Coal has a long and complex history as a fuel source. Humans started mining and burning coal, which is formed from dead plants that sank to the bottom of swamps millions of years ago, during ancient times. By the 19th century, coal was increasingly used to power households, steamboats, and steam-powered trains, and to make oil and gas. Today, coal has taken a back seat to other fuel sources that offer cheaper or more sustainable alternatives.
The biggest energy sources at play in the U.S. are petroleum, which accounts for 38% of total energy consumption and is mainly used in the transportation sector, and natural gas, which accounts for 36% and is used in the industrial, residential, and commercial sectors. Coal, nuclear, and renewable energy account for around 9% each.
Coal’s contribution to total energy consumption in the U.S. has dropped from 37% in 1950, mainly because the electric power sector has steadily been turning to other energy sources.
In 2023, around 60% of electricity was generated from fossil fuels, but this was mostly from natural gas. Coal accounted for about 16% of electricity generation that year, according to the Energy Information Administration (EIA). The remaining 40% of the nation’s electricity was generated through nuclear power (19%) and renewables — mainly wind, hydropower, and solar.
Coal-fired power output has been steadily decreasing since the mid-2000s as the electric power sector has embraced other sources of fuel. One motivator for this shift is U.S. targets to reduce carbon emissions. Coal power output in the first four months of 2024 was 1.8% lower than the same period in 2023, and 30% less than in 2021.
However, the decline in coal is likely to be slower than anticipated over the coming years. The longer, hotter summers and cold winters across the U.S. demand a large amount of electricity that cannot be fully supplied by more sustainable sources. The U.S. drive to be a leader in artificial intelligence (AI) and manufacturing is also piling on pressure, and electricity demand may grow by 4.7% over the next five years, according to a forecast by consultancy Grid Strategies.
Almost 90% of the energy produced by coal in the U.S. ends up as electric power. Coal is burned to create heat, which turns water into high-pressure steam that turns turbines, generating electricity.
Eleven percent of the energy produced using coal is used in industry, including in cement plants, paper manufacturers, pharmaceutical industries, and steel production. The steel industry uses a more expensive metallurgical coal — a grade that is low in moisture and high in carbon content — which produces coke when heated. This strong, dense substance burns at extremely high temperatures and is used to smelt iron ore into the molten iron needed to make steel.
With coal use in domestic electricity generation at its lowest in decades, coal exports have increased: exportation of thermal coal (or steam coal — the type used in electricity production) reached a five-year high in 2023 and brought in more than $5 billion. More than a third of U.S. thermal coal exports went to India, where coal is still a core fuel source for generating power.
There are coal plants all over the U.S., with the highest density in Pennsylvania, which had 16 stations as of July 2023. Texas and Indiana both had 13 as of that time, and the former is the country’s biggest coal-fired polluter. Three of the country’s 10 “dirtiest” coal plants, which lack pollution controls and are linked to premature deaths, are located in Texas. Kentucky and Wyoming had 10 plants each as of July 2023. Wyoming’s Powder River Basin is the nation’s largest mining region, with the biggest remaining coal deposits in the world.
Coal plants all over the country are being retired, with half of the coal generation capacity that was available at its peak in 2011 due to be shut down by 2026, even with the disruption to timelines caused by the COVID-19 pandemic. The Institute for Energy Economics and Financial Analysis, which has been tracking transitions in the U.S. electricity sector, last year stated that fewer than 200 large-scale coal plants remained that had not already announced retirement dates. The closures are partly driven by aging infrastructure: the majority of the coal units soon to be closed are at least 50 years old.
In 2022, more energy was generated from renewables than from coal for the first time, largely due to growth in the wind and solar sectors, according to EIA data. Advances in these technologies have driven down costs by 70% for wind energy and 90% for solar power over a decade, according to the American Council on Renewable Energy. California is the leading state for solar power, contributing 26% of the U.S. total of sun-powered electricity, followed by Texas, which also contributes the most wind generation in the country.
The EIA expects solar power generation to increase by 75% between 2023 and 2025, and wind generation to increase by 11% during that time. Meanwhile, battery storage capacity, which enables providers to store excess power generated from renewable sources in times of low electricity demand, is expected to almost double in 2024.
Nuclear’s contribution to the U.S. energy mix is predicted to remain at current levels.
Along with widespread closures across the coal industry, more than 100 plants have been replaced by or repurposed to burn natural gas instead. Due to new gas turbine technology, natural gas is not only cheaper and more efficient but also meets emission standards more easily. The higher operation and maintenance costs of aging coal units mean keeping coal generation going is increasingly uneconomical.
From autonomous mining systems and virtual reality (VR) training for miners to carbon capture and sequestration — where carbon dioxide emissions are injected deep underground — the coal industry has adopted several measures to improve safety, increase efficiency, and reduce greenhouse gasses.
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