Carbon footprint bottled water

What is the carbon footprint of bottled water?

We know that plastic is bad for nature, rivers, lakes and oceans but what’s the environmental impact beyond this? What is the carbon footprint of manufacturing of plastic, filling the bottles, transportation and end of life depositing or recycling?

If you search online you will find a wide range of articles on this topic but most are either very academic or just refer to one study. Some of them are published by the bottled water industry and thus not entirely objective. Others are by the glass bottle producers with a completely different take.

Rather than redoing the research ourselves we will summarise the key studies in this article to give you a range of what the CO2 footprint of bottled water is depending on who you believe and how you count.

What is Carbon Footprint?

Carbon footprint (or CO2 footprint) is defined as the total emissions caused by an individual, event, organization, or product, expressed as carbon dioxide equivalent.  Although there are established standards for calculating the CO2 footprint in manufacturing, transportation, agriculture, etc there are also great levels of uncertainty. This is one we reason that the results of studies vary so widely. Another reason is that they are often partial based on the interest of the group presenting the results.

Summary carbon footprint of bottled water

Want to know the high level data and not all the details. Here’s a table with a high level overview from the lowest to highest estimates and medium of bottled water CO2 footprint. We’ve tried to illustrate the CO2 footprint by comparing it to cars and the total global carbon footprint. 

Variable

Low

Medium

High

CO2 footprint per 50 oz (1.5 liter) bottle cradle-to-cradle

1.6 ounces (44 g)

9 ounces (250 g)

22 ounces (633 g)

CO2 footprint total bottled water

31 billion pounds
(14 billion kg) CO2

176 billion pounds
(80 billion kg) CO2

446 billion pounds
(203 billion kg) CO2

Equivalent in distance driven by a car*

52 billion miles
(84 billion km)

298 billion miles
(480 billion km)

757 billion miles
(1,218 billion km)

Equivalent in distance driven by a car*

5 million cars

29 million cars

74 million cars

% of total CO2 released globally per year***

 0.038%

 0.21%

0.54%

* Using 6 km / kg CO2 which is the average between US and Europe
** Using average of 10,200 miles per year which is the average of (Europe 10,816 km per year) and (US 13,746 miles per year)
*** Global Carbon footprint 2017 was 37 billion tons

About the CO2 footprint studies of bottled water

Based on the most cited study it’s about 0.5 lbs (200 g) per 50 ounce (1.5 liter) bottle which means that 800 bottles per year consumed by the average bottle drinking household is equal to 350 lbs (160 kg) CO2 or the equivalent of driving 368 miles (592 km) with a car. But the range of estimates of CO2 footprint per bottle is from 1.6 ounces (44g) to 23 ounces (663g). The more recent studies are in the higher range.

The studies all differ when it comes to the exact breakdown. Some include cradle to cradle (from material to end of life waste) and others focus on the materials and manufacturing. Neither of them included transportation to the end consumer in the total measure. Therefore we first summarise the total CO2 footprint from the studies and then break down the components.

We’ve generally used the original measures of the studies which is why the tables include a mix of metric and imperial measurements.

Total CO2 footprint of bottled water excluding transport

We included the most cited / references studies in this analysis. Some were also excluded due to lack of data backing up the research.

We used a 50 ounce (1.5 litre) bottle as a benchmark as this is the most common size water bottle bought in supermarkets. However, it could just as well be argued that we should use the smaller bottle size served in kiosks, coffee shops and major transportation hubs. Anyone can easily translate these metrics into smaller bottle sizes for comparison.

Study

CO2 footprint

CO2 footprint 50 ounce (1.5 l) bottle

CO2 footprint 50 ounce (1.5 l) bottle

Water footprint network summarised on sciencing.com

Water footprint network sum-marised on sciencing.com

82.8g per 0.5l of PET bottled water.

82.8g x 3 *80% = 199g

Assumption that total footprint of a 1.5l is 80% less per 0.5l.

EPA

1 ounce of carbon dioxide is emitted for each ounce of polyethylene (PET) produced

1 ounce of carbon dioxide is emitted for each ounce of polye-thylene (PET) produced

1.95 g x 75% (1.5 l) x 28.3 g (1 ounce) = 44.1g

The weight of a 2 liter PET bottle is between 42-68 grams or 1.48-2.4 ounces. We therefore use 1.95 ounces

Science Direct

1.538 kg carbon dioxide is emitted for each kg of 85% recycled polyethylene (PET) produced cradle to grave.

1.538 kg carbon dioxide is emitted for each kg of 85% recycled polye-thylene (PET) produced cradle to grave.

1.95 g x 75% (1.5 l) x 28.3 g (1 ounce) x 1.538 (per kg) x (29%+30%+8%) = 45.3g

1.95 g x 75% (1.5 l) x 28.3 g (1 ounce) x 1.538 (per kg) x (29%+
30%+8%) = 45.3g

The weight of a 2 liter PET bottle is between 42-68 grams or 1.48-2.4 ounces. We therefore use 1.95 ounces

UWISC

280 g per 750 ml PET bottle

560g per bottle

This includes transportation

This includes transpor-tation

Natureworks

Nature-works

EU: 2.15 kg CO2 per kg PET US: 2.73 kg CO2 per kg PET

EU: 94.5g US: 120g

Total CO2 footprint of plastic bottles compared to glass and aluminium

In our research we only found one peer reviewed comparison study of plastic bottles to glass and aluminium. Although credible it should be noted in advance that it’s by a glass bottle manufacturer.

It would also be interesting to compare to paper cartoons such as tetrapak water bottles that are coming more common. Especially since these also contain plastic film making them difficult to recycle.

OI split the breakdown in US and European bottles due to primarily the sourcing of material but also the mix in energy production. US had a higher CO2 footprint on all measures.

Based on bottling in the US

Study

CO2 footprint

CO2 footprint 1.5 l bottle

Notes

OI – PET

214 g per 355 ml

214 g x 4.2 x 70% = 633 g

Assumption that total footprint of a 1.5l is 70% less per 0.355 l = 4.2x

OI - Glass

171 g per 355 ml

171 g x 4.2 x 70% = 503 g

Same as above

OI – Aluminium

401 g per 355 ml

401 g x 4 = 1604 g

4 cans

OI - Glass refill

6 g

6 g x 4 = 24g

Assumes each bottle is reused 30 times

Based on bottling in Europe

Study

CO2 footprint

CO2 footprint 1.5 l bottle

Notes

OI – PET

152 g

152 g x 4.2 x 70% = 447 g

OI - Glass

110 g

110 g x 4.2 x 70% = 323 g

OI – Aluminium

122 g

122 g x 4 = 488 g

OI - Glass refill

6 g

6 g x 4 = 24g

Assumes each bottle is reused 30 times

Notes:

Glass – Only a few countries have glass bottle deposit and recycling schemes, which means they are only used once and then recycled as glass.

Transportation – The studies we found all excluded transportation of bottles to the end consumer as this depends so much on the brand. Therefore you need to add transportation on top of these figures.

Manufacturing of PET incl transportation of raw materials

Transporting the raw material including mainly oil to start with and the production of the plastic resins used to produce bottles contribute to a bottle’s carbon footprint in a major way.

Study

CO2 footprint

CO2 footprint 1.5 l bottle

Notes

Water footprint network summarised on sciencing.com

Water footprint network sum-marised on scien-cing.com

82.8g per 0.5l of PET bottled water whereof: Transportation of raw materials: 29% Plastic resins: 30% Creating the bottle: 8%

82.8g per 0.5l of PET bottled water whereof: Transpor-tation of raw materials: 29% Plastic resins: 30% Creating the bottle: 8%

(29%+30%+8%) x 82.8g x 3 *80% = 133g

(29%
+30%+8%) x 82.8g x 3 *80% = 133g

Assumption that total footprint of a 1.5l is 80% less per 0.5l.

What is the CO2 footprint reduction from recycling

Recycling can reduce carbon dioxide and other greenhouse gasses by an estimated 30 to 70 percent. Based on the breakdown it looks more likely to be 30%. Today only about 10-20% of water bottles are made out of recycled PET in Europe and North America.leo.

Filling, packaging and storing the bottle

Filling the bottles, packaging and storing the bottles prior to distribution also contributes to the total CO2 footprint of plastic bottles. Storage in refrigerators for longer periods of time could be a major carbon dioxide contributor. 

Study

CO2 footprint

CO2 footprint 1.5 l bottle

Notes

Water footprint network summarised on sciencing.com

Water footprint network sum-marised on scien-cing.com

82.8g per 0.5l of PET bottled water whereof: 33%

(33%) x 82.8g x 3 *80% = 66g

Assumption that total footprint of a 1.5l is 80% less per 0.5l.

CO2 footprint of transporting bottled water

Transportation of bottled water is another big cause of carbon footprint due to the great distances some bottles travel. Fiji water for example may travel as far as 9050 miles (14,500 km) to reach a consumer in the United States. Even most locally produced bottled water travels a great distance due to the transportation hubs used by e.g. Walmart to distribute the water to stores.

 

We found surprisingly few studies on the transportation of bottled water beyond news articles about Fiji water from 2007.

 

One of the more extensive studies looked at 8 bottled water brands in Italy and concluded that the carbon footprint of transporting bottled water locally in Italy is 300 times that of tap water. Italy generally has good tap water but yet Italians love bottled water almost as much as they love a good espresso. The brands put great pride in the source, content, taste and design of the bottle.

 

But local consumption of bottled water is at least better than shipping premium bottled water around the globe. This is also an example where glass bottles are actually worse than plastic bottles due to weight and volume.

How do we calculate the CO2 footprint of transporting bottled water?

Calculating the CO2 footprint of bottled water is relatively easy thanks to the fact that the weight of 1 liter of water is close to 1 kg. Using the standard measures defined by ECTA Alan McKinnon we can then multiply this by the metric tonne per kilometre.

The mean of transportation makes a big difference as ship is more efficient than trucks. For example:

  • A ton of Tasmanian rainwater travelling 7938 miles by ship uses 15.44 gallons of fuel and emits 342.77 pounds of CO2.
  • A ton of Poland Springs going by truck travelling 1141 miles from Maine to Chicago uses 16.54 gallons of fuel and emits 367.19 pounds of CO2.

But the reality is that the Tasmanian rainwater will also be transported by the equivalent miles on truck to reach the consumer.

Study

CO2 footprint

CO2 footprint 1.5 l bottle

Notes

ECTA Alan McKinnon

Ship: 8.4 g CO2/tonne-km Truck: 62g CO2/tonne-km

Local Water: 47g International: 375g

Local Water: 47g Inter-national: 375g

See examples below

Example: Local water

Assuming an average shipping distance of 312 miles (500 km) by truck it’s about 31g per liter or 47g per average bottle.

Example: International Water (Fiji Water)

The transport distance from Fiji to the center of the United States is  7800 miles (12,500 km) in bird distance translating to an average of about 944 miles (15,000 km) by ship and 1250 miles (2,000 km) by truck. This means 126 kg + 124 kg per ton = 250 kg or 250 g per liter and 375g per average bottle. (Note: Fiji normally comes in 0.5 l bottles so not entirely fair comparison).

What is the carbon footprint of tap water?

The CO2 footprint of tap water comes from pumping it up from the ground or surface water, treating it for drinking and pumping it into the water pipes to reach the consumer. Multiple comparison studies have shown that the carbon footprint of tap water is about 1/300 or 1/1000 compared to bottled water. The most cited is an Italian study summarised in Nature.

What is the CO2 footprint of TAPP 2 water filters?

We started this article by mentioning that the carbon footprint can be a measure of any product. However calculating it can be extremely complicated and water filters is no exception.

TAPP Water is still pending to complete a cradle to cradle study of our product that would pass the scrutiny of academics. Until this is finalised we’ve done a back-of-the-envelope calculation to estimate the carbon footprint of TAPP 2.

Calculation of TAPP 2 CO2 Footprint

The filter weighs approximately 923 g including one cartridge. Each cartridge weighs approximately 365 g.

Our assumption is that the Cradle-to-Cradle CO2 footprint of TAPP 2 and TAPP 2 cartridges is about the same as a PET bottle with mineral water shipped internationally per kg. This is a rough assumption since the product in addition to ABS plastic consists of PLA plastic, a stainless steel connector but the materials, raw material transportation, production method and transportation to customer is about the same on average. The Crade to Cradle CO2 footprint of PET bottles is about 1.5 kg to 3 kg depending on source. ABS plastics have a CO2 footprint of 1.4x PET but on the other hand PLA has a CO2 footprint of 1/4 vs PET. This means the carbon footprint of the plastic part of TAPP should actually be less than PET. The other materials make up less than 20% of the total weight/material.

Based on this assumption and the weight of TAPP 2 including packa the CO2 footprint of a TAPP 2 filter is about 2 kg including filter and 4 refill cartridges.

The average customer consumed 2 bottles of water per day prior to installing TAPP 2. This means 730 bottles per year. The average cradle to cradle CO2 for a bottle is about 200 g to 633 g depending on which study is used. This is 146 kg to 456 kg CO2 per year compared to TAPP of 2 kg. This is a saving of over 98%.

In addition to this TAPP uses biodegradable cartridges made of PLA that in an industrial compost leaves zero plastic residue.  

What is the CO2 footprint of a refillable bottle?

Refillable bottles are a great way of staying hydrated while avoiding buying bottled water. Especially bottles that last for years.

Since we plan to launch a new refillable bottle we will be calculating the CO2 footprint of refillable bottles ourselves.

In the meantime University of Wisconsins has done a pretty good general study on the topic.

 

Summary

Recent estimates of CO2 emission from bottled water have resulted in higher estimates than before. This means that the problem is even worse than we imagined.

With approximately 480 billion plastic bottles consumed in 2018 with an average size of 1 liter this means that the CO2 footprint was between 67 billion and 192 billion kg of CO2 per year. That is the equivalent of

  • Driving 248 to 710 billion kilometers by car or the annual CO2 output of about 5 to 74 million cars.
  • The entire yearly CO2 footprint of a nation like Greece (72 billion kg) or Netherlands (175 billion kg) in 2017.
  • Up to one third of the entire aviation industry (543 billion kg)

And this is just part of the problem with bottled water. Other issues include plastic pollution including microplastics, water waste and where the water is sourced.

Note: The CO2 amount released is assumed to be 1 kg CO2 per 2.4 miles (4 km) in an average US car) and 5 miles (8km) for Europe. We therefore use 6 km as an average.

Sources:

Sciencing article: Carbon footprint of plastic bottles
https://sciencing.com/carbon-footprint-plastic-bottle-12307187.html

Pacific Institute:Carbon Footprint of Bottled Water
https://iopscience.iop.org/article/10.1088/1748-9326/4/1/014009/pdf

Stanford: Carbon footprint of bottled water
https://alumni.stanford.edu/get/page/magazine/article/?article_id=30619

Science Direct 2013: Carbon footprint analysis in plastics manufacturing https://www.sciencedirect.com/science/article/pii/S095965261300019X

Natureworks study on PLA vs PET, ABS, PP and other plastics: https://www.environmentalleader.com/2015/07/

OI validated by AMR research: Complete look at carbon footprint from glass packaging
https://www.easyfairs.com/uploads/tx_ef/y.agniel_global_engineering.pdf

University of Wisconsin: Carbon footprint of refillable botled water vs bottled water
https://sustainability.wisc.edu/refillable-water-bottles-research-in-progress/

US Massachusetts’s University study on carbon footprint of bottled water:
http://www.mwra.state.ma.us/

Nature: Carbon footprint comparison of tap water and bottled water
http://precedings.nature.com/documents/3407/version/1

Dieselnet: CO2 emission for European cars by country:
https://www.dieselnet.com/news/2019/03jato.php

EPA: CO2 emission for American cars:
https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle

Truck emission:
https://www.transportenvironment.org/

ECTA Transport emission:
https://www.ecta.com/

Study of carbon footprint of 8 Italian bottled water brands compared to tap water:
https://core.ac.uk/download/pdf/288584.pdf

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