In a previous article (https://edenergy.be/the-myth-of-flexibility-production/?lang=en), we drew conclusions about the optimal production park and the measures to take regarding grid investments and research development, aiming to limit the societal and individual costs of electrifying two major needs: dwelling heating and individual transport.
Although the conclusions were straightforward, nuances were expressed concerning the figures. Indeed, using historical consumption patterns raises questions in a world where the evolution of needs is as significant as those related to the energy transition.
As announced, I made calculations to estimate the consumption of cars when the fleet will consist entirely of electric vehicles.
The statistics published by Febiac enable us to make the following assumptions:
These figures must then be distributed across the year using the following assumptions:
These assumptions imply that, except during holidays, the distribution of mileage is flat over the year, on average, no day is different from another. Further, some people use their cars for holiday travel. According to published statistics, 45% of Belgians take holidays, and among them, 60% use their car for travel. The average holiday travel mileage is 2,000 km (to the destination, around the site, and back). Multiplying 2,000 km by 45% and 60% gives an annual holiday mileage (spread across the entire car fleet) of 540 km.
However, these holiday travels are primarily made in July and August, with a known preference for July. Thus, this annual mileage will be distributed across these two months as follows:
Lastly, we assume an average electricity consumption for the cars:
I know some people will argue that the figure of 15 kWh/100 km is on the low side for existing cars. However, as mentioned earlier, heavy, inefficient cars are unsustainable and, I hope, will no longer be accepted in the coming years, at least before 25% of the car fleet is electrified (see another article for more information: https://edenergy.be/is-there-enough-lithium-on-earth/?lang=en).
A figure of 8 kWh/100 km is already easily achievable today. Moreover, the lower the consumption figure used in the calculation, the smaller the demand for car charging. Consequently, what follows cannot be seen as an exaggeration; on the contrary, it is conservative.
We can now calculate the additional consumption of a fully electric car fleet over the months of a year.
July and August show higher average mileage per car due to holiday travel. One might argue that the additional consumption will occur abroad, not in Belgium. That’s mainly true, but not totally and besides, people from other countries (e.g., the Netherlands, Scandinavian countries, and Germany) will drive through Belgium, and some will charge their cars here.
The variations in the remaining months result from differences in the number of days (e.g., 31 in January, 28 in February … yes, sometimes 29).
The yearly total amounts to 13,5 TWh (13.500 GWh), roughly 16% of today’s annual electricity consumption (excluding electric cars and other electrified needs).
To translate this consumption into infrastructure requirements, we must examine charging strategies and compare several approaches.
Broadly, three categories of strategies were considered. The first involves charging the car once a day for one hour, with scenarios for when this hour occurs: from 18:00, 22:00, or 05:00. These timings matter when adding car charging consumption to existing demand since 18:00–22:00 aligns with peak consumption, likely causing more issues. The second strategy involves charging the car once a week for five hours, with scenarios such as 18:00–01:00 or 22:00–05:00, on Saturday or Sunday. The third strategy consists of charging cars on workdays during work hours (e.g., 09:00–16:00).
The last strategy is expected to have the least impact on the grid.
The table reflects the number of 15-minute intervals (qh) during which charging occurs for each scenario for 2021, 2022 and 2023. Differences between years are minimal (only weekend shifts), as are variations between scenarios within the same strategy (A to C: strategy 1; D and E: strategy 2).
For each scenario, we can calculate the additional power (in GW) needed for production and grid capacity.
Tables for 2022 and 2021 are nearly identical to the 2023 table.
The impact of the strategy is clear: daily (workday) one-hour charges require more than three times the power of a better-planned five-hour charge on weekends, which itself requires twice the power of well-distributed over the workday charging (five seven-hour sessions).
A mix of these six scenarios as follows leads to an additional 5 GW of power and is thus comparable with the scenario D or E:
This analysis shows that a well-distributed charging strategy, such as charging throughout the day or during off-peak night hours (22:00–05:00), minimizes stress on the grid and production capacities, as well on the users (reducing the so-called battery depletion anxiety). The impact is even lower when charging occurs during work hours and off-peak night hours. Exceptions may occur but should remain limited to genuine necessity.
Furthermore, since there are more charging hours than needed, low-power (3,7 kW) charging poles are sufficient. Installing them at every parking place allows cars to support the grid (e.g. charging during supply excess and even injecting during scarcity). Injection would discharge the battery, but it’s simply a matter of setting a limit on the necessary remaining charge for each car.
By adopting such a strategy, electric cars could transition from being a potential problem to becoming part of the solution, provided they are used and, above all, charged soundly.