What is the Environmental Impact of Coal?

Two coal miners in mine shaft
••• Getty Images/Tyler Stableford

Coal has several environmental issues associated with its burning, including the release of CO2, which is now known to be associated with global warming. As the Union of Concerned Scientists notes:

Coal has long been a reliable source of American energy, but it comes with tremendous costs because it is incredibly dirty. The same chemistry that enables coal to produce energy—the breaking down of carbon molecules—also produces a number of profoundly harmful environmental impacts and pollutants that harm public health. Air pollution and global warming are two of the most serious.

With growing concern about climate change now in the forefront and the significant CO2 emissions associated with coal, it is perhaps an opportune time to ask whether coal is now keeping us and our planet just a bit too warm?

An Old Friend

It is hard to turn away an old and loyal friend. Coal has been keeping people warm for 2,000 years or more. According to www.energy.gov, archaeologists have found evidence that the Romans in England used it in the second and third centuries (100 – 200 AD). In North America, the Hopi Indians burned coal for cooking, heating and baking clay pottery. From heating, coal transitioned to become the key energy source for steam power. In the Industrial Revolution, coal was used to generate steam for the steam engine.

Coal-powered steamships and steam-powered railroads dominated transportation in the 1800s. Coking coal had replaced charcoal as the main fuel for iron blast furnaces by 1875.

In the 1880s it was first used to generate electricity, and by 1961, it had become the major energy source for electricity generation in the U.S., a distinction which it retains to this day, still dominating domestic production. With the increased use of coal, however, the environmental impacts of coal were increasingly felt.

What Countries Use the Most Coal?

A 2017 report on coal consumption outlines that China dominates world coal usage. It consumes around 51% of coal worldwide, more than the rest of the world combined. Other major consumers of coal include India (11%), the U.S. (9%), Japan (3%) and Russia (3%).

The good news, from a greenhouse gas emission perspective, is that coal consumption is showing signs of waning in major consuming countries. 

In the U.S., evidence of declining coal usage is more evident. According to a more recent study from the U.S. Energy Information Administration, the U.S. consumption dropped 4% from 2017 to 2018, now at its lowest level since 1979. It has been falling since its peak in 2007. The decline is mainly driven by reduced coal usage for electrical power generation. While coal has dominated as the largest energy source for electrical production (63%), it is being partially displaced by competition from natural gas and renewable sources.

What are the Environmental Impacts of Coal Usage?

There are a lot of things not to like about coal. Coal plants are responsible for 42% of U.S. mercury emissions. Mercury is a heavy metal that can damage the nervous, digestive, and immune systems as well as threaten child development. Other pollutants of note include sulfur dioxide (SO2), Nitrogen oxides (NOx), particulate matter (soot), other heavy metals including lead, cadmium, and others, as well as volatile organic compounds and arsenic. Various technologies such as scrubbers and other pollution controls have been introduced over time to prevent some of the pollutants from entering the environment, although as the Union of Concerned Scientists notes, “Most of these emissions can be reduced through pollution controls—sometimes by a significant amount—though many plants don’t have adequate controls installed.”

In addition to the pollutants listed above, the major concern with coal as an energy source is CO2 emissions.

According to the U.S. Energy Information Administration, between 214 and 228 pounds of CO2 are emitted for every million British thermal units produced by coal, versus 161 pounds for diesel, 139 pounds for propane and 117 pounds for natural gas.

Alternatives to Present Coal Energy Generation

Cleaner fossil fuel alternatives are listed above. The continued emergence of renewable energy sources will also be critical in reducing carbon emissions. Clean energy sources continue to grow at a rapid rate, but they still have a daunting challenge in terms of eliminating CO2 emissions. They still only account for 12% of energy generation.

Our hope for the future lies in the continued growth of renewable energy, as well as in the growth of novel geoengineering technologies such as carbon capture that will prevent the leakage of CO2 into the environment and enable us to utilize abundant resources such as coal without exasperating the climate change problem.