Clean Coal: The Oxymoron That Won't Die

For decades, you've probably heard the phrase "clean coal" in advertisements, news reports, and public discussions. Coal companies have spent hundreds of millions of dollars advertising it. "Clean coal" became a talking point, a promise, a lifeline for an industry watching itself die.

There's just one problem: clean coal doesn't exist.

Not in any meaningful way. Not at any scale that matters. Not in a form that's economically viable or environmentally significant. Even coal company CEOs admit it privately.

"It is neither practical nor economic, carbon capture and sequestration," said Robert Murray, CEO of Murray Energy (one of America's largest coal companies), in 2017. "It is just cover for the politicians that say, 'Look what I did for coal,' knowing all the time that it doesn't help coal at all."

This is the story of coal, what makes it so dirty in the first place, what "clean coal" actually means (and doesn't mean), why the technology has failed, and why the myth persists despite overwhelming evidence that it's just that: a myth.

What Is Coal and Why Do We Use It?

Coal is fossilized plant matter, compressed over millions of years under heat and pressure until it becomes a dense, carbon-rich rock that burns hot and long.

For over 200 years, coal powered the Industrial Revolution and built modern civilization. It's still massive today: about 30% of U.S. electricity comes from coal (as of recent years), and globally, coal generates about 37% of electricity.

People use coal because it's:

• Abundant: The U.S. has centuries worth of coal reserves

• Energy-dense: A little coal produces a lot of heat

• Reliable: Coal plants run 24/7, providing "baseload" power (unlike wind or solar, which depend on weather)

• Cheap (historically): For decades, coal was the cheapest way to generate electricity

But coal has a catastrophic downside: it's the dirtiest fossil fuel on Earth.

Why Coal Is So Dirty

When you burn coal for electricity, it releases a horrifying cocktail of pollutants:

Carbon Dioxide (CO₂)

Coal produces more CO₂ per unit of energy than any other fossil fuel. About 15 billion tons of CO₂ per year come from burning coal globally. This is the primary driver of climate change.

To put this in perspective: coal produces about 2.2 pounds of CO₂ per kilowatt-hour of electricity. Natural gas produces about 0.97 pounds. Renewables produce essentially zero.

Sulfur Dioxide (SO₂)

Sulfur in coal becomes sulfur dioxide when burned. In the atmosphere, SO₂ reacts with water to form sulfuric acid, which falls as acid rain. Acid rain corrodes buildings, kills forests, and acidifies lakes and rivers, wiping out fish and aquatic life.

Nitrogen Oxides (NOₓ)

Burning coal at high temperatures creates nitrogen oxides, which contribute to smog and ground-level ozone. This causes respiratory problems, aggravates asthma, and damages lung tissue.

Mercury

Coal contains mercury, a neurotoxin. When released, mercury accumulates in fish, making them dangerous to eat. Mercury exposure damages the brain and nervous system, especially in children.

Particulate Matter (Soot)

Tiny particles from coal combustion lodge deep in lungs, causing heart disease, lung disease, and premature death. The American Lung Association estimates that coal plant pollution contributes to 13,200 deaths per year in the U.S.

Coal Ash

After burning, coal leaves behind ash containing heavy metals (arsenic, lead, mercury, chromium). This toxic waste is stored in ponds or landfills, where it can leak into groundwater.

A 2008 spill at the Tennessee Valley Authority released 1.1 billion gallons of toxic coal ash, contaminating rivers and burying homes. It was one of America's worst environmental disasters.

Mining Destruction

Before coal ever reaches a power plant, getting it out of the ground causes environmental devastation:

Mountaintop removal mining: Literally blowing up mountains and dumping the rubble into valleys, burying streams, destroying forests, and poisoning water supplies. About 5% of U.S. coal comes from mountaintop removal.

Underground mining: Dangerous for workers, causes lung disease (black lung), and can lead to mine collapses and water contamination.

Coal transportation: Moving coal by train and truck creates pollution and infrastructure strain.

So coal is dirty from extraction through combustion to waste disposal. Every step harms human health and the environment.

What "Clean Coal" Actually Means

"Clean coal" is a marketing term, not a scientific category. It refers to technologies that reduce (but don't eliminate) some pollutants from coal plants.

Old Definition: Reducing Traditional Pollutants

For decades, "clean coal" meant technologies like:

Scrubbers (flue gas desulfurization): Remove up to 97% of sulfur dioxide from smokestack emissions before they reach the atmosphere.

Electrostatic precipitators and filters: Remove 99% of fly ash (particulate matter) from exhaust.

Low-NOₓ burners: Reduce nitrogen oxide emissions.

These technologies work! They've dramatically reduced SO₂, particulates, and NOₓ from coal plants since the 1970s, preventing acid rain and improving air quality. But here's the critical point: these technologies do nothing about CO₂. Zero. They remove traditional pollutants but don't address the primary climate problem.

When coal companies said they had "clean coal" in the 1990s and 2000s, they meant "coal that doesn't cause as much acid rain." They weren't talking about climate change.

New Definition: Carbon Capture and Storage (CCS)

Today, when the coal industry talks about "clean coal," they mean coal plants with Carbon Capture and Storage (CCS), which attempts to capture CO₂ before it reaches the atmosphere and store it underground permanently.

This is the only technology that could legitimately make coal "cleaner" in terms of climate change. And it's a spectacular failure.

How Carbon Capture and Storage Works (In Theory)

CCS involves three steps:

Step 1: Capture CO₂

There are three main approaches:

Post-combustion capture: After burning coal, pass the smokestack gases through a chemical solution (often ammonia-based "amines") that binds with CO₂. Heat the solution to release the CO₂ as a concentrated gas.

Pre-combustion capture: Before burning, convert coal into a gas (gasification), separate out the CO₂, then burn what remains.

Oxy-fuel combustion: Burn coal in pure oxygen instead of air, producing mostly CO₂ and water vapor, making capture easier.

Step 2: Transport CO₂

Compress the captured CO₂ into a liquid and transport it via pipeline to storage sites.

Step 3: Store CO₂ Underground

Inject the compressed CO₂ deep underground into geological formations (depleted oil and gas fields, deep saline aquifers, or basalt rock formations) where it should theoretically stay trapped for thousands of years.

This all sounds plausible. The technology exists. We know how to do each step.

So why isn't clean coal everywhere?

Why Clean Coal Has Failed: The Problems with CCS

Problem 1: It's Insanely Expensive

CCS is prohibitively expensive to build and operate. Here's why:

Capital costs: Building CCS equipment costs billions. The Kemper County IGCC Project in Mississippi was supposed to demonstrate coal gasification with carbon capture. Budget: $2.4 billion. Actual cost: $7.5 billion. Triple the budget. After years of delays and cost overruns, they gave up on coal entirely and converted the plant to run on natural gas.

Energy penalty: Running CCS equipment requires 20-30% of the power plant's energy output. You lose a quarter of your electricity just running the carbon capture system. This means you need to burn more coal to get the same electricity, or your plant produces way less power.

Operating costs: The chemicals, energy, and maintenance for CCS are ongoing expenses that make electricity from CCS coal plants vastly more expensive than electricity from natural gas, wind, or solar.

Bottom line: CCS can't compete economically. Without massive government subsidies or carbon taxes that make releasing CO₂ more expensive than capturing it, no utility will voluntarily install CCS.

Problem 2: It Barely Exists

As of 2026, only two coal power plants in the entire world use CCS:

Boundary Dam (Canada): Captures about 90% of CO₂ from one 110-megawatt unit. But it runs at reduced capacity because CCS equipment uses so much energy. It only operates successfully about 60-70% of the time (versus 90-95% uptime required for modern power plants).

Petra Nova (Texas, USA): Built in 2017 as the world's largest CCS facility. It captures 90% of CO₂ from one 240-megawatt unit (out of four total units at the plant). But here's the kicker: it gets energy to run CCS from a separate natural gas plant (without carbon capture). So while it captures 90% of coal emissions, the natural gas plant releases CO₂, meaning the net carbon reduction is only about 70%. And as of 2020, Petra Nova shut down because it wasn't economically viable.

That's it. Two plants. Capturing a tiny fraction of their emissions. Often not working. One shut down.

A 2024 report by the Institute for Energy Economics and Financial Analysis found that 13 major CCS projects globally capture a combined 39 million tons of CO₂ per year. That's 0.01% of global emissions. It's a rounding error.

Problem 3: The Technology Doesn't Work Well

Even when CCS technically functions, it has serious problems:

Low capture rates: CCS projects typically capture far less CO₂ than promised. Some capture as little as 15% (not 80-90%). The rest escapes into the atmosphere anyway.

Reliability issues: CCS equipment breaks down frequently, operates at reduced capacity, and requires constant maintenance. Plants shut down for repairs more often than conventional coal plants.

Leakage risks: Stored CO₂ can leak back to the surface through cracks in rock, old wells, or faults. If this happens, the "permanent" storage becomes temporary, and you've accomplished nothing. The Sleipner project in Norway (often cited as successful) showed CO₂ migrating to upper geological layers faster than expected, creating new environmental risks.

Groundwater contamination: If stored CO₂ leaks into aquifers, it can acidify groundwater, making it unsafe to drink and harming underground ecosystems.

Induced seismicity: Injecting massive amounts of liquid underground can trigger earthquakes. Oklahoma experienced dramatic increases in earthquakes after large-scale injection of wastewater (from oil and gas operations). CCS could cause similar problems.

Problem 4: It Doesn't Address the Full Problem

Even if CCS worked perfectly on every coal plant (which it absolutely doesn't), coal would still be environmentally destructive because:

Mining damage continues: CCS does nothing about mountaintop removal, stream contamination, habitat destruction, or worker safety in mines.

Coal ash remains toxic: Capturing CO₂ doesn't eliminate heavy metal waste. You still have toxic coal ash to dispose of.

Other air pollutants persist: While CCS targets CO₂, mercury, particulates, and other pollutants might still be released.

Water use is massive: CCS requires enormous amounts of water for cooling and chemical processes, straining water supplies.

Problem 5: Economics Have Changed

While the coal industry has spent billions researching CCS (with massive government funding), the energy market moved on:

Natural gas got cheap: Fracking made natural gas abundant and inexpensive. Natural gas plants produce half the CO₂ of coal plants, cost less to build, and don't need CCS to be cleaner than coal.

Renewables got cheaper: Wind and solar costs have plummeted. In many places, new wind or solar is now cheaper than even existing coal plants, let alone building new coal plants with expensive CCS.

Batteries got better: Energy storage is solving the "renewables aren't reliable" problem, making it possible to use wind and solar for baseload power.

By the time CCS might become viable, nobody wants coal anyway. Why would you invest billions in experimental CCS technology when you can build wind turbines, solar panels, and batteries that work right now and cost less?

Problem 6: It's a Delay Tactic

Many environmentalists argue that "clean coal" is really about delaying the transition to renewable energy. As long as the industry can say "we're working on clean coal," they can justify building new coal plants and keeping old ones running.

It's called "greenwashing": making something seem environmentally friendly when it isn't. Coal companies have spent over $35 million advertising "clean coal" while actual investment in making it real remains tiny.

Why "Clean Coal" Persists Despite Failure

"Clean coal" persists as a concept because it's useful for multiple stakeholders:

For regions dependent on coal: It offers hope that coal jobs and economies can continue while also addressing environmental concerns.

For coal companies: It prolongs their industry's life, delays stricter regulations, and attracts government subsidies for research.

For utilities: It justifies building or keeping coal plants by promising future carbon capture retrofits (that almost never actually happen).

But the industry itself knows it's not real. When Robert Murray, CEO of one of America's largest coal companies and a member of the American Coalition for Clean Coal Electricity (which spent tens of millions promoting "clean coal"), admits CCS is "neither practical nor economic," the truth becomes clear.

What Really Happened to Coal

Coal didn't die because of environmental regulations (though those helped). Coal died because economics killed it:

Natural gas: The fracking boom made natural gas abundant and cheap. Natural gas is cleaner, more flexible, and costs less to operate. Utilities switched because it made financial sense, not because of regulations.

Renewables: Wind and solar are now the cheapest sources of new electricity generation in most of the world. Even in cloudy, not-very-windy places, renewables often beat coal on cost.

Automation: Modern coal plants require far fewer workers than old ones. The coal jobs that existed decades ago aren't coming back regardless of regulations.

Global trends: Every developed country is moving away from coal. China, historically coal's biggest consumer, is building more renewable energy than the rest of the world combined.

Coal is simply being out-competed by better, cheaper, cleaner alternatives. No amount of "clean coal" rhetoric changes that.

The Bottom Line

Coal is the dirtiest fossil fuel on Earth. It produces more CO₂ per unit of energy than any other fuel, releases toxic pollutants that kill thousands of people annually, generates toxic waste, and requires environmentally destructive mining.

"Clean coal" originally meant technologies that reduce sulfur dioxide, particulates, and nitrogen oxides. Those technologies work and have improved air quality. But they do nothing about CO₂, the primary climate pollutant.

Modern "clean coal" means Carbon Capture and Storage (CCS), which attempts to capture CO₂ from coal plant emissions and store it underground permanently.

CCS has comprehensively failed:

• Only two coal plants in the world use it (and one shut down)

• It captures only a tiny fraction of global coal emissions (0.01%)

• It's prohibitively expensive (often triple the budget)

• It has a massive energy penalty (20-30% of plant output)

• It doesn't work reliably

• It doesn't eliminate mining damage, coal ash, or other pollutants

• It's economically nonviable compared to natural gas and renewables

Even coal company CEOs admit CCS is "neither practical nor economic."

"Clean coal" is an oxymoron. It's a marketing myth. It's greenwashing that helped justify building coal plants and delaying climate action while pretending to care about the environment.

Coal isn't coming back, and it can't be made clean. The technology doesn't work at scale, the economics don't work, and better alternatives already exist.

Coal had a good run. It powered the Industrial Revolution and built modern civilization. But its time is over. Not because of regulation alone, but because economic progress left it behind.

The facts speak for themselves.

Sources

Center for Energy Research and Analysis (CERAH). (2024). Can Coal Be Clean? Examining the Reality of CCS. Retrieved from https://www.cerah.or.id/publications/article/detail/can-coal-be-clean-examining-the-reality-of-ccs

Columbia Climate School. (2013). What's the Real Story With Clean Coal? Retrieved from https://news.climate.columbia.edu/2013/07/01/whats-the-real-story-with-clean-coal/

FactCheck.org. (2018). Clearing Up the Facts Behind Trump's 'Clean Coal' Catchphrase. Retrieved from https://www.factcheck.org/2018/11/clearing-up-the-facts-behind-trumps-clean-coal-catchphrase/

Green America. Why Clean Coal Is A Myth. Retrieved from https://greenamerica.org/fight-dirty-energy/amazon-build-cleaner-cloud/coal-why-it-dirty

Institute for Energy Economics and Financial Analysis (IEEFA). (2024). Carbon Capture Project Performance Report.

Kleinman Center for Energy Policy, University of Pennsylvania. (2022). Carbon Capture's Clean Coal Ambition. Retrieved from https://kleinmanenergy.upenn.edu/commentary/podcast/carbon-captures-clean-coal-ambition/

PBS NewsHour. (2017). Could carbon capturing make 'clean coal' a reality? Retrieved from https://www.pbs.org/newshour/show/carbon-capturing-make-clean-coal-reality

ThinkProgress. (2017). Coal CEO admits that 'clean coal' is a myth. Retrieved from https://archive.thinkprogress.org/clean-coal-isnt-real-eda3e2841060/

Wikipedia. (2026). Coal pollution mitigation. Retrieved from https://en.wikipedia.org/wiki/Coal_pollution_mitigation

World Nuclear Association. Clean Coal Technologies, Carbon Capture & Sequestration. Retrieved from https://world-nuclear.org/information-library/energy-and-the-environment/clean-coal-technologies

Yale E360. The Myth of Clean Coal. Retrieved from https://e360.yale.edu/features/the_myth_of_clean_coal