How sustainable is an e-bike?

by Podbike | December 30th

Cycling has long been considered a healthy and environmentally friendly form of transportation because the only thing it burns is calories. The CO² emissions created by a bicycle’s manufacture are also relatively limited. But how sustainable is an e-bike, also known as pedelec? These require additional materials to manufacture, such as rare earth minerals, lithium, and cobalt. It stands to reason that the consumption of these elements would worsen the carbon footprint of an e-bike. But that’s not necessarily true when you consider other aspects. In relative terms, it’s possible for an e-bike to be more sustainable than a standard push-bike, as we explore below.

1. How sustainable is the manufacturing process of an e-bike?

About a quarter of the greenhouse gas emissions of a bicycle occur during its manufacture. The choice of materials plays an important role here. According to the World Steel Association, the production of steels emits an average of 1.9 kilograms of greenhouse gases (CO², methane, N²O, and so on). For aluminum, the figure is ten times higher at 18 kilograms, unless the manufacturers use recycled aluminum. Then the number drops to 5 kilograms. Since the amount of greenhouse gas released depends heavily on the kinds construction materials used, we will rely on the European Cyclist’s Federation (ECF) estimate of 96 kg of greenhouse gases created per regular bicycle, and 134 kg for an e-bike.

We divide these values by the average number of kilometres the bicycle covers between manufacture and disposal to arrive at a total carbon footprint number. In the case of an e-bike, we add the emissions from the electricity generation. These last values will fluctuate depending on whether the power for the produvtion of the bike comes from renewable or fossil fuel sources. Even in the worst-case scenario though, production emissions are not the decisive factor. A much larger share of overall greenhouse gas emissions is comes from the bike rider’s diet and this is what makes an e-bike more sustainable for most of us.

2. What does the bike owner eat?

Emissions not only play a role in the manufacture of the e-bike, but also by the growing of food that gives cyclists the energy they need to ride. About three quarters of the greenhouse gases caused by cycling can be attributed to the production of additional food to fuel the cyclist. This is where an e-bike has a decisive advantage because, thanks to electrical assistance, the cyclist burns fewer calories. To put this into numbers, we calculate how many additional calories for each kilometre of riding and multiply that by the average emissions created by food production per calorie. Before things get too complicated, let’s take a step back and briefly summarise the biggest factors that create farming (food generation) emissions. 

If you get your energy for cycling primarily from meat, you significantly increase the amount of greenhouse gas emissions per kilometre. Beef creates 52 grams of greenhouse gases per calorie, according to a study in the journal Science. A plant-based diet built around wheat, rye, potatoes, and corn however, produces only one gram of greenhouse gases per calorie. People with a high meat consumption could therefore improve their carbon footprint simply by switching from a conventional bicycle to an e-bike, because they would burn fewer calories during the ride and would theoretically also have to eat less. At least, that’s the theory.

It’s hard to say in reality if a person really would eat less because of the power boost they get from an electric-assist motor. Rather than cutting back on food, the cyclist might actually eat the same amount of food and use the extra energy to do other things. For our purposes though, we focus only on the calories that are actually burned while riding, which leads to our fourth question.

3. How many calories are burned during the ride?

The number of calories burned while cycling depends on various factors: the length of the ride, the gradient, the speed, and the rider’s body weight. One thing remains constant though: if you pedal less, you will use less energy. With a pedelec you do just this because it suppplements your human energy by power from the bike’s battery. Since electricity production, on average, emits fewer greenhouse gases than food production (especially animal), electric bikes have a smaller carbon footprint than conventional bikes. Even when we take the additional emissions from battery production and electricity consumption by the motor into account.

It’s obvious that human-powered bicycles and e-bikes are significantly better for the environment than any car when it comes to carbon footprint. Therefore, the critical question is: Should we use a bicycle or e-bike only for recreation? Or should we consider replacing cars with bikes?

4. Could you use an e-bike to replace a car?

The more comfortable cycling becomes, the more likely it is we will pedal instead of drive. The only way we will reduce greenhouse gas emissions substantially is to reduce our dependence on cars for personal travel. For example, even a small car emitted an average of 1,695 kilograms of CO² based on 2020 numbers from Germany. Luxury vehicles emitted 2,595 kg of CO². Electric cars perform much better, but their CO² footprint is still many times higher than that of a bicycle. 

Add an electric motor to a bike and cycling becomes more accessible to a bigger demographic. The physical effort required becomes less. Simple things like taking off from a standing start at traffic lights become much easier. There is one key thing that traditional two-wheeled bikes can’t solve. What do you do when it’s cold and rainy? That’s exactly why we at Podbike developed the FRIKAR e-bike. It has four wheels which makes it stable like a car and protects the rider from the elements. The clear canopy also offers riders 360-degree visibility, allowing riders full view of the traffic around them. We hope that our FRIKAR e-bike will become a viable alternative to car ownership.

For more on Podbike and its FRIKAR e-assist bike, check out the articles below:

Against gravity: riding uphill with the FIRKAR

Why vehicle weight and resources matter