The 10th anniversary of the Paris Agreement is approaching in December. Since the accord was agreed upon in late 2015, multiple energy-intensive industries, including the glass industry, have been under increasing pressure to decarbonize. In response, the glass industry has developed and engineered new technology, improved energy efficiency and increased recycling rates in the past 10 years.
According to the United Nations, the Paris Agreement strengthens the response to climate change by keeping the global temperature rise this century below 2 degrees Celsius above pre-industrial levels and pursuing efforts to limit the temperature increase even further to 1.5 degrees Celsius.
A 2023 study by the National Renewable Energy Laboratory of the United States Department of Energy reported that more than an 80% reduction in energy demand and greenhouse gas emissions can be achieved in the glass industry by applying a combination of methods. These include increased cullet use, energy efficiency or reduction, increased electrification, hydrogen combustion and a more renewable electric grid.
Environmental Product Declarations
Among the steps the glass industry has taken is publishing third-party verified Environmental Product Declarations (EPDs). Vitro Architectural Glass was the first North American manufacturer to do so in 2017, when it published EPDs for flat glass and processed glass products. Vitro updated its EPD for flat glass in 2024 and achieved a global warming potential of 1,240 kilograms of carbon emissions (CO₂) equivalent. Other glass manufacturers and fabricators, including Guardian Glass, Cardinal Glass and Walker Glass, followed.
Launching Low-Carbon Products
In 2023, NSG Group launched a new glass range, Pilkington Mirai, with 50% less embodied carbon. Company officials say the glass range is manufactured using a combination of alternative fuel, high recycled glass content and 100% renewable electricity. Guardian also launched its own low-carbon product, Nexa, which maximizes cullet use. Guardian officials say Nexa reduces embodied carbon by more than 30% compared to standard four-millimeter Guardian ExtraClear float glass.
Carbon Capture
NSG Group and its subsidiaries have played a vital role in the CO₂ reduction push. In 2021, the company launched the world’s first float glass production using hydrogen, and in late 2023, it started a carbon capture trial alongside Glass Futures and C-Capture. In July 2024, Pilkington United Kingdom Limited, part of NSG Group, announced that it would open a new hydrogen plant at its Greengate Works site in St. Helens, U.K.
Cardinal Glass also stepped into the carbon capture game. Cardinal officials say that after several years of research, the company, along with Italy-based K2-CO₂, achieved a 95% CO₂ capture rate in summer 2025 in its glass production process. According to officials, the annual CO₂ captured by one of K2-CO₂’s systems surpasses the amount sequestered by planting 1.6 million trees and growing them for a decade.
Further Steps
Other notable moves include Saint-Gobain officials announcing that the company has reduced carbon emissions by around 4,000 tons since 2021. This was achieved by boosting oxygen in the float process and a combination of waste heat recovery, renewable energy and furnace design optimization. In March 2024, Guardian partnered with Velux Group to develop manufacturing processes and capabilities to meet the growing demand for vacuum-insulating glass.
Even small adjustments matter. In 2019, Guardian’s Kingsburg, California, plant implemented a ramp-down mode on a coater to avoid energy spikes when restarting. This saved the energy equivalent of keeping 1,000 kilowatt-level light bulbs running for a year.
“Sustainability is essential for most companies because we have to lower carbon emissions and the cost of energy for users,” Dave Robson, sales director for CoolTemper, told USGlass magazine during glasstec 2024. The international glass tradeshow focused heavily on circularity and sustainability last year. “We’ve spent the past few years developing and patenting new systems to save companies money. Our systems are starting to get out into the market now.”
Robson says one of CoolTempers’ systems, a convection tempering furnace featuring a Dynamic Quench and Dynamic Windbox system, helps the furnace save between 10% and 35% on the energy of the quench kilowatt power usage on varying glass loads. CoolTemper can shut off sections of the quench that are not actually required.
Throughout the past decade, the U.S. government has sought to spur sustainability throughout the built environment. The U.S. Department of Energy’s (DOE) Building Technologies Office sponsored several programs to reduce glass carbon emissions in the built environment, including the American-Made Building Envelope Innovation Prize. The program targets innovative solutions for upgrading inefficient windows to enable building retrofits and optimize building envelopes for electrification.
Of note, the White House issued an executive order in January 2025 to begin the process of withdrawing from the Paris Agreement, with the formal withdrawal set to take effect in January 2026.
Improving Glass Recycling
Efforts are also underway to improve recycling rates. In 2024, Solarcycle officials announced that the company would open a solar panel glass recycling plant in Cedartown, Georgia. The facility is the first in the U.S. to use recycled materials from retired solar panels to make new solar glass. The need for glass circularity is vital as around 11 million tons of architectural glass are disposed of in landfills each year.
According to a study in the International Journal of Applied Glass Science, “Reducing the Environmental Footprint of Glass Manufacturing,” the glass industry faces three main challenges to lowering greenhouse gas emissions and reaching zero-carbon manufacturing.
These challenges include developing, planning and implementing technology roadmaps to meet the decarbonization targets driven by the Paris Agreement and other government-and company-set climate zero carbon targets. Additional challenges encompass profitability concerns due to changes in operating costs and the industry’s reluctance to accelerate development and implementation, even as consumer demands for energy-efficient products grow.