Is it more environmentally friendly to keep driving an old Diesel or to buy a new electric car?

28 Feb 2022

What’s more environmentally friendly: keep driving an old car running on diesel/gasoline, or buying a new EV? A new EV consumes resources and emits CO2 for its production, but it has much lower CO2 emissions during driving. An old Diesel already has “amortized” its production energy and emissions, but it continues burning fossil fuels and emitting greenhouse gasses.

How to answer to this dilemma was recently asked on Twitter and led to a deep discussion (including some experts like Auke Hoekstra from TU Eindhoven and Michael Liebreich from Bloomberg NEF:

In a nutshell, the high-level answer is: It depends on your driving behavior: If you are planning to buy a new car eventually, and you drive a lot: buy a new EV immediately and scrap the old diesel/gasoline car. (Scrapping avoids that the old combustion engine vehicle remains on the road, just driven by someone else). If you drive very little, and the car you own is likely your last car (for elderly folks, or if you are planning not to own a car anymore at all in the future): keep driving it and don’t buy a new vehicle!

In between these two extremes, there are various tradeoffs and different scenarios, which aren’t easy to summarize for everyone. Furthermore, besides the CO2 emissions factor, there is also the question of the effect on your household budget. Luckily, one of the researchers who answered in the thread developed a great tool, which lets you calculate the carbon sustainability and financial sustainability of switching to an EV, based on your specific driving characteristics, car type, etc. The tool is available here.