Will aluminum cans replace plastic bottles?

Mackenzie Wood

Plastic pollution is a global problem. The statistics are alarming – and emotional. WWF reports that 8 million tonnes of plastic are dumped into our oceans each year and that 90% of seabirds have plastic in their stomachs.

However, it remains the packaging material of choice in the modern world. About a third of the 350 Mt produced worldwide is used in packaging applications. But as public perception changes and the issue becomes a political priority, the tide may turn.

The battle of the bottles

The humble single-use plastic water bottle has become a powerful symbol at the heart of the debate. Bottles used for beverages like water and soft drinks are typically made from polyethylene terephthalate (PET). And according to a European Commission study, PET bottles and their lids are among the most common objects found among ocean debris.

The consumption of PET bottles is increasing. As our report on the European Directive on single-use plastics, in Europe, it is now around 140 units per person per year. In the United States, it’s 290 units.

Globally, around 57% of these are collected, according to the latest figures from our global supply demand analysis service RPET. Political pressure will see this figure increase. One of the most ambitious goals of the European directive is the call for the collection of 90% of PET beverage bottles by 2029. Significant investments in new waste management infrastructure are needed to achieve this goal .

But collection does not guarantee recycling. In the United States, 70% of plastic collected for recycling goes to landfill. It’s 30% in the EU. Many argue that the real mission is to find a cleaner, greener alternative.

Mackenzie Wood

Aluminum is a competitor. Coca-Cola Co.’s Dasani water brand, for example, will soon be available in cans in the United States as part of its efforts to reduce plastic waste.

So how does a can compare to a plastic bottle?

The environmental impact of production

Based on the first use, neither material gets a high score.

Plastics depend on the extraction of crude oil. It’s an energy-intensive process, from drilling and refining to extrusion and molding. A 2017 life cycle assessment study of CPME’s PET resin showed that the production of virgin material requires 69.6 GJ / tonne.

Aluminum is mined and refined from the mined bauxite ore. It’s complicated, expensive and energy intensive. We calculate that it takes an average of 14,000 kWh of electricity to produce one tonne of aluminum. Aluminum Association life cycle assessment studies indicate that the total primary demand for aluminum production is 138 GJ / tonne. Electrolysis accounts for the majority of total primary energy needs and it has also been shown that 36% (depending on location and value chain) of this energy demand can come from renewable, often hydraulic, sources.

In terms of temperatures, the polymer can be produced and extruded at about 250-300 ° C. The melting of aluminum requires temperatures above 1000 ° C.

Recyclability: PET

PET has the highest recycling levels among the six most commonly used resins in packaging. By 2029, we predict that 68% of PET bottles will be collected globally . However, there will be some disparity in regional collection rates: 30% in the United States, 57% in Europe and 82% in China.

Some are embarking on closed-loop recycling, creating new food-grade bottles. Others are entering open loop recycling, intended for sheet or fiber applications. The environmental impact is variable. The fibers that end up in the quilt padding will likely stay in landfill much longer than a poor quality “fast fashion” t-shirt.

In 2018, 19.7 million tonnes of PET bottles for food and drink were produced, of which 845,000 tonnes were mechanically recycled into bottles for food and drinks. By 2029, we expect this to reach 30.4 million tonnes, with over 3 million tonnes mechanically recycled.

The demand for recycled PET (RPET) is growing. The EU directive includes a target to incorporate 25% recycled content in all PET beverage bottles from 2025, rising to 30% from 2030. Major brands such as Coca-Cola, Danone and PepsiCo have all called for 50% use of RPET in their bottles by 2030. We expect demand for RPET in Europe to grow six-fold by 2030.

Recyclability: aluminum

Recycling aluminum is a real closed loop. According to the Aluminum Association, it is one of the most recycled materials on the market. Recycling it saves more than 90% of the energy needed to produce new metal.

Recycling rates for aluminum cans vary around the world. UK recycling rate reportedly hit 75%, its highest level ever . In the United States, a 2017 report showed that the consumer recycling rate had dropped to 49.4%. In Brazil, it is over 90%. In some countries, rates are increased by income disparity, as the value of aluminum creates an economic impetus for collection.

Durability and flexibility

When it comes to durability, plastic bottles have an inherent advantage. While dented cans often end up on retail shelves, plastic is less likely to warp during transit.

Flexibility is another advantage of PET. While supermarket shelves are filled with resealable water bottles of various convenient sizes, a two-liter can of water is much less practical.


Shelf life is often defined more by content than packaging, but that’s a consideration. Beverages in cans generally have a longer shelf life than those in PET bottles.

Additives can improve the barrier properties of PET to extend shelf life, but there is often an environmental impact. Some are introduced in small enough quantities that recyclability is not affected. Others, like dyes, mean the bottle cannot be recycled for food grade applications.

The food quality factor

Not all PET can be recycled into new water bottles. Contamination, polymer degradation and additives can all affect suitability for food grade applications.

New technologies could help solve this problem. Chemical recycling is promising as a way to turn lower grade PET into virgin grade resin. We believe this is a medium-term trend, with significant volumes of chemically recycled materials in at least 5-10 years. So while 3 million tonnes of PET bottles will be mechanically recycled into food and drink bottles by 2029, the total will increase to 4.6 million tonnes with chemical recycling volumes.

In the case of aluminum, the recycling process itself has a sanitizing effect.

Cost of materials

Aluminum currently costs around US $ 1,750 to US $ 1,800 per tonne. A 330ml can weighs approximately 16g.

Polyester for PET is about US $ 1,000 to US $ 1,200 per tonne. A PET water bottle weighs approximately 8-10g and contains 500ml. However, since soft drinks need a stronger bottle, the average weight will be around 22-25g per 500ml.

Plastic costs less and goes further. Per liter, a drink will cost less to dispense, with less energy required to transport it.

If the product is water, rather than a higher value beverage such as beer, the cost impact is magnified. The additional costs are usually pushed up the value chain to the customer. Price-sensitive consumers may not tolerate the increase, so brand owners may be forced to absorb the additional cost.

Mackenzie Wood

Stock availability

In the UK alone, 7.7 billion plastic water bottles are used each year. We estimate that replacing that with 7.7 billion cans would require an additional 99,000 tonnes of aluminum foil inventory.

In recent years, the aluminum rolling industry has shifted away from the production of cans to more profitable sheets for automotive applications. To trigger a reversal of this investment, the conversion margin would have to change. Rolling mills should be encouraged by a significant increase in the price of box stock.

Such a drastic change would not happen overnight. But regulation could lead to a drastic shift in demand for polymers, impacting investment cycles as a result.

So, will aluminum cans replace plastic bottles?

Brands offering water cans may find a receptive market, and it will be interesting to see how consumers respond over time. However, our data shows a downward trend in the consumption of aluminum beverage packaging over the next ten years, with the exception of a few emerging markets in Southeast Asia.

At the same time, the consumption of PET bottles is increasing, globally and in most regions. A healthy lifestyle is an important driver. Simply put, people prefer a bottle of water to a can of soft drink.

And the industry is changing. Targets are set throughout the value chain to improve collection and recyclability and further maintain a closed loop.

Is there a better alternative to PET?

There is no easy answer. Each “solution” has its own challenges. Paper or card options usually have a polymer coating which can be difficult to recycle. Glass is heavy and inefficient to transport. Bioplastics have been criticized for diverting arable land from food crops, among other potential environmental compromises. And will consumers pay for greener but more expensive alternatives to water on the go? Or will we all have our own refillable water bottle in the future?

For a closer look at whether aluminum cans could have a new lease of life in the future, check out our report later this year.

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