Electrifying Glass Production: A Case Study of Supply Chain Innovation

Addressing emissions in the supply chain is the ultimate challenge for many companies on their journey to a low carbon future. This supply chain pressure is encouraging glass manufacturers to rethink existing glass production technology. Many are considering “all-electric” melting to offer low or zero carbon glass for their clients. Our experts share some details about this exciting example of low-carbon innovation.

Gary Cafe, Consultancy Manager – Sustainability

Gary has worked in the Oil & Gas, Chemical and Telecommunications industries and now helps multiple sectors consider the risk and opportunities presented to them as they manage their journey to net-zero in 2050.

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René Meuleman, Business Leader Global Glass Eurotherm

René started his career in the glass industry in 1969 at Vereenigde Glasfabrieken in the Netherlands. During his early years, he developed broad knowledge and experience in design and development of electronic quality equipment for container glass manufacturing. Over 11 years ago, he joined the Eurotherm by Schneider Electric group where he is responsible for the technical and commercial glass business development.

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Glass manufacturers are challenged by aggressive carbon targets

Glass is everywhere, just look around you while reading this article: the window in front of you, the screen you are reading this on, your drink bottle or your glasses that help you read. Glass is everywhere and will likely be around for many centuries. For many of its uses, there is simply no viable replacement. But glass production is an energy intensive process, and the burning of fossil fuel as an energy source in the glass melting process results in significant carbon emissions. GHG emissions in the EU from the glass production chain account for around 20 Mt CO₂ equivalent.

Consequently, companies using glass for their end products are increasingly concerned about its influence on their carbon footprint. This is especially important for organizations that have set a baseline for scope 3 emissions reduction as part of their Science-Based Targets (SBTs). For example, beverage companies using bottles made of colored glass produce an average of 370 kg CO2 direct GHG emissions per ton – that’s 150 g CO2 in every bottle. Heineken, the world’s second  largest brewery group, has created ‘Drop the C’ program which aims to significantly and systematically reduce emissions. After setting ambitious targets, committing to reduce CO₂ emissions from production by 80%, Heineken is focusing on logistics, packaging and cooling. Glass bottles are a major part of this initiative, as the packaging of drinks is responsible for 36% of the company’s 2018 carbon footprint across the entire value chain.

Traditional glass melting has a long history and technological boundaries

In a very simplified way, glass-making is a melting and fusion process of raw materials typically consisting of: sand, soda ash (sodium carbonate), dolomite, limestone and salt cake (sodium sulfate). The raw materials are mixed in a batch process, then fed together with waste glass into a furnace where it is heated to approximately 1350 °C. Once molten, the temperature of the glass is stabilized, and a stream of molten glass is then processed into formed glass.

Glass melting has been practiced for nearly 6,000 years, and for most of that time, wood was used as the energy source. It was around 1880 that the industry began to use fossil fuels like oil and natural gas. Nowadays, traditional technology has reached its limits. Traditional side and end port furnaces have been developed and optimized to a level of efficiency, emissions and lifespan that simply cannot be improved further. Oxy-fuel firing, batch pre-heating, waste heat recovery, submerged burners, etc. are great modern advances, but the bottom line remains the same: they all increase the complexity of the melting system, increase capital expenditures, do not avoid CO₂ emissions, and usually cannot reduce NO_x emissions. The use of fossil fuels has become the fundamental problem—and traditional technology cannot overcome these issues in a way that meets modern demand for low-carbon glass products.

Opportunities (and threats) of all-electric melting

Moving to electric heating methods has many benefits including improved energy efficiency, more flexible control and less combustion-related emissions. With all-electric melting, most of the electrical power is consumed during the melting process. Relatively low energy losses come from transformers, busbar and control efficiency. Compared to traditional fossil fuel heating at 1.1MWh/ton, net energy use is around 35% lower. An electrical furnace is easier to control and maintain compared to the most efficient fossil fuel fired smelter systems.

All-electric furnaces are sophisticated but very straight forward in terms of design. Regenerators, filter systems or burner skids are not required, and expensive high temperature crowns are not necessary. Manufacturers can also achieve higher pull rates without any issues. From an emissions standpoint, electric methods release no direct combustion-related CO₂, thermal NO_x or SO_x emissions. Powered by green electricity, the system can theoretically run without any CO₂ emissions.

Although all-electric furnace concepts are simple in principle, there are some implications to consider when changing over to this technology. Despite some changes in overall production process (pre-heating, glass composition, electrodes maintenance), an all-electric furnace needs a stable, reliable power grid. Electrical tariffs need to come down in price to compete with combustion-based furnace production costs, and in order to lower the carbon footprint, electricity would need come from renewables. The evolving electricity market is bringing about interesting opportunities to achieve this. A glass furnace, containing a huge amount of molten glass, should be able to accommodate the flexibility needed to profit from rewards, grants or lower tariffs offered for demand response.

However, most glass smelters are extremely risk averse, as they perceive their melting process as complex enough, and are not keen on modifying it further. There are several key barriers preventing the industry from making a sustainable transformation. Most manufacturers want to focus on their core business, without the issues of installing, managing and maintaining complex industrial installations requiring high numbers of technical personnel.

For decades now, the desire to keep systems simple has prevented any improvements. The life time of furnaces being up to 15 years is also working against this change. Most glass manufacturers only have one opportunity every 10 to 15 years to introduce a new innovative melting process, but the need for change is urgent. The bottom line is that in order to continue to thrive in an increasingly sustainability-minded environment, glass manufacturers face the need to either begin thinking ‘out of the box’ and stepping away from tradition or accepting the grim fate of the business that do not adapt.

 Switching energy sources entails a new energy risk and opportunity profile which we can help you manage and connect you with innovators to make change a success. To learn more about how scope 3 emission reduction targets will affect how your industry operates, we invite you to download our eBook: Answering the Call for a Low-Carbon Future: Ensuring Success with Science Based Targets