The beating heart of glass: how furnaces are key to sustainability

Fiacre O’Donnell* outlines alternative fuels for gas-fired furnaces, as well as Encirc’s plans to create a low carbon, hybrid furnace with industry partners Glass Futures and Nikolaus Sorg as part of the HyNet project.

Furnaces have always been integral to glass production. To create glass bottles and containers, glass is melted at temperatures of over 1500°C, making the process highly energy intensive.

This process consumes 75% of energy in glass production operations, and with furnaces like our 206m² industrial oven at our Elton site (UK) - see right - capable of processing 900 tonnes of glass each day, these emissions quickly add up.

The heat generated for this operation is created from the combustion of natural gas, this consequently releases carbon emissions into the atmosphere.

As a company invested in disrupting this carbon intensive process, we know that with a bold mission, combined with the will to make it happen, and collaboration with the right organisations, furnaces in the glass sector can become truly sustainable.

The future of the furnace

Glass is uniquely positioned to embrace a sustainable, circular economy, given its ability to be infinitely recycled without any reduction to quality and performance. Furnaces play a central role for creating glass’ circular economy - allowing recycled material to be melted down and re-used over and over again.

Indeed, on average, more than 50% of the raw material used in glass production is typically now recycled glass (cullet - see left). Green and brown coloured containers can be made of more than 80% recycled glass. Albeit this is dependent on the UK’s recycling system providing enough recycled glass to producers. But manufacturers can only go so far by focusing solely on the recycled content of containers.

Developing furnaces to operate on low carbon fuel sources is necessary for both the sheet glass and container glass sectors, to mitigate, and ultimately remove the carbon footprint of the glass sector. The glass sector must transition away from fossil fuels such as natural gas. It’s therefore vital that progress continues to be made in the use of alternative fuels in furnaces.

The push to hydrogen

Hydrogen power is one option currently in the spotlight, presenting great potential to energy-intensive manufacturers, being a fuel that can be adaptable to heavy industry. When hydrogen is burnt, only water is emitted, reducing CO₂ emissions in the high-temperature processes. For larger furnaces that require a combustible flame, hydrogen is proving that it has much promise as a gas alternative in trials.

Making the change

We’re incredibly excited by the opportunity that hydrogen power presents and believe it has a lot of potential as a long-term alternative to traditional fuels. In addition, much progress is being made in this area.

In the UK, the government backed HyNet project is playing a crucial role in making the large-scale manufacturing of glass containers using hydrogen, carbon capture and storage a reality.

At Encirc, we have partnered with Vertex Energy, a key part of HyNet, and a joint venture between Essar Oil UK and Progressive Energy. Vertex Energy will produce and supply the low carbon hydrogen we need to produce our ultra-low carbon, and ultimately, zero carbon bottles of the future.

Working with industry body Glass Futures, furnace providers Nikolaus Sorg and others, we plan to create a new low carbon furnace, which will significantly reduce carbon emissions, using a mix of low carbon electricity and hydrogen.

From 2030, we plan to capture and store the remaining carbon emissions released from the burning of raw materials in the furnace.

The possibilities of biomethane

Biomethane is also another exciting low carbon fuel that can be used effectively in furnaces.

In fact, we have already produced bottles using biofuels in a trial at our Northern Ireland plant. The successful trial reduced the carbon footprint of each bottle by up to 90%. We will continue to explore the benefits of biofuels in furnaces. Many leading Northern Irish organisations will have a part to play in the development of low carbon fuels.

The process works by anaerobically breaking down organic matter, like livestock manure, into biogas, which can then be upgraded to biomethane. Biomethane is far more sustainable than natural gas. Importantly, it can be sent to wherever gas is consumed currently, using existing infrastructure, including the furnaces used in glassmaking. This is due to refined gas being completely indistinguishable from the regular natural gas stream.

The possibilities of biomethane are fascinating, and working collaboratively with the agriculture industry could be the solution to decarbonising two industries that have traditionally had high levels of carbon emissions.

There’s certainly still work to be done to make furnaces more sustainable. But the next steps are clear for the glassmaking industry, and support through legislation and schemes like HyNet are helping equip manufacturers, and their partners with the tools they need to evolve furnaces as we know them.

*Director of Sustainability, Encirc, Elton, UK

https://www.encirc360.com/