All hands on deck. In 2022, the construction business is still responsible for nearly 40% of all greenhouse emissions on the planet. It’s time to change course to contain the effects of climate change as much as possible. In particular, it’s time to examine the energy consumption and carbon footprints of buildings…
While the sector has made a lot of progress in the last few years, it still has a long way to go to reach the carbon-neutrality-by-2050 goal established by the Paris Agreement. All over the world, the leaders of the construction business are getting on board, considering extensive changes in order to offer constructive low-carbon solutions. Namely, improving the performance of their materials and decarbonizing their manufacturing practices.
A three-way challenge
There are actually three sides – environmental, economic and regulatory – to this issue. “With its RE2020 environmental regulation, France is showing the way to decarbonizing the building sector’s practices and approaches,” states Pascal Eveillard, Sustainable Construction Director of Saint-Gobain. Following in its wake, Finland, Denmark and Sweden have already planned on integrating low-carbon requirements into their regulations, and the European Union is examining how to establish low-carbon indicators for its Construction Products Regulation and for the directive on building energy performance, under revision.” Regulations are on the move, reinforced by voluntary labels such as HQE (High Quality Environmental standards) and LEED (Leadership in Energy and Environmental Design). To construction companies, these are all opportunities for developing new, more sustainable, more virtuous solutions.
Here are five ways that the building industry is striving to lower its carbon emissions to deal with climate and environmental challenges.
1/ Eco-designed fiberglass with bio-sourced binder
There’s nothing new about using fiberglass or stone wool as insulation. In the construction sector, they are first-rate insulation materials requiring no introduction. But they can still be optimized, and indeed Research and Development teams are examining how to increase their energetic performance while lowering their environmental footprint. ISOVER has come up with a convincing solution by introducing a new type of fiberglass. This patented eco-designed version was developed with regard to the life-cycle assessment (LCA) of the product. It features a new bio-sourced binder taken from the byproducts of the cereal and sugar industries. In addition to its sound-proofing and thermal insulation qualities, it is more convenient to install, offering a lower dust rate than the traditional version.
In what way is this a Net Zero Carbon product?
Because it takes into account the full life cycle (from the extraction of the raw materials to the recycling of the product following use), this stone wool with a bio-sourced binder reduces both energy consumption and greenhouse gas emissions. Its manufacturing process makes use of a minimum of 40% cullet, or recycled glass particles from industrial or household products such as windshields, bottles, and so on. The use of cullet offers two advantages. Firstly, it saves on natural resources and considerably reduces energy consumption during the glass fusion process. Secondly, the exploitation of cullet is not carbon-dependent, unlike that of virgin raw materials.
In addition to using cullet in its manufacturing process, ISOVER has established a closed-circuit fiberglass recycling system in France. These mineral wools generate nearly 90,000 tons of waste* annually – principally in the form of scraps from construction or deconstruction sites – which otherwise would have been buried. That part of the fiberglass life cycle is reorganized in this new recycling system, which helps reduce pollution while exploiting a lower volume of raw material.
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2/ Concrete is decarbonizing
6 billion**: that's the number of cubic meters of concrete poured each year on a global scale. This is not surprising, since concrete, with its well-established properties, is a local material, produced in a short circuit. A material that is, moreover, entirely recyclable... in a short circuit! At the heart of its formulation: aggregates, water, admixtures and cement! The problem with cement (a mixture of limestone and clay) is that its manufacturing process emits a great deal of carbon. Sintered at a high temperature (1500°C / 2732°F) in kilns mainly powered by fossil fuels, the mixture releases CO2 as it is heated, producing clinker. The result: one ton of traditional cement emits 850 kg / 1874 lbs of CO2.
Based on that observation, concrete manufacturers are increasingly offering low-carbon concrete. One example is Weber, a Saint-Gobain subsidiary, which is working on new low-carbon formulations which replace the cement and sand by what teams are dubbing “wasterials.” The term refers to waste materials created using a mixture of mineral co-products and/or waste products from other industries. While Chryso, a global player in construction chemicals and also a subsidiary of Saint-Gobain, designs innovative admixtures that reduce the carbon footprint of cement and concrete!
How is it Net Zero Carbon?
Just as effective as traditional cement and offering the same level of performance, Weber’s decarbonized cement is obtained through the use of volatile ashes produced through biomass combustion (when organic materials, such as wood or plant-based agricultural waste, are burned). This ecological binder makes it possible to produce a sustainable material that reduces the carbon footprint by up to 70%.
Chryso's EnviroMix® admixture technology allows for greater integration of "supplementary cementitious materials" into the concrete mix, such as slag (a byproduct of metallurgy and combustion), fly ash, pozzolan (a volcanic rock) or even calcined clays. And more supplementary cementitious materials mean a carbon footprint reduction for concrete. CHRYSO®EnviroMix reduces the weight of CO2 in concrete by up to 50%.
And because the transportation of materials is also a key factor in the production of CO2, Chryso, with its CHRYSO®Quad solution, makes it easier for its industrial customers to use the sand that is available where their sites are located - even if they only have access to difficult-to-work sand. In addition, this solution enables to integrate recycled aggregates from deconstruction into their mix design.
An approach that supports the circular economy, limits CO2 emissions related to transport, for a real environmental benefit in terms of natural resources conservation.
And for tomorrow, manufacturers are already imagining new sustainable formulations... Published in 2021, the European standard for low-carbon cements should broaden the scope for innovation. Neo-cements made of lime, slag (a by-product of metallurgy and combustion), ashes, pozzolan (a volcanic rock), or calcine clay should make it possible to significantly reduce CO2 emissions, even as new, yet-more-sustainable formulations are set to be launched… Such as a mortar made from plastic waste, or concrete based on micro-particles of carrots or beets3 that reinforce its mechanical properties. Mortar with a natural flavour, so to speak!
3/ Facades and lightweight construction
In the construction sector, lightweight materials are the new heavyweights of decarbonization pursuits. Whether it’s drywall, glazing or insulation, Research and Development departments are working to reduce the density of materials, seeking to determine the minimal proportions of materials that will achieve the sought-after performances. Less wasting of resources means less consumption of energy and a controlled carbon footprint. Lightweight construction is clearly buoyant!
In addition to saving on material, lightweight construction is also flexible and adaptable. As demonstrated by the F4 facades by ISOVER and Placo®. These new-generation outdoor wall materials may be dismantled to facilitate extension and deconstruction work, in addition to offering rapid installation and a reduced carbon footprint compared to traditional systems.
In what way is this a Net Zero Carbon product?
Pre-cut at the factory and assembled using a dry process, the F4 facade is energy-efficient. Its water consumption and CO2 emissions only amount to half of those used for a traditional concrete shell. The results: going from 120 kg / 265 lbs of CO2/m2 to 60 kg / 132 lbs of CO2/m2! This easily “deconstructible” system improves the entire lifestyle of the product, since it breaks down into materials that may be reused in various industries.
In addition to lightening the load, construction leaders are considering new exterior wall concepts to get in on the ground floor of passive building. In the Netherlands, the Building Integrated Photovoltaics (BIPV) facade is representative of the “Zero Energy Building” trend. With exterior siding that works as a photovoltaic panel, this type of outdoor wall produces its own electricity while fulfilling the functions of energy performance, mechanical resistance, weatherproofing and soundproofing. Another innovation: active façades peppered with captors which make it possible to automatically close the windows and blinds when the weather requires it.
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What if smart glazing turned out to be one of the best solutions for building net zero carbon buildings with net zero energy consumption? That’s the promising prospect of innovations, which seek to eliminate energy loss at the very least. One solution is low-emission double-glazed glass, designed to block infrared rays in order to improve thermal insulation. Developed by Saint-Gobain, ECLAZ ONE is a low-emission glass that works as a shield. In the summer, it reflects the sun’s rays towards the exterior. In the winter, it keeps the heat indoors. The secret behind the glass: a fine, transparent layer of metal oxide that reacts to thermal infrared rays selectively, according to their wavelengths.
In what way is this a Net Zero Carbon product?
The “zero carbon” performance does not come from the glass itself, but from its manufacturing process. Saint-Gobain has completely modernized its float glass plant order to reduce the quantity of CO2 emitted during its manufacture. These ultra-efficient lines are equipped with kilns that make it possible to reduce energy consumption loss by 19%... Moreover, adding cullet (scraps of glass) to produce the glass limits its CO2 emissions. For the anecdote, producing one ton of glass using new raw materials emits 500 kg / 1,102 lbs of CO2. The same amount of glass produced using cullet only produces 200 kg / 441 lbs. That’s one of the qualities of glass: It can be endlessly recycled, without losing its chemical, mechanical and aesthetic properties, thus preserving natural resources.
Sustainable and energy-efficient, low-emission glass opens the horizons of innovation for intelligent glazing. Glazing industrials certainly think outside the box, and they are now designing “dynamic” glass (such as SageGlass glazing by Saint-Gobain) which changes color according to the level of sun exposition. Other promising innovations should become widespread in the years to come, such as lightweight triple glazing, with a carbon footprint equivalent to double glazing for improved thermal insulation. And let's not forget the magnetron coatings that are applied to the glass. Their carbon impact is low compared to the performance they bring to glazing, whatever the climatic zones.
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5/ Manufacturing processes
While materials help reduce greenhouse gas emissions, there is another area of innovation to watch: industrial processes, which are continually being improved to reduce their energy consumption. To optimize these production lines in order to reach the “zero carbon" goal by 2050, Saint-Gobain is committed to electrifying its processes. The Group recently invested 25 million euros in its Norway-based plasterboard production site, making it the world’s first carbon-neutral factory.
In what way is this a Net Zero Carbon process?
Up until now, the Fredrikstad site had been powered with natural gas. However, green energy will now be taking over, since 96% of the electricity produced in Norway is hydraulic. Finalized in early 2023, this zero-carbon project should make it possible to save more than 20,000 tons of CO2 emissions annually while reducing energy consumption. By 2025, the Group plans to extend this type of industrial transformation to other sites (on several continents) while broadening the capacity of this process to use most types of locally available renewable energy: green electricity, biomass, biogas, green hydrogen, etc.
Another major investment to greatly increase the “Zero carbon” effort: the use of SBM (Submerged Burner Melter) kilns for the production of mineral wool. Out with the old-fashioned, energy-intensive coal-fueled kilns, and in with submerged combustion melters, which emit little nitrogen oxide (NOx). Also used to recycle waste, this type of high-yield kiln ensures a more homogeneous fusion and can make use of biomass as a combustible.
As you can see, the decarbonization of the construction industry entails innovation across the horizon. From upstream to downstream along the value chain, three principal drivers will make it possible to take the “zero carbon” leap: the development of new materials and new formulations to protect resources, the modernization of manufacturing processes, and the establishment of a circular economy. This more sustainable, more virtuous “Net Zero Carbon” approach opens the door to tomorrow’s building sector… Where the environmental footprint diminishes with every step forward.
* L’Usine Nouvelle – « Isover installe un nouveau four pilote pour recycler la laine de verre en Anjou »
** Planetoscope – World concrete production
*** PlaceTech - Carrots could be key to stronger concrete
Photos credits : Lorillard, Semon Rapaport/Medialibrary and Franck Dunouau/Medialibrary