PROJECT DESCRIPTION
BACKGROUND
Highway noise is a serious environmental problem in urbanised areas. Noise barriers, of various shapes and design, have been erected along highways in densely-populated areas for over 20 years. These have lowered noise levels and can make a contribution to improving air quality. Meanwhile, electricity is being increasingly produced from solar power using photovoltaic (PV) cells, which help to lower greenhouse gas emissions. Solar panels have been installed on existing noise barriers, but the results are sub-optimal. In many cases, the use of solar panels is adapted to the chosentype of noise barrier or the noise barrier is adapted to the requirements of the solar panels. In recent years, bi-facial solar cells have been developed that can produce electricity from light falling on both sides of the PV module. Such a module can produce over 30% more power on an annual basis compared to a standard module with a white back-sheet. Furthermore, the power output of the module is less sensitive to orientation, and the module does not need to be placed facing south: east-west is also possible. These modules have great potential for integration with noise barriers.
OBJECTIVES
The main objective of the LIFE Solar Highways project was to demonstrate the technical feasibility and the environmental, social and financial benefits of using multifunctional constructive elements for building highway noise barriers with integrated bi-facial PV modules. A successful demonstration would simultaneously accelerate the use of PV modules and noise barriers along Europes highways, contributing to EU policy goals for climate change, noise reduction and improved air quality. Specific objectives were also to: develop a technological-financial model to convince investors that the return on investment is sufficient to open up new business opportunities and to facilitate broad implementation; test the prototype with an integrated bi-facial PV solution along a stretch of highway in the Netherlands; demonstrate the energy yield that can be achieved during an 18-month testing period in the field; and elaborate a business case that will lower the financial threshold for noise barriers and solar panels.
RESULTS
The LIFE Solar Highways project successfully demonstrated a highly innovative bi-facial solar panel technology as part of a motorway noise barrier, which could lead to considerable benefits in terms of climate change mitigation through the production of renewable energy, and reductions in vehicle noise and air pollution. Besides, the use of highway noise barriers and other existing transport infrastructure to generate renewable energy can reduce the pressure on land required for solar panels or other means of generating renewable energy.
Bi-facial PV modules were laminated between two glass plates to serve as noise barriers. Their module nature means that individual parts can be replaced if required. The bi-facial nature of the PV modules means that they are less sensitive to orientation toward the sun to generate electricity.
Following a consultation concerning best practices in Europe, the project partners built a preliminary design of the photovoltaic noise barrier. At the same time, a draft techno-financial model of this innovative technology was developed. Through a public procurement for Design and Construct, the contractor built a demonstration photovoltaic noise barrier along the A50 motorway in Uden, in the Netherlands.
The certified barrier was connected to the electricity grid. Over an 18-month monitoring period, between January 2019 and June 2020, the barrier produced 325.5 MWh of solar electricity, which corresponds to approximately 220 MWh/year. This is enough to provide electricity for 60-70 households, and avoids yearly emissions of 121 tons of CO2. The new barrier is designed to operate for around 30 years. A wide range of parameters were also monitored, under various combinations of maintenance and cleaning scenarios. This monitoring operation data was used to update and verify the techno-financial model.
Output in terms of energy production was lower than foreseen, while the CAPEX (capital expenditure) was significantly higher than anticipated due to contract costs. The project partners therefore made recommendations to further improve the energy efficiency and reduce costs, resulting in a positive business case. For instance, monitoring showed no measurable effect of cleaning on energy performance, so cleaning costs (an important operational cost) can be reduced to zero. Encouraging signals were already present by project end, with concrete replication projects (municipal, provincial and regional motorways) and a transfer project to the railway sector.
The projects socio-economic study helped the municipality of Uden and the coordinating beneficiary Rijkswaterstaat to understand the level of public acceptance for this new type of noise barrier. The high level of acceptance by the local inhabitants, and the strong interest in consuming electricity produced by the barrier, was very encouraging for the roll out of similar initiatives across the Netherlands. Moreover, a type of social control to prevent damage or vandalism was put into place by those living near the barriers.
In the coming years the beneficiary intends to lease the electric installation to an energy cooperative of citizens living in the direct surroundings of the barrier. By doing so, the beneficiary aims to make them more involved in the good operation and maintenance of the barrier (e.g. early warning system in case of damage). This approach, to gain citizens support, is also seen as a leverage for the replicability of the technology generally.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
