With this interactive calculator, you can compare the ecological merit of an electric vehicle (EV) with a thermal vehicle motored by an internal combustion engine (ICE). The comparison is based on the lifecycle global warming potential, that is counting equivalent CO₂ emissions. Other interesting comparison criteria such as effects on human health (like particulate matter or NOx emissions) are not included here.
The general idea is that, for its manufacturing, an EV requires more energy than an ICE car because of its battery. The EV has thus a “CO₂ debt” that can be repaid after traveling some distance if, as one may expect, the EV indeed emits less CO₂ during usage (CO₂ per unit distance). The computation of this “distance to CO₂ parity” is the objective of this calculator.
Particular feature of this app: it accepts uncertain inputs. Read more below…
The distance to CO₂ parity depends on several inputs which value is difficult to know precisely, so this calculator allows you to input lower and upper bounds in addition to nominal values. Then, using interval arithmetic, it propagates uncertainties down to the final result.
This procedure allows checking the robustness of the conclusion on whether or not an electric powertrain is better than thermal one. Spoiler: EV generally wins to ICE, unless using highly pessimistic inputs, like using 100% coal-based electricity for EV charging or the overly optimistic ICE fuel consumption data from the NEDC standard test.
Looking further than this slightly frivolous computational exercise, my conclusion on this is clear: vehicles should be light and small. If electric, they should be recharged with low carbon electricity.
(Perhaps the lightest one I know is my e-bike: 0.4 kWh battery, and about 7 Wh/km 😉.)
All the input choices in the calculator are reflected in the address bar. This means that sharing the complete URL (including the
?bs=...&round=true part) does include all input values. The summer 2020 app update includes a “Share” button that copy this URL in one click.
Comparisons of Electric vs Thermal vehicles have been done several times. Perhaps the most recent one, is the online tool “How clean are electric cars?” which was released in April 2020 by Transport & Environment (T&E). The companion report is well detailed. I’ve updated my calculator with their charging losses.
One striking feature of T&E’s analysis is to consider, over the lifetime of the electric vehicle, the forecasted decrease of CO₂ emissions for the electric grid of each European country.
More information (data sources, inspiration for the app) in the app presentation page.