The government’s strategy to promote the use of plug-in electric vehicles (EVs) as part of its bid to cut carbon dioxide emissions brings its own problems, especially for the distribution network operators (DNOs) whose responsibility it is to deliver the power needed to charge the vehicles’ batteries. The most obvious implication is the additional loading the uptake of EVs would impose on the network.
Last June, the Office for Low Emission Vehicles (Olev) published Making the Connection, a document setting out the government’s framework for the development of a recharging infrastructure to support EVs. Central to this strategy is the creation of a network of public charge-points that will allow EV drivers to travel long distances – that is, beyond the range of a single battery charge – confident that they will be able to recharge their vehicle at their destination or en route.
Many of these public charge-points would be located in parking bays, along urban streets or in other publicly accessible locations such as supermarkets and leisure centres. “Roadside charging is not an issue for us,” says Paul Smith, director of operations at the DNOs’ representative body, the Energy Networks Association (ENA). “Because they are installed knowingly to our members, we can identify the location and can bill the customer.
“If somebody installs a series of charge-points in a private car park or office block, we’d need an examination of the site or at least some notification. If the installer notifies the DNO, then no problem. The problem is going to be domestic installation,” he warns.
What worries the ENA is the prospect of localised surges in EV ownership, creating “hot spots” of demand. “You can go out and buy an electric car, take it home and plug it into a domestic socket straight away. That equates to an additional 3kW on your domestic supply and the DNO won’t know anything about it,” says Smith.
The odd one or two in a residential street will not make any difference to the DNO because the network is designed with some headroom built in. Problems could arise, however, if a sufficient mass of households in a street were to switch to plug-in EVs. Then, the local network could come under strain, risking localised failure. Besides the disruption this would cause, the cost of restoring service and reinforcing the network would have to be met by the DNO.
But will the problem ever actually materialise? At the high voltage level, Making the Connection says “the level of uptake in plug-in vehicles to 2020 is not expected to represent an issue for National Grid”. The Society of Motor Manufacturers and Traders has calculated that even by 2020, EV electricity demand will not exceed 0.3 per cent of total electricity consumption.
Nevertheless, Olev acknowledges that “clustering of plug-in vehicles recharging in particular locations could lead to the need for local grid reinforcement”.
Not everybody sees the need for EV infrastructure as a problem. For newly-formed independent connections companies, which mostly offer turnkey utility connections to new residential and commercial developments, a growth in the use of EVs simply adds another service to their portfolio.
“A demand for charge-points isn’t a headache for us,” says John Dale, head of engineering at independent infrastructure provider GTC UK. “We are installing assets into new land, so we can plan for providing charge-points.”
Unlike existing DNOs, which inherit the legacy of decades-old networks, the independent DNOs can start with a clean slate.
Others believe the increased use of plug-in vehicles should not be viewed as a problem by existing DNOs. Flora Heathcote, commercial director with leading charge-point manufacturer POD Point, says charge-point installers could provide useful detailed information to DNOs to help them smooth out fluctuations in demand, avoid system overloads and plan changes to the network on a local basis.
POD Point maintains a database of all of its charge-points and, because each charge-point can monitor customers’ usage, the company collects detailed local data. Heathcote says this is the information the DNOs currently lack. “They will know on a wider basis where the demand is getting near the limit, but they won’t know on a house-by-house basis … They need to work with us to turn the problem on its head and make it an advantage,” he says.
Furthermore, says Heathcote, POD Point is able to not only monitor charge-point use but also control each one remotely. The typical EV owner will arrive home at the end of the day, put the car on charge and leave it plugged in overnight. But an EV, even on slow charge, does not need all night to recharge. So if POD Point, or another charge-point provider, knows what the local network capacity is, they can limit the number of chargers operating at any one time, thus managing the load for the DNO.
Until the widespread introduction of smart meters, this sort of data sharing could help DNOs avoid what ENA’s Smith calls EV “hotspots” on the local network.
However, at present many EV buyers will be plugging their cars into a standard three-pin domestic socket and not into one of POD Point’s purpose-designed charge-points. “In five years’ time there are going to be a lot more EVs out there,” says Heathcote. “And most of those will be using proper charge-points.”
David Taylor is a freelance journalist
Not our fault
Although there are incentives to establish a national EV charging network as quickly as possible, delivering the connections is not something the DNOs can do at the drop of a hat. And if there are delays, people should not conclude that the DNOs are being slow or un-cooperative, says ENA director of operations Paul Smith.
“If you’re talking about domestic charging – which is going to be the main method – then we’re not involved. Roadside charging is different and that would normally go on to the DNO’s work programme and could be delayed by issues like planning and notification.”
The biggest issue for the DNOs is forward planning. “We are highly regulated and can only spend what the regulator says we can,” says Smith. The current spending round runs until 2015 and was set in 2010, “so the thinking for where we are now was done in 2007/08”, which is well before the current drive to promote EVs.
This article first appeared in Utility Week’s print edition of 20 April 2012.
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