Electric vehicles offer more than just eco-friendly transportation; they hold the enticing prospect of putting extra cash in the pockets of their drivers. At a time when nearly half of Britons are struggling to pay their monthly expenses, can electric vehicles add a new layer of appeal to eco-friendly transportation?

Keith Bell is a professor based at the University of Strathclyde, where he holds the Scottish Power chair in future power systems. He is one of eight members of the UK Climate Change Committee. He frames the discussion around sustainability and its impact on UK citizens by emphasising the significant progress achieved in adopting renewable energy over the past decade. Bell highlights the UK’s increasing capacity to fulfil a substantial portion of its energy needs at more affordable rates.

“The cost of energy from renewables, especially from wind and solar, has come down dramatically over the last 10 years,” Bell says. “But it’s not always super reliable.”

Bell discusses the complexity of the energy system, acknowledging the persistent demand for energy regardless of weather conditions and time of day. Addressing this reliability challenge is where energy storage plays a pivotal role.

“We’ve got this conundrum with the whole energy system, that the demand will be what it will be. How do we meet that reliably? And that’s where energy storage comes in,” Bell says.

Bell adds that while energy storage is not a new concept, its significance is growing as we transition away from fossil fuels. Unlike fossil fuels, which are one-time use resources, renewables like wind and solar are intermittent and require storage to ensure continuous supply.

“It’d be good if the demand moved to meet the availability of wind and solar, that’d be a first thing. And we think about electric vehicle charging, that looks like a great opportunity, provided the vehicles are plugged in. You don’t need to spend the whole time a vehicle is parked and plugged in, charging the vehicle, when the average vehicle is parked for 95% of the time.”

That’s a vast pool of battery capacity, sat in parking spaces, garages, and driveways. Other forms of energy storage will support HGVs, and industry.

“You can flex that to when there’s spare wind and solar power available,” says Bell, “But you’ll have days that are still and maybe quite dark. In Germany, they call that a dunkelflaute period, literally the dark doldrums. But we’ll have other periods when we have a surplus of wind and solar. 

“We can use that surplus to make some sort of fuel that we can store and then use in meeting the end use of energy, when it’s not so windy, or sunny. And one of those is hydrogen. “

Renewable sources of energy must be spread across the country: if they were all in the same place, then all would be generating—or not—under the same weather conditions. But that then requires connections between multiple wind or solar sources, storage systems, and end users.

“It’s a question of how all these things fit together,” says Bell. “None of these resources have the perfect mix of characteristics in terms of ability to turn them up or down easily. We’re going to have to build lots of transmission, and lots of distribution network capacity as well. As you electrify that end use of energy, you need more from the distribution network as well.”

Building that transmission and distribution network will take new technologies and techniques.

“Underground cables with an alternating current are actually technically very challenging,” Bell explains. “You can’t use very long sections of underground cable. And undergrounding is very much more expensive than using overhead lines. That’s the reason why we’ve got the vast majority of our network already overhead.”

And it will also require new thinking on planning processes.

“Maybe the biggest challenge for the transmission network is just getting permission to build it. There have been a couple of major overhead line developments of 400,000 volts in the last 20 years, one through North Yorkshire and another one through from near Inverness to near Stirling, where the planning inquiry for them itself took a number of years, and then construction is another four or five years.”

That doesn’t leave long to reach Net Zero goals. One way to shortcut those planning constraints may be through local generation and storage. That could mean domestic solar and battery, or it could be something larger, such as a local industrial cluster or an urban community heat and power system.

“It makes perfect sense. If you’ve got a convenient bit of roof space that’s pointing vaguely south, solar PV is relatively cheap as a source of energy. Why not make use of it? But we lack the economies of scale. All of that helps, but it doesn’t solve the whole problem. And it’s a variable resource. So, we’ve still got to meet that peak demand for electricity. That sets the dimension of the distribution network, how big it needs to be, that we can point towards local energy storage.”

Across the country, new network capacity will be needed.

“The distribution network is a real patchwork,” says Bell. “There’s a huge local variation in how much spare capacity there is, you know, part of the distribution network historically might have been built for some kind of manufacturing, some factory that maybe has long since closed, and you look at it more closely, and actually, conveniently, there’s lots of spare network capacity here. But in another place, there won’t be spare network capacity, and that needs to be reinforced.

Energy storage will help support that network capacity. As more and more drivers switch to electric vehicles, or EVs, a vast distributed storage system will become possible.

“The big thing about vehicle to grid or grid to vehicle is the fact that you’ve got this replenishable energy store. It’s a very flexible means of moving energy around,” says Bell. “I had a bit of a back of an envelope estimate of how much energy storage capacity there would be if we’ve got the same number of battery electric cars as we’ve got today in the UK. With current battery designs, that adds up to something 300-350 gigawatt hours of total energy storage capacity. Well, that’s a lot! The total potential EV capacity is 10 times the energy that all of the pumped hydro in the UK added together could store.”