Smaller, lighter, cheaper electric vehicles have helped to kick-start a personal transportation revolution in China. Will a movement to the same kind of vehicles in the West allow solar to play a bigger part in our energy future? At the very least, personal and local generation could put a lot less stress on the central grid.
The reality is that no amount of development in photo-voltaic cells is likely to yield the kind of power needed to move a full-sized EV along a road in real time. That said, the sun isn’t going anywhere and EVs spend a lot of time parked without moving, so how can we best use the freely available energy from the sun?
As we have reported before, the cost of solar panels has been dropping steadily – at the same time that their effectiveness at trapping/converting sunlight into electrical power has improved. Our recent feature on solar development included an overview of where the technology is and where it might head.
Since 2008, the price of solar panels per kilowatt produced, has dropped by 78%. At the time of going to press, that figure was less than 20p per watt. In real-world terms, the cost to completely cover the roof of a four-door vehicle has dropped from over £200, down to less than £40.
Toyota has the option of a solar roof on some of its Prius models. Hyundai is beginning to make solar roofing an option on its new EVs – starting with the Ioniq 5. Triton has also proposed a vehicle with plenty of panels (see sketch above).
Elon Musk is one of the world’s biggest advocates for solar energy, but even he’s sceptical about how big a role photo-voltaic cells can play in delivering miles.
Musk previously tweeted that, “It’ll be an option to add solar power that generates 15 miles per day, possibly more. Would love this to be self-powered. Adding fold out solar wings would generate 30 to 40 miles per day. Average miles per day in US is 30”.
Fold out solar is the kind of technology that SpaceX might be looking at for the modules that it launches into space, but the practicalities of deploying large ‘solar sails’ on Earth – even when stationary – are questionable. That said, Tesla will have a solar option for CyberTruck owners and the large pick-up area might allow for fold-up wings.
The US producer Lightyear, unveiled the Lightyear One at the Goodwood Festival of Speed in 2019. It has tried to integrate close to five square meters of solar panels on its first commercial version, the Lightyear 2. They are hoping to launch it into the UK around £40,000 and – based on the average daily mileage of a British driver – they estimate that Lightyear 2 customers could spend 66% less time attached to the grid for power. The RAC estimate that Brits drive around 20 miles a day, obviously includes the few that spend hours each day behind the wheel – but then you also need to take into account the large number of people who only do school/shopping runs. The ability to have your EV constantly trickle charging, every time the sun’s over the horizon, could massively reduce the cost of transportation. There is no easy way to top up a petrol or diesel tank every day, for free, just by leaving it parked in the street.
So, here in 2023, what is the physical limit on how much we might get from solar?
The Guinness Book of Records has a section for the fastest EV over 1,000km on a single charge. That was set by the University of New South Wales Sunswift 7 at the end of 2022. Coming in at 500kg (25% of the weight of some Teslas), Sunswift 7 managed the 621 mile/1,000km journey in just 11 hours 52 minutes – which meant that it maintained an average speed of 53 miles per hour.
To put that journey into perspective, if you could draw a straight line from London to Edinburgh, then going to the Scottish capital and back would be around 660 miles. On one charge. Without solar panels all over the body, this would clearly not be possible.
Lightyear 2 will be launched this summer and (all being well), it should go into full production for 2025. You can get more info here.