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Glassmaking has dramatically evolved in the thousands of years since ancient artisans crafted their first decorative beads and perfume bottles. But the underlying recipe remains virtually the same: Combine sand, sodium carbonate, and limestone, then blast the ingredients with scorching heat in a kiln or furnace.
Today, the vast majority of that heat is supplied by burning fossil fuels. Whether manufacturers are turning glass into windows, beverage bottles, smartphone screens, or coatings for solar panels, their methods require lots of energy to reach superhigh temperatures and, as a result, can be very carbon-intensive.
Global glassmakers in recent years have begun working to curb their emissions, spurred by environmental laws and the growing demand for low-carbon products. Companies are testing and deploying new furnace technologies that get their heat from electricity — not fossil gas or heating oil — or from alternative fuels such as hydrogen and biogas.
The latest of these emerging efforts comes from Bavaria, Germany, where the multinational firm Schott recently began building a large-scale electric melting tank inside its existing plant in Mitterteich. The tank is the first of its kind for the type and amount of glass it’s making, and it will run primarily on renewable energy sourced from the grid to turn materials into molten glass.
Schott says its electric tank could slash greenhouse gas emissions from the melting process alone by 80% owing to the reduction in fossil gas use. The 40-million-euro ($47 million) pilot tank is expected to fire up in early 2027 and will produce specially engineered glass tubing for syringes, vials, and other pharmaceutical products.
Jonas Spitra, Schott’s head of sustainability communications, said that replacing fossil fuels with electrified technology — while still meeting strict quality requirements for specialty glass — marks ​“one of the most challenging yet decisive steps on the industry’s path to decarbonization.”
Schott, which operates in over 30 countries, will use the experiences from its all-electric tank initiative ​“as a foundation for expanding electrification to other sites, wherever technically and economically feasible,” he told Canary Media.
The German pilot project is moving forward just as a few ambitious low-carbon glass initiatives in the United States have fallen into limbo. In May, the Trump administration’s Department of Energy canceled awards worth roughly $177 million for projects aiming to demonstrate cleaner glassmaking methods in California and Ohio, forcing manufacturers to reevaluate their plans.
“Domestic glass manufacturers across the country are advancing energy-efficient technologies, reducing emissions, and working to try and keep jobs onshore,” Scott DeFife, president of the Glass Packaging Institute, said in a June 6 statement in response to the DOE’s decision. ​“The Department should lean into glass, not ignore it.”
Worldwide, manufacturers made more than 150 million metric tons of glass in total in 2022. Although glass is used across many sectors, it is produced on a smaller scale than other carbon-intensive materials. Cement production, for instance, surpassed 4 billion metric tons in 2023, while steel production reached nearly 2 billion metric tons that year.
Still, glassmaking remains a significant source of planet-warming gases and local air pollutants like nitrogen oxides. And the challenge of slashing those emissions is essentially the same one vexing other heavy industries: figuring out how to reach hot enough temperatures to make materials without cooking the planet in the process.
Chemical producers are pilot-testing their own electric furnaces to make important compounds like ethylene, which is the building block of many plastic products. Cement startups are developing electricity-driven processes and thermal storage systems to replace traditional kilns. Global steelmakers, meanwhile, are investing in technologies that sidestep the need to use coal, such as hydrogen-based ironmaking facilities and electric arc furnaces.
For glass, the biggest hurdle to decarbonization lies in the melting process, Schott’s Spitra explained.
Glass furnaces require temperatures of between 1,200 and 1,700 degrees Celsius (2,192 and 3,092 degrees Fahrenheit) — hotter than lava — to liquefy the raw materials and mix in recycled glass. The process is responsible for about two-thirds of total carbon dioxide emissions from glass production. Most of that CO2 comes from burning fossil fuels, though some emissions result from the chemical reactions that happen when heating up sodium carbonate (soda ash) and limestone.
In a conventional furnace, gas is injected into a combustion chamber to melt the ingredients into a glowing orange liquid. In an electric version, electrodes pass currents through a conductor to generate heat. Today, the industry mostly uses electric equipment only for smaller-scale furnaces or to supplement the fossil-fuel-based heat inside larger furnaces — a step known as ​“electric boosting.”
Facilities that make high-volume products like container glass and windows are trickier to fully electrify. Existing electric designs have struggled to operate with the same consistency and flexibility as gas furnaces, and they can’t incorporate as much recycled material into the glass mix. Electric furnaces also tend to wear down and need replacing about twice as fast as their gas-burning counterparts, according to glass industry experts.
In Germany, Schott is aiming to address those problems with its new industrial-scale melting tank, which must also meet the exacting standards for bubble-free, high-quality pharmaceutical glass. The initiative, which Schott began developing in 2021, is partly funded by the German government and a European Union–backed program to decarbonize energy-intensive industries in Germany.
The company is investing in electrification in part to meet European climate regulations, including a CO2 emissions cap for heavy industrial sectors. But it’s also responding to the demand from pharmaceutical customers that are working to reduce their supply-chain emissions. Schott views decarbonization as a ​“strategic opportunity to strengthen its competitiveness,” Spitra said.
Beyond the technical issues, a few other barriers stand in the way of electrifying glassmaking at a wider scale.
In some locations, the local grid may be unable to support a major increase in electricity use, requiring companies and utilities to upgrade that infrastructure or build more wind, solar, and other electricity resources. For producers of mass-market packaging like soda bottles, it can be harder to convince beverage companies to pay more for low-carbon glass if it means raising the sticker price of the final product, especially if the competition is cheap plastic containers.
Another challenge for U.S. glassmakers in particular is that switching to electricity very likely means paying higher utility bills, making it harder to justify ditching fossil gas.
Sonya Pump, the global sustainability director for Ohio-based O-I Glass, said that gas pricing is one of the key factors the company weighs when evaluating low-carbon furnace technologies — along with potential technical constraints or risks to its manufacturing capabilities. O-I Glass makes billions of glass containers every year in facilities in nearly 20 countries, and the criteria it considers vary by market, as well as the type and quantity of glass it’s producing.
For that reason, in the U.S., ​“a fully electric melter is not currently the best solution for our business,” she said. ​“Though, in other geographies — areas in Europe, for example — energy pricing, carbon costs, and intense interest from our customers in emerging sustainability solutions make for analyses that look very different.”
In central France, O-I Glass is investing $65 million to build a hybrid-electric melter that can use up to 70% electricity and is set to come online in 2026. Pump said her team is also learning from its participation in electrification projects conducted through the nonprofit consortium Glass Futures and from other industry efforts. At the same time, O-I Glass is replacing some of its older furnaces in the U.S. and globally with modern systems that use oxygen and waste heat to reduce facilities’ total fossil-fuel use.
The manufacturer recently set a goal of slashing its overall greenhouse gas emissions by 47% by 2030, relative to 2019 levels, in addition to boosting its use of electricity from renewables and increasing the use of recycled glass.
O-I Glass had planned to rebuild an aging furnace in Zanesville, Ohio, and combine five cutting-edge technologies — including for electric boosting, preheating materials, and recovering waste heat — to see how much they could offset gas consumption when working together. The project was slated to receive up to $57.3 million from the DOE. Now that the federal funding has been canceled, the company is considering its next steps, Pump said.
Other initiatives to electrify glassmaking or test replacing gas with hydrogen are also now ​“slightly paused” under the Trump administration, said Matthew Kirian, director and technical program manager of the Northwest Ohio Innovation Consortium. The nonprofit works with O-I Glass and other manufacturers such as solar-panel-maker First Solar to advance innovation within the region’s long-standing glass industry.
“On the energy and fuel side of things, it’s hard to set a firm strategy, especially for the next two to three years, because of federal policy that is so clear … that combustion is king,” Kirian said.
For now, he added, glass manufacturers are largely focusing on other strategies to lessen their environmental impact, including improving the energy efficiency and operating performance of existing facilities and working to increase recycling rates for glass containers — only about 30% of which get recycled nationwide — so that less material winds up in landfills and more is melted into fresh glass.
“Their sustainability goals aren’t going away,” Kirian said of the glassmakers. ​“We’re hoping to really move the needle for generations to come.”
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