With its lithium battery and recharging needs, the electric bike is not neutral for the environment, even if it pollutes much less than an electric vehicle and nearly 100 times less than a thermal car.
It has the power to disgust other cyclists on every climb. But, of course, we’re talking about the electric bike and its battery. This small but efficient machine can reach 25 km/h (15 mph) without pushing too hard on the pedals.
Less tiring than the mechanical bike, accessible to the less athletic and older people, is it such an ecological solution for city transportation?
Many do not see any environmental disadvantage when we ask the riders of these gleaming machines. “It doesn’t pollute at all; it’s zero pollution,” says a rider I met on the road. “Yes, it’s polluting because we don’t know how to recycle the batteries,” moderates another rider.
To better evaluate how and why an electric bicycle pollutes, we must study its entire life cycle:
- Its end-to-end manufacturing process, from the extraction of raw materials and the manufacturing stage in the factory.
- It’s day-to-day use by the cyclist.
- It’s the end of life once the e-bike is thrown away.
The manufacturing stage is by far the most polluting. About 95% of the carbon footprint of the electric bicycle is linked to the manufacture of the bicycle itself.
Suppose this indicator allows us to quantify the share of responsibility of our e-bikes in global warming. However, in that case, it only allows us to evaluate some of the pollution generated by the production of our bikes, which contain electronic components with severe consequences for ecosystems and biodiversity.
An electric bicycle battery contains several metals of varying degrees of rarity. A large part is copper, aluminum, lithium, manganese, cobalt, and nickel. In a 500-watt battery, there are about 40 grams of lithium, according to figures provided by Bosch, one of the sector’s giants.
Its extraction from giant pools, mainly in Bolivia, Chile, and Argentina, requires enormous quantities of water and could endanger fragile ecosystems. For example, in Chile, mining activities are responsible for 65% of the region’s water consumption. These water-hungry activities are already pushing local farmers to seek supplies from further away.
Cobalt is mined under challenging conditions by underpaid miners in the Democratic Republic of Congo. Unprotected, they often dig with their bare hands, in contact with dangerous materials.
A Tesla battery for 140 e-bike batteries
However, we can put these environmental impacts into perspective if we compare them to those of the electric car, whose technology also depends on lithium-ion batteries. On average, an electric bicycle battery weighs 3 kilos, about 100 times less than an electric car.
When questioned, the Bosch brand reminds us that about 5000 to 8000 cylindrical lithium cells are used for a car battery, compared to only 40 to 60 for a recent electric bicycle. A Tesla Model S battery consumes the same number of lithium cells as 140 electric bicycle batteries.
Fortunately, the second stage in the life cycle of an electric bicycle is much less polluting. The consumption of electricity to charge the battery of a bicycle has minimal impact on climate change.
Recycle your bike?
The third step for our e-bike: is its end of life. With the number of electric bicycles still relatively new, the question of managing used batteries is only beginning to be addressed. But for the past three years, specialized channels have been recycling this unique waste.
This process gives 70% of the plastic and metal components a new life. The recycled metals can be reused in other applications as secondary raw materials, not necessarily to make batteries.
Once unpacked, these batteries are then meticulously dismantled. Inside the rigid shell, a series of colored cylinders: the cells. A battery is a succession of small cells placed end to end. Next, the plastic envelope is isolated, as are the printed circuits and electronic components.
The cells themselves spend several hours in the oven. Then, they are heated to several hundred degrees in a thermolysis furnace to recycle them. Once carbonized, the cylinders are crushed and separated. As a result, iron, copper, aluminum, and lithium carbonate will have a second life.
Despite the efforts of the cycle industry, the recycling rate of used batteries is currently still quite low. As a result, many used batteries sleep in our drawers instead of being collected and processed. Others are reconditioned and will only be recycled later.
To reduce the environmental impact of your electric bike, use it as long as possible. That means amortizing its footprint by spreading it over many kilometers. If you buy an electric bike on a whim and only use it for 1,000 miles or kilometers. In that case, the carbon footprint per kilometer traveled is ultimately as high as that of using a car.
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Riding, testing, and writing about e-bikes since 2017.