The U.S. aluminum plants are producing tons of a potent greenhouse gas that is not released by their counterparts in other countries.

A Century Aluminum plant in Kentucky vented tons of perfluorocarbons, or PFCs, which are among the most potent and longest-lasting greenhouse gases on the planet.

This article has been published in partnership by Inside Climate News , an independent news outlet that covers climate and energy.

ROBARDS (Ky.) — The smelter Century Aluminum Sebree is protected by protective hoods. It’s covered by a hard crust. Large pots of molten aluminum bubble in the long, metal buildings. This is the largest source of a potent greenhouse gases, tetrafluoromethane CF4, which remains in the atmosphere for over 50,000 years.

According to the U.S. Environmental Protection Agency, the aluminum plant produced 23 tons of CF4 and a ton hexafluoroethane in 2021. Both are perfluorocarbons (or PFCs) that are among the most potent, longest-lasting, and harmful greenhouse gases on Earth. This pollution is equivalent to 40,000 cars’ annual greenhouse gas emissions, which will continue on the road for many thousands of years.

Century Aluminum, a subsidiary of Nordural, has published reports that show that a newer, also owned and operated in Grundartangi by the company, produces just one-sixth of the PFC emissions per ton aluminum compared with its Sebree plant.

In 2017, a worker at Century Aluminum Company in Hawesville (Ky.) uses a crane for lifting a container of molten aluminium. Luke Sharrett via Getty Images file

This is a story of two smelters, one older U.S. plant with the highest PFC emission rates in the world and the other with much lower PFC emissions. These plants are owned by different multinational companies. Environmental advocates argue that this contrast shows why the U.S. aluminium industry must be revived, even though it has fallen precipitously in recent years.

Nadia Steinzor, a Washington, D.C.-based policy and research consultant, said that although they have become less than they once were, that doesn’t make them a big polluter.

According to the EPA, Alcoa’s Intalco smelter, Ferndale, Washington, emitted almost 50 tons of PFCs in 2020, in a similar case to Century Aluminum. The company then temporarily stopped production in the same year.

This contrasts with Alcoa’s Fjardaal smelter at Fjardabyggd in Iceland which has a lower PFC emissions intensity than the recently shuttered Intalco smelter. According to an Inside Climate News assessment EPA data, the company’s production data was obtained through a public record request, and data that the company publishes about its Iceland facility.

Alcoa spokesperson Jim Beck said that they did not disagree with the assessment. Beck stated that emissions from Intalco were high because of the facility’s older technology and its operational instability.

Century Aluminum provided a similar explanation for the Sebree plant in the United States, which is currently at full capacity. It was built in 1973.

Steinunn Dogg Steinsen (Vice President of Health Safety and Environment for Century Aluminum) stated in an email that “It’s important to remember that the Iceland facility” is a more modern and technologically advanced facility. Steinsen said that the Iceland plant’s smelting process is more automated, which results in more efficient production. The Sebree plant, on the other hand, relies more heavily on manual controls that are more precise. She said that this explains the differences in PFC emissions between the plants.


The Century Aluminum Company plant in Sebree, Ky.


Phil McKenna/NBC News

Despite being non-toxic, CF4 and hexafluoroethane are classified as synthetic fluorine-containing chemicals. This is because they can remain in the atmosphere for so long. The EPA states that the gases become ” essentially permanent extensions to our atmosphere” and pose a threat to “the public health, welfare, and well-being of current as well as future generations“.

However, unlike carbon dioxide which is the main driver of climate change and the EPA doesn’t regulate PFCs,

American aluminum vs. Chinese aluminium

Twenty years ago, the United States was the world’s leader in aluminum production. The UN’s Intergovernmental Panel on Climate Change stated that PFCs are thousands of times more harmful to the climate than carbon dioxide. According to Inside Climate News, only 1.5% of the global aluminum smelting or production takes place in the United States. However, efforts to reduce PFC emissions from the U.S. have stalled. Meanwhile, the cleanest smelters across the globe have brought down emissions of this potent greenhouse gas to almost zero.

Experts in the industry believe it is too late to reduce PFC emissions from U.S. smelters.

Barry Welch, a professor of chemical engineering at the University of New South Wales, Sydney, believes that the U.S. smelters age like Model T cars. He has also consulted for many of America’s most prominent aluminum producers.

Welch stated that the U.S. smelters currently in use are “out of date.” The current fleet was built between 1902 and 1980. They should be closed.”

Security experts warn that the U.S. must find ways to close down the aluminum plants. This strong, lightweight metal is used for making lighter cars and planes, as well as solar panels or satellites.

“Just like we are dependent on the Middle East oil, we will soon find ourselves in a position where we will rely on China and Russia to supply aluminum,” stated Joe Quinn, vice president of strategic industrial material at SAFE Commanding Heights, which is based in Washington, D.C., and advocates for U.S. energy safety. For national security reasons, there is a legitimate need for stabilization of the aluminum sector.

Century Aluminum executives claimed that aluminum producers were being “decimated by the unfair practices of Chinese aluminum producers” in written testimony to the U.S. International Trade Commission.

Officials from the company wrote that American smelters in New York, Indiana, Washington, and Washington had already shut down, displacing local workers and communities with scarce jobs and tax revenue. “The viability of the aluminum sector outside of China and in America is dependent on a quick and effective solution to China’s overcapacity, overproduction, and other issues.”

Trump imposed tariffs on aluminum imports in 2018. These tariffs are still in effect. Century, however, announced in June that it would temporarily stop production at its largest U.S. facility, an aluminum smelter located in Hawesville, Kentucky.

Century Aluminum Company’s Hawesville, Ky smelter was temporarily closed in June.

It was the US’s only smelter that produced high-purity, “military grade” aluminium. This aluminum was used in fighter jets as well as lightweight armor plating. Century stated at the time the closure would take “nine to 12 months” and was caused by “soaring energy costs.”

Aluminum smelting is one of the fastest and most complete industries.

Andy Thompson, president of the United Steelworkers of America union, Robards stated that there were 23 aluminum smelters operating in 2000, and now five.

Only two of the remaining facilities are still operational: the Century Aluminum Sebree in Robards (which employs 625 people) and the smaller Alcoa plant at Massena, New York.

Brad Schneider, who is the judge executive or head of Henderson County’s county government, stated that the Century plant would be a major loss to the region if it ever closes.

Schneider stated that “generations of people have worked there. The same families.” It would be a serious blow.

He said, “We are all deeply saddened at what happened in Hawesville.” “If we don’t solve or at the very least protect our heavy industries and their energy needs then we will regret it. On multiple levels.”


Henderson County Judge Executive Brad Schneider.


Phillip McKenna/NBC News

Century Aluminum’s Steinsen stated that the company does not intend to close its Sebree plant in Robards. Steinsen stated that Sebree offers unique commercial and operational advantages over Hawesville and that Sebree is well-positioned to continue its operations.

76% decrease in PFC emissions

Aluminum smelters convert alumina ore to aluminum by running large amounts electricity through the mixture in a cell or “pot” and feeding it into a bath with molten salt.

If the concentration of alumina drops too low, PFCs can quickly form, a unwanted byproduct.

The issue was first discovered by the EPA in the early ’90s. However, rather than proposing regulations, they worked closely with aluminum producers to find a way to reduce PFC emission without regulation.

A 2008 EPA Report concluded that participation not only has environmental benefits but also improves the operational efficiency of companies and helps them achieve their bottom line.

The EPA cut off its industry partnership in 2015 as U.S. aluminum production was declining rapidly. The program ended without any impact on plant activities. However, the EPA didn’t respond to repeated questions about why they don’t regulate PFC emissions from aluminum plants, or if they intend to do so in the future. They also declined to answer repeated requests to speak to an expert on the agency’s emissions policies. The agency spokesperson stated that the Greenhouse Gas Reporting Program continues to monitor facility-specific emissions from the aluminum industry.

Today, PFCs make up only a fraction of aluminum production’s greenhouse gas emissions. According to a study published in 2019 in The Journal of The Minerals, Metals & Materials Society, the vast majority, or 70%, are indirectly caused by the burning of fossil fuels in power stations to run the energy-intensive smelters.

However, the PFCs still remain significant. According to the EPA, 7,510 metric tons of PFCs from global aluminum production were emitted in 2019.


Aging technology, Inflation Reduction Act

Alcan Aluminum, former owner of Century Aluminum Sebree, made a $1.6million investment in new equipment to the facility in May 1998. Alcan implemented a demand feed system to optimize the rate at which aluminum was being fed into the pots.

According to a 1999 EPA report, the investment reduced the intensity of CF4, the primary PFC emitted during aluminum production by half. It was emitted from 2 to 3 tons of carbon dioxide equivalent per tonne of aluminum to just under 1 tonne of carbon dioxide equivalent.

Alcan was a leader in climate mitigation among aluminum producers by the end of the ’90s. Twenty-four years on, Alcan’s emissions intensity from CF4 remains almost unchanged at just below 1 ton of carbon dioxide per ton aluminum. Century, the current owner of the plant, is a climate laggard.

Steinsen stated that the company is focusing on reducing the Sebree facility’s PFC emissions intensity this year. Steinsen stated that new controls were installed and that “we anticipate these changes will lower the plant’s PFC intensity.”

Inflation Reduction Act was the largest climate investment made in U.S. history. It provided $5.8 billion in grants, incentives, and other financial support for heavy industry to adopt emission-reducing technologies. According to Quinn of SAFE Commanding Heights (the U.S. energy security advocacy group), aluminum manufacturers could use the money for better control systems that reduce PFC emission and improve production efficiency.

In addition, the act appropriated $500 million to “enhanced use” of the Defense Production Act. Quinn stated that the extra money could be used for subsidizing the cost of electricity to make aluminum. This was a critical mineral , as the act defined it.

Mike Tanchuk, an aluminum industry veteran, stated that the Inflation Reduction Act could give new life to the U.S. aluminium industry. Tanchuk is able to leverage funds from the act with the support of Blue Wolf Capital Partners (a private equity firm) and the AFL-CIO labor federation. This will allow him to purchase Alcoa’s Intalco Smelter, improve its technology, and provide renewable energy to power the facility to produce “green” or low-carbon aluminum.

Tanchuk, who is the head of Green Aluminum — Intalco Works, stated that there was potential federal funding through the Inflation Reduction Act. He also said that the support from Governor Inslee as well as other Washington leaders have rekindled my hope that Intalco could be saved. (Jay Inslee, the governor of Washington.

Beck of Alcoa stated that the company had participated in negotiations with a potential buyer, but the conditions for a successful sale transaction have not been met yet.

Tanchuk was previously an executive at Alcoa where he managed the reopening in 2002 of the Intalco plant. He also worked for Century Aluminum where he managed the expansion of the Nordural smelter, Iceland, in 2006. Tanchuk stated that technology upgrades at Intalco would lead to significantly lower PFC emissions, similar to the Nordural plant.

He stated that the planned modernization at Intalco would result in significant emissions reductions, including greenhouse gasses. While we still face certain obstacles due to recent geopolitical turmoil such as high energy costs, these events only reinforce my conviction that there is a need for dependable domestic aluminum supplies now more than ever.

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