Deep Decarbonization of Glassmaking

Originally published in The American Ceramic Society’s May 2023 ACerS Bulletin. https://ceramics.org.

At the end of the day, many like to relax with a glass of wine or a bottle of beer. As you open that bottle, you are holding a piece of glass that is responsible for between 60 and 160 grams of CO2 emitted into the atmosphere.¹*

In the United States, the government aims to achieve a net-zero greenhouse gas (GHG) emission economy by 2050.² The U.K. and Europe have the same net-zero goal for 2050, as well as a shorter-term goal by 2030 to reduce GHG emissions by 68% and 55%, respectively, compared to 1990 levels.

How does the glass industry reach that goal?

While 2050 may seem decades away—after all, many engineers and researcher working on these problems today will be retired by 2050—the magnitude of the manufacturing process changes and capital investments shift the urgency of acting into a near-term, easily foreseeable timeframe.

For example, “Float glass furnaces typically have a lifespan of 20 years. To meet the 2050 net-zero carbon target, a CO2 -neutral furnace must be developed by 2030. Achieving such an ambitious target requires years of development,” says Cyril Jean, R&D portfolio manager at Saint-Gobain Glass.

Significantly reducing the amount of CO2 emissions associated with energy-intensive industries such as the glass industry is paramount to mitigating the effects of climate change. Incremental changes in the glass industry have led to an overall decrease in carbon intensity (kg CO2 emitted per kg of glass made), but a near net-zero or “deep decarbonization” of glass manufacturing is the ultimate goal.

The first step to decarbonization is to account for how much greenhouse gases are emitted by a company across the full manufacturing value chain. Green House Gas Protocol,³ an organization that provides standards, guidance, tools, and training to measure and manage GHG emissions, offers a standardized framework for evaluating the embodied emissions of an entity.

The framework divides an entity’s GHG emissions into three categories or scopes. Scope 1 covers emissions from sources that an entity owns or controls directly, for example, from burning fuel in a furnace. Scope 2 are offsite emissions, such as the electricity purchased and used within the glass manufacturing process. Scope 3 emissions are all GHG sources not within scope 1 and 2 boundaries, including those from sources up and down the value chain, for example, emissions associated with raw material suppliers.

Once the carbon emissions are accounted for, the next step is to develop a strategy to accomplish significant reductions. The U.S. DOE roadmap for industrial decarbonization includes four key technology pillars to significantly reducing carbon emission: energy efficiency; low-carbon fuels/energy sources; industrial electrification; and carbon capture, utilization, and storage (CCUS).⁴ To this list, we add the glass-specific issue of decarbonizing raw materials. Here we explore each of these areas in detail.

*Assumes a 300 tpd air-fuel furnace with electric boost and 50% cullet emitting 332 kg CO2 per metric ton glass (Reference 1) and beer and wine bottles of 180 g and 500 g, respectively. This estimate does not include emissions associated with a bottle after it leaves the plant. 

¹Kobayashi, H. (January 2021). “Future of oxy-fuel glass melting: Oxygen production, energy efficiency, emissions, and CO2 neutral glass melting.” In 80th Conference on Glass Problems (pp. 1–12). Hoboken, NJ, USA: John Wiley & Sons, Inc.

²“Tackling the climate crisis at home and abroad: A presidential document by the Executive Office of the President,” Federal Register, 27 Jan. 2021. https://www.federalregister.gov/documents/ 2021/02/01/2021-02177/tackling-the-climate-crisis-at-homeand-abroad

³Greenhouse Gas Protocol, https://ghgprotocol.org.

⁴“DOE Industrial Decarbonization Roadmap,” Department of Energy Office of Energy Efficiency & Renewable Energy. https://www. energy.gov/eere/doe-industrial-decarbonization-roadmap

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