Rolling out cars of the future

Could our roads and cities cope with electric cars en-masse?
29 January 2019

Interview with 

Darren Capes, Institution of Engineering and Technology


Carbon neutral cars certainly sound like a good idea, but could towns and cities actually cope if they were adopted en-masse? How might infrastructure need to change to make electric cars viable at scale? Chris Smith spoke with Darren Capes, a transport expert from the Institution of Engineering and Technology. First up, Chris asked, what's actually involved in powering an electric car?

Darren - Simply, we plug it in and away it goes. But of course there's an awful lot of technology behind that and the way this develops is likely to be that more and more charging gets done at home. As range increases the need for you to to charge the vehicle away from home or at the shops or at work will reduce and most people will find themselves charged in the car overnight at home.

Chris - What sort of energy demand though Darren?When I plug my car in how much energy a I transferring from the grid into that vehicle. What's the electrical tank capacity if you like in an electric car?

Darren - It's actually quite high and it depends what type of vehicle you buy but it is quite high. But but but the issue really is how fast you charge the vehicle and if you want to charge the vehicle very quickly you end up with a very high amperage you end up with a very high amount of power, that's quite difficult to accommodate in a domestic setting. If you're willing to charge the vehicle overnight then that becomes more acceptable and you find that actually you could charge a vehicle overnight for 13 amp socket for example, depends on the kind of where we want to do this in the future.

Chris - I know lots of people who live on a street and they park their car on the street. They certainly don't have a cable that they could easily put the car into because their cars off of their property it's on the street. So we're going to have to think about this aren't we, because there is not just the huge amount of energy. You know are domestic power lines capable of delivering that amount of energy if everyone in the street plugs in their car at the same time but there's also the how do we get access to the grid in the first place for a parked car.

Darren - Absolutely and there are two challenges, well there are three challenges, the first challenge is people tripping over cables draped across footways which we would like to avoid. But the two main challenges there are how do you charge your vehicle when you live in a terrace house. Do we alters street lights? Or do street lights have plug in points, or do we put plug in points in the ground and recess them in footwear. And that's really a challenge that we're working on and some of the larger cities certainly some of the boroughs in London have been looking at that. The second question you read is the important one about how we actually distribute that amount of power to vehicles. One line of thought is yes actually we made double the amount of power that we need to provide to homes if every vehicle became electric.

Chris - This is literally the mains cables might have to double in diameter in order to deliver that much energy.

Darren - And it probably wouldn't be that because batteries are becoming more efficient and the way that we use power in the home is reducing.  So it won't be that but it's of that order of magnitude, actually providing the power in the home isn't a problem. But getting the power to the home is and we have a distribution network around our cities which just is not ready for that level of electrical usage at the moment.

Chris - People are talking though about maybe rederiving and rebuilding our entire energy grid anyway with what they dub a ‘smart grid’ in mind whereby we were talking earlier in the program about trying to store electricity because renewables like wind, like solar produce a surfeit of power at one time, but that doesn't necessarily line up with when we need the energy so we need a way to store it. People are saying car batteries are extremely good at storing large amounts of energy and then releasing large amounts of energy very quickly. Therefore maybe we see a future coming where people share their car battery storage capacity with the national grid. So when you plug your car in you agree your car could be borrowed for a bit in energy terms to top up the grid. That will definitely need us to have better supplies to homes won't it.

Darren - Absolutely. As we move towards electric vehicles, vehicles will not only become electric but they will become a lot more intelligent and they will have a lot more monitoring technology. They will have a lot more communication technology on them. So the ability of us individually to know how our vehicles are charging and how we're using them and the ability for the city to know collectively what the vehicle is in in the city are doing and how much power they're using and when when it's available, means that there will be a lot more opportunity to do that to work out strategies for sharing power and keeping vehicles plugged in so that we charge them at quiet times and then lend the power back to the grid at busy times. These are all opportunities and this is something that's really been looked at now, how an intelligent vehicle can act as an intelligent ourselves as well as just been charged from the grid.

Chris - I think the statistic I saw was that the car is on average the second most expensive asset the average family buys after the house and it's the one that they get the least use out of because it spends more than 90 percent of its time just park doing absolutely nothing. So that would be a one way to make your investment go a bit further wouldn't it. But what about the roads we drive these cars on and the cities we drive them around? Because at the moment the infrastructure is all rigged up with the petrol engine in mind. Have people actually gone away and started to look at the feasibility of wide scale mass adoption of these sorts of vehicles?

Darren - Certainly. Again there's some really interesting questions. I think one thing to say is that truly autonomous vehicles without any steering wheel at all is probably a long way in the future. Actually what we're looking at now is increasing levels of autonomy and that has benefits of cars because as we're already starting to see with things like adaptive braking and adaptive cruise control we can build better surface systems into the vehicles by taking some of the responsibility off the driver. Autonomy can help us with that. We have to think about how vehicles they react to road signs and road markings. At the moment they don't. But people are now looking at systems where vehicles can read road signs and road markings while argument is actually we won't need any of that. You can just program all the rules into the vehicle and you won't need any road markings or anything like that, but of course the road markings and road signs and junctions and pelican crossings are also used to cyclists and pedestrians not just vehicles. So they're likely to be with us for an awfully long time and until we get to a sort of golden future where vehicles are completely self aware and completely autonomous which is a long way away, it's very much going to be about how we accommodate autonomy and how we use the growing levels of autonomy in a city which fundamentally because of the other uses of the city won't change that much.


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