By Eamonn Mulholland
For well over one hundred years, the internal combustion engine has reigned supreme over our roads. For one small but significant transport sector, the humble city bus, its reign has neared its end.
The most recent quarterly sales data for buses this year shows that the share of diesel-only vehicles sold has dipped below its majority stake, giving way to battery electric to take a leading role. This marks the first time that a zero-emission technology has become dominant in a road transport sector in Europe.
City buses make up about 60% of all heavy-duty passenger vehicle sales (the rest are coaches and interurban buses). Their conventional form tends to have high emissions, emitting about 1kg of CO2 per kilometer compared to less than 100g of CO2 per kilometer for cars, although buses carry many, many more passengers than cars do. City buses are also in a prime position for electrification; they operate predictable routes which eliminates range anxiety, they’re usually stored in depots overnight where they can be charged, and they’re normally publicly procured, giving their purchase access to a wider amount of capital compared to the private transport market.
But this switch hasn’t so much emerged due to a significant rise in zero-emission sales—which has hovered around 30% for the last year—but rather from a fall in diesel-only sales giving way to a hybrid buses, which also overtook the share of diesel this year.
As manufacturers are not (yet) required to ditch high emitting buses, we can thank the market demand for the fall of the internal combustion engine. A few Member States and many major cities plan to phase-in zero-emission buses in the coming years. The Netherlands and Denmark are by far the most ambitious, setting their eyes on a full phase out of the internal combustion engine in bus sales in 2025, followed by Ireland from 2030, and Austria from 2032. There are more pledges from major cities in Europe than we have space to count here (in brief, over half our Europe’s capital cities plan for only zero-emission buses to roam their roads by 2040), but a full list can be found in our publication from last year.
The Clean Vehicles Directive which came into play in August of 2021 has also played an important role. The Directive requires Member States to purchase between 24%–45% alternatively fueled buses (i.e., anything that isn’t a diesel-only bus) between August in 2021 and December 2025. The impact is clearly seen by the sharp drop in diesel-only bus sales at the end of 2021. Half of these targets need to be achieved through zero-emission powertrains. The targets increase in 2026 to 33%–65%, so expect to see another dip for diesel in a few years.
You can see the sales share by country in the figure below. Four of them—the Netherlands, Denmark, Lithuania, and Ireland—purchased only zero-emission buses, albeit with very low sales volumes representing much less than one quarter of their usual sales in a year (see column on the right side of the chart). Hybrid vehicles are playing a strong role in Europe’s largest countries, but still a worrying number of investments in natural gas engines are being made in France, Spain, and Italy, which provide little climate benefit over diesel-only. A recent life cycle analysis we carried out showed that a natural gas city bus reduces greenhouse gas emissions by 17% relative to its diesel counterpart, whereas a battery electric bus running off Europe’s grid mix between 2021 and 2040 brings a reduction of 75%.
The European Commission has recently proposed that by 2030 only zero-emission city buses can be sold in the Union. While this is certainly an ambitious target, the strong performance of zero-emission buses over the last few years, supported by the commitments from Member States, cities, and manufacturers, show this is a realistic (and necessary) target to set.
But Europe’s strong performance with zero-emission buses is far from being a leader; the technology has held a dominant share in China for years, where the sales share of zero-emission buses reached an incredible 91% in 2022. Nevertheless, this is a monumental moment for Europe, seeing the fossil fuel powered bus step down from the limelight for the first time in over a hundred years. In the decade that unfolds, we will likely start to see the rest of the passenger transport market follow suit, leaving zero-emission to reign for much, much longer.
This article has been sourced from the International Council on Clean Transportation and can be accessed here