What is SolaRoad?
SolaRoad is a new concept for the generation of sustainable energy. Here, the road surface also acts as a solar panel. The generated electrical energy can be used for various applications, such as road lighting and traffic systems. Households may benefit from it as well. In time, electric cars might possibly be able to make use of the energy. The energy will then actually be generated at the place where it is needed: this is a big step towards an energy-neutral mobility system.
Who is developing SolaRoad?
The idea for SolaRoad was born at TNO. The Province of Noord-Holland, Ooms Civiel and Imtech have joined to develop SolaRoad. Together they form a consortium.
What is a solar cycle path?
A solar cycle path is an application of SolaRoad in a cycle path. In other words, it is a cycle path that absorbs solar energy and converts it into electrical energy.
Is it possible to cycle on glass?
The SolaRoad cycle path will be safe, comfortable and sustainable. We realize this with several technical solutions:
Skid resistant road surface
The surface of the SolaRoad cycle path consists of a layer safety glass with a skid resistant coating on it. The coating ensures that the road users have sufficient grip and are able to safely drive and walk on it. In the laboratory the skid resistance of the road surface is being tested. The skid resistance may not be lower than that of a normal cycle path, not even in the long run.
Strong road surface
Special attention is paid to the strength of the road surface. The tempered glass in the top layer and the solar cells underneath are applied in such a way that they can withstand everyday use. Not only cyclists must be able to ride on it, but for example service vehicles as well. In addition, shock loads of falling objects should be taken into account. Influences from the environment (heat, cold, salt, …) must not cause any problems. These aspects are being examined in the laboratory using various mechanical and thermal tests.
Comfortable road surface
SolaRoad consists of prefabricated elements, which are placed end to end to form a cycle path. In order to achieve a good riding comfort for the cyclists, the elements are interconnected to one another. This link ensures that no height differences can arise at the transitions between the elements. The road construction is designed to avoid damage from in the soil underneath, or from expansion and contraction due to temperature changes.
Why would you include solar cells in the road and not next to it or on rooftops?
It is not either-or, but both-and. The total electricity consumption in the Netherlands lays around 110,000 GWh and increases annually by about 3% (according to CBS Netherlands). This means that if all suitable roofs in the Netherlands would be equipped with solar panels, they could only supply approximately 25% of the Dutch electricity demand. In order to reach a larger share of solar energy, a larger surface area of solar panels is required and therefore alternative types of solar cell applications than only rooftops must be found. In this regard, roads are an interesting option. The approximately 140,000 km of roads in the Netherlands cover a total area of about 400-500 km2, which is significantly larger than the total (suitable) roof surface area. With the integration of solar cells in road infrastructure, a great potential has come into existence, creating a complementary market for solar panels.
Why is the pilot a cycle path (and not a highway)?
A cycle path is more practical as a pilot site (than for example a highway) for various reasons. A cycle path is less heavily loaded, because the means of transport that use it are lighter. It is also easier on a cycle path to make any possible adjustments and to implement improvements. This way, we can learn and develop faster. In addition, a cycle path is a typically Dutch product.
Why has the location in Krommenie been chosen?
The pilot location in Krommenie meets several important criteria. It is a separate cycle path with free space on both sides. This is important in order to be able to make measurements next to and around the cycle path easily and to make any possible adjustments or improvements. In addition, the cycle path is located conveniently with respect to the sun. The path is intensively used, so that the influence of the use can properly be monitored. Also, the location is easily accessible by both car and train, the cycle path is under the control of the Province Noord-Holland and the current asphalt surface is to be replaced soon. Finally, we prefer working with an enthusiastic and progressive community that is engaged in renewable energy. This is how we ended up in Zaanstad. These arguments together make the selected cycle path in Krommenie a suitable location.
Why isn’t SolaRoad applied over the full width of the bicycle road?
We aim at maximum efficiency in the process of learning and improving, using a combination of (lab) experiments, pilot testing and further development. This helps us to make the time to market as short as possible. In June we made the final decisions on the pilot-design. At that stage, we chose to use apply SolaRoad on only one lane of the bicycle road in Krommenie. This allows us to execute the planned research and monitoring programme in full, while saving costs in the pilot. The extra money can be deployed for further development.
Moreover, the other lane on the bicycle road will be used for specific R&D to improve the transparent top layer. In a number of test sections in this lane, dedicated measurements will be carried out to evaluate various solutions for the top layer e.g. on pollution and wear. Loads and exposure are almost identical to the adjacent SolaRoad-lane. The test sections can easily be replaced, to support accelerated optimization of the top layer.
What is the position of the consortium compared to Solar Roadways from the U.S.A.?
The SolaRoad consortium uses an approach that is comparable to that of Solar Roadways. The developments are at a similar stage: the stage of the prototype. There are differences too, for example in the technical details. Solar Roadways aims at the integration of many different features, which include making texts (STOP, SLOW DOWN) by means of LEDs in the road and the signalling of crossing pedestrians. We have chosen to focus entirely on the generation of electricity and only afterwards to consider the integration of other functions. This way, we are working as fast as possible towards a well-functioning and practically applicable solution.
What is the difference with heat extraction from asphalt (www.wegvandetoekomst.nl)?
For heat extraction from roads commercially viable solutions exist. Road Energy Systems is a product of Ooms Civiel (partner in the consortium), consisting of water filled pipes that run through an asphalt road. The sun heats the road surface, the temperature of the water in the pipes increases, and the hot water is pumped out of the road. SolaRoad generates electricity using solar cells in a translucent road surface. The advantage of electricity is that it can be transported more easily and that it can be used for more purposes. In the future, both systems may possibly be combined.
