Emissions scopes: three levers for decarbonizing industry
The three scopes are essential concepts for decarbonization, guiding companies that wish to quantify and reduce their CO2 emissions. To better understand them, this Story explains the three emissions categories with concrete examples linked to the production of Saint-Gobain’s iconic material, flat glass.
How can we limit global warming to 1.5°C? How can we reduce emissions by 45% by 2030, or even 55% as proposed by the European Union? The first step is to adopt a common language, across all industrial sectors.
Launched at the end of the 1990s, the international Greenhouse Gas Protocol (GHG Protocol) was the first international standard enabling companies in the public and private sectors to measure their greenhouse gas (GHG) emissions. It was within the framework of this protocol that scopes 1, 2 and 3 were created.
Scope 1: direct emissions
This first, restricted scope measures the GHG emissions generated directly by the company, on its sites and facilities and through its activities.
In the case of glass, scope 1 emissions have two main sources. First, the combustion of natural gas in the glass furnaces. Then comes a lesser-known but equally important phenomenon: the decomposition of carbonates in the raw materials. When calcium carbonate, limestone and soda ash are heated in the furnace to form the oxides that are the basic components of glass, they release CO₂ into the atmosphere.
For glass, scope 1 accounts for just over half of total reported emissions.
Scope 2: focus on energy consumption
Scope 2 accounts for all secondary energy consumption (electricity, steam, cooling) in order to assess indirect GHG emissions.
In flat glass production, electricity is mainly used in the float process, the crucial stage where the glass is poured onto a bath of liquid tin kept hot using electricity. Electrification is also gaining ground in the glass furnaces themselves, with the development of “electric boosting”. With this technology, electrodes are installed at the bottom of the furnace and the passage of an electric current through the molten glass increases the temperature through Joule heating. This technique can currently provide up to 10-15% of the total energy required for melting.
In today's glass industry, scope 2 generally represents around 10% of total emissions.
Scope 3: indirect emissions
This is the broadest scope, as it accounts for indirect GHG emissions throughout a product’s life cycle: procurement and extraction of raw materials, transport, supply chain, waste management, recycling, etc.
In the glass sector, scope 3 is dominated by to contributors : the carbon emitted in the production of natural gas – including its extraction, refining and transportation to production sites ; and the carbon emitted in the production of some raw materials by the chemical industry.
Scope 3 also includes other sources of emissions that are less important for the glass industry, but which are essential to the overall calculation: transport of raw materials, transport of finished goods, business travel by employees, and packaging.
For today's glass, scope 3 represents approximately 40% of emissions.
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The 15 scope 3 categories in the construction sector
Given the breadth of scope 3, the international protocol organizes these emissions into 15 categories, divided into two sub-groups: upstream emissions linked to the goods and services that a company buys for its production lines, and downstream emissions once the solutions produced by the company are in the hands of its customers and consumers.
These categories vary considerably from one company to another, depending on its sector of activity. Returning to our example of flat glass production:
Upstream emissions:
- Purchased goods and services: raw materials (sand, limestone, soda ash)
- Capital goods: industrial equipment and machinery
- Fuel and energy: production and transportation of natural gas
- Upstream transport and distribution: principally moving raw materials but also any transport (upstream and downstream) paid by Saint-Gobain
- Waste generated by operations: treatment of production waste
- Business travel and commuting by employees
Downstream emissions:
- Downstream transport and distribution: delivery of finished products but also any transport (upstream and downstream) paid by Saint-Gobain
- Transformation of the products sold: processing by customers (for example, energy used by our customers to produce insulating glass)
- Use of the products sold: for an equipment using energy, it corresponds to associated emissions (gas for vehicles, electricity for appliances…)
- End-of-life of the products sold: recycling and disposal
- Assets leased downstream, franchises and investments
Concrete actions to decarbonize: glass shows the way
In practical terms, what are these indicators really used for? True compass for any deployment of a CSR policy, they enable organizations to identify and quantify the source of their emissions. And then to act accordingly, as Saint-Gobain has done in glazing and many other fields besides!
ORAÉ®, for example, is the first low-carbon glass on the market. Launched in September 2022, this glass combines a high recycled content (scope 1 and 3) and renewable electricity (scope 2) to achieve a 42% reduction in emissions1.
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The Group is also exploring alternative energy sources. One example is the successful trial of glass production using 30% bioliquid at the Aniche plant (France). This initiative has reduced CO₂ emissions by over 80% (scopes 1 and 3). As for electrification, the Volta project is a world first. Carried out in conjunction with our competitor AGC at the Barevka site in Czechia, it combines electric melting with oxy-gas combustion to achieve 50% electrification. This unique collaboration, financed by the European Union, aims to achieve a 75% reduction in scope 1, 2 and 3 emissions, while maintaining float glass quality standards.
Closed-loop recycling to meet a strategic challenge: with the aim of continuously increasing the use of recycled cullet – ORAÉ®for example, with its high recycled content – Saint-Gobain Glass has developed the Glass Recycling program to supply its own needs. This circular approach is particularly effective, as 1 ton of cullet reduces from 700 kg of CO₂eq emissions across all scopes. This initiative enables the Group to meet its growing need for recycled materials while drastically reducing its carbon footprint in Scope 3.
This ambition to decarbonize the entire sector has a ripple effect, the efforts of one company cascading on others. By reducing the carbon footprint of its products, Saint-Gobain enables its customers – carpenters, façade builders, developers and constructors – to reduce their own Scope 3 emissions.
More than just carbon accounting, the scopes thus become a lever for collective transformation towards a decarbonized future.