The charging debate

As the automotive industry continues its journey towards full electrification, one of the most hotly debated topics is whether the UK’s charging infrastructure is keeping pace – and indeed whether it will ever be able to cope with an all-electric car parc.


Commentary on the topic is typically partisan, with warring factions debating the details vehemently on social media. What’s interesting is that a lot of the discussion focuses purely on the number of chargers needed, and how far ahead or behind these seemingly arbitrary targets the network currently is.


The problem here is that couching the debate in terms of charger numbers is to over-simplify what is a highly nuanced issue. There are other metrics that ought to be factored into our forecasting.


For instance, one way of approaching the subject might be to look at how much energy production we will actually need by, say, 2030. Afterall, this is the deadline by which sales of ICE vehicles must cease.


To do this we first need an accurate estimate of the 2030 electric car parc size. Estimates vary depending on what source you read, but around eight million is about the median. Next, we need to consider what the average daily and annual mileage of a vehicle is. Currently, these numbers sit at around 22 and 8,000 respectively.


Once we know how many EVs there are likely to be, and how many miles they are going to be doing on average, every day and every year, we can extrapolate the data to arrive at a predicted daily and annual mileage for the entire UK EV parc. In essence, this tells us how many electric miles need to be powered. So far, so simple.


The next step involves making an educated assumption as to the proportion of charging that will be done on home chargers versus public ones. Current data suggests that around 40% of all charging is done on the public network. So, we take 40% of our daily and annual mileage figures to arrive at a more accurate number of total EV miles that need to be powered by public charging. More importantly, this enables us to determine the amount of energy required.


For reference, National Grid recently calculated that we would need 100 terrawatt-hours of additional energy if we electrified all the cars on the road today. That’s based on a vehicle parc of over 30 million, so if we take our more conservative figure of eight million EVs by 2030, the energy requirement should be nearer 25 to 30 terrawatt-hours.


Next, we need to consider the infrastructure and different charger types that we have at our disposal. How much energy can each charger type produce every day and every year? Taking the example of a 7kW charger, we know that it can produce 7kWh of energy per hour. Multiplied by 24 and then by 365, that gives us its annual theoretical maximum energy output (in this case, it’s 61,320kWh). Doing the same equation with a 150kW ultra-fast charger, however, demonstrates just how much more energy can be supplied (1,314,000kWh, or 21 times as much energy as the 7kW charger). A key point to note here is that we are generating a theoretical maximum output per charger, because we are assuming that the charger is in constant use.


In order to build a more rounded picture, you therefore need to focus on the way in which these different chargers are used. For example, we are less likely to see back-to-back utilisation of a 7kW charger. Most chargers of this type are used only once or twice a day. Rapid and ultra-fast chargers, however, have a very different use-case. They are more likely to be located in high traffic areas where back-to-back utilisation is the norm. It stands to reason, therefore, that an ultra-fast charger is more likely to deliver against its theoretical maximum annual energy output, while a 7kW unit will be further from the mark.


Applying what we know about the utilisation of different charger types, we are able to arrive at a more realistic figure. For example, taking 40% or 50% of the theoretical maximum output might give us the ‘true’ yearly output of a given charger type.


Armed with this collection of data, you can then work out how many chargers are needed to produce the amount of daily and annual energy that we calculated at the beginning. Of course, the answer will depend on the ratio of slow to ultra-fast chargers. You will see huge swings in the numbers as you play with the ratio. Taking our example above, we know that an ultra-fast charger can produce 21 times the amount of energy of a 7kW over the course of a year.


Another major factor that affects utilisation and, ultimately, the number of charge points required, is location. We’re lucky that the existing garage forecourt network and the traffic patterns around it gives us an enormous head start in creating a targeted network of charging in areas where it’s needed most.


We already have excellent data about where cars are and where they go. It shows us where we get aggregations of vehicles that need to move around and refuel (and therefore recharge in the future) across the UK. Studying that data gives us a reliable sense of where we need to put charging points now and in the future, so there can be less ‘waste’ in the form of poorly positioned, underutilised units.


Hopefully that provides a good starting point for those who are interested in exploring the various permutations for the 2030 EV charging network. When you examine it through the lens of key metrics – vehicle parc size, required energy output, realistic utilisation and charger potential – a different picture emerges to the one that can be found in various corners of Twitter. This picture shows a network that is more strategically built, more achievable, more sustainable, and more affordable for users.


The debate over charging infrastructure is just one example of how complex the transition to electrification is to articulate. Specialist agencies like Torque are ideally placed to help companies navigate these challenging times, communicate their message clearly, and gain them a share of voice in an increasingly noisy marketplace.