Fuel for thought
Glass Times editor Luke Wood, talks to Schneider Electric’s Gary Cafè, on how float glass manufacturers can transition away from fossil fuel powered furnaces.
Luke Wood (LW): Can green electrical energy replace fossil fuel powered glass furnaces entirely?
Gary Café (GC): Currently, smaller furnaces have the opportunity to become fully electrified, and we are witnessing projects emerge that can boost energy efficiency by up to 50%, even in float glass production.
Many of our customers are anticipating a future where both container and float glass furnaces will rely on 80-100% electric power, with biofuels or green hydrogen serving as complementary energy sources to balance the process.
Considering that green hydrogen is produced using renewable electricity (albeit in larger quantities than what is required for a fully electric furnace), the use of this energy source would still result in 100% renewable electricity powering the furnaces. However, an intermediate energy medium transition would be required.
Furnace designs, shapes, and footprints may need to be altered, which would pose an additional challenge in transitioning towards an all-electric glass melting process.
LW: Is there an increased cost to electrifying float glass manufacturing?
GC: Electric melting is highly energy efficient, with a potential efficiency of up to 85% in cold-top melting furnaces, meaning that the majority of energy is effectively used in the glass melting process. In comparison, hydrogen has an overall energy efficiency of approximately 30%, which may make it a less cost-effective option if it is utilised in combustion.
LW: How does Schneider Electric systems integrate into float glass furnaces – and what do they do?
GC: Schneider Electric services and systems are crucial to ensuring that energy flows smoothly to and through a furnace. With over 2,000 consultants in our energy division, we specialise in managing the cost and risks associated with the energy entering the furnace, whether it comes from renewable sources through PPAs or more traditional power and gas sources.
Our team of climate consultants are equipped to measure emissions and develop decarbonisation strategies for entire enterprises. Additionally, our electrification engineers and consultants work to optimise the capital and operational expenses, as well as the resilience, of these new, larger electrical systems worldwide.
Our integrated power and process control systems regulate the power entering the furnace, whether it is from a utility or integral to the melting process when boosted, seamlessly under one control system. Furthermore, our AVEVA industrial software and digital twins empower model-based predictive control, predictive maintenance, and digital twin-based training systems for the next generation of furnaces.
AVEVA and ETAP offer digital twin software solutions for plant mechanical design, automation, and electrical systems. This allows engineers to pinpoint where efficiency gains can be made and how downtime can be avoided. Such tools also help provide maintenance teams with more efficient training and troubleshooting options. ETAP digital twin can simulate existing electrical network characteristics and test and measure the impact of changes to a plant’s electrical system without disturbing the live system.
LW: Can they be retrofitted?
GC: Absolutely, our consultancy and engineering services, along with AVEVA industrial software, are designed to be completely hardware agnostic. However, retrofitting an existing furnace to become fully or partially electric is often an extremely challenging, and sometimes impossible, task.
LW: What are the benefits for float glass manufacturers? For example, how much carbon output can they reduce per year?
GC: Our model based predictive control systems typically generate energy savings ranging from 2-5%, although an optimistic estimate would be around 1-3%, depending on the furnace’s current state and control.
When you factor in boosting systems that are supported by our strategically sourced renewable energy, the potential for energy savings is limited only by the level of electrification. In fact, it’s possible to achieve savings of up to 80% when you consider that roughly 20% of the energy comes from the batch mix itself.
LW: Can you give an example of an existing electric float glass furnace?
GC: At Schneider Electric we’re currently working on several exciting projects with key customers that could potentially boost energy efficiency by 30-50%.
Electric melting is not a new concept and has been in use for as long as gas-fired furnaces. Some glass manufacturers have already implemented all-electric furnaces, particularly in the production of lower pull type of furnaces such as tableware and special glass like borosilicate/pharmaceutical glasses. Container glass is likely to be the first high-pull commodity industry to follow this route.
While the float industry has also made some progress in this direction, transitioning to an all-electric or 80% hybrid system will be more challenging due to the amount of power required and the number of electrodes needed to accommodate it.