A world first: carbon-neutral flat glass is made using green energy

In a world first, carbon-neutral flat glass has been made using green energy and recycled materials. The innovation was made by Compagnie de Saint-Gobain, the French glass manufacturing company.

French glass manufacturing giant Saint-Gobain has become the first company to create zero-carbon production of flat glass – the glass that is used for windows, windscreens glass doors and transparent walls.

The glassmaking trial ran over the course of a week at its Aniche plant using only 100% recycled glass and 100% green energy produced from decarbonised electricity and biogas.

In total, the company made around 2,032 tonnes of carbon-neutral glass during this week – enough for 101,605 windows. The production saved approximately 1,016 tonnes in carbon emissions.

In a statement on Monday, the company said that the achievement was proof of its commitment to reach carbon neutrality by 2050. 

Read more: MakerBot & Ultimaker to merge to accelerate global adoption of 3D printing

There was, however, one downside of the sustainable innovation: the process was more expensive than usual. In fact, production costs were “several tens of percent” higher, said Benoit d'Iribarne, Senior Vice-President for Technology and Industrial performance. 

In order to make the innovative glass financially viable, European Union carbon-emission permits would need to rise from 90 euros to approximately 200-300 euros a ton (1.016 tonnes). Moving forward, another option for the company would be to try and find a balance by creating low-carbon, rather than zero-carbon, products.

For Saint-Gobain, this is only the beginning, and the new technology paves the way for future projects. “We will soon be able to market a range of glass with a lower carbon content, without compromising the energy performance of the glazing,” said Joana Arreguy, Saint-Gobain’s Industrial Director of Glass Business.

The company has also created a thermally insulating glass, which has a special metallic coating to help improve energy efficiency. Saint-Gobain, which also makes manufacturing goods, also shared plans to build the world’s first carbon-neutral plasterboard plant.

The design and manufacturing corporation is also focused on using more cullet – broken down the recycled glass – when creating its products.

“A site like Aniche consumes an average of 740 tons of raw materials to ensure daily production. We try to replace as many of these raw materials as possible with cullet,” said Matthieu Jourdier, Saint-Gobain’s Industrial Director.

As a result, the company has set itself a second set of sustainability targets. It now aims to achieve 50% cullet usage in its French locations and 40% at its other worldwide production sites.

There are three main areas where cullet can be sourced: internal cullet from production lines, cullet from customers’ processing workshops, and a third, largely unexplored area: end-of-life glazing from renovation and deconstruction sites, which may have as much as 203,209 tonnes’ worth of cullet annually.

In the future, glass may play an even larger societal role as it is a sustainable substance. Although it does not degrade, glass can be broken up into cullets which can then be reheated and formed into new objects.

As well as this, cullet melting produces no direct CO2, and furnaces don’t need to burn as fiercely when they are being used to melt cullet glass.

Read more: Google & augmented reality will help e-scooter users park

Then of course glass – which is made from sand, limestone and soda ash – is infinitely abundant, another reason it is an important resource as companies try and become more sustainably minded. In November the science journal Nature went so far as to call glass “the hidden gem in a carbon-neutral future”.

The UN’s International Year of Glass started in 2022, pushing businesses and industries of all kinds to probe the potential of glass, particularly as a means to achieve a more sustainable world.

For years France has been at the forefront of industry-focused green policies, setting itself the target to achieve net-zero by 2050 in 2019.

In 2015 France had set out an Energy Transition Law (laying out in law its commitment to green energy), which built on its 2008 – 10 Grenelle Environment Acts (further setting out France’s sustainable objective).

Back to Homepage

Back to Technology & Innovation