Why fleets have to invest in smart chargers for EVs

As employers begin massive investment programmes in electric vehicle chargers, new research has exposed the importance of smart charging technology. 

Across Germany alone, Volkswagen is installing 4,000 charge points at its factories for its workers to use, in a programme that will cost €250 million.

Thomas Ulbrich, Member of the Volkswagen Brand Board of Management responsible for E-Mobility, said: “Adequate facilities for charging at the workplace are an important element in our electric offensive.”

He added that the 11kW charge points, powered by renewable electricity, will also be available to other electric vehicle users, and urged other businesses to follow Volkswagen’s lead. Workplace charging is essential to provide a solution for drivers who cannot charge at home. VW estimates that in future 20 percent of all charging operations could take place at the workplace.

“We will also need more public charging options going forward,” said Ulbrich. "However, demand for charging stations cannot be primarily covered by such public facilities. Conditions for installing private charging points should be improved, and companies should contribute to that."

EVs can overload transformers

These private, domestic chargers will have to be smart chargers to support national electricity grids, warned Scott Lepold, partner account manager, Fleetcarma, part of Geotab. Citing evidence from Canada, he said: “Four EVs can have an impact on a transformer if they charge simultaneously. And at a city level it’s very common to have four or more EVs per transformer.”

Smart chargers can control the times when drivers recharge their cars, matching demand with periods of adequate or excess electricity supply. However, for smart charging to succeed, power companies will have to offer incentives to encourage drivers to recharge their car batteries at times of low power demand, such as late at night and the early hours of the morning.

Philip New, Chief Executive Officer of the Energy Systems Catapult, said: “Rewarding consumers for charging smartly is absolutely essential. The country (UK) will save billions of pounds in infrastructure costs if we are able to harness the potential of the electric vehicle to work with and be part of the energy system, as opposed to being a dumb off-take at the end of the energy system no different to the way a diesel fuel tank is today.”

Smart charging behaviours

Electricity distributor Western Power Distribution commissioned a major study of 673 drivers of plug-in vehicles to assess their recharging behaviours and power demands, and found that:

• The average EVs with smaller batteries (0 to 25kWh) require about 1,800-1,900kWh per year.
• Larger battery EVs (35kWh plus) use about 3,500kWh per year.
• Annual household electricity consumption (without an EV) ranges from 1,900kWh (small house) to 4,600kWh per annum (large house).

Ricky Duke, Innovation and Low Carbon Network Engineer at Western Power Distribution, said: “Each EV uses typically as much power as a household. So if everyone drives an EV we would need twice as much power.”

Smart charging recharges car batteries when demand on power stations is at its lowest.

The Western Power Distribution study found that that time of use incentives appear to be highly effective at moving demand away from the evening peak – particularly when supported by smart charging (with an app) that makes the process simpler for drivers. It also identified that the most popular time to plug-in EVs is during the evening peak (17:00 – 19:00) on weekdays, when the majority of drivers get home from work. However, three-quarters of vehicles only need to charge for 40% of the time that they are plugged in.

“People plugged their cars in for 12 hours but only needed five hours' charge,” said Duke.

PHEV drivers recharge more than BEV drivers

He added that most drivers only charged their cars three to four times per week (0.5 charging sessions per day), although this frequency is higher for PHEV drivers whose vehicles have a shorter zero emission range. Western Power Distribution's research also found that January and February had the highest charging frequency, probably due to colder weather reducing battery efficiency.

Above all, the study found that even modest price savings could lead to huge changes in charging behaviour, with drivers keen to use an app that let them recharge only at off-peak, low cost times.

These findings echo the results of the Consumers, Vehicles and Energy Integration (CVEI) project, conducted by TRL, the centre for innovation in transport.

248 electric Golf drivers 

The study gave 248 drivers either a VW eGolf or a Golf GTe hybrid for two months, and tracked their recharging behaviours. The drivers were split into three groups; the first group were free to recharge at will; the second group had financial incentives to recharge at specific times of day; and in the third group, participants specified the charge they required and the time they required it by, and allowed the electricity company to control the timing of charging to maximise cost savings.

Drivers whose charging was not managed typically charged at home in the late afternoon/early evening (with a peak in charging between 5-6pm for PHEV participants, and 6-7pm for BEV participants). However, this peak was avoided if either drivers or power companies had the opportunity to delay it layer into the evening or overnight, with only a small financial incentive required.

Dr George Beard, TRL’s Head of ULEV Consumer Research, said: “Without intervention drivers will charge at peak times and this can lead to challenges with supply and demand in capacity.”