Most people have no idea how glass is made
The Carbon Footprint of Plate Glass
Glass production is energy intensive at around 10EJ/t (similar to steel). Like steel, it also cannot be eastly decarbonised. Alternatives to the process below that burn hydrogen or carbon-free synthetic methane (made from captured CO₂) remain about 5x more expensive.
~90% of the energy used to make glass comes from natural gas! Australia's single manufacturing plant, like all plants globally, is dependent on fossil energy.
Diagram 1 - Issue 15
Raw Material - Sand, soda, dolomite, limestone, cullet.
Float Bath - A moving ribbon of molten glass floats on the surface of a perfectly flat molten tin.
Furnace - materials are melted by a gas furnace at 1,600°C.
Annealing Lehr - Glass is annealed and gradually cooled to 200°C to prevent splitting during the cutting phase.
Cutting - The glass ribbon is cut automatically as it moves.
Stacking and Off Loading - Stackers and cranes offload the glass to warehouses for distribution.
But amorphous silicon can be added to the plate glass to create a transparent, electricity-generating window - a convenient and invisible contribution to lower carbon intensity.
Diagram 2 - Issue 15
About 1% of all primary energy is used to make glass
10% of the total energy used on earth 500 EJ/year
SMIL, V. 2022 IEEE Spectrum April 2022: 18-19
Making the modern world, Vaclav SMIL, 2014
Australian Govt, Clear Float Glass Industry Report, April 2021
Prepared for you by Ian 🙂