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It is possible to innovate with solar energy in a conservative sector such as construction. What’s more: it has to be from Europe. The expertise and knowledge are available in Belgium. Now we have to wait for the construction sector to make a turnaround.
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‘These are like mini solar panels. We connect them manually. They come on a pool shutter.’ In the workshop of the solar energy company Soltech in Tienen, Stefan Dewallef, responsible for product development, shows a pendulum of slats. He has been working for Soltech for almost thirty years, which specializes in building integrated photovoltaics (BIPV), the technical term for building materials with integrated solar cells.
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Bipv is an important application that can help the construction industry to become more climate-friendly and ultimately CO₂ neutral. Europe aims to be the first climate neutral continent by 2050. A first deadline is not so far away: by 2030, CO₂ emissions must be reduced by 55 percent compared to 1990.
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Now 36 percent of CO₂ emissions and 40 percent of energy consumption come from homes and buildings. The European Commission will impose its own trajectory on each country to reduce emissions from the construction sector, just like the transport sector is a major polluter. The EU wants to see the energy consumption of buildings reduced by 1.5 percent annually between 2024 and 2030. 3 percent of government buildings must become almost climate neutral.
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‘You need solar energy to meet those guidelines,’ says Bart Vermang, who conducts research into new materials for solar energy for the Leuven research institute imec and Hasselt University. ‘Solar panels on roofs will not suffice. So innovation with materials is becoming essential.’
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That means that the construction industry has to experience that change. That’s no mean feat: the sector is known for being rather conservative. ‘The b in BIPV is important. But if I look at the sector, in recent years it has been too little b and too much pv’, says contractor Bas van de Kreeke, who joined Soltech’s recent relaunch. ‘The construction industry’s point of view has been completely absent in recent years: how does a contractor think, what does he need, how does an architect think? That has to be included in the production process right from the start.’
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The generation of green energy already starts on the drawing board.
Jean-Didier Steenackers
Architect and founder of Sunsoak
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Nevertheless, a turnaround seems to be in the making, says Brussels architect Jean-Didier Steenackers. In 2015, he founded Sunsoak, an architectural firm specializing in integrated energy design construction projects. ‘The scale is increasing: architects and developers are beginning to realize that it is not a question of a covering layer of solar cells, but that the generation of green energy must already start on the drawing board.’
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The basic components at BIPV and ordinary solar panels are the same: solar cells. ‘Standard panels are designed to generate as much energy as possible and to place as many cells as possible on the ideal surface’, says Olivier Demeijer. He is the CEO of the Liège company Issol, which makes roof tiles – roof tiles with integrated solar cells. ‘With BIPV, the ratio per panel is lower, but it has other advantages, such as the surface area.’
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Dewallef gives an example. ‘At BIPV you will sometimes lose capacity if you have to work on a vertical plane instead of a pitched roof. But with vertical facades we have more yield when the sun is low. The time of day or season matters less. You can fill the east facade and the west facade, generating energy around the clock.’
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Aesthetic and efficient
Building materials with integrated solar cells also have a lot to offer from an architectural point of view. ‘The roof is not always the best place to generate solar energy. Due to excellent skylights or fire escapes, you can usually only use 50 percent of the surface of large industrial or commercial buildings for solar panels,’ says Steenackers. ‘Office buildings and museums still have a lot of surface area that you can convert into energy. There it is important that it is done in the most beautiful way possible, so that it fits into the cityscape’, says Vermang.
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Office buildings and museums still have a lot of surface area that you can convert into energy.
Bart Vermang
Researcher Hasselt University
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Aesthetics are an important asset of BIPV. But it’s also about efficiency, says Dewallef. ‘Putting a building and then climbing it up to put a second layer on it is neither sensible nor efficient from a material-technical point of view. It wouldn’t be the first time they tear down the scaffolding at a completed site, and another company puts up new scaffolding a week later to install solar panels. We have to get the CO₂ emissions down and reduce the use of materials, then you almost automatically come to BIPV.’
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