If you can remember as far back as November, you may recall the announcement that the Netherlands had just designed and installed the world’s first solar cycle path in the town of Krommenie. At just 70-meters (230 ft) long, the SolaRoad project has been a proof-of-concept pilot to test out feasibility and practicality of such installations. Now, six months on, Dutch engineers have reviewed its performance and, perhaps surprisingly to skeptics, it has reportedly been more fruitful than anticipated.
According to Al Jazeera, during its first half-year of life, the green path managed to produce over 3,000 kilowatt-hours (kWh), or roughly the same amount of electricity required to power a single occupancy house for a year.
“If we translate this to an annual yield, we expect more than the 70 kWh per square meter per year,” said Sten de Wit, SolaRoad spokesman. “We predicted [this] as an upper limit in the laboratory stage. We can therefore conclude that it was a successful first half year.”
To create the innovative trail, engineers sandwiched cheap, mass-produced silicon solar cells between concrete and a translucent layer of tempered glass. The panels are hooked up to the grid, but they are also connected to smart meters that either optimize its output or direct the electricity generated to street lighting. Although currently only forced to cope with the modest loads of cyclists, this version could withstand the weight of a 12 tonne truck without sustaining damage. However, according to Gazette Review, engineers are already working to improve its resilience so that it could be installed on roads occupied by motor vehicles.
Since light penetration is pivotal to the success of solar panels, the path was installed on a slight tilt to encourage rain to wash off dirt that could accumulate on the surface and thus obscure the underlying cells, which was a potential problem quickly identified by critics last year. It was also given a skid-resistant coating for extra grip, but despite five years of research and development, a small section has already peeled. This was due to temperature fluctuations that caused the material to expand and contract, something engineers are taking on board for future versions.
SolaRoad already has plans to extend the prototype next year to 100 meters (330 ft), which will hopefully produce enough electricity to power three houses. While this all sounds great, and we all know how important it is to reduce our dependence on fossil fuels, the project does come with some glaring issues. First off, there’s the price tag: The prototype cost $3.75 million (€3 mn), so even at optimal efficiency, it will probably never be cost effective. Second, because the path cannot be adjusted to the position of the sun, the cells will generate around 30% less energy than those installed on roofs. Finally, this is a cycle path, occupied by around 2,000 cyclists a day—these busy commuters are also going to obstruct the sun’s rays from reaching the panels.
Still, it’s certainly a laudable pilot, and it will be interesting to see whether other countries follow suit after more trial data is gathered, or whether the crowdfunded U.S. project “Solar Roadways” ever comes to fruition.