2023-11-19 09:07:09
Published on Nov 19, 2023 at 10:07 a.m.
It is a popular product: 84% of French people had a good image of glass, revealed last month a CSA study carried out for the French federation of the sector. 62% of those surveyed favor this “infinitely recyclable” packaging over plastic or aluminum for the same food product. Good news for France, whose glass sector is number two in Europe behind Germany.
The non-governmental organization Zero Waste Europe, however, threw a wrench into the water last June. When we compare the weight of different containers, the manufacture of a glass container produces three to four times more greenhouse gas emissions than those made from plastic (PET) or aluminum, “throughout their respective decarbonization trajectories,” specifies a study then published by the NGO.
Lightening glass bottles, a marginal lever
Without denying the problem, the glass manufacturers have started moving. Romain Barral, director of operations at Verallia, underlines that the weight of glass certainly gives it a disadvantage in this study compared to PET and aluminum, which are much lighter. The world number three and European number one in the sector is also targeting a 3% reduction by 2025 in the weight of its standard range of bottles.
And already 12,800 tonnes of glass have been saved since 2019, underlines Wendy Kool-Foulon, CSR and legal director of Verallia. “It’s a technological challenge but also an educational one because a heavy bottle is synonymous with better quality for the consumer,” she explains.
Lightening the bottles will also only make a marginal contribution to the group’s objective of achieving carbon neutrality in 2050. A visit to the Verallia factory in Madrid is enough to understand this. Two gigantic ovens enclosed in refractory bricks like a sarcophagus melt daily at 1,500 degrees Celsius a mixture of 800 tonnes of sand, soda ash and limestone which flow into it through two immense silos to manufacture 3 million bottles and jars.
Glass melting, main source of emissions
In the sultry surroundings, an incessant ballet of glowing drops of glass comes out of the ovens and pours down slides towards cast iron molds. The ring of the pot or bottle is outlined in a flash of a second using a punch, before being inverted and transferred to a second mold where the glass elongates with the help of air to reach its final form. 90 minutes later, the bottles are ready to be delivered on pallets.
The energy efficiency of the ovens at the Azuqueca factory, north-east of Madrid, certainly reaches 75% and the site is already supplied exclusively with green electricity. But although optimized, this hypnotic process still emits a lot of greenhouse gases. The melting of glass is in fact the main source of CO2, i.e. 77% of emissions, the lion’s share (72%) going to the gas which powers the ovens.
From 2028, the group will replace these with 100% electric or hybrid models, where the remaining 20% of gas will have to be replaced by biogas or hydrogen in the medium term. A first electric oven developed in partnership with the Fives group is due to start up on the Cognac site in early 2024, while a hybrid model will be put into operation in Zaragoza in 2025, then in the historic Saint-Romain-le-Puy factory. in 2026.
The limits of glass recycling
This process, for which Verallia will already mobilize 230 million euros by 2030, is not expected to be completed before 2040: the group does not want to rush the replacement of ovens whose average lifespan is twelve years. The former Saint-Gobain spin-off is therefore working in parallel to replace the soda ash and limestone used in the smelting process. These in fact release 22% of CO2 emissions during the manufacture of glass paste.
Two alternatives have been identified for limestone while a first industrial test should begin in the coming weeks to replace soda ash. However, a new recipe with these substitutes should not see the light of day on an industrial scale before 2030. In the meantime, Verallia must therefore also increase the share of recycled glass – cullet – in glass production.
This recycling being carried out at a lower temperature than conventional fusion, it saves 5% of CO2 but also 2.5% of energy for 10 additional cullet points used. “Since 2019, we have saved 95,000 tonnes of CO2 thanks to cullet,” explains Wendy Kool-Foulon. The glassmaker already uses 55.7% recycled glass to produce its containers and is aiming for 66% in 2030.
However, this lever also has its limits: the lack of cullet but also the efficient sorting of the latter to produce white glass. In northern Europe as in Germany, where sorting is organized by color, the share of cullet in the manufacture of white glass only reaches 50%. However, the latter represents 30% to 40% of Verallia’s production.
Thanks to these different levers, “in 2030, we will have already reduced our CO2 emissions by 45% compared to 2019,” assures Romain Barral. The road to complete decarbonization still promises to be long and difficult.
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