How will the generated energy be used?
During the pilot, the generated electrical energy will be supplied to the electricity grid, just like most solar panels on rooftops. It is expected that the pilot cycle path of approximately 100 m will generate as much electricity as is used by 2-3 average households annually. When SolaRoad is going to be applied extensively, straightforward supply to the electricity grid will not be an optimal solution anymore. For example, smart ICT applications that help to distribute the energy production at peak times (lots of sun) and dip times (night) as efficiently as possible are needed then. This issue will be addressed in the pilot study as well.
How can the solar cells be protected against use (load and shock), environment (heat and cold) and vandalism?
The solar cells are located between two sheets of tempered glass in a concrete housing. The results of the mechanical and thermal tests of the prototype show that the elements are able to withstand everyday use very well. The glass surface can also resist large impact loads. Damage caused by vandalism, however, can never be ruled out. We use safety glass. When this type of glass breaks, it will break in the form of a lot of small pieces. There will be no dangerous shards. Moreover, the glass remains in its place due to the coating on the surface and the frame. Thus, even when the glass is broken, it can still be safely walked and cycled on, until repair can take place.
How strong is the glass?
We use tempered glass that is particularly strong and that is mounted in a concrete housing. The strength of the glass in the housing is being mechanically tested in different ways. For example, extreme traffic loads are simulated in a bench press, pressing different tyre types on the surface with great force. Also, we drop steel balls and bags with marbles of different sizes and from different heights on the SolaRoad surface, in order to test the resistance to impact loads. This is based on internationally recognized standards. In this way, we test whether the glass is safe for use in practice.
Do shards occur if the road breaks?
No, we make use of safety glass. When this type of glass breaks, it will break in the form of a lot of small pieces. There will be no dangerous shards. Moreover, the glass remains in its place due to the coating on the surface and the frame. Thus, even when the glass is broken, it can still be safely walked and cycled on, until repair can take place.
Will SolaRoad break due to tree roots that may grow under the road?
The current version of SolaRoad has been tested in the laboratory on structural strength. A specific ‘tree root test’ was not possible, but the concrete elements are designed and produced in such a way that they will not break very easily. To prevent height differences at the transitions of the elements, we pay special attention to the way in which they are interconnected. When dealing with factors from the (natural) environment, we make full use of existing knowledge and experience with prefabricated slabs.
Is it possible to use existing solar cells or do they have to be adapted? If so, what are the costs?
Technically, there is no need for special solar cells. In the pilot, we make use of standard silicon solar cells. Of course, the solar cell, the translucent surface and the other components must be adjusted to one another. We develop the SolaRoad concept in such a way that in time we can integrate other types of solar cells, for example thin-film solar cells. A decisive factor for the choice of the best solar cell technology is the economical assessment of costs versus benefit (revenues).
