The world’s first bike path constructed from solar panels has been extended by 20m, using improved materials that take it one step closer to becoming a viable option for large-scale rollout, according to its creators.  

Installed in the Netherlands’ town of Krommenie in November 2014, the initial three-year, 3.5 million euro SolarRoad prototype consisted of 70m of concrete modules fitted with solar cells underneath a tempered glass top layer approximately 1cm thick.

Since its installation, the technology’s potential to create a previously untapped source of renewable energy has attracted international attention. The consortium behind the project says the generated electricity can be used for street lighting, traffic systems, households and electric vehicles.

Participants in IPWEA’s 2016 International Study Tour got up close and personal with the pathway and were impressed by what they saw. Speaking about the highlights of the trip, Andrew Ryan, the Director for Infrastructure Services at the Sunshine Coast Council, says it was “hard to go past” SolaRoad.

“Their vision is to be able to use future road construction projects as opportunities to generate power and ultimately create conductive systems that may then power electric vehicles as they pass along the road ways,” he says.

So far, the project has experienced both ups and downs. In May 2015, it was announced SolaRoad had generated more energy than expected, reaching 3000kWh in its first six months. The path also seems to have passed the test with cyclists, with researchers reporting that riders have adapted well to the technology. However, the longevity of the tempered glass was called into question when a part of it peeled off due to large temperature fluctuations that caused the glass coating to shrink.

And although the project has generated a lot of buzz among green energy advocates, it also has its detractors. Commentators have expressed the view that the technology’s cost makes it a far less attractive option than rooftop solar.

Triple pundit’s Scott Huntington explains it in this way:

“Consider that the SolaRoad cost 3.5 million euros to build, and in the Netherlands, solar energy costs $2 per kilowatt. That means the money spent for the SolaRoad could have bought 520,000 kilowatts of electricity. Compare that amount with the 3000 kilowatts produced by the SolaRoad, and it’s easy to see why some people aren’t convinced the project was worthwhile. That’s 173 houses that could have been powered instead of one.”

It’s a problem the consortium’s researchers are working hard to solve, starting with the new installation, SolaRoads Spokesperson Sten de Wit told intouch.

"We made several changes to the technological design of the solar modules in the bike road elements, to better tailor them to the application in roads and make them more suitable for industrial production. More efficient material use equals cost reductions, less sensitive to local shading equals an increase of efficiency and less sensitive to damage equals a longer life span,” de Wit says. 

“Moreover, SolaRoad elements in the extension are based on thin-film solar technology. This technology is developing rapidly and is potentially interesting for future application in SolaRoad. The field test with this technology will provide relevant information about the performance and potential of this technology.”

Of course, reaching the technology’s full potential will mean taking SolaRoad from the bike path to the road.

“The bike road is designed for exposure to incidental axle loads up to 12 tonnes. The pilot in Krommenie shows that occasional use by heavy vehicles – i.e service vehicle, agricultural vehicle, emergency vehicles – does not affect the integrity and performance of the SolaRoad bike path. However, we do not know yet what the long-term effect will be of frequent use by heavier vehicles. Our current R&D is focusing on identifying and resolving these issues within now and two years,” de Wit says.

De Wit says SolaRoad aims to build “one or two” pilot projects in applications for regular traffic by the time the Krommenie pilot comes to an end in 2018.

“Our focus is on a) making the technology applicable for use in regular roads, and b) developing SolaRoad into a large scale, industrially manufacturable product.”

De Wit says SolaRoad signed a memorandum of understanding earlier this year to start a cooperation with the California Department of Transportation to work towards a pilot in California.