In my last series of posts, I focussed on the war of attribution between electric vehicles (EVs) and traditional internal combustion engine vehicles (ICEs). Due to the recent slump in oil prices, EVs are on the defensive. They need increased volume to get down their cost curves and punch out of their current redoubt of super cars (Tesla) and green credential statement cars (Nissan Leaf). Low gasoline prices has made such an offensive a lot more tricky to pull off.
But let us suppose that a commercial super battery were to emerge that had high energy density and was cheap. What would happen next? Let’s run this thought experiment in a UK context.
First, let’s look a the UK’s existing fleet. Great Britain has a population of 64 million people, who between them drive around 29 million registered cars (source: here, click for larger image).
And annually each car is driven for an average of 8,000 miles, which translates into 22 miles per day (click for larger image; also remember we are smoothing out weekends and holidays).
From a previous blog post, I republish the following chart, which shows the kind of mileage per kilowatt-hour (kWh) a battery achieves at present.
Currently, the BMW i3 achieves around 5 miles per kWh. However, current generation EVs spend an awful lot of energy lugging around bloody great big batteries. With a super battery, like the lithium air batteries (li/O2) in the chart below (see my last post), you get four times as much energy for the same given weight. Let’s suppose that the auto makers double the battery capacity to get the required 200 mile range, but still halve the battery weight. Throw in even more use of modern materials and it is not unrealistic to guestimate that our future car would achieve 10 miles per kWh.
Using these numbers, 22 miles translates into 2.2 kWh per car. Next, we find the average number of cars per household in the UK, which is 1.1 (here, click for larger image). So we are looking at EV energy expenditure per household of about 2.4 kWh.
Meanwhile, average domestic daily electricity consumption per household in the UK is around, 4,200 kWh, which works out at 11.5 kWh per day (here, click for larger image).
We are now in a position to compare the daily EV energy expenditure of our hypothetical future household with current electricity consumption. In short, expending 2.4 kWh per day on the future EV will raise electricity consumption by 21% from the current level of 11.5 kWh. While that is a lot, it is not nearly as much as I would have originally thought.