Locale : Global (English)
Electric cars charging on the street

Massive challenges ahead as UK moves to electric vehicles

Dr Simon Harrison, Mott MacDonald’s strategic development director, weighs up what the mass-electrification of vehicles would mean for electricity utilities.

First you need to understand how electricity supply works at the street level

The average demand of you and your house is about 1.5kW. The way the power system is designed assumes that people along your street are not all having electric showers at once – because people have different habits, power use is diverse and load is spread fairly evenly. But if everyone in your street turned on their electric showers at the same time and left them on for an hour, you’d cook the local distribution system. EVs are now visible on the high street. If, or when, we hit a tipping point and EVs become ubiquitous, then the local power system is going to be put under intense strain.

What happens when EVs enter the mix?

EVs have a high charging load which is there for a long time. Depending on charge rate, you might have 3-5kW for a slow charge or around 7-22kW of load for a fast charge. In the case of the 3-5kW load you will be charging for several hours. People who own electric vehicles are also more likely to have people who buy electric vehicles as neighbours. It won’t be long before we are seeing a large change in electricity demand at the very local level. More positively, if an EV is plugged in and not charging, it should in future be able to sell power back from its battery, making its owner some money when power is short.

How might that be met?

One option is to use a smart grid to control the timing of charging and to offer variable tariffs to incentivise charging when the neighbours aren’t. If the network companies invest in smart technologies, for a while at least, we won’t need to put a lot of additional cable in the ground to provide more capacity. Another is for owners or communities to install batteries at home that can help charge the vehicles and relieve the grid. You can buy these kinds of batteries today, they are expensive but will get much cheaper.

How far will that get us?

The issue is scale. If you electrified the whole of the UK vehicle fleet, you could be doubling national electricity use and having a big impact on peak demand. Additional generating, transmission and distribution capacity could be provided but at a hefty price and involving much disruption. Also there will need to be large scale street works to put in ubiquitous charging facilities for the large numbers of people who can’t park off-street.


Yes, but there’s an alternative scenario. As others have pointed out, there are technological and social revolutions afoot. If automation converges with sharing and people don’t own their own EVs, it may take pressure off the local parts of the power grid and the need for street works.


The key question is where are autonomous shared vehicles going to get their juice? The chances are that the fleet owner-operator will do a deal with somebody who has land and a stiff grid supply point next to it. It might be the local supermarket car park or a piece of land next to an electricity substation. What they won’t do is charge up outside people’s houses. The risk though is that we go through a phase of needing vehicle charging in streets before moving to autonomous shared vehicles a few years later – a lot of investment could be stranded.

How likely is this?

The bit that nobody has really got to grips with yet is how society is likely to react to this opportunity and what proportion of the population are going to take it up. You’ll probably have buy-in from all the people who aren’t independently mobile at the moment, such as the elderly, the disabled, for whom this could open up life changing opportunities. Young millennials and the noughties generation are less fixated on owning stuff and might go for it. Maybe the middle aged might still want to own a vehicle, but maybe not if the price is right. Maybe those living in the countryside might want to own a vehicle, shared vehicles might take too long to arrive.

How far and how fast?

It’s a fair bet that it will be dictated by consumer instinct, which in turn can be influenced by what’s brought to the market in ways that consumers believe in and trust. People’s preferences can shift extremely fast. Someone like Uber or Tesla might do a deal in a major city to supply shared autonomous vehicles and facilitate change almost overnight. This is at complete odds with the behaviour of utilities that operate to committed spending plans, within a regulatory cycle. They’re not set up to react swiftly to disruption and there’s a real risk that, if they make the wrong investment decisions, they’ll have redundant kit.

What about generation?

A lot of the same issues apply to generation. More maximum demand and more energy means we need more generation – and more storage, whether that be renewables, nuclear or fossil (hopefully with carbon capture and storage if for more than just backup), and whether localised or centralised. And at just the time the last coal will be retiring from the GB system. We’ll need to be able to cope with several windless days in winter at a significantly higher level of power demand.

If you were a betting man?

In the British and French governments carry through on their announcements this could create some fairly fast movement. If fossil fuel vehicles won’t be sold after 2040 then their resale values will start to plummet well before then. This would likely drive faster uptake of low carbon vehicles. In turn that could cause filling stations to close as uneconomic. Range anxiety, current the scourge of the EV owner, might become a major issue for fossil fuel vehicles. And costs and range of EVs are improving all the time. We’re not at the tipping point yet, and we probably need a lot more street charging points before things really start to change. What’s really interesting is what happens in the world’s fastest growing car markets – in Asia. A full policy shift to electric in say China could really drive fast change by pushing technology and driving down prices.

Simon Harrison

Group strategic development manager

expand-image mail-envelope icon-icon-linkedin-mmdv-green icon-close arrow-left icon-section icon-section-white arrow-down icon-arrow-down-sml icon-arrow-left-lrg icon-arrow-left-sml icon-arrow-right-lrg icon-arrow-right-sml icon-arrow-up-sml icon-champions icon-section icon-section-white icon-download icon-education icon-email icon-grid-view icon-language icon-link-to icon-list-view icon-location icon-login-register ec-icon-login-register icon-ec-apply-arrow icon-ar-apply-arrow icon-mm-icon-search-ec icon-minus icon-more icon-phone icon-plus icon-recently-viewed icon-search icon hash key-facts-corner-sash quote-underline social-icon-facebook social-icon-googleplus social-icon-linkedin social-icon-twitter social-share-icon-facebook social-share-icon-facebook social-share-icon-googleplus social-share-icon-googleplus social-share-icon-instagram social-share-icon-instagram social-share-icon-linkedin social-share-icon-linkedin social-share-icon-twitter social-share-icon-twitter social-share-icon-youtube social-share-icon-youtube sina-weibo MM-Shape01-Quote-Views MM-Shape03-Quote-Locations MM-Shape05-Quote-Projects MM-Shape12-Quote-Sectors MM-Shape13-Quote-Expertise MM-Shape14-Quote-About-Us MM-Shape14-Quote-Careers checkmark icon-expand-view icon-apply-now menu linkedin-mmdv-green icon-ad-close mail-mmdv-green icon-ad-menu menu-close ec-menu-close sphere icon-cookies icon-legal icon-registered-companies target rotate-screen video-replay-flat video-replay audio-mute audio-play
Mott MacDonald main logo

Would you like to hear more from us?

Sign up to receive notifications