[Science Scope] Are Electric Vehicles Truly Eco-Friendly? ② The Real Battle Is Fought on the Grid, Not on the Road

Carbon Emissions Vary Depending on the Source of Electricity Used for Charging
How Electric SUVs, Hybrids, and Spent Batteries Change the Environmental Report Card

Editor's Note'Science Scope' is a special series that takes an in-depth look at specific scientific and technological phenomena, analyzing their significance and future impact.

The environmental scorecard of an electric vehicle charged in Seoul is not the same as that of the same electric vehicle charged in France. This is because the indirect carbon emissions generated during operation vary depending on whether the electricity used by the electric vehicle is produced with coal and natural gas or from nuclear, solar, or wind energy.

Where and how the battery was manufactured is also crucial. If the battery is produced using electricity with a high carbon intensity, the carbon burden mounts even before the vehicle leaves the factory. Conversely, manufacturing and charging the battery with low-carbon electricity can significantly reduce its lifecycle greenhouse gas (GHG) emissions.

Workers are dismantling used electric vehicle batteries at the lithium-ion battery recycling facility of Cawleys, a waste and recycling specialist company in the UK. Utilizing materials recovered from waste batteries in new batteries can reduce the environmental impact associated with raw material mining and refining. Provided by Cawleys

The eco-friendliness of an electric vehicle is not guaranteed simply by switching its power source to electricity. The entire chain—power plants and the grid, battery factories, vehicle size, driving patterns, and the recycling of used batteries—are all interconnected.

Even the Same Electric Vehicle Differs Depending on the Charging Source

Electric vehicles do not have exhaust pipes, but the electricity to charge them is produced at power plants. Even if the vehicle does not directly emit carbon dioxide, the carbon generated in producing the electricity is counted as part of the vehicle’s emissions during operation.

Coal-fired power plants emit significant amounts of greenhouse gases. Even liquefied natural gas (LNG) power plants still emit carbon. Although nuclear, solar, and wind power plants have lifecycle emissions related to facility production and construction, their carbon intensity is lower than that of fossil fuel plants.

Sora Lee, Senior Research Fellow at the Circulation Economy Research Department at the Korea Environment Institute, explained, "Even for the same electric vehicle, charging with coal power results in more greenhouse gases than charging with nuclear or renewable energy. Even in power systems like Korea’s, where the share of fossil fuels is relatively high, electric vehicles already have an advantage as of now. And as coal is phased out and renewables expand, the environmental benefit structurally increases."

Europe is already seeing concrete results. According to an International Council on Clean Transportation (ICCT) analysis, based on the EU’s power grid, the lifecycle greenhouse gas emissions of electric vehicles in 2025 are projected to be 24% lower than the 2021 analysis. The researchers cited the decarbonization of the grid as the main cause.

An end-to-end analysis led by Ioan Zimber, Senior Data Analyst at Transport & Environment (T&E), further highlighted the stark contrast of energy sources. For example, an electric car with a battery produced in China, operated in coal-dependent Poland, still produced 37% less lifecycle CO2 emissions than a gasoline vehicle. If the battery is produced and operated in Sweden, emissions can be reduced by up to 83%.

In Korea, electricity is likewise the most critical variable. Wonjae Choi, Professor at the Department of Human-Machine-Bioengineering at Ewha Womans University, stated, "Above all, the emissions coefficient of electricity has the greatest impact. Reducing greenhouse gases during power generation is the most direct way to decrease electric vehicle emissions."

Even Within the Same Country, 'When' You Charge Matters

Even when driving the same electric vehicle in the same country, the time of charging can affect emissions. This is because the generation mix—how electricity is produced—varies throughout the day.

Research by Ewha Womans University’s Jooha Lee, Jarung Kim (Director of Future Vehicle Research at the Korea Transportation Safety Authority), Professor Choi, and others, published in the 2024 Korean Hydrogen and New Energy Society Journal, analyzes the greenhouse gas (well-to-wheel) emissions of electric vehicles depending on the time of charging. They calculated changes in well-to-wheel emissions using Korea’s hourly power generation mix in 2022.

Their findings showed that, compared to average emissions without regard to grid composition by the hour, the well-to-wheel greenhouse gas emissions of electric vehicles could be up to 16% higher or 28% lower depending on the charging time. In other words, the environmental scorecard for the same electric vehicle changes depending on when it is charged.

This suggests that, in the future, "smart charging" can evolve from simply saving on electricity costs to becoming a means of carbon reduction—for example, encouraging charging during hours of abundant renewable energy and delaying it during peak demand periods.

Electric vehicles not only add new demand to the grid, but can also serve as energy storage units, allowing for the adjustment of charging times.

Electric SUV or Hybrid: Vehicle Type and Size Also Change the Score

Another variable determining the eco-friendliness of an electric vehicle is its size.

Large electric SUVs require larger batteries and more materials such as steel and aluminum than small EVs. This increases greenhouse gases during production and raises energy consumption during operation due to the heavier body. Having the "electric car" label does not guarantee equal environmental performance.

The International Energy Agency (IEA) quantifies these differences. Among EVs sold in 2023, the average battery size of electric SUVs was 25% larger than that of similarly ranged mid-sized EVs. The power consumption of electric SUVs was also, on average, 20% higher than for other electric passenger vehicles.

The resources saved by reducing vehicle size are also considerable. The IEA estimated that if all electric SUVs sold globally in 2023 were replaced by mid-sized EVs, battery demand could have been reduced by around 60GWh, with little impact on driving range. This resource saving translates to roughly 6,000 tons of lithium, 30,000 tons of nickel, 7,000 tons of cobalt, and over 8,000 tons of manganese.

In other words, the larger the electric vehicle, the more battery resources are required.

Comparing hybrids and EVs is even more complicated. Hybrid vehicles use both internal combustion engines and electric motors. Their smaller batteries result in a relatively lower carbon burden during production, and regenerative braking combined with efficient engine operation reduces fuel consumption compared to traditional gasoline cars.

In Professor Choi’s analysis of Korean passenger vehicles, the lifecycle greenhouse gas emissions gap between electric vehicles and hybrids narrows when vehicle production and disposal are included. Internal combustion engine vehicles (ICEVs) have high emissions during operation, while battery electric vehicles (BEVs) have no direct operational emissions but release carbon during power generation, vehicle, and battery manufacturing.

Professor Choi explained, "In Korea, electric vehicles’ greenhouse gas emissions tend to be lower than those of hybrids, but the difference is not as absolute as people think—it’s certainly not 100 to 0."

The more the power grid decarbonizes, the lower the operating-phase emissions of electric vehicles. On the other hand, if hybrids become more fuel-efficient or begin using low-carbon fuels, their emissions could also decrease.

Professor Choi emphasized, "The comparison between electric vehicles and hybrids must continue, analyzing all stages—fuel used, car production, utilization, and disposal. Objective comparisons grounded in real-world, end-to-end analysis are essential."

The IEA also found that, on a world average, the lifecycle emissions of mid-sized electric vehicles sold in 2023 were more than 40% lower than equivalent hybrids. However, in countries like India, where coal dependence is high and annual mileage is relatively low, the gap can narrow to under 10%.

Ultimately, you cannot answer the question of "electric or hybrid" by name alone. Vehicle size, battery capacity, power mix, fuel efficiency, mileage, and lifespan all need to be factored in.

After End of Life: Environmental Scorecard Continues Beyond Retirement

What happens after a battery reaches the end of its life cycle also affects the environmental scorecard. Recovering lithium, nickel, cobalt, and other materials from used batteries for reuse in new batteries can reduce the energy consumption and carbon emissions involved in mining and refining minerals.

The impact of battery raw materials themselves is considerable. According to the IEA, the processing of key minerals accounts for about 55% of the lifecycle emissions of nickel-manganese-cobalt (NMC) batteries. For lithium iron phosphate (LFP) batteries, manufacturing represents nearly 50% of total emissions. Increasing the proportion of recovered materials used in new batteries is critical.

LG Energy Solution is accelerating its battery recycling business through Ultium Cells, a joint venture with General Motors (GM), by signing a battery recycling contract with Li-Cycle, the largest battery recycling company in North America. Photo by Yonhap News Agency, provided by LG Energy Solution

However, recycling also consumes energy. Transporting and dismantling batteries and separating and refining materials all emit carbon, and the benefits depend on the technology used.

Professor Choi explained, "Battery recycling can vary greatly in its reduction of greenhouse gases depending on the technology, and lightweighting a vehicle also depends completely on the choice of materials."

Senior Research Fellow Lee sees the decarbonization of the electric grid as the most important task for improving the environmental performance of electric vehicles. He emphasized, "From a greenhouse gas perspective, decarbonizing the grid is the most fundamental and impactful factor. Within the scope that the automotive and battery industries can control, improving manufacturing processes for batteries and materials, recycling used batteries, and building robust safety management systems are realistic solutions."

Electric vehicles are not "perfect eco-cars" that emit no carbon at all. They leave a carbon footprint throughout manufacturing, driving, and disposal. However, unlike internal combustion engine vehicles, there is much greater room to reduce these emissions—in battery factories, power plants, grids, and recycling facilities. That is why the real contest of the EV era is not on the road, but outside the car itself.

This content was produced with the assistance of AI translation services.