Defossilizing mobility requires the widespread electrification of road traffic. Expanding public transport is thereby a key strategy to improve the efficiency of mobility as well as minimize the material investments needed. It is thereby essential that new busses are electric straight away. Lots of technologically mature options for electric busses are already available on the market. But what about all 15 million diesel busses still on the road today?

Gradually replacing all of them with new electric ones will slow down the expansion of the bus fleet, as some of the new electric busses would need to go into the replacement of old diesel busses. That would delay the expansion of public transport. The existing busses are not a problem for the climate, it is only their diesel drive trains. Replacing the diesel engine with an electric motor, battery, and electric auxiliaries can retain the value, structure and integrity of the bus itself, while only scraping those components which cause the CO2 emissions. Most diesel busses are technically in good shape and do have a long enough remaining lifetime to be interesting for retrofitting. And when standardizing retrofit-kits and –procedures, the necessary works can be carried out with minimal financial investments, material requirements, and time.

Multiple companies all over the world have started bus conversions, for example in Germany, Turkey, UK, Kenya, Nigeria, or Senegal. Our CircEUlar partner Empa is currently investigating how this circular strategy can scale and evaluate the potential to accelerate the transition as well as reduce environmental impacts.

by Empa