future view

SolaRoad’s new phase: a motorway that also generates electricity

7 March 2019 • 4 min reading time

It began with a bicycle path in Noord-Holland that attracted worldwide attention as the first road surface to generate energy. SolaRoad technology is now being applied at various locations in the Netherlands and France. The next phase is now commencing: projects with heavy traffic on public roads. If part of our 140,000-kilometre road network were to produce energy, it could make an important contribution to the energy transition.

Energy producing SolaRoad: from cycle path to motorway

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“One of the most important challenges for the large-scale production of solar energy is fitting solar panels into our limited space,” says Sten de Wit, Commercial Director of SolaRoad BV. “You can’t install solar panels on an unlimited number of water surfaces or fields. You have to make clever use of what already exists, such as roofs, facades or roads. Our road network has a total paved surface of about 1,200 square kilometres. By equipping the suitable parts of this with solar panels, at least ten percent of our electricity needs could be covered. And a third of our road network can produce enough energy to power nine million electric cars.”


The principle is simple: the road is covered with robust solar panels, covered by a transparent and non-slip coating. Sunlight passes through the coating to the crystalline silicon solar cells, where it is converted into electricity. The challenge was for the solar panels to capture as much light as possible and at the same time be strong enough to allow vehicles to drive over them. Experience has already been gained in various bicycle traffic projects, but the load from buses or heavy goods vehicles is another story. In recent years, through close collaboration with TNO and Strukton, the SolaRoad road surface has been made suitable for use on roads with heavy traffic. The provinces of Noord- and Zuid-Holland are now applying these solar road surfaces for the first time in two projects: a bus lane along the N218 in Spijkenisse and on the parallel road of the Fokkerweg (N232) at Schiphol.

Large scale application required

“Now that we have proven that generating electricity from bicycle paths works, this is a logical next step,” says Prof. Dr. Wim Sinke, Principal Scientist Solar Energy at ECN part of TNO. “We need to move towards large-scale application of this technology, towards generating volume and realising economies of scale. If that happens, the technology will become cheaper and we will enter a positive spiral. Pilots are an essential step in this. We will demonstrate that SolaRoad also works when heavy traffic drives over it for long and intensive periods. Once it has been demonstrated that the road is safe and reliable while still providing substantial energy, market introduction will be one step closer.”

Sustainable innovations

The provinces are active in stimulating sustainable innovations concerning mobility and infrastructure, leading to energy conservation, energy generation and a cleaner environment.
In Zuid-Holland, solar panels are being installed 100 metres from a bus lane at the Halfweg-Molenwatering business park near Spijkenisse. In Noord-Holland, this is taking place on a road over which lorries travel to and from a large distribution centre. As road authorities, both provinces want to gain experience in the management, maintenance and, in the future, tendering of solar road surfaces. It will be interesting to see the difference in energy yield between the road surface on which buses run with a more or less fixed frequency and weight and the road surface with much more intensive and load-varying lorry traffic. The projects will be monitored for three years.

Permanent monitoring

Everything is being constantly and accurately measured by the sensors in the road surface and in the surroundings. Both test sites are also equipped with a weather station to determine the influence of temperature, air pressure, wind and other factors on the amount of energy generated. “The conditions on the road are completely different from those of panels on a roof. We will carefully monitor all of this. The measurement results provide essential information about the performance of road surfaces and what we can do to improve them in the future,” says Sten de Wit.

“The energy transition requires a mix of innovations, to which roads with solar panels can make an important contribution.”

The Province as a launching customer

The pilot with the bus lane near Spijkenisse is one of many projects within the energy transition programme for mobility and infrastructure in the province of Zuid-Holland. “In a number of cases, we take on the role of launching customer,” says Programme Manager Jan Ploeger. “There is a working product, but market introduction is too risky. It is then difficult for market parties to obtain financing for further development. The province can play a stimulating role here. By purchasing innovative products as a public client, we give the market the signal that we have confidence in them. This will hopefully be the prelude to market introduction and large-scale use.”

The province is collaborating with Noord-Holland and other provinces on the formation of a purchasing consortium, in order to be able to buy products such as solar panels for the road on a massive scale. If the pilot project meets expectations, an assessment will be made of which parts of the many hundreds of kilometres of provincial roads are to be converted into SolaRoads. It should also show to what extent solar panels outweigh tarmac roads in terms of costs and revenues.

“The energy transition requires a mix of innovations, to which roads with solar panels can make an important contribution.”

This TNO project supports the following Sustainable Development Goals

Energy producing SolaRoad: from cycle path to motorway

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