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The Understand Energy Learning Hub is a cross-campus effort of the Precourt Institute for Energy.


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Fast Facts About

Principal Energy Uses: Electricity, Heat
Form of Energy: Chemical

Coal is the most carbon-intensive fossil fuel and a huge contributor to climate change, air pollution, and land disruption. It is a chemically complex, rock-like hydrocarbon that contains heavy metals (e.g., mercury and lead), sulfur, and radioactive material. Coal is mined from the Earth and burned to convert chemical energy to heat.

Mining, producing, and combusting coal all have significant impacts to human health and the environment. Additionally, underground coal mining has higher risk for miners than surface mining. While more widespread use of surface mining and machinery for underground mining have improved worker safety, some countries continue to use underground mining and rely on human labor.

A widely-available but non-renewable resource, coal is still the second-largest source of energy in the world and the most-used fuel for electricity generation. Its usage has been on decline in the US since its peak in 2007, but global coal use has continued to increase, primarily due to high demand in China, India, and Southeast Asian countries.


Energy Mix

27% of world 🌎 (#2 resource)
10% of US 🇺🇸 (#3 resource)

Electricity Generation

35% of world 🌎 (#1 resource)
20% of US 🇺🇸 (#2 resource)

Global Coal Use

Electricity: 68%
Heat: 20%
Steel making: 13%

Change in Global Consumption


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43% of world 🌎
20% of US 🇺🇸
energy GHG emissions are from coal
(includes fugitive emissions)

Energy GHG emissions are ~75% of global GHG emissions.

Coal seams contain methane, which is released when the coal is mined. Coal Mine Methane (CMM) represented more than 10% of total methane emissions from human activity in 2022.

(Visit our Natural Gas page for more information on methane leakage.)

Coal Use is a Major Contributor to Outdoor Air Pollution

Coal combustion emits numerous hazardous air pollutants that impact human health and the environment.

Particulate matter contributes to human health impacts like asthma and respiratory illness. Particulate matter smaller than 2.5 microns (PM2.5) emissions pose the greatest risk. And PM2.5 from coal may be twice as deadly as PM2.5 from other sources, according to a recent study by Harvard’s School of Public Health and others.

Nitrous oxides (NOx) contribute to asthma, respiratory tract damage, and lung disease, and can lead to ozone which is harmful to human health.

Sulfur oxides (SOx) can harm the human respiratory system and can also cause acid rain.

Hydrochloric acid (HCl) can cause acid rain.

Heavy metal (e.g., mercury and lead) toxicity can cause birth defects and damage the functioning of the brain, lungs, kidneys, liver, and blood composition. Simultaneous exposure to two or more heavy metals may have cumulative effects.


Largest Proved Reserves

US 22% 🇺🇸

Largest Producer

China 52% 🇨🇳

Largest Consumer

China 55% 🇨🇳


Largest Proved Reserves

Wyoming 35%

Largest Producer

Wyoming 41%

Largest Consumer

Texas 12%

Global Trade

Amount Traded

of global consumption

Largest Exporters

Indonesia 34% 🇮🇩
Australia 25% 🇦🇺

Largest Importer

China 22% 🇨🇳

Change in Global Trade



  • Abundant
  • Relatively low private costs (but note that high social and environmental costs are not factored into the price)
  • Easy to store
  • Sunk cost of infrastructure
  • Historical dependence of some communities on coal industry
  • Domestic availability of coal


  • Many externalities: air pollution, methane leakage, CO2 emissions, heavy metals (e.g., mercury), coal dust, coal ash, water contamination, high water use, land subsidence
  • Health and safety of mine workers; public health impacts on local communities
  • Regulations are increasing
  • New and existing coal plants are no longer cost competitive in many major markets
  • Coal-fired power plants are inflexible, making it hard to integrate with increasing renewables
  • Bankruptcy plaguing the US coal mining industry
  • Legacy issues such as abandoned mines and leftover coal ash that require ongoing treatment and management

Climate Impact: High

High gradient
  • The most carbon-intensive energy source
  • Escaping coal bed methane is also a potent greenhouse gas

Environmental Impact: High

High gradient
  • Combustion releases air pollutants (e.g., mercury, PM2.5, NOx, SO2)
  • Extraction/mining and coal ash harm landscapes and water quality
  • Surface mining and mountaintop removal are particularly damaging

Updated April 2024

Before You Watch Our Lecture on

We assign videos and readings to our Stanford students as pre-work for each lecture to help contextualize the lecture content. We strongly encourage you to review the Essential readings and videos before watching our lecture on Coal. Include selections from the Optional and Useful list based on your interests and available time.


Optional and Useful

Our Lecture on

This is our Stanford University Understand Energy course lecture on coal. We strongly encourage you to watch the full lecture to understand coal as an energy system and to be able to put this complex topic into context. For a complete learning experience, we also encourage you to watch / read the Essential videos and readings we assign to our students before watching the lecture.

Diana Gragg

Presented by: Diana Gragg, PhD; Core Lecturer, Civil and Environmental Engineering; Explore Energy Managing Director, Precourt Institute for Energy, Stanford University
Recorded on: October 10, 2023   Duration: 56 minutes

Table of Contents

(Clicking on a timestamp will take you to YouTube.)
00:00 Introduction 
03:13 Significance of Coal 
13:33 What is Coal 
15:38 Upstream: Mining and Processing 
26:34 Midstream: Transportation 
30:54 Downstream: Electricity Generation 
32:48 Environmental & Social Impacts 
47:32 Economics and the Future of Coal

Lecture slides available upon request.

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Additional Resources About

Other Resources

  • Energy Institute Statistical Review of World Energy Coal Chapter (great resource for global coal production and consumption data)
  • National Energy Education Development (NEED) Coal

Fast Facts Sources

More details available on request.
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