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Electric cars scares some people of the dark: their batteries produce much less carbon dioxide but require more power to run, prompting ominous warnings that Britain and other wealthy countries could plunge their citizens into darkness if they ban new petrol and diesel sales.

In recent months, UK net-zero skeptic newspapers have warned that a shift to EVs “risks overwhelming the grid and causing catastrophic blackouts” if intermittent solar and wind don't provide the needed power. Another article argued that “we don't need an enemy force to plunge us all into darkness – just some electricity customers doing their normal thing on a normal winter's night.”

But many who work in the electric vehicle industry believe these fears may be unfounded, arguing that the transition to electric vehicles is an exciting, potentially lucrative opportunity to build a smarter, greener energy system.

In the UK, polluting coal-fired power plants have been largely replaced by wind farms and solar panels. These renewable energies do not emit carbon dioxide, but they suffer from intermittency problems and cannot provide enough power on cloudy days or at night when there is no wind. Add in the prospect that all new cars will be electric by 2035 and it is not an exaggerated question how the power grid will keep supply and demand in balance.

Shifting demand

The transition to electric vehicles will undoubtedly require more electricity generation as electric vehicles, rather than land-based fossil fuels, become the primary source of energy for transportation, but smart technology can be used to shift demand away from peak times, such as 5pm in winter, when demand for electricity risks outstripping supply.

This isn't just a pipe dream: home charger company MyEnergy calculates that if balancing services were enabled across all installed compatible chargers, it could “provide over 1GW of demand-shifting flexibility to the grid, more than 98% of the UK's major fossil fuel power stations.”

Octopus Energy, which has quickly grown to become the UK's largest electricity supplier, says its Go electricity tariff manages the charging of the batteries of 150,000 electric vehicles. Charging them all at once would require 1GW of power, but smart chargers hold off charging until off-peak hours at night, shifting demand away from peaks. Electricity is also cheaper during off-peak hours, with clear benefits for consumers: Octopus says its customers save an average of about £600 a year.

One gigawatt is the equivalent of a medium-sized power station, enough to power 600,000 homes. Electric vehicles on UK roads are already on the rise in the UK. Peak electricity demand in winter is 61.1GWAccording to the National Grid, delaying charging for just a few hours can help reduce energy consumption.

Jack Fielder, chief strategy officer at MyEnergy, said: “If every EV charger could provide a grid balancing service and every driver took part in a grid balancing program, we could collectively eliminate periods of strain on the grid.”

It could also be useful when power supply exceeds demand, such as on warm, windy nights, said Chris Pateman-Jones, chief executive of charging company Connected Curve.

“Instead of wasting renewable energy, I see EVs as a giant sponge,” he says. For consumers, there will be little change: Connected Curve data shows that most cars are already charged by midnight, leaving them idle for hours before they're needed.

Powered by car battery

It's not just the timing of when electrons flow into car batteries that will help the National Grid Electricity Supply Operator (NGESO), the company responsible for balancing the U.K. power grid: It calls demand shifting a “low-regret action that will help reduce the impact on peak demand and reduce renewable curtailment,” but it also wants electrons to flow in the other direction.

Vehicle-to-grid technology is an attractive prospect: instead of building power plants, hydroelectric storage, or stationary battery fleets, the idea is to harness the energy stored in car batteries. Cars could become portable power packs, providing backup for homes in the event of a blackout, and even allowing drivers to earn money by selling power back to the grid.

NGESO is Annual estimate It predicts what the UK electricity system will look like in 2035 and 2050. It sees a growing role for cars feeding power back into the grid, and in the most optimistic scenario, capacity could reach 39GW (equivalent to one-tenth of the vastly expanded generating capacity).