As electric vehicles (EVs) become increasingly mainstream, a new challenge emerges, not under the bonnet, but in the wires and substations that power our world. The integration of EVs with renewable energy sources and the national grid is a complex, evolving puzzle. In a recent interview, engineers John Samuel and Pete James unpacked the technical and systemic hurdles we face, and the innovative solutions that are already taking shape.
The Intermittency Problem
Renewable energy is clean, abundant, and essential to a sustainable future. But it’s also unpredictable. “The problem of intermittency with wind and solar is well known,” said John Samuel. “What a battery can do is smooth out the supply, depending on its duration.”
He offered a vivid example: “In California, everyone comes home at 5:00 in the evening and switches on their air conditioning. The sun’s just going down. You’re in big trouble.”
To address this, energy must be stored during peak generation hours and released when demand surges. This is where long-duration energy storage systems, like Vanadium Redox flow batteries, come into play. “They can store energy over long periods,” Samuel explained. “Lithium is efficient up to about four hours. Vanadium can go up to twelve hours.”
Grid Frequency and Inertia: The Hidden Crisis
Beyond energy storage, there’s a subtler but equally critical issue: grid frequency stability. “When we had oil-fired power stations, there were these great huge generators rotating with a lot of inertia,” said Pete James. “The grid frequency didn’t change very quickly.”
But with renewables like wind and solar, that stabilising mass is gone. “Now we need other methods to regulate the grid frequency,” James continued. “Electric vehicles, with vehicle-to-grid (V2G) connections, can offer some stability by outputting energy from their batteries.”
Samuel agreed: “One of the biggest issues is stabilising the frequency on the grid, dealing with intermittent renewable generation, and fluctuating loads. That’s where batteries come in.”
Charging Smart: Timing is Everything
Another key to balancing the grid lies in when EVs are charged. “The clever thing is that you can control your charging time,” Samuel said. “A lot of wind farms have to be shut down at night because there’s too much wind and no load, generators have to be compensated for shutting down making the economics for the consumer worse..”
By charging EVs during these off-peak hours, we can absorb excess renewable energy instead of wasting it. “It’s no good having megawatt chargers without the grid support,” Samuel warned. “That was hugely lacking in the early days of rapid charging.”
The Role of Infrastructure: Supermarkets, Solar, and Storage
James believes that infrastructure innovation is just as important as vehicle technology. “People like the big supermarket chains, Sainsbury’s, Tesco, Asda. If they had hundreds of chargers, one on every parking bay, that would make a huge difference.”
He envisions a future where a weekly shop doubles as a charging session. “If a normal shop takes 45 minutes to an hour, and you could be full within that time, people would accept that.”
Samuel pointed to developments in France, where large car parks are now covered with solar panels and equipped with chargers. “They need a big storage battery in there as well,” he added, “so they can draw power at high rates and time-shift the load.”
The Urban Dilemma: Charging Without a Driveway
Despite these advances, a major barrier remains for urban dwellers. “We’re getting to a saturation point in the British market,” Samuel said. “A lot of people don’t have a driveway. You’ve got cables running across the pavement, and there aren’t enough lamppost chargers.”
He shared a cautionary tale: “One chap I met loved the electric car he bought at the showroom. Had it delivered to his house. The delivery guy asked, ‘Where are you going to charge it?’ He said, ‘I don’t have a charge point.’ He had to send it back.”
A Change in Mindset
James believes that part of the solution lies in changing public expectations. “Petrol has given us this desire to just rock up at a filling station and have another 400 miles within a couple of minutes,” he said. “There needs to be a change in mindset.”
He also highlighted the sheer scale of energy involved. “If you wanted to fill your car in two minutes with electricity, you’d need something like 23 megawatts, about six of your very biggest wind turbines.”
Efficiency Matters - Even with Renewables
One of James’ most thought-provoking points was about energy conservation. “It seems that if it’s renewable, you can waste it,” he said. “But mankind needs to be more conservative with energy in general. Even though we have renewables, we can’t just waste that energy. We need to be efficient with it too.”
Building the Backbone of the EV Era
The transition to electric vehicles is not just about replacing engines with motors. It’s about rethinking how we generate, store, and distribute energy. It’s about timing, infrastructure, and public behaviour. And it’s about building a grid that’s as smart and resilient as the vehicles it powers.
As Samuel put it, “There’s a huge challenge. But the direction of travel is now rapidly in the right direction”
Further Reading: Dive Deeper into EV Technologies
If you found John Samuel and Pete James’s insights compelling, you’ll want to explore their book Electric Vehicle Technologies: Renewable energy for the road, available now from the IET Bookshop. Drawing on decades of engineering experience, the book offers a comprehensive look at the systems, challenges, and innovations shaping the future of electric mobility, from battery chemistry and charging infrastructure to grid integration and policy frameworks.
Whether you're an engineer, policymaker, or simply curious about the future of transport, this book provides the technical depth and practical context to understand the EV revolution.
Get your copy from the IET Bookshop: https://shop.theiet.org/electric-vehicle-technologies
We’d love to hear your thoughts
What do you think is the biggest challenge in making EVs work seamlessly with our energy infrastructure? Have you experienced any issues, or successes, with EV charging in your area? Share your thoughts and your story below!