Use of cullet to reduce raw materials and energy consumption
Use of cullet to help reduce raw materials & energy consumption
We are dedicated to enhancing the energy efficiency of our manufacturing processes and minimizing our resource consumption. One approach to accomplishing these objectives is to maximize the use of cullet – broken or rejected glass – in the float glass production.
The use of 1 ton of cullet saves approximately 1.2 tons of virgin raw materials such as sand, dolomite, soda ash and limestone.
Using cullet also reduces process-related emissions. As it has already undergone the mineralization process, it releases fewer greenhouse gas emissions during melting than virgin raw materials. Every ton of cullet used allows to avoid the need for 2 million BTUs (586 kWh) of natural gas and to reduce up to 700 lbs (318 kgs) of CO2 emissions.
While our efforts may vary across our global fleet, in general, we are working to increase the cullet ratio in our batch by:
- Optimizing use of internal cullet
- Sharing best practices across the fleet
- Testing and implementing new cullet types
- Maximizing cullet sourcing
Europe
Guardian Glass EU plants achieved an increase in the cullet ratio (broken or rejected glass from internal processes and external sources) in glass from 22% on average in 2019 to 28% cullet on average in 2023.
Collecting glass cullet from our customers: when we deliver glass, bins containing customer cullet can be returned in the same trip, therefore helping decrease road traffic and the associated carbon emissions when compared to collecting this cullet via separate, standalone trips.
Logiform
North America
In 2023, the plant in Carleton, MI experimented with making Guardian PrivaGuard™ glass using 70% cullet as percentage of batch weight, and Guardian Clear glass using 100% cullet as percentage of batch weight.