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Environmental impact during a product’s life – part 3

The third article in this series considers the aspect of footwear production.

by Nicola Pichel-Juan

Recent research has found that the fashion industry is likely to be responsible for at least 4 per cent of all global greenhouse gas emissions. For an organisation looking to minimise the environmental impact of the footwear it is manufacturing or sourcing, the tooling and production of the finished footwear itself, as well as the wider impact of the manufacturing facility, can provide a number of opportunities to make improvements to an item’s environmentally-friendly credentials.

This article will discuss various different areas that can be considered from a sustainability perspective. Interestingly, many of these are areas that have received significant attention in the past from the cost-saving and efficiency point of view, but can in parallel be leveraged to deliver some significant reductions to a product’s environmental impact. A final related consideration is how over-supply and the disposal of unwanted products contributes to the environmental impact of the fashion industry and the organisations involved.

Dealing with waste

For most footwear, the item on the bill of materials that is likely to have one of the biggest (if not the biggest) environmental impacts is the upper material. This is also likely to be one of the most expensive items. It is therefore crucial to optimise the use of the material and reduce waste as much as possible. This can be done by ensuring that the upper patterns themselves are engineered for optimal cutting efficiency and that the material is then cut in the most efficient way possible. The SATRASumm software package – first introduced in 1981 – does just that and, by calculating the optimal way to interlock pattern sections, it will typically reduce material consumption by 4 to 8 per cent. This saving in material consumption will also provide corresponding savings in the environmental impact and the overall cost of the product.

However, all production processes, even the most efficient ones, are likely to generate some level of waste material. It is therefore crucial to identify all the different waste streams throughout the manufacturing process, to investigate how this waste could be minimised and, finally, to consider the methods of disposal being used for the waste. For example, are the waste streams being separated to allow some materials to be repurposed or re-consumed in the production process by implementing best practice? Are materials being segregated for recycling where viable recycling streams exist, or is everything simply being sent to landfill? The article ‘Minimising and repurposing waste materials’ covers this topic in detail.

Avoiding pollutants

Another consideration relevant for cemented footwear is to transition from traditional solvent-based adhesives to water-based versions. In a project undertaken by SATRA last year at a factory making children’s footwear, changing from solvent-based to water-based adhesives was estimated – over an annual output of 500,000 pairs – to have reduced the volatile organic compounds (VOCs) being released into the atmosphere by between 5.4 and 5.9 tonnes. VOCs are pollutants that have been identified as contributing to numerous health issues. Once in the atmosphere, they react in sunlight with nitrogen oxides to create ozone molecules which, in turn, cause smog.

Changing from solvent-based adhesives to water-based versions can significantly reduce the volatile organic compounds being released into the atmosphere

SATRA can support any manufacturing sites wanting to make the change to water-based adhesives through our ‘three-phase’ process. The first phase is an audit of the current adhesive process, resulting in a list of corrective actions. The second phase involves a further visit to implement the correct actions and support the transition to water-based adhesives. The final phase involves a third visit to ensure that all corrective actions remain in place and to resolve any outstanding issues with an annual audit. From the research SATRA has undertaken, we estimate that this transition from a cost-perspective is at worst cost-neutral but should, in most circumstances, save money alongside the substantial benefits for human health that are being realised – both in the factory and the environment.

Cutting energy costs

The energy consumption associated with the production process also needs to be taken into account, and there are two distinct areas to consider – energy efficiency and the source of the energy. To understand how much energy is being consumed per unit of production, a simple calculation can be carried out to divide total energy used in a period by the output, and this provides a good starting point. Ideally, however, it would be best to understand the energy consumption at each point in the production process to truly understand where any ‘hot spots’ are and to identify opportunities for energy reduction.

The link between electricity consumption and environmental impact

Electricity generated in a coal-fired power station will have an environmental impact per unit of energy produced that is much greater than the impact per unit of energy generated through renewable sources, or even by a nuclear power station. In data published by the Intergovernmental Panel on Climate Change (IPCC), the ‘g CO2e’ per kWh of coal falls within a range of 740 g to 910 g through the entire lifecycle of the supply of the unit of energy, whereas an off-shore windfarm would have an impact in the range of 8 g to 35 g.

In the UK, the Department for Environment, Food and Rural Affairs (DEFRA) publishes a value for the CO2e of a unit of electricity using grid average emission factors. In 2021, the CO2e factor per unit of energy decreased by 9 per cent compared to the previous year, due to a decrease in coal use and an increase in the generation of electricity from renewable sources.

DEFRA’s current value for the CO2e impact of consuming 1 kWh of electricity in the UK is 0.21233 kg of CO2e. To put that into context, a 9 watt domestic bulb, used on average for three hours a day would consume 9,855 watt hours or 9.8 kWh of electricity per year with an equivalent CO2e impact of 0.7 kg. In industrial settings operating energy-intensive machinery, the associated environmental impact can account for a significant proportion of a product’s total carbon footprint.

With rapidly escalating energy costs being seen in many countries, anything that can be done to reduce energy consumption will not only lower the environmental impact of making something but also substantially reduce costs. There are some fairly obvious recommendations, such as avoiding leaving machines switched on when they are not in use, or turning off lights in areas not being used, such as storage facilities. Could more efficient LED lighting be installed? In some instances, more modern energy efficient equipment and machinery may be available, that with current energy prices could have very short pay-back periods. A less obvious consideration could be to check any compressed air systems in use for leaks. These systems can consume considerable amounts of energy and, with today’s energy prices, any leaks which reduce the efficiency of the system can be very costly.

What is the environmental impact of compressed air?

As part of our own sustainability initiatives, SATRA has been undertaking a detailed review of the compressed air system used at our main testing site. Our research estimates that a compressed air leak that can easily be heard is probably wasting 1 kW per hour which, based on the hours/days for which the site is operational, amounts to 8,500 kWh annually. Based on UK conversion factors, this equates to 1,809 kg of CO2e (the ‘e’ stands for ‘equivalent’) and, at current energy prices, is probably costing well over GBP 1,000 per year.

How the electricity being consumed is generated will also affect the environmental impact of a product. An item being made in a factory using electricity from its local energy grid that is being generated from coal-fired power stations (burning fossil fuels) will have a higher environmental impact than the same item – being manufactured in the same way – in a factory taking energy from a grid with a higher proportion of renewable energy, or that is generating its own energy on-site from one of the renewable sources.


Any operation generating its own electricity through renewable sources will decrease its environmental footprint considerably

Any operation generating its own electricity through renewable sources will reduce its environmental footprint considerably. This is because it is purchasing and consuming less grid energy, which is usually going to include some proportion of fossil fuel-generated energy. However, for most carbon or environmental impact reporting protocols, simply signing up to a renewable energy deal (where that is an option) is not going to be sufficient to reduce the company’s impact. It is generally required to also make a report using location-based grid average emission factors, taking into account all the energy that is generated in an area.

A mountain of unsold products?

GrigoriosMoraitisd |

It is clearly not sustainable to continue producing and shipping items that are destroyed without ever being worn

Another impact that is often not considered is the amount of unwanted and unsold products that ultimately end up having to be destroyed. Consumers today are used to everything being available on demand, with next-day delivery services from e-commerce sites being commonplace in many parts of the world. In order to fulfil this demand and to not risk losing sales, there can be a tendency to over-stock and therefore over-produce. When there is then surplus stock, businesses are left with two choices – they can either sell the stock at a heavy discount, potentially incurring a loss, or pay to have the stock taken away and destroyed.

In fact, it is estimated that 40 per cent of all items produced by the fashion sector are sold at markdown prices. It is clearly not sustainable to continue producing and shipping items that are destroyed without ever being worn, and legislation is likely to restrict this activity in the future. For example, in its EU Strategy for Sustainable and Circular Textiles, the European Union outlines its intention to oblige large companies to publicly disclose the number of products they destroy, and ultimately aims to ban the destruction of unsold products.

The adoption of a business model which, for instance, would reduce stock holding and minimise the number of different product options being marketed, would be a considerable change from what is generally the ‘status quo’ today. However, this level of change may ultimately be necessary in order to reduce the industry’s impact. Improved forecasting processes and the use of ‘product lifecycle management’ (PLM) software and data analytics can all be used to support this transition.

How can we help?

This article has introduced a number of different areas that are of relevance to minimise the environmental impact of a product – either by directly examining the engineering of the product itself or the indirect impacts of the manufacturing environment. Please email for further information on any of these areas or for support on how to build more sustainable products and

Publishing Data

This article was originally published on page 20 of the December 2022 issue of SATRA Bulletin.

Other articles from this issue ยป