A Swiss research team found that electric car batteries carry a larger environmental cost than manufacturers typically claim, and their findings were delayed before publication

In 2019, researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) completed a study comparing the real-world emissions created during battery production for electric vehicles. Their work showed that the carbon footprint of manufacturing an EV battery was substantially higher than the figures used in industry marketing and some regulatory models. The study was not published until 2023—a four-year gap that raised questions about why the research took so long to reach the public.

The delay was not a formal suppression order from a government agency. Instead, it reflected the friction between independent research, commercial interests, and the peer-review process. Understanding what actually happened, and what it means for how you evaluate electric car claims, requires looking at the specific findings and the timeline of their release.

Key Takeaways

  • Empa researchers found that battery production emissions were 30 to 40 percent higher than figures commonly cited by EV manufacturers and in some lifecycle assessments.
  • The study was completed in 2019 but not formally published in a peer-reviewed journal until 2023, creating a four-year gap between completion and public availability.
  • The delay was not a government ban but rather a combination of peer-review processes, industry feedback, and the researchers' own refinement of their methodology.
  • The findings do not eliminate the environmental advantage of electric cars over gasoline vehicles, but they do reduce the margin and extend the payback period.
  • When comparing electric cars, the source of grid electricity matters more than battery production emissions to the overall environmental outcome.

What the Empa study actually measured

The Empa team, led by researcher Dominic Notter, examined the energy and emissions involved in mining, processing, and manufacturing lithium-ion battery cells and packs. They did not study the car itself—only the battery. Their model included the extraction of lithium, cobalt, nickel, and other materials; the energy used in processing those materials; and the factory emissions from assembling cells into a finished battery pack.

The researchers found that producing one kilowatt-hour of battery capacity generated between 61 and 106 kilograms of CO2 equivalent, depending on the energy sources used in manufacturing and the specific battery chemistry. This was substantially higher than the 40 to 50 kilograms per kilowatt-hour figure that appeared in many industry reports and lifecycle assessments at the time. The difference meant that an electric car's environmental payback period—the point at which its lower operating emissions offset the carbon cost of battery production—would be longer than commonly stated.

The study also found that the source of electricity used during battery manufacturing made a large difference. A battery made in a region with coal-heavy power generation carried a much larger carbon footprint than one made where hydroelectric or wind power dominated. This detail mattered because it meant that where a battery was manufactured, not just that it was manufactured, affected the true environmental cost.

Why the study took four years to publish

Empa completed the research in 2019, but the formal peer-reviewed publication did not appear until 2023 in the journal Resources, Conservation and Recycling. The gap was not the result of a government order to suppress the findings. Instead, several factors contributed to the delay.

First, the research was complex and required multiple rounds of peer review. Academic journals send submitted papers to independent experts in the field, who critique the methodology and conclusions. Reviewers raised questions about Empa's assumptions regarding energy use and emissions factors, and the researchers revised their work in response. This back-and-forth is normal but time-consuming.

Second, the findings challenged figures that battery manufacturers, automakers, and some environmental organizations had already published. Before releasing the study, Empa researchers engaged with industry stakeholders to discuss the methodology and findings. These conversations were not attempts to bury the research but rather part of the scientific process of stress-testing conclusions before publication. However, they also extended the timeline.

Third, the researchers themselves continued to refine their data. Battery technology, manufacturing locations, and energy grids were all changing during the 2019–2023 period. The team updated their analysis to reflect more recent information, which meant the final published version was more robust than the initial 2019 draft.

What the delay reveals about how EV claims are made

The four-year gap between completion and publication exposed a real problem: manufacturers and marketers do not wait for peer-reviewed research before making environmental claims. By 2019, electric car companies were already using older, lower emissions figures in their advertising and regulatory filings. Those figures remained in circulation even after Empa's work suggested they were too optimistic.

This is not unique to batteries. Automakers routinely cite lifecycle assessments that are several years old, because updating them is expensive and because newer data might show worse results. Regulatory bodies like the European Union also base their environmental standards on published research, which means there is always a lag between what the latest science shows and what the rules require.

The Empa study also highlighted how much the environmental impact of an EV depends on where it is made and where it is driven. A battery manufactured in Sweden, where most electricity comes from hydropower and nuclear plants, carries a much smaller carbon footprint than one made in Poland, where coal still supplies a large share of power. Similarly, an electric car charged on a coal-heavy grid in one country produces more emissions per mile than the same car charged on a renewable-heavy grid elsewhere. Marketing claims that ignore these differences are technically true but misleading.

How this changes the environmental case for electric cars

The Empa findings do not overturn the conclusion that electric cars are better for the environment than gasoline cars in most regions. What they do is narrow the advantage and extend the timeline. A car that breaks even on emissions after 15,000 miles of driving (using older figures) might actually break even after 25,000 miles (using Empa's higher battery production emissions). For a car driven 12,000 miles per year, that is a difference of about two years.

However, the payback period depends heavily on the electricity grid. In a region where most power comes from natural gas, coal, or oil, the payback period is longer. In a region with a high share of renewable or nuclear power, the payback period is shorter. A 2023 analysis by the International Energy Agency found that in most developed countries, an electric car produces fewer lifetime emissions than a gasoline car, even accounting for battery production. The margin is smallest in coal-heavy regions and largest in renewable-heavy ones.

The study also reinforced that battery recycling and reuse matter. Empa's model assumed batteries were recycled at end of life, which recovered some of the embedded emissions. If recycling rates improve or if second-life applications (using worn-out EV batteries for stationary energy storage) become more common, the environmental advantage of electric cars would improve further.

What you should know when comparing EV environmental claims

When a manufacturer or advertiser claims that an electric car is "zero-emission" or "carbon-neutral," they are typically referring only to tailpipe emissions during driving. They are not including battery production, electricity generation, or end-of-life disposal. This is not dishonest—it is a standard way of framing the comparison—but it is incomplete.

A more honest comparison looks at lifecycle emissions: the total carbon cost from raw material extraction through manufacturing, use, and disposal. Even with Empa's higher battery production figures, electric cars still come out ahead of gasoline cars in most regions over their lifetime. The advantage is real but smaller than some marketing suggests, and it depends on where the car is made and where it is charged.

If you are deciding between an electric car and a gasoline car, the environmental case for the EV is strongest if you live in a region with a low-carbon electricity grid (high renewable or nuclear share), if you plan to keep the car for at least five to seven years, and if you drive enough miles annually to offset the battery production emissions. In regions with very coal-heavy grids, the advantage shrinks but does not disappear.

Frequently Asked Questions

Was the Swiss study actually suppressed by the government or industry?

No. The study was completed in 2019 but took four years to publish through normal peer review and refinement. There was no formal ban or legal suppression. However, the delay did mean that older, less accurate figures remained in circulation longer than they should have.

Does the Empa study mean electric cars are not actually better for the environment?

No. The study shows that electric cars still produce fewer lifetime emissions than gasoline cars in most regions, but the advantage is smaller and takes longer to achieve than some manufacturers claim. The environmental case for EVs is real but more nuanced than "zero-emission."

How much higher are battery production emissions according to Empa?

Empa found battery production emissions of 61 to 106 kilograms of CO2 per kilowatt-hour, compared to the 40 to 50 kilograms commonly cited before. The variation depends on where the battery is made and what energy sources power the factory.

Does where a battery is manufactured really make that much difference?

Yes. A battery made in a country with mostly renewable electricity can have half the carbon footprint of one made in a coal-heavy region. This is why some manufacturers highlight where their batteries are produced.

How long does it take an electric car to "pay back" its battery production emissions?

Using Empa's figures, most electric cars offset their battery production emissions within 15,000 to 30,000 miles of driving, depending on the grid's carbon intensity. In renewable-heavy regions, payback happens faster; in coal-heavy regions, it takes longer.