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Study compares glass, aluminum and plastic

Owens-Illinois, the world’s largest manufacturer of glass packaging, has released the results of a global study of the complete life cycle of glass containers. O-I’s life cycle assessment (LCA), which measures the carbon emissions generated by each phase in the life of a glass container, is foundational to the company’s ambitious new sustainability program (read the report).

O-I’s study is claimed to be the first in the packaging sector to follow the complete life of a package – from the extraction of raw materials to the reuse or recycling of the container. The model used for the study also allowed an assessment of cradle-to-cradle life cycle data on aluminum and plastic (PET) containers, enabling a comparison between the packaging materials.

“Widespread inconsistencies in carbon footprint assessments have made it nearly impossible to compare the impact of one packaging material with that of another,” said O-I CEO Al Stroucken.

“Many assessments used today only take into account a portion of the full life cycle of a product, resulting in incomplete and inaccurate data. Customers are sometimes unknowingly making packaging decisions based on incomplete data. We knew we needed to take the best and most complete approach possible to bring clarity to the conversation and provide an accurate picture of how glass compares with other packaging materials.”

O-I used manufacturing and publicly available data on the production of aluminum and PET to compare glass with these other packaging materials. O-I’s life cycle assessment model was tested and validated by AMR Research, a firm specialising in supply chain and sustainability research.

“Our assessment shows that glass clearly has the most favourable carbon footprint,” said Jay Scripter, O-I vice president of sustainability. “When you look at the complete life cycle of glass, commonly held misconceptions are disproved.”

Assessing the the carbon footprint of packaging

Iinternational standards for measuring and reporting carbon footprints are open to interpretation. As a result, there are wide variations in the ways companies and industries measure carbon footprints. Some assessments ignore what happens before the raw materials reach the factory and after they leave (a “gate-to-gate” assessment). In instances where raw materials require extensive processing, like extracting and processing petroleum to make plastic pellets for PET plastic water bottles, this can comprise a sizeable portion of the product’s complete carbon footprint. In the case of the PET water bottle, extraction and processing of raw material is responsible for more than 50 percent of the container’s carbon emissions.

Other assessments disregard what happens after the finished product leaves the manufacturing plant (a “cradle-to-gate” assessment). The remainder of the product’s life cycle – the transportation of finished products to distributors and retailers, use by consumers and reuse, recycling or disposal of the material – are not included.

Still another type of assessment doesn’t reflect the impact of recycling or reuse (a “cradle-to-grave” assessment) on the carbon footprint. In the example of the PET water bottle, this type of assessment doesn’t take into account the fact that of the PET containers captured for recycling, most are downcycled into plastic chairs and clothing. As a result, a new phase of the product’s life cycle is created. This is in sharp contrast to glass, which can be infinitely recycled in to new glass containers. This is called closed loop recycling.

The problem is that these variations in life cycle assessments are not easy to identify. While there is an International Organization for Standardization (ISO) standard that applies to LCAs – ISO 14040 calls for assessment of the complete life cycle – there are no means for enforcing the standard. As a result it is virtually impossible to compare the carbon footprint of one package with that of another. In the packaging sector, that has left consumer products companies, retailers and environmental groups confused and uncertain of what to believe.

O-I says it is attempting to be as clear as possible in measuring and reporting its carbon footprint data by taking a complete – or “cradle-to-cradle” view – of the carbon footprint of its glass containers: "Only by looking at each and every step of the life cycle of each packaging material can accurate carbon footprint comparisons be made. We encourage all other manufacturers of packaging materials to adopt the complete life cycle assessment method".

O-I is tol use its LCA data as a baseline for tracking the company’s progress in reducing its environmental impact through the next decade.

Key Insights from the O-I LCA

While every stage of the packaging life cycle generates carbon dioxide, carbon footprints vary dramatically based on a number of factors including geography, the completeness of the assessment and variations in electrical grids and recycling rates. O-I’s LCA provided some important new insights into the carbon footprint of glass packaging, including:

  • A typical 355-ml (12-oz) glass container – the size of an average beer bottle – generates 0.171 kg of carbon dioxide from the time raw materials are extracted until the glass container is reused or recycled.
  • The transportation of finished glass containers contributes only 4 to 5 percent of glass’ complete carbon footprint.
  • The reduction in emissions brought about by the use of recycled glass in the production of new glass containers more than offsets emissions resulting from finished goods transportation.

Glass Compared with Other Packaging Materials

To encourage other packaging makers to share their complete life cycle information, O-I also calculated the complete carbon footprint of aluminum and PET containers as part of its assessment, using industry and publicly available data.

The chart below shows the carbon footprints of the most commonly used carbonated beverage container (355ml, or the size of an average beer bottle), as measured in kilograms of carbon dioxide. This comparison showed that glass has the most favorable carbon footprint in North America, Europe and Asia; in Latin America glass and aluminum were equivalent.

Environmental Benefits of Glass 

Glass is made from pure, abundant natural resources including sand, limestone and soda ash. Glass also is reusable and infinitely recyclable. A refillable glass bottle is typically reused 20 to 30 times. Reusing a bottle at this rate could cut the carbon footprint of that bottle from 0.117 kg of carbon dioxide to as low as 0.006 kg.

Each year O-I uses nearly five million tons of used glass to make new bottles and jars, making O-I the world’s largest user of post-consumer glass. On average, each O-I glass container is made up of 36 percent recycled content. In Europe, recycled content can be significantly higher – reaching up to 90 percent – due to the region’s robust and successful recycling programs. 

In addition to reducing landfill waste, recycling glass yields immediate energy and carbon emissions savings. Every 10 percent of recycled glass used in production results in an approximately 5 percent reduction in carbon emissions and energy savings of about 3 percent.

O-I is investing heavily in its R&D capabilities and is actively engaged in research aiming to improve processes and products to reduce the environmental impact of glass. O-I research is yielding lighter weight containers and significant reductions in energy usage.

About O-I
Established in 1903, the company employs more than 22,000 people with 78 plants in 22 countries. In 2009, net sales were $7.1 billion. For more information, visit


1 May 2010 - Felicity Murray