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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge

Julia Oswald

Evaluation of the Energy Use of Packaging in the Food Industry

Julia Oswald

Evaluation of the Energy Use of Packaging in the Food Industry

 

About 80% of a product’s and packaging’s environmental impact is fixed in the design process (Granta, 2011). Although there are vast amounts of information available regarding packaging, an extensive literature review found that a comparison of packaging and their energy use does not exist. Therefore, this study examines the energy requirements associated with different packaging types to support designers and manufacturers in making an informed packaging choice.

The analysis compares a glass jar, a steel can, an aluminium can, a rigid plastic container, a food carton and a pouch as well as their corresponding secondary (grouping) packaging. Based on a materials database, the energy contained (material’s embodied energy and manufacturing energy) in packaging considering 100% virgin material content, a typical recycled content and end-of-life treatment is determined. In addition, the packaging types’ product to packaging ratios are examined. A high ratio reduces material use and packaging waste but also increases the efficiency of shipping space used. To enable fair comparison, all data is normalised to a reference unit of 500g pasta sauce containment.

Considering a typical recycled content for glass, steel and aluminium, the energy-ranking yields that the carton (1.20 MJ/500g), pouch (1.27 MJ/500g) and steel can (1.56 MJ/500g) perform best, while the plastic container (3.33 MJ/500g), aluminium can (5.56 MJ/500g) and glass jar (6.31 MJ/500g) have higher energy requirements.

Ranking the packaging on basis of the product to packaging ratio and energy use, the lightweight pouch, carton and plastic container have the lowest energy use while providing the best ratios between 15:1 to 19:1. Packaging including a recycled content such as the steel can (7:1 ratio) and aluminium can (17:1 ratio) perform poorer. Particularly the heavy weight glass jar is the least favourable (2:1 ratio).

The conclusion is that lightweight packaging is most favourable when considering energy use and ratio. Recycling reduces the energy use of aluminium cans by 50%, while there are only minor savings for glass jars and steel cans. Increasing current recycled content levels improves the performance but they still do not become competitive with lightweight plastic and composite materials regarding low-energy use and at the same time high product to packaging ratio.

Another main finding is that of the total energy use, the embodied energy constitutes 89-95%, which proves that material choice is a crucial packaging eco-design decision.