Electric Vehicle (EV) uptake is expected to surge in the coming years, which will put considerable strain on the electricity networks. Simply put, once a critical point of EV uptake is reached in a particular area, if everyone tried to charge their cars at the same time, the local distribution network could fall over. Our analysis suggests that there is a risk of shortfalls in network capacity at the low voltage level by 2025, even under moderate levels of clustering.
Assuming we want EV uptake to continue to accelerate, with the environmental benefits it brings, there are two basic ways to deal with this: reinforce the network (which will cost a lot and may not be feasible in time to meet demand), or be smarter about when we charge our cars.
If EV charging was shifted away from popular times (such as after work, between 7-9pm) to times of lower demand (such as overnight) we would avoid high peaks and, therefore, reduce the need for reinforcement. This could save consumers between £1-4.5bn by 2050, according to the analysis we undertook as part of the Energy Technologies Institute’s Consumers, Vehicles and Energy Integration project (CVEI).
In the UK, two distribution networks, Western Power Distribution (WPD) and Scottish and Southern Electricity Networks (SSEN), have led trials to understand how consumers would respond to incentives that attempt to move their EV charging away from peak times, and requests to pause their charging temporarily to protect the network. Results so far have shown a material response from consumers, who were found to change their charging behaviour in response to incentives, and often accepted requests to pause charging when they didn’t need their car fully charged.
However, these trials have divided opinion, as in each case the distribution network had control of assets at the point of EV charging giving them the ability to unilaterally switch off EV connections in the event of network overload – a ‘big red button’. If the distribution networks take ultimate control of EVs in this way, they would become monopoly controllers of EV battery flexibility, could reduce customer choice, and could limit opportunities to utilise that flexibility elsewhere on the system.
An alternative vision is to open up the coordination of EV charging to the market – “smart charging”. New, innovative companies are developing new products, using sophisticated optimisation technologies to assess when is cheapest for their customers to charge their cars, taking into account driving needs and wholesale prices, and in some cases utilising battery flexibility to sell balancing services back to the grid and save them more money. A third trial, the central part of the CVEI project, is currently underway, with a focus on mass-market customers, testing their response to this type of proposition.
Without a clear blueprint for smart charging, many permutations of who does what, and what services are offered, are being explored. The big question is whether the market alone can coordinate EV charging, or whether the distribution networks require a ‘big red button’ to intervene in emergency situations where market mechanisms cannot account for all factors, and the network starts to overload. A key barrier to investigating this is that in the UK there are currently no price signals in the market to reflect local DNO network conditions for 3rd parties to take account of – and it’s the DNOs who would need to provide these.
If DNOs are to demonstrate whether a ‘big red button’ is needed, the alternative will also need to be explored, with DNOs providing price signals to the market to enable 3rd parties to manage network constraints. If network operators can get comfortable that market-based mechanisms work, then this would remove a potential barrier to connecting EVs ahead of any reinforcement that might be needed further down the line.
The race is on for the market to deliver a workable solution that can avoid unnecessary duplication, or redundancy, of technology in a way that keeps a firm focus on customer experience and requirements. If it does so, the big red button could turn out to be a big red herring.