For thousands of years, pitched roofs have been tiled to protect homes from the weather. Now, they could also help to protect us from climate change, by aiding the transition from fossil fuels to renewable energy.

Existing solar technology is installed as panels mounted on top of existing roofs. This design suffers from various potential weaknesses: the mounting can damage the roof trusses and cause structural damage to the roof over time; the equipment has to be strong enough to endure high winds; and in the space between the panel and the roof, weathering from the repetitive freezing and thawing of snow and ice, for example, can cause damage to both the panels and the roof itself.

In the EU-funded TilePlus project, researchers designed a new generation of roof tiles, with photovoltaic technology seamlessly embedded. The tiles provide all the protective properties of normal roof tiles, while offering a way for residents to gather their energy directly from the sun. As the solar panels create energy where it will be used, this also reduces losses incurred during energy transport and transmission.

“You get two in one. The proven roof technology that will keep your house safe from weather, and a low-maintenance solar solution,” explained Selma Kveim, senior executive at Skarpnes roofing firm and TilePlus project coordinator.

Getting to grips with conductive glue

As the new photovoltaic tiles must function in the same way as roof tiles, there are physical limitations on the size of the tile. That meant the TilePlus team had to improve the way the panels could produce electricity within that area.

Normal photovoltaic cells are covered in horizontal metal thread, which conducts electricity around the panel and out through the cable in the rear.

A redesigned cell from project partner Autarq, a German climate technology firm, incorporated conductive glue which increases the surface area available to absorb solar rays, increasing peak energy production in the panel by 15%.

Electrifying Europe’s homes with solar

There are upwards of 200 million homes across the EU, most of which lack solar panel technology. “All of these roofs and all of these buildings should be upgraded to use less energy,” said Kveim. “Let’s take this rooftop space and start using it to produce electricity, so that every household can be their own energy producer.” This is particularly pressing in light of climate change and increasing energy prices in Europe.

In the TilePlus project, there were three main goals. The first was to improve the efficiency of the solar panels to harness electricity. The second was to develop the machinery to create the new laminates and to improve the assembly process. And the third was to develop the value chain, including all the training procedures for all actors in the value chain.

The technology is now undergoing trial in four pilots. The first installation was carried out by retrofitting a property in Skien, Norway, in July this year. Further tests are being conducted in Lyngdal, Norway, as well as installations in two nearly zero-energy buildings, one in Bergen and another in Aalborg, Denmark.

The tile capabilities, and the whole user experience, will be monitored over the next few years. A weather station was also installed onto the roof to track the local conditions.

TilePlus panels are expected to be available on the market by mid-2024. “The plan is to post real-time production data on our website to educate people on solar,” said Kveim. “That’s a large part of our job now moving forward.”