Will Clare, who works in the npower EV team, explores the likely impact that the growth in electric vehicles will have on our national electricity grid – and the role that consumers can play to help balance, rather than increase, peak demand.


A pivotal question about the future of the electricity grid was raised recently at the annual Future Networks Conference – Can electric vehicles (EVs) fix the balancing woes of the nation’s grid?


Surprising perhaps, when we often hear the exact opposite.


Indeed, picture the scene… Every household in the UK fitted with an EV charger. Every commuter driving to work in their quiet electric car and then plugging it in at their workplace, all before grabbing their morning coffee.


If all our cars were drawing power from the grid throughout the course of the day, the grid just couldn’t cope.


Or could it?


EVs to increase electricity demand by 20%

Let’s delve a little deeper into the numbers, shall we…

  • An electric car today will get around four miles from a kilowatt hour of energy. The average car in the UK travels about 8,000 miles a year. That means that a typical electric car will use about 2,000 kWh a year.


  • At the end of 2017, there were 37.7 million vehicles on the road in the UK. The total amount of energy required to power these if they were all electric would be just over 75 TWh a year. (A terawatt hour is a billion kilowatt hours.)


  • The total consumption of electricity in the UK last year was about 300 TWh. So if all transport was electrified, the total amount of electricity needed would rise by approximately 25%.


So how can we easily accommodate this increase?


Incentivising off-peak charging

Instead of everyone charging during or right after work at the very peak of demand, the charging could largely be done at night. This can be encouraged by measures the government and energy companies can collectively put in place to encourage off-peak charging.


Currently, around 60% of EV charging occurs when people return home from work and plug in (with the remainder of charging largely happening in the workplace and at shopping and leisure locations).


But your car can be set to charge over the cheaper night-time period, when electricity demand falls and wholesale energy prices tend to be lower. The increment to night time electricity demand is estimated to be about 15 GW (120 GWh over eight hours).


In other words, if users are incentivised to charge their vehicles overnight, demand will be essentially flat between 2200 and 0600.


So what other measures could help reduce grid overload?


Tapping into smart technology

Forthcoming legislation from the UK government will set into law the requirement that all EV chargers are equipped with smart technology. This will enable private users to schedule when to charge and when not to charge, all through setting price caps on the price per kWh.


If the price hikes above their cap, the car will not charge, moving charging to periods of lower demand.


Furthermore, many EV charging points will be ‘vehicle-to-grid ready’. This means they are capable of returning power from the car’s battery back into the grid if the price is right for the customer, providing the grid with a further balancing tool.


Cutting capacity requirement by half

This technology is expected to reduce demand by half.


So, with an estimated nine million electric vehicles on the road by 2025, the grid would require an additional 8 GW of generation capacity if users charged their EVs whenever they liked.


However, this could be reduced to 4 GW with smart charging infrastructure, purely by charging at off-peak times and returning power to the grid during periods of peak demand.


There is still a lot of work to be done to ensure we create the right environment for sufficient flexibility to benefit both consumers and energy providers (as in the grid itself as well as suppliers and distributors).


But if we get it right – and effective legislation and market forces drive consumers to charge and discharge when the grid requires – then the overall impact of EVs on peak energy demand should be limited.


To find out more, or for help and support with your own business EV charging – or EV hardware or software requirements – get in touch with our EV Team via evcharging@npower.com.