It may sound like a pipe dream but road designers are experimenting with solar powered highways which could charge up the electric cars of the future, as they drive along.
It would mean company cars and delivery vans could potentially run on solar energy with unlimited range, and small businesses may never fear staff being kept away from the office or important meetings by bad weather or roadworks again. Solar panel heated roads would never freeze and repairs could be as simple as unbolting a small section of solar panel and replacing it, potentially in just minutes.
Not only would energy-producing roads power cars, they would also provide electricity for road signs, traffic signals and street lighting. Power would be supplied directly during daylight hours when batteries would be charged up for overnight power.
The first solar road is already being trialled in Normandy, France in a village called Tourouvre-au-Perche. A 1km stretch of road, believed to have cost 5m Euros is being monitored for how much energy it produces and how dirt deposits and tyre marks impact production levels. It is one of 10 pilot projects of the Wattway solar road technology developed by French road builder, Colas and the country’s solar power research institute, INES. In another project, a stretch of car park powers electric car chargers for patrons using a concert hall and sports arena at La Roche-sur-Yon, in the Vendée.
The Wattway road surface resembles a thin polymer sandwich in which central photovoltaic cells are protected by tough polymer layers with a top surface designed to provide at least as much grip as a conventional road. So long as there is a flat base, the thin solar road layer can simply be glued in place. According to Philippe Harelle, technical director at Wattway, the aim is to launch many more test projects in and beyond France to hopefully prove the technology can withstand daily traffic use.
“We’re aiming to launch a hundred pilot projects so by 2020 we can hopefully show that our surface performs as well as a normal road and costs the same as a conventional solar panel,” he says.
“The electricity can be used not just for street lighting and signs but also surrounding buildings. In a couple of months we hope to announce a fifty square metre installation at a toll where we will be powering a booth.”
Welcome, but costly
Professor Amin Al-Habaibeh, intelligent engineering systems at Nottingham Trent University believes such projects are worthy of considerable interest but will face major challenges. These include how the surfaces will perform over years of use as well as whether they can generate significant amounts of energy when they are laid flat, rather than being angled at the sun. The largest issue of all, though, is cost.
“A square metre of solar panels would cost on average £1,500. This will increase the ‘payback period’ – the time until you see a return on investment – which makes the appeal in investing in such technology very limited,” he surmises.
Going Dutch
In the Netherlands, consortium Sola Road claims last Autumn’s upgrade to a test cycle lane it installed near Amsterdam two years ago, is proving successful. It gives the company hope that solar technology could one day mean roads can benefit the environment, explains Sten de Wit, lead innovator at the joint venture.
“We’ve calculated a ten metre stretch of cycle path three and a half metres wide gives roughly enough electricity to power a house for a year,” he claims.
“So, if houses had ten metres, or maybe a little more, solar road in front of them, we could provide them with power. Also, you’d be relieving pressure on the countryside to install renewables infrastructure because you’d instead have roads that are already there and lead to where people need electricity with no need for new equipment.
“We have more pilot projects coming and in 2018 we’re hoping to build a road to show the technology is not just for cycle lanes. Ultimately, we hope to be able to show how induction technology could be used to power electric vehicles, direct from the road. It’s in its infancy now but it would be particularly useful for bus lanes where you could have public transport permanently powered by a solar road.”
Solar freaking roadways
In the United States, Solar Roadways, whose “solar freaking roadways” viral video has been viewed more than 22m times on YouTube alone, has just unveiled the country’s first public test project. Thirty of its hexagonal solar panels have been built into the town square in Sandpoint, Idaho. Two more test sites are also being prepared for trial. A stretch of pavement in Missouri, at a rest area alongside Route 66, and a harbour-side pedestrian area in Baltimore are due to be installed this year.
Co-founder Julie Benwell reveals the company, through US Department of Transport funding, hopes to evaluate these test sites before the technology is considered for use on public roads.
For now, solar roads are in the middle of many years of testing before we are likely to see them deployed at scale. It’s a technology that is yet to be proven as robust or cost-effective enough to rival concrete or asphalt. However, the notion of roads that harness sunlight to power lighting, signs, buildings and even the cars driving over them is likely to maintain the public’s interest for the foreseeable future while performance is tested and economics probed.
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