Electric vehicles (EVs) are more and more numerous on the roads. Global sales of electric vehicles increased by 168% in the first half of 2021 compared to 2020, and are expected to cost as much or less than combustion cars (gasoline and diesel) by 2028 later. Accompanied by a proposal government bans On the sale of combustion vehicles in many countries, electric vehicles will become more and more common over the next decade.
But adopting EVs brings its own set of challenges. While the UK’s national energy supplier has assured consumers it “certainly enough energy” To facilitate the mass adoption of electric vehicles, the problem lies in the sustainable and inexpensive supply of electricity to cars.
Our local grids were not designed to simultaneously recharge millions of cars with energy and, as we move towards a zero carbon wind and solar variable output power system, the energy may not be there when we need it most.
The key to managing this is to ensure that electric vehicles can charge affordably when there is plenty of wind and solar energy available. Coordination requires significant planning and government investment in a smart charging network.
How to charge
When we are deciding how to charge an EV, a key element is the ” residence time “ at its charging location.
If the driver is at home for the night or at work for the day – and therefore in no rush to invoice – he can use a seven kW charger, a standard UK home charger, to charge their car during a driving week (about 250 km) in an eight hour session. But if the driver decides to charge his car on the same charger while driving to the supermarket for just 45 minutes, he will only have about 30 km of extra range – barely enough for a day’s driving.
Residence time and charge speeds
In the latter situation, a “DC Fast” charger – which generally provides between 50 and 150 kW – is more suitable. Although they are much more expensive – usually at least ten times the cost of a standard home charger – you get what you pay for: using these chargers will get you about a week of driving in just 45 minutes.
The problem with these fast charges is that in addition to being expensive, they place significant strain on the electrical infrastructure, which could lead to local breakdowns. As, on average, cars spend about 95% of their parking time, you would ideally want them to slowly recharge from excess renewable energy during that time, with quick charges reserved for long road trips and the occasional emergency charge.
In the future, cars could also help support their local electricity grid by unload electricity in times of high demand when renewable energy production is low – a technology known as “From vehicle to network”. To enable this technology, communication between chargers and cars must be a two-way street, allowing drivers to simultaneously recharge and take over the network.
Access to power is also a financial issue. For those with off-street parking at home, staying plugged in is easy, but many don’t have that option. This means that connected households will have access to low-cost travel, while those without home charging will face higher costs due to expensive street charging. In the United Kingdom, approximately 7 million households, many of them low-income, belong to the latter group.
We need to expand access to charging not only to help the grid, but also to reduce social inequalities. Street chargers could be automatically assigned to the car owner’s account when they plug in, allowing those without home charging to access a full range of services for the same cost as a person with a home charger.
In the UK we would need around 750,000 street chargers to ensure that those without a home charger can recharge once a week. If we are to use the energy storage in these cars to help balance grid production and consumption – and to meet the UK target net zero goal – I would estimate that we would need up to 5 million chargers. This would require the installation of 500 new street chargers every day by 2050.
Using our cars to help balance our grid will likely be cheaper than energy storage alternatives like hydropower by pumping Where liquid air storage, since we already have some of the infrastructure we need. But for that to happen, automakers, grid operators and energy providers – and the UK government – need to coordinate to put the right chargers in the right places at the right times.