A very valid question when considering using reusable nappies!

With all the washing and effort, is it actually worth it for the environment or is this greenwashing?

After all, there are many marketing claims out there about this or that being better for the environment. But it is often hard to know if our choices are making a difference.

 

 

 Well luckily for us, an updated Life Cycle Assessment study has been published in the UK in early 2023, which compares the environmental impact of reusable vs disposables.

Here is a link to the study reports: Science Search (defra.gov.uk)

 

If you don't want all the deets, just skip to the end of this blog for the summary.

 

Life Cycle Assessment

But first, what is a Life Cycle Assessment?

Life cycle analysis or assessment (LCA) is a method used to evaluate the environmental impact of a product through its life cycle encompassing extraction and processing of the raw materials, manufacturing, distribution, use, recycling, and final disposal.

From: Journal of Environmental Management, 2010

 

So it looks at the environmental impact from start to finish of a product which gives a reliable assessment when doing a comparison.

 

 Image from Deloitte.

 

Study Aims

The study took 2 years, £47,575 (NZD 100,416) to complete; and the objective was to determine the cumulative environmental impact of the use of a disposable and a reusable nappy ‘system’ for the first 2.5 years of a child’s life in the UK.

 

 What nappies did they look at?

Researchers used aggregated data sets (2020-2021) for disposable nappies from major manufactures and 4 reusable nappy producers combining 8 different reusable nappies from 13 different washable/ reusable nappy components (nappy systems).

The results are based upon the following nappy formats:

• Disposable nappies - single use nappies with super absorbent polymer (SAP) and cellulose fluff to retain the urine. They are available in a range of sizes from new-born upwards.

• Reusable nappies (home laundered) covered in this study had three different designs:

o ‘Pocket nappy’ - consist of a waterproof outer and a fleece inner. An opening along the back of the nappy allows an absorbent pad to be inserted and to change soiled pads.

o ‘All-in-one nappy’ - incorporates an absorbent inner (‘core’) with an attached waterproof outer layer sewn together and can be used without additions as a complete nappy system.

o ‘All in two nappy’ - incorporates an inner absorbent pad (‘insert’) that attaches to the outer waterproof layer (‘wrap’) with poppers to form a one-piece nappy. The pads can be removed for washing independently of each other and reuse. Both the absorbent inner and waterproof outer must be used together to comprise a complete nappy system. - Real Nappies fit into the "All in 2" category.

 

Results

The Global warming potential (GWP) (carbon footprint) for disposable nappies for the first 2.5 years of a child’s life is 456.91kgCO2eq. The largest environmental impact (CO2eq) is due to the materials and production (~63%) followed by the end of life (EOL) treatment of the nappies, faeces and urine (~33%). 

For the reusable nappies the GWP is 344.57kgCO2eq. The use phase (energy use in washing and detergent impact) is by far the largest contributory factor to the carbon footprint (~85%).

 

 

 

The report also looked at another 18 main environmental impact categories plus consumer water and material consumption. Examples of these are stratospheric ozone depletion, Ionizing radiation, Terrestrial acidification or Mineral resource scarcity.

The disposable nappies have a higher environmental impact in 7 categories out of 18 and in addition, the overall consumption of materials used is also higher than reusable nappies.

On the other hand, reusable nappies have a higher environmental impact across 11 of the impact categories. The main contributing factors (aside from materials) is electricity used in pre-washing, washing and drying operations, detergent use and the treatment of wastewater (toilet flushing and washing machine).

 

In any case, user behaviour plays an important role in understanding and mitigating the environmental impact of nappies.

 

In the case of electricity use for reusable nappies, that can be minimised to some degree by doing things such as:

• washing at lower temperatures such as 40degC instead of 60,
• ensuring the main wash load is a full load,
• running the washing machine during the night from midnight to 4am when electricity demand is low (plus some power companies have cheaper night rates so you can save some money too!),
• drying nappies on the line instead of using the drier.

 

 

Another thing to consider is that the study was conducted in the UK, where in 2022, 40% of electricity came from renewables according to the London School of Economics and Political Science.

Compare this to the NZ situation where over 80% of electricity generation is from renewables, so it would be very interesting to have the numbers in a NZ context.

Does anybody want to do a phD on this in NZ??

 

Other interesting findings

Consumer research indicated that since the last LCA study, a percentage of children are being potty trained at a later stage in their development. The results also showed that at 2.5 years, 37% of babies using disposables and 35% of babies using reusable nappies were still in nappies. This is an increase of 19.4% and 17.4% respectively over the previous LCA studies.

This is not a good thing since extending the use of nappies, whether disposables or reusables will have a detrimental environmental impact.

 

Summary

• The study aimed to determine the cumulative environmental impact of the use of a disposable and a reusable nappy ‘system’ for the first 2.5 years of a child’s life in the UK.

• The following types of nappies were evaluated: Disposable nappies (aggregated data between sizes) and 3 types of reusables: Pocket nappy, All-in-one nappy and All in two nappy - Real Nappies fit into the "All in 2" category.

• The Global warming potential (GWP) (carbon footprint) for reusable nappies was 25% lower than disposables (344.57kgCO2eq. vs disposable nappies 456.91kgCO2eq.) So overall there are less CO2 emissions from using reusable nappies.

• Disposable nappies have a higher environmental impact in 7 categories out of 18 and in addition, the overall consumption of materials used is also higher than reusable nappies.

• On the other hand, reusable nappies have a higher environmental impact across 11 of the impact categories. Mostly due to the electricity used in pre-washing, washing and drying operations, detergent use and the treatment of wastewater (toilet flushing and washing machine).

• The study was done in the UK context where 40% of electricity came from renewables. Compare this to NZ where over 80% of electricity is generated from renewables, so the results are likely to be much better in the NZ context.
• the environmental impact of production is over 90% lower for a reusable nappy than for a single-use nappy
• single use nappies use approximately 98% more resources to produce than reusables.

 

So there you have it! Reusable nappies are better for the environment than disposables, helping to reduce our carbon footprint.

 

Minimising the use of electricity being the main one!

Hot tips: 

1. Wash at lower temperatures such as 40degC instead of 60,

2. Run the washing machine during the night from midnight to 4am when electricity demand is low (plus some power companies have cheaper night rates so you can save some money too!),

3. Dry nappies on the line instead of using the drier.

 

 

References:

https://randd.defra.gov.uk/ProjectDetails?ProjectId=20622

 https://www.lse.ac.uk/granthaminstitute/explainers/how-much-do-renewables-contribute-to-the-uks-energy-mix-and-what-policies-support-their-expansion/

https://www.mbie.govt.nz/about/news/energy-in-new-zealand-2022-shows-a-strong-share-of-renewable-energy/