The world’s first photovoltaic guardrail might turn roads and highways into energy sources. Developed to enhance sustainability, this groundbreaking innovation could help decarbonize Europe’s transport infrastructure. Yet, experts warn: “For such solutions to become reality, we need more opportunities to implement our innovative approaches.

If in a few months you happen to drive on the highway from Turin to Trieste, not far from the small Italian town of Erbusco, you might notice its medieval castle, catch a glimpse of its beautiful 16th- and 17th-century mansions, and inevitably come across a motorway service area. Yet, you will likely overlook a groundbreaking technological innovation with the potential to revolutionize both transport infrastructure and the energy sector. At first glance, it appears to be an ordinary guardrail, but on closer inspection, you’ll notice it is partially covered with an ultra-thin solar panel. This is the world's first photovoltaic guardrail. “Its estimated annual production is about 623 kilowatt-hours per kilowatt peak, which translates to approximately 25 megawatt-hours per kilometer,” explains Eduardo Román, Head of the Photovoltaic Team at Tecnalia, the Spanish company that developed the solar panels. “A family of three consumes about 100 kilowatt-hours per month on average. So, with that amount of energy, we could power around 20 such households.” The idea emerged from the enormous potential of European road networks: approximately 136,700 km of roads that could be transformed into energy sources, supplying electricity to over 8 million people.

“In Europe, guardrails line thousands of kilometers of roads and highways. These vast, unused surfaces seemed like a valuable opportunity to promote sustainability, so we thought of using them to generate energy,” says Irina Mella Burlacu, founder of Vita International, which co-developed the photovoltaic guardrail with Tecnalia. “Compared to traditional guardrails, ours includes an additional safety feature for motorcyclists in the form of a flat sheet slightly tilted upward, which is where we mounted the photovoltaic panels.” While its full potential is still being assessed, this pioneering solution is primarily designed to decarbonize transport infrastructure and enhance road safety. “Amongst other benefits, the photovoltaic guardrail will produce clean energy to power streetlights, traffic signals, and tunnel ventilation systems, leading to significant savings for road operators. But it will also enable the addition of signage and lighting in areas without access to the electrical grid,” Burlacu adds.

Expected to be tested on a 100-meter stretch by the end of the year to evaluate its performance across all seasons, the photovoltaic guardrail was developed under Liaison, a European project promoting circularity and sustainability in transport infrastructure. “Europe has more than 136,000 kilometers of roads and over 234,000 kilometers of railways. This transport infrastructure network is continuously upgraded through construction and maintenance activities, such as pavement replacement and ballast maintenance,” says David Garcia Sanchez, Liaison’s coordinator. In 2020 alone, the European Union used over 600 million tonnes of aggregates, nearly 44 million tonnes of cement, and more than 208 million tonnes of asphalt for these purposes. “Civil engineering solutions for transport infrastructure have traditionally been carbon sinks. That’s why we need to not only extend their lifespan as much as possible but also develop circular solutions,” he emphasizes.

Designed with this philosophy in mind and in line with Liaison's goal to reduce emissions from road and rail infrastructure, the photovoltaic guardrail represents an unprecedented effort to combine photovoltaics with road safety requirements. “Its impact resistance is equivalent to that of a regular guardrail. However, in the event of a crash, the solar panels along the affected section would obviously need to be replaced,” Burlacu explains. Hence, its particular design ensures their easy cleaning, removability and replacement, as well as the use of special coatings and protective layers, to minimize the risk of damage and abrasion. One more challenge faced by its developers was addressing the impact of shadows cast by passing vehicles on energy production. “There are two ways to tackle this issue,” Román explains. “One approach is to use advanced power electronics to isolate the shaded panel without affecting the performance of the others it’s connected to. Another option is to design the PV panel in a way that minimizes the impact of shadows by strategically connecting the cells in series-parallel connection schemes.”

In addition to working on procurement and tender processes to help stakeholders implement these innovations, promoting such advanced technological solutions is a central focus of the Liaison project. “We are developing a new type of concrete slab for roads made with eco-friendly geopolymers instead of cement, as well as using 3D printing to create beams from recycled materials,” says Garcia Sanchez. And when recycling is not feasible, technologies such as blockchain and digital twins help track the materials and components needed. “The most impactful ones, from an environmental perspective, are concrete, steel, and asphalt. Since our goal is to reuse them as many times as possible, we also collaborate with ‘banks of materials’—repositories where you can both find and contribute materials when you no longer need them.”

Yet, for this approach to be truly effective, technology alone is not enough. Crucial to success is what he calls a ‘holistic approach:’ “We need to ensure resilience to climate change, while also considering the safety of workers and citizens, durability, and public acceptance of new technologies.” Despite the available solutions, the greatest challenge lies in convincing administrations and other stakeholders that “circularity is the way forward,” he says. “Engineering and transport infrastructure are highly segmented sectors, characterized by strong inertia and resistance to change. Shifting this mindset is very challenging.” While the photovoltaic guardrail is set to undergo real-world testing in the coming months, his message to industry stakeholders and policymakers is clear: “We are creating new opportunities for circularity, sustainability, and resilience in terrestrial transport sector” he says. “We are not here to create problems but to provide decarbonized solutions. Yet, for them to become reality, we need more opportunities to implement our innovative approaches.”

Article by Diego Giuliani with contributions from:

• Eduardo Román, Head of the photovoltaic team, Tecnalia
• Irina Mella Burlacu, Founder Vita International
• David Garcia Sanchez, Liaison project coordinator, Tecnalia

CONTACTS
Project coordinator:
David Garcia Sanchez
david.garciasanchez@tecnalia.com
Tecnalia

Communication Manager:
Gustavo Jacomelli
Gustavo.jacomelli@icons.it
Fondazione ICONS

Project website: https://liaison-transport.eu/
LinkedIn: LIAISON