myElectric cars make some people afraid of the dark. Although batteries produce far less carbon, they require much more electricity to run. This has led to ominous warnings that Britain and other rich countries determined to ban new petrol and diesel cars risk plunging their populations into darkness.
In recent months, British newspapers sceptical of net-zero energy have warned that the shift to electric vehicles could “overwhelm the grid and threaten catastrophic blackouts” when intermittent sun and wind fail to provide the power needed. Another article claimed: “It won’t take an enemy powerhouse to put us all in the dark – just get customers to do normal things on a normal winter afternoon.”
But many in the electric car industry think these fears may be unfounded. They argue that the shift to electric cars offers an exciting – and potentially lucrative – opportunity to build an energy system that is smarter and greener.
In the UK, polluting coal-fired power stations have been largely replaced by wind farms and solar panels. These renewables produce no carbon emissions, but they suffer from an intermittency problem: they don’t provide much power on calm, cloudy days and nights. Add to this the prospect of all new cars becoming electric by 2035, and it’s not unreasonable to wonder how the grid will keep supply and demand in balance.
Change in demand
The shift to electric cars will undoubtedly require more electricity generation as it becomes the primary source of energy for transport, rather than land-based fossil fuels. However, smart technology can be used to shift demand to off-peak times, such as 5pm on a winter’s day, when electricity demand threatens to outstrip supply.
This is not just a pipe dream. Home charger company MyEnergi estimates that if balancing services were enabled on every one of its compatible installed chargers, “we could offer the grid over 1GW of demand shifting flexibility – more than 98% of the UK’s major fossil fuel generators.”
Octopus Energy, which has grown rapidly to become the UK’s largest energy provider, says its Go electricity tariff manages the charging of 150,000 electric car batteries. It would take 1GW of power to charge them all at the same time, but smart chargers hold the charge until the quiet hours of the night, diverting that demand away from peak times. Electricity is also cheaper during quiet hours, which is a clear benefit to the consumer. Octopus says its customers save around £600 a year on average.
One gigawatt is equivalent to a medium-sized power station, enough to power 600,000 homes. Electric cars on British roads could already make a dent in the UK. Peak winter electricity demand of 61.1 GWAccording to National Grid, simply by delaying charging for a few hours.
Jack Fielder, myenergi’s chief strategy officer, says: “If every EV charger could offer grid balancing services and every driver opted into grid balancing programs, we could collectively eliminate periods of grid pressure.”
It could also help when electricity supply outstrips demand, such as during a hot, windy night, says Chris Pateman-Jones, chief executive of Connected Kerb, a charging company.
“Rather than diverting renewable energy into the ground, my view is that electric vehicles could act as a huge sponge,” he says. Users would be largely unaffected. Most cars finish charging at midnight, according to Connected Kerb data, leaving hours of downtime before the car is needed.
Powering the grid with car batteries
It’s not just about timing when electrons flow into car batteries, which could be useful for the National Grid Electricity Supply Operator (NGESO), the company charged with balancing Britain’s grid. The company sees demand shifting as an “unrepentant move to help reduce the impact on peak demand and reduce curtailment of renewables,” but it also wants electrons to move in the opposite direction.
Grid-connected vehicle technology is a tantalizing prospect. Instead of building power plants, hydroelectric storage systems or stationary battery banks, the idea is to use the energy stored in car batteries. The car becomes a portable power source, a backup for power outages at home and even allows drivers to make money by selling energy back to the grid.
NGESO produces annual guesses The report shows what Britain’s electricity system will look like in 2035 and 2050. A major role is envisaged for cars to feed energy back into the grid. Capacity could reach 39GW in its most optimistic scenario (equivalent to one-tenth of the massively expanded electricity generating capacity).
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Figures from Pod Point, another home charger company, suggest that most cars only draw power for a third of the time they are plugged in. That means there is plenty of flexibility to sell small amounts back to the grid at expensive times, before buying power back in at night when things are cheaper.
However, James McKemey, director of external affairs at Pod Point, warns that bi-directional charging is further away than a much simpler demand transfer.
“Getting 5kW out of a car is a lot harder than telling five different cars to use 1kW less,” he said. For now, the extra costs – particularly for the inverters needed to switch from DC power from batteries to AC power from grids – have prevented many carmakers from including them in their cars as they race to cut prices.
However, carmakers are starting to install the technology needed for bi-directional charging. Models from BYD, Hyundai, Renault, Nissan and SAIC’s MG are capable of bi-directional charging, and more are likely to follow. Shan Tomouk, a charging analyst at consultancy Rho Motion, says charger companies are also starting to produce wallboxes that are ready for bi-directional charging, though he adds that it is “still far from a reality” on a large scale, in part because of questions about which technology will become standard.
No one knows exactly how the money from the valuable network-balancing service will be split, and there is likely to be a dispute between businesses (and consumers) over who gets what share of the investment.
“We are providing the technology to reap the benefits,” says Nissan’s Friederike Kienitz, who oversees sustainability across all markets, including Europe.
“There will be a fight over who has access to the customer,” he said last month at Nissan’s Sunderland factory. But he says early pilot projects in partnership with energy companies “already show there is a win-win situation.”
There are so many moving parts in the energy transition that it will be unclear exactly how countries, including the UK, will avoid blackouts. Fiona Howarth, chief executive of Octopus Electric Vehicles, says business models are not yet fully defined, but adds that electric cars can help keep the lights on.
“Electric vehicles are really part of the solution,” he said. “They are batteries on wheels.”
There are one million electric cars on the UK’s roads. When that number reaches 10 million, Haworth says, “we could literally power the whole of the UK at peak times.”
