Noise barriers with solar panels show great energy potential

Researchers from Hasselt University and imec are building a 13-metre-long test rig of noise barriers with integrated solar cells as part of the EnergyVille collaboration. For a year, they will monitor the energy yield and stability of the panels. "With this, we will show the public, industry and investors that this technology is feasible along our motorways and cycle paths," says Prof. Dr. Michaël Daenen (UHasselt/EnergyVille). "The possibilities are endless in urbanised Flanders, and offer many opportunities to the energy and construction sectors," adds Tom Vandeput, Deputy for Economy.

Within the Interreg project Rolling Solar (Euregio Meuse-Rhine), scientists are investigating whether and how solar cells can be integrated into road infrastructure such as cycle paths, motorways and noise barriers. At the Thor Park in Genk, the Belgian partners in this project are working on a test set-up of noise barriers with integrated solar cells. Dutch partners are working simultaneously on similar pilot installations in the Netherlands in order to achieve rapid large-scale application of the technology.

On walls measuring a total of 13 metres long and five metres high, they will soon be testing whether solar panels can be integrated on non-transparent walls. They will do this by gluing traditional solar panels and wafer-thin flexible thin-film solar panels to concrete retaining walls or attaching them to frames. "In addition, we are also investigating the potential of a semi-transparent arrangement. This consists of metal frames into which we insert solar panels that can capture solar energy from both sides, so-called bi-facial PV. These will be installed in a few weeks' time," says Michaël Daenen, principal investigator within the project from UHasselt and EnergyVille.

Commissioner for Economy and POM Chairman Tom Vandeput: "This project is very innovative. The space taken up by the road infrastructure is given a greater public return through its new function as an energy producer. It also ensures greater sustainability. This creates endless possibilities in urbanised Flanders. If we were to succeed in applying this new technology in the road infrastructure of the municipalities in Limburg, then Limburg would only excel in the energy transition."

Monitoring energy yield and acoustics

For a year, the researchers will monitor the energy yield of the various types of solar cells and also look at the stability of the materials used. To this end, they will place numerous sensors in the modules, which will enable them to continuously measure factors such as temperature or mechanical stress. This way, they will gain insight into the impact of (extremely) high or low temperatures on the energy yield and they will also investigate the effect of a heavy, passing truck or a strong gust of wind on the stability of the technology.

The researchers will also have the acoustic qualities of the sound barriers tested according to the standard. "Of course, our sound walls must not only produce energy but also absorb sound in the first place. To this end, we place transparent sound absorbers against the walls and then record how much loss of efficiency this causes in the panels," says Michaël Daenen.

The expertise of imec was called upon for the material and technology choices and the modelling of the energy yield. "It is our mission to help our partners translate new ideas into real-life demonstrations," says Eszter Voroshazi, who heads the photovoltaic research group at EnergyVille/imec.

Potential of the technology

With this project, which is led by the Dutch research organisation TNO, the researchers and industrial partners want to demonstrate the potential and the diversity of possibilities of solar cells integrated in road infrastructure. Bas van de Kreeke (industrial partner): "As an infra contractor, we see a lot of potential. The cooperation with the knowledge institutes gives us the opportunity to further industrialise the process. I foresee that we will soon be attaching the solar panels to the noise wall in the factory under optimum conditions, and then all that remains is to place them along the road. A plug comes out of the sound wall, which we connect to the electricity grid."