The “Green” Way to Get Around Town
Assessing the life cycle of a method of transportation is particularly complex as it involves three major factors: the impact of the vehicle, the footprint of its fuel, and how the vehicle is used (individually or shared, in town or on the open road, number of kilometers covered, long or short lifespan). Here are some comparisons of the carbon footprints of several urban transportation methods, including two-wheelers, buses, cars and subways, as the world gradually shifts to electric motors. For comparison’s sake, the figures are often given in terms of emissions per kilometer and per person transported.
The All-Round Winner: The Push Bike
Push bikes emit zero particles and their carbon footprint is limited to the manufacture phase (plus a small amount during maintenance). Naturally, more sophisticated, top-range or sports bikes require more materials. However, a study led by French electric vehicle nonprofit AVEM found that the CO2 emissions per kilometer traveled were very low – around 5 grams of CO2 per kilometer. The calculation is based on the assumption that you keep the bike for eight years and cycle at least 200 kilometers per month. If you change bike after one year, you will not have offset the manufacture emissions. Of course, in theory, the bike’s “fuel” emissions should also be taken into account, that is, what the cyclist eats when they work up an appetite... which is very difficult to calculate! Do cyclists eat more than when they are sitting in front of the television with a packet of potato chips? Will they eat meat or bananas to make up for the lost calories? Some studies put forward “food” emissions of 15 grams of CO2 per kilometer. This photo shows a bicycle factory in the north of China.
Batteries Are Central to New Systems
The lithium-ion battery is the key component for electric two-wheel mobility solutions, from bikes to motor scooters and kick scooters. They provide a less polluting source of power than gasoline, but they are becoming the main contributor to vehicles’ carbon footprints. According to a Swedish study, the manufacture of a 500-watt-hour battery for a large electric bike emits 100 kilograms of CO2 across the full production chain, owing to the extraction, purification and integration of rare materials. If the battery were used over 10,000 kilometers, it would therefore release 10 grams of CO2 per kilometer. The main takeaway, then, is to look after the battery well – don’t leave it in the sun or in a damp place for too long, and avoid under- and over-charging.
Are Electric Bikes Really “Green”?
Manufacturing the battery more than doubles the carbon cost of an electric bike’s production. Emissions from the electricity used must also be added in, which vary depending on how carbon-intensive a country’s electric mix is. However, these emissions are lower than for the battery. According to an AVEM study, an electric bike that travels 200 kilometers per month over eight years would be “responsible” for 16 grams of CO2 per kilometer, compared with 5 grams from a regular bike. Advocates of electric bikes argue that cyclists use fewer calories and so eat much less. Additionally, they generally cover more kilometers over the year than a non-assisted rider. The electric bike is therefore almost as laudable as its peddle-powered equivalent. However, it should be noted that these figures do not include the battery’s end-of-life impact, which varies depending on the method used to recondition, recycle or (to be avoided at all costs) landfill it.
Reassessing the Electric Scooter
Electric scooters are increasingly popular. Theoretically, their carbon footprint should be similar to that of electric bikes. However, that’s not the case. Scooters are more of a novelty, a fleeting fad, meaning users generally take less care of them and keep them for shorter periods of time. And they have gained wide popularity mostly because of digital rental platforms that use free floating systems, which allow the scooter to be left anywhere. Many break or end up under water. This photo shows the “catch of the day” in the old port of Marseille.
Trucks to Transport Two-Wheelers...
There is another negative side effect of the rise of free floating rental platforms. As there are no fixed bases that automatically recharge the scooters, fleet managers call on helpers to collect the scooters during the night, bring them to often distant charging stations, and return them early in the morning (see photo). The result is catastrophic. Already, the extremely short lifespan of the scooter/battery (sometimes just one month!) bumps the carbon cost of the manufacture phase up to 70 grams of CO2 per kilometer. Transporting the scooters in trucks adds up to 50 grams, according to an American study. This brings the total to over 120 grams – eight times more than an electric bike used over several years. There is a quick fix to save scooters: treat them as well as a personal bike.
Is Public Transportation a Greener Alternative?
The simple problem with assessing the carbon footprint of urban buses, trams and metros is that it is tiny when they are full, and enormous when they are almost empty... For this reason, the amount of CO2 per kilometer and per passenger must be calculated in grams, resulting in only approximate amounts. In Paris, the RATP public transportation operator estimates 95 grams of CO2 per kilometer-passenger for buses, 4 grams for metros and 3 grams for trams. Only rough amounts can be given for personal cars too. Many studies put the figures at between 200 and 250 grams in urban areas, taking everything into account, particularly the fact that commutes to and from work have a low occupancy rate (1.16 people on average in France).
And Motor Scooters?
The carbon footprint of motor scooters varies substantially. If they are electric, their environmental impact is substantially higher than that of electric bikes, but it is still in a very satisfactory range. Scooters with an internal combustion engine generally have a footprint two-thirds the size of an individual car. However, certain factors play a great role in improving environmental performance: smooth driving, avoiding accelerating and braking; regular maintenance and servicing; and care not to overload the scooter beyond its capacity, particularly by taking several passengers. This photo shows scooters available from Paris’s digital scooter rental platform.