John Kendall looks at how charger numbers and efficiency needs to be improved to match the growing demand and volume of EVs on the road.  

The site at Exeter Services is 12 megawatts – enough to deliver 80 x 150kW DC rapid chargers

Rising fuel prices are probably the greatest trigger for increased interest in switching to EVs, as fleets search for ways to reduce their ever-increasing fuel costs. A cynic might argue that while that’s a good thing, more rapid take-up of EVs will only serve to show the weaknesses in our charging infrastructure.  

I drove to Edinburgh and back last summer in our then long-term test Citroën ë-Dispatch and found that, while the motorway charging network was in disarray at the time, the lack of charging facilities in public car parks and hotels was in many ways as much of an issue.  

Since then, the Government has launched the rapid charging fund, a £950m pot designed to ensure adequate future provision of charging facilities at motorway services and major A-road service areas. The fund is not yet open for applications but since we are only just reaching the stage where suitable infrastructure is available, the cash will hopefully be available once the hardware is ready to go.  

At Exeter Services, just off the M5, Western Power Distribution is installing a new power supply, designed to ensure that the service area’s charging needs will be taken care of for around the next 20 years. It’s a pilot project put together with government-backed innovation funding and, if successful, it could be rolled out at other motorway service areas across the parts of the country served by Western Power Distribution. That includes 65 service areas in total – around half the total number of service areas in the country, because of the density of motorways in the areas on WPD’s patch. 

Numbers game 

As domestic electricity consumers, we think in terms of 230V and 13-amp circuits at home or, if we have electric cookers, showers or domestic charging points, we might reach the dizzy heights of 32 amps to serve 10kW showers and 7.4kW charge points. When your business is planning electricity supplies to towns and cities, you need a bit more than that.  

“What we spotted was that when you look at motorway services and work out the amount of electrical capacity that’s going to be required, you need to go big,” explains Paul Jewell, system development manager, Western Power Distribution.  

Paul Jewell, system development manager, Western Power Distribution

“In our world, we can do a few megawatts as a standard sort of supply that we’d fit to a housing estate. So, if you see a 3m x 3m box in the middle or on the edge of a housing estate, it’s a proper solution for us.”  

Strange as it may seem, that may not be enough to future-proof the supply to a motorway services site.  

The Government’s project is rapid, which when considering those charging needs is predicting power needs of over 40 megawatts to some sites (one megawatt is 1,000kW).  

“When you’re looking at that level, the answer has to be to go up one voltage and go one size bigger,” continues Jewell. “In our world, the one-size bigger that we’ve got here is a transformer that we’d normally use to feed a small town.” 

It might be helpful to add a few other numbers in here too. When Jewell speaks of going up one voltage, he is talking about taking power off the national grid at 33,000V and passing it through a transformer to bring it down to 11,000V, which should provide all the charging they are going to need at Exeter Services. These are fairly standard figures for electricity suppliers feeding power to a small town anywhere in the country. 

“When we build what we call primary substations to do that job, it’s probably in a large site, it might be 40m by 40m square, it’s got floodlights, switch rooms and all sorts of things,” explains Jewell.  

“If we came to motorways services and said, ‘Can we do that on your site?’ the motorway service operators would probably have quite a short conversation with us.” 

“So, the plan that I had a few years ago was to go to a manufacturer and say, ‘Can you shrink one of those primary sub-stations that feeds a town into a couple of shipping containers?’, because suddenly I’m then talking a language that motorway service operators understand, a footprint they understand and something that genuinely would fit, which is important, and this is the result.” 

The idea was that if you can fit everything into two 20ft shipping containers, they can literally be transported to the site on a standard truck and lifted into place with a crane. In fact, it was the crane that proved to be the bigger transport job – it needed three trucks to bring it in. 

Why 33,000-volts?  “Go to a 33,000-volt solution in our world and when you’ve laid the two sets of 33,000-volt cables that have come to this site, you’ve immediately created yourself a pipe that’s good enough for 40 or 50 megawatts. The transformer we’ve got here is only 12 megawatts, so again, a change of transformer and there’s a bit of futureproofing here,” says Jewell. 

“What I don’t want to do, and I don’t want government to do, is to spend money digging up roads and laying cables that we then have to rip out at some time in the future,” he adds. “Digging cables from the local network to where they are needed is a really expensive thing to do and you only want to do it once. This site is 12 megawatts, so that’s 12,000kW, so 12,000 kilowatts’ worth of 150kW chargers – that’s 80 DC rapid chargers.” 

That’s all very well for cars and vans needing a rapid charge in 45 minutes. But add trucks and coaches into the picture and it quickly changes. The CharIN consortium was set up in 2015 as a group of vehicle manufacturers and charging suppliers to consider the issues concerning charging electric vehicles.  

One of its projects is megawatt charging as Jewell explains: “It’s rapid charging for trucks to fit in with the 45-minute tacho break for drivers. 3.5 megawatts per charger is the current indication that we’re getting. So, here at Exeter, I’ve built a 12-megawatt substation, which is the size of a small town. In the world of HGV rapid charging, that’s four chargers… 

“Certainly, what I want to do is make sure that we can capture overnight truck charging, which is 150-300kW. We need to be able to capture that in whatever we build out.” 

If this much energy is available at motorway service areas, it could equally be used for producing hydrogen for vehicles using hydrogen fuel cells to store electricity instead of batteries.  

“As far as we’re concerned, we’re not really concerned one way or the other whether it’s battery electric or hydrogen, because it’s still electrical energy,” says Jewell. “So, if you’re going to make hydrogen, you need electricity, which means we create electricity, we send electricity in big lumps to places where they make hydrogen and then the hydrogen is distributed as a fuel. If electricity is the end fuel in the vehicle, you’re still sending big lumps of energy, but spread out over a wider area. I’d have no concerns about one of these being at a location where part of the 12 megawatts is being used to charge an electric fleet and another part of the 12 megawatts is being used to run an electrolyser (to produce hydrogen). It doesn’t matter, it’s just a case of getting electrical energy to where it’s needed.  

“It’s not just for motorway services. If you took a big distribution depot that wanted multi-megawatts of capacity for charging – put one of those in.” 

It’s difficult to predict when installations like this will be rolled out across the motorway network. It will partly depend on government funding, but once proved, it should just be a matter of how quickly these systems can be built.  

Systems like this will also provide for future expansion and reliability. Since this installation is similar to that provided for a small town, it should be fairly straightforward to add sub-stations around a service area site as required. 

“We can put a sub-station next to the restaurant, a sub-station next to the petrol station and a substation down next to where the trucks park. We can build a network that’s needed and just add to it,” emphasises Jewell.