and its distance from the surface.

What is the difference between underground mining and surface mining?

Underground mining involves extracting coal from below the surface, while surface mining removes coal from areas near the Earth's surface. Currently, underground mining accounts for a larger share of global coal production.

How is coal used to generate electricity?

Coal is milled into a fine powder to increase its surface area, which allows it to burn more quickly. The heat produced from combustion is used to convert water into steam, which drives a turbine and generates electricity.

What are some other uses of high-quality coal?

High-quality coal can be converted to coke for steelmaking, and it can also be transformed into liquid fuels or synthetic gas, though this is costly.

Why is coal considered a highly abundant and cheap energy resource?

Coal is abundant and cheap because it is widely distributed and can be easily mined, making it a reliable source of energy for many nations.

What are the main environmental concerns associated with coal?

The main concerns include ecological impacts, human safety issues for workers and surrounding communities, and coal’s role in producing greenhouse gas emissions, particularly CO2, which contributes to climate change.

What is 'clean coal' technology?

'Clean coal' refers to technologies that aim to reduce the environmental impact of coal, such as carbon capture and storage, which helps to reduce CO2 emissions from coal combustion.