As an industry that has largely relied on fossil fuels for power, the glass industry has felt significant effects from the push towards decarbonisation, both through increased social awareness as well as global climate initiatives such as the Paris Agreement. Adopted by 196 nations in 2015, the Paris Agreement is a legally-binding treaty that aims to strengthen the global response to climate change. The agreement outlines requirements for limiting global warming to well below 1.5–2°C by the end of the current century. To hit this target, emissions must be reduced by 45% by 2030 and reach net zero by 2050.
Other initiatives such as the Deep Decarbonisation Pathways (DDP), Renewable Energy 100 (RE 100) and Science Based Target initiative (SBTi) have prompted companies in Europe and beyond to not only to explore alternative low-carbon sources of power, but also to further decarbonise their own processes. Manufacturers are also cognisant of consumers’ changing habits and demand for greener products, which further reinforce the need to accelerate decarbonisation.
With its energy-intensive melting phase, the glass industry is faced with the need to adapt and innovate to accommodate CO2 reduction targets, and, indeed, many of the biggest glass companies have committed to decarbonising the melting processes altogether. Glass manufacturers are taking a multi-pronged approach to tackling carbon emissions, not only through alternative energy investment and increased efficiency, but also through converting fossil fuel-fired melting furnaces to greener energy sources.
Given the tight deadlines in international climate agreements combined with increased public awareness and concern about climate change in general, it is truly not a matter of if or when, but rather how decarbonisation in the glass industry can be realised.
An effective strategy is decarbonisation through electrification. Although other options exist, electric is the only power solution that is nearly turn-key, supplying the technology-readiness and proven implementation required for maximum progress and while minimising downtime.
Decarbonisation in glass manufacturing
The most energy-intensive process in glass manufacturing is the melting stage. While some legacy melting furnaces are powered by oil, most use natural gas – a choice driven by the availability and price of the fuel. One of the quickest and most impactful ways to lower carbon emissions, therefore, is to reduce the use of fossil fuels for melting by transitioning to green power.
Of course, it is not practical to simply replace all the furnaces at a glass plant at one time. To maximise ROI on a furnace, it is unusual to replace it mid-campaign. While the occasional greenfield installation offers an opportunity to start with brand new tech that uses 80–90% green energy, the more common scenario finds manufactures transitioning their heating technology over time. Companies typically undertake the transition when a given furnace reaches its end of life and needs to be rebuilt. This offers a natural opportunity to upgrade and adopt green energy.
Current energy alternatives for reducing the carbon footprint of industrial processes include electricity (when generated by renewable energy sources), biofuel and hydrogen. The choice of green energy is typically a practical one that depends on the location of the plant, availability of the energy source and engineering know-how. For all three types of energy, availability at scale can be a challenge. While some smaller furnaces can be 100% powered by green energy, in reality most are a hybrid, with green energy providing a percentage of power in combination with natural gas. The percentage of green energy can be increased over time as its availability increases and can be secured from the local utility companies.
The demand for decarbonisation must be balanced against economic factors. The cost of energy also affects the speed of decarbonisation in glass furnaces. For instance, although the cost of natural gas has increased significantly, electricity is currently more expensive than natural gas in Europe. Taking a hybrid approach to heating and transitioning over time still enables manufacturers to meet the specified benchmarks and legal commitments, while continually reducing carbon emissions.
Why choose electric?
Most glass furnaces have a relatively long lifespan: eight to 12 years, on average, for bottles and 15–18 years for flat glass manufacturing. Unfortunately, this long life can complicate the transition process, especially for bigger manufacturers that have more than 10 furnaces, all with different end-of-campaign dates. These larger companies have to balance scheduling upgrades that would normally occur at an end of campaign against decarbonisation deadlines to ensure compliance.
Planning for upgrading a furnace typically starts well before the rebuild. This allows manufacturers to order the required equipment and plan for break in service during the cold repair, which can last from 60 to 90 days. Technical decisions, engineering and equipment orders must be made several months (and in some cases up to two years) before any work begins, especially when transitioning to new power requires additional substations. Of the green energy options, electric power currently meets the requirements driven by this long lead time and what can be a decades-long planning process.
Electricity is ready for large scale decarbonisation projects now, offering a near turn-key solution for companies concerned about transitioning to new technology. While few large, electric-only melting furnaces are in use, most gas-fuelled heaters already use some electric power to boost the melting process. Increasing electrical capacity in stages, for instance, by adding five-to-10 megawatts of electric power during a rebuild, allows manufacturers to flexibly meet decarbonisation goals as the availability of green electricity increases over time.
Use of established technology lets glass companies minimise downtime during the cold swap. Any downtime is costly, and using an electric solution – as opposed to a hydrogen or biofuel solution – helps make the transition more predictable, with fewer unexpected delays.
Adoption of biofuel and hydrogen power is not increasing at the same rate as green electricity, and current availability of these sources is extremely limited. Unlike electricity, these types of fuel are not already in use in melting furnaces, hence the level of engineering know-how is likewise limited. There are concerns over the availability of hydrogen and biogas at scale, which is especially important when planning decisions require a long lead time.
This is not to say that these approaches would never be part of a large-scale solution for greener energy. They likely will factor heavily into future decarbonisation efforts. The argument here is simply that manufacturers need to solve this problem now – hydrogen and biogas, for their part, are not ‘tech ready.’
Tech ready solution
A solution with a high ‘technology readiness level’1 offers a more turn-key approach to decarbonisation. Glass manufacturers need to remain profitable and guarantee glass quality in an energy-intensive industry, while adapting to legal and societal pressures to reduce their carbon footprint. Increasing the use of electric heating – a mature, known technology – is a practical solution that minimises the risks associated with upgrading and allows for precise planning and transition.
Although many glass companies are only embarking on this decarbonisation journey now, the technology for electrification is well known and established. While on-site engineers may not be experts in green energy, it is more than likely that they are familiar with electric power. At the same time, the availability of expert consultants is currently much wider for electric than biofuel or hydrogen.
A global leader in providing thermal application solutions, Watlow [which acquired Eurotherm in 2022] offers customers in the glass industry a consultative approach to planning for and executing upgrades to electrical power for decarbonisation. Its proven thyristor electrical boosting technology offers higher efficiency with less maintenance and more flexibility than legacy heaters. Watlow brings decades of experience to customers in the glass industry transitioning their melting furnaces from fuel-burning to electric.
Watlow is a registered trademark of Watlow Electric Manufacturing Company.
1. Technology Readiness Levels (TRL) are used to assess the maturity level of a particular technology.
Image: Each power skids controls a boosting zone greater than 500kVA to 1.2MVA each and is made, among other components, of an EPower SCR Power Controller in automatic load tap changer (inset: Mikael Le Guern).