A long and expensive study comparing the environmental impacts of disposable and cloth nappies is seriously flawed, says Women’s Environmental Network (WEN).

The lifecycle analysis (LCA) for the Environment Agency has taken four years and cost more than £200,000 and concludes there is “no significant difference between any of the environmental impacts”. But the conclusion is based on poor quality data and misses the point of its own findings.

“This lifecycle analysis is a wasted opportunity to put the long-standing debate about nappies and the environment to rest,” says WEN’s Ann Link. “It says what most other LCAs have: that both systems use similar amounts of energy but the disposable system uses more materials and puts more into landfill. But it has missed the point of its own findings. Even in its current flawed state it shows that parents who use cloth nappies can save waste confident in the knowledge that washing them will cause no more global warming than disposable nappies.

“The biggest impacts it identifies are all to do with energy production and use - abiotic resource depletion (fossil fuel use), global warming and acidification - yet if parents use 24 nappies and follow manufacturers' instructions to wash at 60oC using an A rated washing machine they will have approximately 24% less impact on global warming than the report says.”

The LCA measures the environmental impact of reusable and disposable nappies from the raw material stage (e.g. coal, trees or cotton plants) through manufacturing processes to their use, disposal and emissions (e.g. CO2) back into the environment.

Data used for key assumptions is unsatisfactory in many instances. The report itself raises concerns with regard to assumptions that result in ‘a high level of uncertainty associated with the reusable nappy systems’.¹ It admits that ‘the amount of analysis and quality of the results might be improved with a larger sample and by refining the questions.’ ²

Over 2,000 parents using disposable nappies were surveyed. By contrast, most of the survey results for reusable nappies were drawn from a sample of 117 parents, further reduced to 32 because users of terry towelling nappies were relied on for most assumptions. This resulted in as few as two respondents being used for certain key assumptions.

The study gives little useful advice and will confuse parents.

The reusable system has enormous potential for improvement in environmental performance. This is hinted at in the LCA but not highlighted. Consumer guidance from sensitivity analyses has not been provided on what practice would achieve a significant reduction in environmental impact. WEN has found that a 17% reduction in global warming impacts can be achieved by using an A rated washing machine and following manufacturers’ guidance to wash at 60oC. With A rated washing machine sales at near saturation by early 2005 many real nappy users are already achieving this saving. Parents only need use 24 real nappies, rather than the 47 the LCA assumes, reducing their global warming impact by another 6.9%.³

While WEN welcomes the Environment Agency’s undertaking to carry out further work in this area it is urgently required to bring the report in line with recent technological and product developments.

Disposable nappies are the largest single product category in household waste. While waste amounts are still rising, the EU Landfill directive requires a reduction of 35% in biodegradable waste over a 25 year period.

Elizabeth Hartigan, co-ordinator of WEN’s real nappy project, says: “Using real nappies puts parents in control. With a good washing routine parents can minimise the environmental impact of their babies’ nappies, reduce waste and save themselves money.”

ENDS

Contact: Elizabeth Hartigan or Liz Sutton,
Tel: 020 7481 9004 email:comms@wen.org.uk

Notes to editors

Further information is available below under Some Areas of Concern, WEN Consumer Advice

Waste: Britain throws away nearly eight million nappies a day. With a disposal cost to individual local authorities in hundreds of thousands of pounds per year (Nottinghamshire estimates £1 million per year) it is not surprising that nappy schemes now play a key role in local authorities’ waste strategies.

Cost: WEN estimates that washing nappies at home could save parents around £500. Hospitals can save money too by using real nappies on wards where disposables incur clinical waste charges. Local authorities save on waste disposal charges.

Modern nappies have advanced considerably over recent years. They are shaped and fitted and fastened without the need for pins. They come in a variety of styles and patterns. A biodegradable liner can be used inside the nappy and this can be removed so that the contents are flushed down the loo. Nappy washing services make things even easier, collecting dirty nappies and leaving fresh clean ones in their place.

Women’s Environmental Network (WEN) is a registered charity which campaigns on issues which link women, health and the environment. Other current issues include food, chemicals and the environmental impacts of disposable sanitary and continence protection. email nappies@wen.org.uk T: 020 7481 9004 F: 020 7481 9144

SOME AREAS OF CONCERN

Home Laundry
The LCA assumes an average ownership by real nappy users of 47.5 nappies. This is based on two respondents.⁴ The report identifies this as a ‘weak assumption’⁵ and supports it with assumptions based on the ‘reusable nappy wearing population’ a finding which is also insecure due to shortcomings in the survey methodology.

A more realistic and typical ownership of 24 nappies gives a 6.9%⁶ reduction in the CO₂ emitted by the average home user of washable nappies.

Table 1

KWh use derived from National Energy Foundation information using the distribution of washing temperatures from the LCA. www.natenergy.org.uk/washing.htm

Energy use, with its global warming potential, is a major impact of both systems. Use of washing machines from 1997 was assumed for the reusable system. The effect of using machines as bought in 2000 was tested, and gave a reduction in CO₂ of 6%. The report finds that “electricity use for nappy care is the most significant single contributor to the impacts assessed”,⁷ yet the effect of further improvements in washing machines, and of following nappy companies’ instructions and washing at 60^oC or below was not tested. The LCA assumed a 1.38 kWh wash, but a 0.86 kWh wash will soon be the average.⁸

Laundry Service
Only one data set was used for the manufacture of prefold nappies which was shown to be significant⁹ in determining the impact of laundry service provision.

Sensitivity analyses were not applied to provide useful data on the reduction of environmental impact when laundry service has a more concentrated customer base although this was found to be another significant contributor to overall impact.¹⁰

Disposable Nappies
The Environment Agency recommendation that disposable nappy manufacturers reduce the weight of disposable nappies¹¹ seems to be contradicted in the report where the superabsorbent polymers (SAPs) are found to be the largest source of environmental impact upstream of retail for disposable nappies.¹²

Table 2

Notes
1. The Environment Agency Survey found that people washed with the distribution in column 2. (Table 5.7 of LCA) Public information on washing machine energy use uses three temperatures only: 90°C, 60°C & 40°C. To make comparisons with lower energy machines easier, the percentages were redistributed as fairly as possible so that some of those washing at 70°C were moved up to 90°C, and others down to 60°C; and similarly with those washing at 50°C. This gave a modified distribution with the same energy use as the EA: 1.38 kWh. This distribution was used to obtain all the other washing energies.

2. Table 2 tests the effect of no-one washing above 60°C

3. Table 1 calculates the approximate effect on the global warming potential in kg of CO2 equivalent. Using the results of the sensitivity analysis in the LCA where a change in machines from those bought in 1997 to machines bought in 2000 gives a 6% drop in CO2 (Fig. 9.5) the approximate drops for other changes in washing machine energy and use are calculated in the final column using Table 8.13.

WEN CONSUMER ADVICE

All nappies have an environmental impact.

The only way parents can reduce environmental impact when using disposable nappies is to use fewer nappies. When paediatricians suggest ten to twelve changes a day in the early weeks, reducing to around six a day later on,¹³ to further reduce the number of nappy changes is not good health practice.
Using real nappies puts parents in control.

By using an A rated machine and following manufacturers instructions to wash at 60o parents can reduce energy use and global warming impact by 17%.

Further reductions in environmental impact may be made by adopting a good washing routine:

Footnotes:

¹ LCA 9.7 Data Quality

² LCA 10.1 Recommendations for Further Work

³ DEFRA’s Market Transformation Programme UK Energy Consumption of Domestic Washing Machines 22/01/2005: www.mtprog.com

⁴ Environment Agency, 2004 Time to Change? A study of parental habits in the use of disposable and reusable nappies. Tables 2.21 and 2.22

⁵ LCA 9.3.5 Number of Nappies Owned, Previous Use and Waste Management

⁶ The manufacture of terries is calculated by ERM to generate 74 kg of CO2 equivalent (Table 8.13). This is all from yarn spinning and weaving processes (Fig 5.2 and Table 5.9) so can be assumed to be directly proportional to the weight of nappies and therefore the number. Halving 74 kg gives 37 kg and is a 37kg reduction. The total CO2 then drops from 559 to 522 kg (Table 8.13) a fall of 6.9%.

⁷ LCA 8.2 Reusable Nappies Home Laundering

⁸ DEFRA Market Transformation Programme: UK Energy Consumption of Domestic Washing Machines 22/01/2005 www.mtprog.com

⁹ LCA 9.4.1 Prefold Nappy Manufacture

¹⁰ “Vehicle use in the delivery and collection of nappies is also a significant contributor” LCA 8.3 Commercial Laundry

¹¹ LCA 10 Interpretation and Conclusions

¹² LCA 8.1.2 Disposable Nappy Manufacturing

¹³ Miriam Stoppard and Dr Christopher Green