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Products that go round: exploring product life extension through design
Journal of Cleaner Production 69 (2014) 10e16
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Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro
Products that go round: exploring product life extension through design Conny Bakker a, *, Feng Wang a, b, Jaco Huisman a, b, Marcel den Hollander a a b
Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628 CE Delft, The Netherlands United Nations University, Institute for Sustainability and Peace, Hermann-Ehlers-Strasse 10, Bonn 53113, Germany
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 June 2013 Received in revised form 5 November 2013 Accepted 8 January 2014 Available online 21 January 2014
Product lifespans of electric and electronic products are in decline, with detrimental environmental consequences. This research maps the environmental impacts of refrigerators and laptops against their increasing energy efficiency over time, and finds that product life extension is the preferred strategy in both cases: refrigerators bought in 2011 should be used for 20 years instead of 14, and laptops for at least 7 years instead of 4. Designers however lack expertise to design for product life extension (through longer product life, refurbishment, remanufacturing) and product recycling. The paper explores a range of product life extension strategies and concludes that tailored approaches are needed. One of the main research challenges is to determine when to apply which product life extension strategy. Ó 2014 Elsevier Ltd. All rights reserved.
Keywords: Sustainable product design Eco design Circular economy Product life extension Life cycle optimization
1. Introduction Product lifespans in industrialized societies have steadily declined over the past decade, leading to an increased throughput of materials in society and more waste (Huisman et al., 2012). As a result, the environmental impacts of materials production and processing are rapidly becoming critical (Allwood et al., 2011). For product designers, three strategies for addressing these problems are material efficiency, product life extension and product recycling (ibid.). Material efficiency, designing products with less material, is dealt with in most design projects as it brings down costs and is considered good business practice. Product life extension (through longer product life, refurbishment and remanufacturing) and product recycling are however not routinely dealt with in most design practices (Hatcher et al., 2011). Hatcher et al. (2011), in their comprehensive review of design for remanufacture literature, conclude that although the relevance of design for remanufacture (DfRem) research has increased in recent years, this does not yet translate into an increase in OEM remanufacturing activity, nor in design for remanufacture efforts by designers and engineers.
* Corresponding author. Tel.: þ31 15 278 9822/þ31 6 2447 2323. E-mail address: [email protected] (C. Bakker). 0959-6526/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jclepro.2014.01.028
Given the rapidly changing market conditions this might however change in the near future. For instance, the prices of most raw materials have increased significantly due to growing demand from emerging economies (Rosenau-Tornow et al., 2009). For several materials supply disruptions were reported, causing concerns about long-term supply security (Erdmann and Graedel, 2011). A few forward-looking thinkers even claim a paradigm shift has occurred with increasing competition and rising prices of everscarcer resources now being the new norm (Grantham, 2012). In such volatile markets, retaining value through careful management of a product’s end-of-life makes sense. Recent developments in legislation and regulation such as (ongoing) revisions of the WEEE and EcoDesign directives in the EU and the EPEAT (Electronic Product Environmental Assessment Tool) in the USA stress the importance of design for end-of-life, product longevity and life cycle extension. The aim of this paper is to explore how product design can more proactively address product life extension (through longer product life, refurbishment and remanufacturing) and product recycling. In order to do so, it is necessary to first develop an understanding of the extent to which product lifespans have been declining, and to assess whether these shorter lifespans are indeed causing overall negative environmental impacts. This assessment will provide starting points for the development of product life scenarios in Section 7. Based on these, a research agenda for the further
C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16
development of product life extension and recycling is outlined in Section 8. The focus in this paper is on energy using products as this is one of the best-documented product categories (a result of legislation like the WEEE directive). It is also the product category where most research on product life extension was done. This paper will add to the body of knowledge by presenting novel data on product lifespans, and considering the implications of this data and the resulting product life scenarios for product design. 2. Theoretical framework and definitions According to Stahel (1998: p 29), the key to product life extension “lies in the transformation of the actual linear productionfocused industrial economy into a utilization-focused service economy operating in loops”. This is a concise summary of the concept of a circular economy that is at the basis of much current design thinking. McDonough and Braungart (2002, 2013) for instance talk about “waste equals food” and “nutrient management” in their cradle-to-cradle design methodology and the Ellen MacArthur Foundation (2013) argues for “circular products” that complement a circular economy. Stahel (1998) likens the linear economy to a river and the circular economy to a lake, creating a useful metaphor of flow and loss versus retainment and preservation of value. This circular thinking underpins the EU Waste Framework Directive (2008/98/EC), which presents a waste management hierarchy of prevention, reuse, recycling, other recovery (i.e. energy recovery) and disposal, with prevention and reuse the preferred waste management approaches. For product designers this translates into the following hierarchy of corresponding design strategies (leaving out the categories of ‘other recovery’ and ‘disposal’, as these do not contribute to a circular economy). The definitions in Table 1 (based on the Waste Framework Directive) show that prevention and reuse partially overlap, as reuse also contributes to reducing the quantity of waste. Prevention and reuse can be achieved through a range of product life extension strategies, like repair, refurbishment and remanufacturing (Den Hollander and Bakker, 2012). By including product recycling it is possible to explore the full spectrum of relevant product life scenarios in a circular economy. The British Standard BS8887-2-2009 (2009) has useful definitions of repair, refurbishment and remanufacturing. Repair is defined as “returning a faulty or broken product or component back to a usable state.” Refurbishment (or reconditioning) is to “return a used product to a satisfactory working condition by rebuilding or repairing major components that are close to failure, even where there are no reported or apparent faults in those components,” and remanufacturing is to “return a used product to at least its original performance with a warranty that is equivalent or better than that of the newly manufactured product.”
Table 1 A hierarchy of design strategies for product life extension and recycling. Hierarchy
Definition (2008/98/EC)
Design strategy
1. Prevention
Measures taken to reduce the quantity of waste.
Material efficiency Longer product life
2. Reuse
Using a product or component again for the same purpose for which it was conceived.
Product repair Product refurbishment Product remanufacturing
3. Recycling
Any recovery operation by which waste materials are reprocessed into products, materials or substances whether for the original or other purposes.
Product/material recycling
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Table 2 Median lifespans of a selection of household products and change over time (delta), based on Dutch data (Wang et al., 2013). Refrigerators and laptops are subject of further scrutiny in the paper. Product category Lamps, compact fluorescent (CFL) Flat display panel TVs Vacuum cleaners Wash dryers and centrifuges Refrigerators Dishwashers Small IT and accessories Tools Small toys Mobile phones Washing machines Laptop PCs Hot water and coffee Printing and imaging equipment Microwaves Small consumer electronics and accessories
Median lifespan in years, 2000
Median lifespan in years, 2005
Delta in 5 years
7.4
7.7
þ3%
10 8.1 14.5
10 8.0 14.3
0% 1% 1%
14.2 10.7 4.5 9.8 3.8 4.8 12.1 4.3 7.0 9.0
14.0 10.5 4.4 9.6 3.7 4.6 11.7 4.1 6.4 8.2
1% 2% 2% 2% 3% 3% 3% 5% 9% 11%
10.9 9.4
9.4 7.8
15% 20%
3. Shorter product lifespans Central to product life extension is the concept of a product’s lifespan, which is defined in this paper as the period from product acquisition to discarding of the product by the final owner (Murakami et al., 2010). It is also referred to as a product’s domestic service lifespan. The period includes any repair, refurbishment or remanufacturing, as well as periods of storage when the product is no longer in use (also called ‘dead storage’ or ‘hibernation’). Reliable data on product lifespans is hard to find. In 2003, Van Nes complained such data was “rarely available from practice” (Nes, 2003, p. 24). In recent years increasingly accurate data is becoming available, for instance Murakami et al. (2010) for consumer durables and cars in Japan, and Wang et al. (2013) for Dutch electric and electronic products. The research of Wang et al. was used to derive Table 2. It shows that in the Netherlands between 2000 and 2005, the lifespan of most domestic appliances and consumer electronics has been in decline, with CFL lamps the only exception. The product lifespan data was obtained from two consumer surveys conducted in 2007 and 2009 in the Netherlands (Hendriksen, 2007, 2009). Each survey collected data from over 90 different product categories, focussing on current product stock (how long in use, use frequency), as well as product acquisition, dead storage, and disposal, in almost 6000 households. Face-to-face visits were conducted to quality-check and validate the responses. The results were further verified by comparison with documented end-of-life streams of Dutch recycling facilities. The lifespan distribution over the years was determined using a Weibull statistical distribution function, and multiple regression analysis was performed to find the most plausible time-varying parameters. This made it possible to determine the median lifespans from 2000 to 2005 (Table 2). For brevity, only a selection of the surveyed product categories is shown here. There are many possible reasons for the observed trend of decreasing product lifespans. In some product categories a shorter product lifespan benefits manufacturers directly and is therefore purposely built into the product’s design, so-called ‘planned obsolescence’. In others, advances in technology or changes in legislation might prematurely render a product obsolete. Also, markets can force manufacturers to change their
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C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16
products in order to keep up with the competition and with customer expectations (Bartels et al., 2012), thus adding to the business rationale for an overall shortening of product lifespans. Finally, the period 2000e2005 was an economic ‘boom’ period in the Netherlands. It is not unthinkable that product lifespans will increase in the current period of economic recession. 4. Determining the optimal product lifespan: methodology The question is to what extent decreasing product lifespans are problematic from a sustainability perspective. According to Allwood et al. (2011) and Nes and Cramer (2006), products with high use energy compared to embedded energy should be replaced frequently, provided a significantly more energy efficient alternative is available. Refrigerators, for instance, are always ‘on’ and some researchers have calculated that early replacement can be an eco-effective strategy (Kim et al., 2006). The trend of decreasing fridge lifespans might thus be a positive development. Laptops on the other hand have a high material density, a relatively short lifespan and low energy consumption. Early replacement will probably not be eco-effective, and decreasing laptop lifespans will therefore be a negative development (Prakash et al., 2012). This research set out to test these assumptions. The optimal product lifespan is the point in time where the environmental impacts that arise from using a product equal the embedded impacts of a (more energy efficient) replacement product. The optimal lifespans of fridges and laptops were calculated using a life cycle optimization model based on Kim et al. (2003, 2006). This model combines life cycle assessment and dynamic programming to analyse the impacts of replacing old, inefficient products with new ones. The inputs to the model consist of life cycle inventory data describing the materials production and manufacturing, distribution and use of the refrigerator and laptop as functions of time and product age. The changing environmental performance of refrigerators and laptops between 1980 (1990 for laptops) and 2020 was modelled, leading to an indication of optimal replacement times. This entailed the following steps: 4.1. Electricity consumption over time National statistics data from the UK and the USA were used to map the decrease in the average electricity consumption of both fridges and laptops over time. Refrigerator data was available from 1980 to 2010, laptop data from 1990 to 2010. The trend in electricity consumption between 2010 and 2020 was predicted with an exponential function (best-fit curve). 4.2. Life cycle assessment A fast track life cycle assessment (Vogtländer, 2012) was used to calculate the life cycle impact of laptops and fridges. The environmental impact data was obtained from the recently updated Idemat database (2012). The ReCiPe indicator was used, which is a composite, damage-oriented indicator that includes the impact categories of human health, ecosystem diversity and resource availability (Goedkoop et al., 2013). The score of ReCiPe is expressed in Points or Pt with higher points denoting a higher overall environmental impact. In calculating the impact score, material production and processing, transport and the use of the products were included. This led to single-year environmental profiles expressed in Pt, that were subsequently modelled as functions of product age and model year. The end-of-life phase was excluded because previous studies have shown that for fridges and laptops the environmental impacts of this phase are small compared to their production and use (Kim et al., 2006; Prakash et al., 2012).
4.3. Dynamic modelling The lifespan modelling starts from a baseline scenario, which is compared with a range of replacement scenarios. In the baseline scenario a product is used until it reaches its median lifespan of yav years. In the replacement scenarios the product is used for a certain number of years yR , and a new product is purchased for the remaining years of yav yR . For example, the baseline year for the refrigerator scenario is 1980. In 1980, the median lifespan of a fridge was 20 years (Huisman et al., 2012). In the baseline scenario, therefore, the fridge lifespan is 20 years. The replacement scenarios are: 1) use the refrigerator sold in 1980 for 1 year, and buy a new refrigerator in 1981, and use this for 19 years; 2) use the refrigerator sold in 1980 for 2 years, and buy a new refrigerator in 1982, and use this for 18 years, .; 19) use the refrigerator sold in 1980 for 19 years, and buy a new refrigerator in 1999, and use it for 1 year. It is then possible to identify the moment of lowest environmental impact by comparing the baseline scenario with the 19 replacement scenarios. The optimal lifespan (Toptimal) can then be concluded from (Kim et al., 2006) with E representing the environmental impact score in the baseline (Ebaseline) or replacement scenario (Ereplace):
Toptimal ¼
yav if Ebaseline < Ereplace ðxÞ; cx ¼ 1; .ðyav 1Þ xoptimal if Ebaseline > Ereplace ðxÞ; cx ¼ 1; .ðyav 1Þ (1)
and
n o Ereplace xoptimal ¼ min Ereplace ðxÞ ;
cx ¼ 1; .; ðyav 1Þ (2)
where minfEreplace ðxÞg is the replacement scenario, and the lowest environmental impact score is obtained in year xoptimal. In order to find the optimal level, all the environmental impacts from Ereplace ð1Þ to Ereplace ðyav 1Þ are calculated and compared, and the year with the minimum score is identified as the optimal replacement year. From Eqs. (1) and (2) follows that if the environmental impact of the baseline scenario is lower than any of the replacement scenarios, the optimal lifespan is the median lifespan (in the case of the fridge, 20 years). This suggests that replacement of the product will introduce an extra environmental burden, which is not preferable. By contrast, if the lowest environmental impact appears in one of the replacement scenarios, this supports the early replacement of the product. 5. Case studies: refrigerator and laptop Following the steps in Section 4, the results of the life cycle optimization modelling are shown for a domestic refrigeratore freezer and a laptop. 5.1. Electricity consumption over time A domestic refrigeratorefreezer (in this paper referred to as ‘refrigerator’) was used for the case study, as this is widely in use in households. The average electricity consumption in kWh/yr per unit of refrigeratorefreezer between 1990 and 2011 in the UK was used (National Statistics UK, 2012). Due to a lack of UK data for the period 1980e1990, the historical figures of refrigerator electricity consumption in the US were used to deduce UK data (AHAM, 2003; Horie, 2004). For laptops, use was made of the average electricity consumption between 1990 and 2011 in the UK (National Statistics UK, 2012). In both cases, the trend in electricity consumption from 2012 to 2020 was predicted with an exponential function.
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Table 3 Overview of environmental impact in points (Pt) and percentages of a refrigerator in 1980 and 2010, and of a laptop in 1990 and 2010. In both cases the impact of the (one year) use phase has declined, which shows how energy efficiency has improved. Fridge (in Pt)
Production Transport Use phase (one year)
Fig. 1. Average electricity consumption per unit of refrigeratorefreezer (1980e2020).
Figs. 1 and 2 show the considerable advances in energy efficiency in both cases. Refrigerators have on average become approximately 60% more efficient since 1980, and laptops 50% since 1990. The improvement in energy efficiency has not been a smooth process. There are for instance ‘flat’ periods when the efficiency did not improve substantially followed by sudden jumps in efficiency. The most likely reason for the sudden efficiency improvements is the introduction of new energy efficiency standards, although inconsistency of measurement data cannot be ruled out as a possible explanation. 5.2. Life cycle assessment The environmental impact per unit of refrigerator was calculated for each year between 1980 and 2020, and likewise for laptops between 1990 and 2020. The material composition data for both products was obtained from a combination of sources (Horie, 2004; Oguchi et al., 2011). According to Horie (2004), material compositions and weight of mid-sized refrigeratorefreezers have remained more or less constant over the past 36 years. To simplify the calculations it was assumed that the material compositions of both fridge and laptop stay constant over time. Also, the deterioration of the energy performance over a fridge’ lifetime (for instance because of leaking seals) or a laptop’s lifetime (battery degradation) was not taken into account, although it is acknowledged that this can in some cases have a notable influence on the product’s energy performance over time (Table 3).
Laptop (in Pt)
1980
2010
1990
2010
34 (44%) 1.5 (02%) 42.1 (54%)
34 (66%) 1.5 (03%) 15.7 (31%)
6.7 (68%) 0.07 (01%) 3.1 (31%)
6.7 (78%) 0.07 (01%) 1.9 (21%)
The laptop’s median lifespan in 1990 was 7 years (Huisman et al., 2012). The results of the LCA and the dynamic modelling are presented in graphical form, see Figs. 3 and 4. Fig. 3 shows that a refrigeratorefreezer sold in 1980 should have been replaced after 8 years. The new model, bought in 1988, should have been used for 13 years; after which the next replacement would have had to take place in 2001, with the new refrigerator to be used for 10 years; then in 2011 the old model would have had to be replaced for a new one which can last for 20 years (and will need to be replaced in 2031). Following the same approach as for the refrigeratorefreezers, Fig. 4 shows that the baseline scenario for laptops (replacement every 7 years) is in all cases the optimal replacement scenario. Had the median lifespan of a laptop been 10 years in the baseline scenario, the optimal lifespan in 2011 would have been 10 years. Prakash et al. (2012) calculated even longer replacement times for laptops, ranging from 33 to 89 years. 6. Findings from the case studies
The fridge scenario’s baseline year is 1980. In this year the median lifespan was 20 years. For the laptop, the baseline year is 1990, which is when laptop computers started to be widely used.
While the energy consumption of laptops and refrigerators has decreased substantially over time, so has their lifespan. The overall effect is negative, for it results in premature replacements where the environmental impacts of production have not been fully offset by the energy efficiency improvements in newer models. The results suggest that fridgeefreezers and laptops bought in 2011 should be used for longer than their current median lifespans of approximately 14 and 4 years respectively. This research shows that for fridges and laptops, product lifespan is the determining factor for the overall environmental impacts. In both cases, product life extension is the preferred strategy. Similar findings were reported by Bakker et al. (2012) for LED TVs, Yu et al. (2010) for mobile phones, and Prakash et al. (2012) and Deng et al. (2011) for laptop computers. Given the current trends towards decreasing energy consumption, increasing material intensity, and declining product lifespans (Table 2), one can wonder whether these findings might be valid for more electric and electronic devices. This would require further
Fig. 2. Average electricity consumption per unit of laptop computer (1990e2020).
Fig. 3. Optimal lifespans for a refrigeratorefreezer based on ReCiPe (Pt.) as a measure of environmental impacts.
5.3. Dynamic modelling
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C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16 Table 4 Design strategies for product life extension and product recycling applied to fridges and laptops. Hierarchy
Fridge
Laptop
Given the trend towards bigger Material efficiency is already important in laptop design fridges, this might be a useful (reduction of weight, ‘thin’ approach. designs) In spite of (or because of?) To make a fridge last for 20 Longer the emotional and aesthetic years, functional as well as product appeal of laptops, early emotional and aesthetic life durability should be addressed. replacement is the norm. Reparability Self-repair and serviced repair Self-repair and serviced should be easy e but are often repair should be easy e this expensive when outside of is however not so for many warranty. laptops (trend towards unibody designs with sealed batteries) Refurbishment Possibilities for refurbishing and Refurbishment (i.e. upgrading of components upgrading might be explored (for instance mid-life efficiency such as RAM, hard drive) can be done, but is check and seal replacement) sometimes discouraged by manufacturers. Remanufacture Not likely, given 20-year Small-scale remanufacturing lifespan? is done, can be much improved (also through better design). Collection from consumers is a challenge. Recycling Most fridges are recycled at the Can be improved, also through design for recycling. moment. There might be Collection from consumers options for improvement is a challenge. through design for recycling. Material efficiency
Fig. 4. Optimal replacement time for laptop computers based on ReCiPe (Pt.).
research. Such research would have to take the limitations of the current study into account: a full LCA would need to be done, including the end-of-life of the products, and the dynamic modelling would have to take into account energy deterioration of the products over time. Also, several future scenarios should be modelled (instead of only one ‘best fit’ curve), that show different possible developments in the energy efficiency of the products. A sensitivity analysis should be performed to determine the robustness of the results. For these reasons, the results of the current life cycle optimization modelling only give an indication of the optimal replacement times. For both products, however, the results clearly point towards product life extension. 7. Design strategies for product life extension The analysis outlined in the previous sections is an example of how design researchers could start mapping product life scenarios. It is possible that the optimal product life requires a shortening of the product lifespan, however, in the case of the fridge and the laptop, product life extension was found to be the most ecoefficient scenario. Using the theoretical framework in Table 1, a range of possible design strategies for product life extension and product recycling was mapped (Table 4). Refrigeratorefreezers are low-interest products. In the Netherlands, 57% of the 6000 households surveyed keep their fridges until they break down (Hendriksen, 2007). Fridges have relatively mature technology, meaning not a lot of breakthrough technological innovation is happening in fridge engineering. Extending a fridge’s life to 20 years therefore means making it reliable and (emotionally, aesthetically and functionally) durable, and ensuring its energy efficiency doesn’t deteriorate over its lifetime due to ageing insulation foam and leaking door seals. Allwood and Cullen (2013, p. 240) suggest that it could be possible to “sell a fridge with a life-time guarantee, if we identified the likely causes of failure and designed into the original product a simple means to repair them.” Also, given the relatively large amount of materials used, the degree of fridge recycling could probably be intensified. Design for recycling might be useful here. In contrast to fridges, laptops are high-interest products subject to dynamic market conditions. The need to compete with other mobile devices drives technological development and design innovation. This creates a volatile market where rapid replacement cycles are the norm. Modular design is often suggested as a way to increase a laptop’s useful life without closing off possibilities for innovation (for instance Prakash et al., 2012) and industrial designers have developed interesting concepts (Heimbuch, 2012; Lee, 2013). Modular designs are however challenging to realize in practice with technology in such a flux. Alternative approaches
include design for (more efficient) remanufacturing and eventual recycling. One of the challenges is the collection of obsolete laptops from consumers, and here design might also make a meaningful contribution. It follows from this description that for refrigerators and laptops different product life scenarios make sense. Fridges are mature, almost sedate, products whose basic technology and layout hasn’t changed very much over the decades. Laptops, in contrast, are subject to rapid innovation cycles that inspire much excitement. Making a fridge last for 20 years is not too great a challenge, but making a laptop last for 7 years or more is currently regarded as economical suicide, which is why for laptops, recycling and remanufacturing are more likely strategies than longer product life. For most products categories, tailored product life extension approaches will be needed depending on product characteristics such as lifespan, technological maturity and resource intensity, and business constraints such as market competitiveness and regulations. All design strategies for product life extension and product recycling could be explored in more detail, and from different practical and theoretical perspectives. For refrigerators, designing for a longer product life means taking into account the functional as well as the emotional and aesthetic durability. Designers may ask, for instance, how a fridge can maintain a hygienic look and feel throughout its life, and how to ensure the fridge and its interior components wear in an acceptable (or even attractive) way. Authors like Chapman (2005) and Nes (2003) have extensively explored emotional durability and product attachment. Moving away from theories that address product-user interactions, designers could ask what constitutes a ‘normal’ lifespan for products such as fridges and laptops and why and how people accept and accommodate ever-shorter product lifespans into their everyday lives. This may provide different insights and starting points for addressing product life extension. Contributions to such questions
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are made in sociology, through for instance practice theory (Shove et al., 2012). For laptops, remanufacturing was pinpointed as a promising product life extension strategy. While remanufacturing is often understood as ‘patching up’ an old product, this is in reality an underestimation of what it could potentially offer. Gehin et al. (2008) stress that remanufacture is a dynamic and innovative strategy, as “remanufactured components can be mixed with innovative parts, making the remanufactured product more attractive than the discarded one if this one was new.” (p 571). Remanufacturing isn’t only about the (re)design of the product. The creation of viable business models and (reverse) supply chains is equally important, for without a feasible business model remanufacturing is unlikely to happen. What this brief overview shows is that product life extension and product recycling are not ‘simple’ strategies, but require and deserve much more in-depth design research. 8. Implications for design research In order to design products that fit within a circular economy (“circular products”), it is important to first of all understand how to optimize product lifespan from a sustainability perspective without compromising the product’s economic viability. The main challenge for design research therefore is to determine when to apply which product life extension strategy. The waste management hierarchy is of limited guidance, as the previous section showed. Different products require different hierarchies of product life extension and product recycling strategies, based on product characteristics (i.e. lifespan, technological maturity, resource intensity) and business constraints (i.e. market dynamics, legislation). As products and markets change dynamically, these hierarchies are not set in stone e monitoring product life and trends in resource efficiency should be an on-going process. Establishing the optimal product life scenario is the first item of a future research agenda for products in a circular economy, and the approach explored in this paper may be a useful starting point. Once the appropriate scenarios have been determined, the next challenge is to find business models that support these. A decision to go for product refurbishment, for instance, could result in the development of a lease concept where the company retains ownership of the product (Vodafone and KPN for instance introduced lease phones). Developing such business models successfully is probably beyond the expertise of product designers, but design research could play a useful role in understanding the factors that influence consumer acceptance of new ownership models and other product service systems (Catulli, 2011; Mont et al., 2006). These strategic decisions (choice of product life scenarios; choice of business model) will have considerable impact on the design of a product. Designing a product that is to be leased and refurbished several times during its life, for instance, will require designers to obtain intimate knowledge of how the product and its parts wear and tear, and of how to decide which parts should last, and which should be replaced, and when. Functional, emotional, aesthetic and economic considerations will all play a role. In the past decades a number of methods and tools were developed to assist design for remanufacturing, design for recycling, and design for end-of-life. Overviews are given in for instance Rose (2000) and Allwood et al. (2011). Most of these tools and guidelines are highly function-oriented, focussing for instance on constructions that are easy to disassemble, but they have little consideration for the emotional, aesthetic and economic consequences of design decisions. It may be worthwhile to consider developing tools that are less geared towards engineers and more towards product designers. On a very practical level, designers will need to learn about
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the different end-of-life treatment and recycling processes that are available, and about the advantages and drawbacks of the application of recycled materials in products. Lastly, it is important that design research tries to answer the question whether the new circular business models and “circular products” in the long run deliver solutions with a lower environmental impact. Leasing and refurbishing or remanufacturing products, may require a lot of extra service kilometers (for instance for reverse logistics) and new parts will need to be produced. A scenario-based life cycle assessment can help determine whether the benefits of a circular business model outweigh the negatives. Finding best practice case studies may be useful to provide models of ‘what works’, and of how environmental impacts can be minimized. 9. Conclusion This research sets out to determine the optimal product lifespans of refrigerators and laptops, with the aim to understand whether product life extension and/or product recycling is the preferred strategy from a sustainability perspective, and to explore what options there are to address these through design. The inquiry was triggered by recent research that demonstrates how product lifespans in the Netherlands have declined (sometimes by more than 10%) between 2000 and 2005, causing unsustainable throughputs of materials. The current refrigerator lifespan is 14 years in the Netherlands, and a laptop’s lifespan is approximately 4 years. After comparing the trends in electricity consumption of refrigerators and laptops against environmental impact data (through life cycle assessment), it was found that whilst the energy efficiency of both refrigerators and laptops has increased over time, the declining lifespans cause a negative overall effect e meaning that product life extension, with newly bought (energy efficient) refrigerators lasting up to 20 years and laptops at least 7 years, is the preferred approach. The conclusion that refrigerator lifespan should be prolonged runs counter to popular belief; here the paper makes an original contribution to research on product life. It could be hypothesized that these findings may be valid for other electrical and electronic products, but this would require further study. Design knowledge on product life extension strategies (longer product life, reparability, refurbishment and remanufacturing) and product recycling is currently underdeveloped. These strategies need to be tailored to the specific product at hand with the generic waste management hierarchy (prevention, reuse, recycling) providing only limited guidance. Laptops for instance need to compete in highly dynamic markets, which makes remanufacturing and recycling more feasible strategies than longer product life, turning the waste management hierarchy “upside down” in this particular case. Understanding which product life extension or recycling strategies should be applied when is one of the main challenges for design research in this field. The consequences of such strategies for new business development need to be mapped, and the current “design for X” tools and methods should be revitalized. The paper has provided a first overview of this new research field. Our research is of direct relevance for design practice. Industry, faced with increasing resource costs, increasing competition from low-wage countries and progressive environmental legislation, is already exploring product recycling and other circular business models and will be on the lookout for designers with relevant knowledge and expertise related to products that “go round”. Acknowledgements The authors gratefully acknowledge the support of the Innovation-Oriented Research Program ‘Integrated Product
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Creation and Realization (IOP IPCR)’ of the Netherlands Ministry of Economic Affairs, Agriculture and Innovation. References Association of Home Appliance Manufacturers (AHAM), 2003. 2003 Home Appliance Industry Fact Book. AHAM, Washington DC, USA. Allwood, Julian M., Ashby, Michael F., Gutowski, Timothy G., Worrell, Ernst, 2011. Material efficiency: a white paper. Resour. Conserv. Recycl. 55, 362e381. Allwood, Julian, Cullen, Jonathan, 2013. Sustainable Materials e With Both Eyes Open: Future Buildings, Vehicles, Products and Equipment e Made Efficiently and Made with Less New Material. UIT Cambridge, UK. Bakker, C.A., Ingenegeren, R.A.C., Devoldere, T., Tempelman, E., Huisman, J., Peck, D.P., 2012. Rethinking eco-design priorities; the case of the Econova television. In: Proceedings of Electronics Goes Green (EGG), September 2012, Berlin. Bartels, B., Ermel, U., Pecht, M., Sandborn, P., 2012. Strategies to the Prediction, Mitigation and Management of Product Obsolescence. John Wiley & Sons, Inc., Hoboken, NJ, USA. British Standard BS8887-2-2009, 2009. Design for Manufacture, Assembly, Disassembly and End-of-life processing (MADE). Terms and Definitions. British Standards Institution. Catulli, Maurizio, 2011. What uncertainty? Further insight into why consumers might be distrustful of product service systems. J. Manuf. Technol. Manage. 23 (6), 780e793. Chapman, Jonathan, 2005. Emotionally Durable Design: Objects, Experiences & Empathy. Earthscan, London. Den Hollander, Marcel, Bakker, Conny, 2012. A business model framework for product life extension. In: Proceedings of Sustainable Innovation 2012, Resource Efficiency, Innovation and Lifestyles, 29e30 October 2012. Alanus University, Bonn, pp. 110e118. Deng, Liqiu, Babbitt, Callie W., Williams, Eric D., 2011. Economic-balance hybrid LCA extended with uncertainty analysis: case study of a laptop computer. J. Clean. Prod. 19, 1198e1206. Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain directives. Off. J. Eur. Union L 312, 2008, 3e30. Ellen MacArthur Foundation, 2013. Towards the Circular Economy: Economic and Business Rationale for an Accelerated Transition (Report). Ellen MacArthur Foundation, UK. Erdmann, Lorenz, Graedel, Thomas E., 2011. Criticality of non-fuel minerals: a review of major approaches and analyses. Environ. Sci. Technol. 45, 7620e7630. Gehin, A., Zwolinski, P., Brissaud, D., 2008. A tool to implement sustainable end-oflife strategies in the product development phase. J. Clean. Prod. 16, 566e576. Goedkoop, Mark, Heijungs, Reinout, Huijbregts, Mark, de Schryver, An, Struijs, Jaap, van Zelm, Rosalie, 2013. ReCiPe 2008: A Life Cycle Impact Assessment Method which Comprises Harmonized Category Indicators at the Midpoint and the Endpoint Level (Report for the Ministry of Infrastructure and the Environment, Report 1: Characterization), first ed. (revised). The Hague, Netherlands. Grantham, Jeremy, 2012. Living on a Finite Planet (Where No-one Likes to Hear Bad News). Paper for University of Cambridge Programme for Sustainability Leadership. Hatcher, G.D., Ijomah, W.L., Windmill, J.F.C., 2011. Design for remanufacture: a literature review and further research needs. J. Clean. Prod. 19, 2004e2014. Heimbuch, Jaymi, 2012. Lifebook Design Combines All Your Gadgets Into One Modular Laptop. Treehugger. Available from: http://www.treehugger.com/ gadgets/lifebook-design-combines-all-our-gadgets-into-one-modular-laptop. html (retrieved April 2013). Hendriksen, T., 2007. Bezit, afdanking en verkrijging van witgoed, bruingoed en grijsgoed. GfK Panel Services Benelux, Dongen, the Netherlands. Hendriksen, T., 2009. Possession, Disposal and Purchasing of Discharge Lamps in Dutch Households. GfK Panel Services Benelux, Dongen, the Netherlands.
Horie, Y.A., 2004. Life Cycle Optimization of Household RefrigeratoreFreezer Replacement (Master’s thesis). University of Michigan, Ann Arbor. Huisman, J., van der Maesen, M., Eijsbouts, R.J.J., Wang, F., Baldé, C.P., Wielenga, C.A., 2012. The Dutch WEEE Flows. United Nations University, Bonn, Germany. ISP e SCYCLE. Idemat, 2012. Idemat Online Database, TU Delft. Available from: http://www. ecocostsvalue.com/EVR/model/theory/subject/5-data.html. Kim, Hyung Chul., Keoleian, Gregory A., Grande, Darby E., Bean, James C., 2003. Life cycle optimization of automobile replacement: model and application. Environ. Sci. Technol. 37, 5407e5413. Kim, H.C., Keoleian, Gregory A., Horie, Yuhta A., 2006. Optimal household refrigerator replacement policy for life cycle energy, greenhouse gas emissions, and cost. Energy Policy 34, 2310e2323. Lee, René, 2013. Obento Note by Woo-Ram Lee. Available from: http://renelee.net/ obentonote/ (retrieved April 2013). McDonough, William, Braungart, Michael, 2002. Cradle to Cradle: Remaking the Way We Make Things. North Point Press, New York. McDonough, William, Braungart, Michael, 2013. The Upcycle: Beyond Sustainability e Designing for Abundance. North Point Press, New York. Mont, Oksana, Dalhammar, Carl, Jacobsson, Nicholas, 2006. A new business model for baby prams based on leasing and product remanufacturing. J. Clean. Prod. 14, 1509e1518. Murakami, Shinsuke, Oguchi, Masahiro, Tasaki, Tomohiro, Daigo, Ichiro, Hashimoto, Seiji, 2010. Lifespan of commodities, part 1. The creation of a database and its review. J. Ind. Ecol. 14 (4), 598e612. National Statistics UK, 2012. Energy Consumption in the UK, Domestic Data Tables (2012 Update). National Statistics UK. Retrieved from: http://www.decc. gov.uk/en/content/cms/statistics/publications/ecuk/ecuk.aspx. Nes, Nicole van, 2003. Replacement of Durables: Influencing Product Lifetime Through Product Design (PhD thesis). Erasmus University Rotterdam, the Netherlands. Nes, Nicole van, Cramer, Jacqueline, 2006. Product lifetime optimization: a challenging strategy towards more sustainable consumption patterns. J. Clean. Prod. 14, 1307e1318. Oguchi, Masahiro, Murakam, Shinsuke, Sakanakura, Hirofumi, Kida, Akiko, Kameya, Takashi, 2011. A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources. Waste Manage. 31 (9e10), 2150e2160. Prakash, Siddharth, Liu, Ran, Schischke, Karsten, Stobbe, Lutz, 2012. Timely Replacement of a Notebook Under Consideration of Environmental Aspects. Report for the Federal Environment Agency, Germany. Report no. (UBA-FB) 001666/E. Rose, Catherine Michelle, 2000. Design for Environment: A Method for Formulating Product End-of-life Strategies (Dissertation). Stanford University, Department of Mechanical Engineering. Rosenau-Tornow, Dirk, Buchholz, Peter, Riemann, Axel, Wagner, Markus, 2009. Assessing the long-term supply risks for mineral raw materials e a combined evaluation of past and future trends. Resour. Policy 34, 161e175. Shove, Elizabeth, Pantzar, Mika, Watson, Matt, 2012. The Dynamics of Social Practice: Everyday Life and How it Changes. Sage Publications Ltd., UK. Stahel, Walter R., 1998. Product durability and re-take after use. In: Kostecki, Michael (Ed.), The Durable Use of Consumer Products. Kluwer Academic Publishers, Great Britain, pp. 29e40. Vogtländer, J.G., 2012. A Practical Guide to LCA, for Students, Designers and Business Managers: Cradle-to-Grave and Cradle-to-Cradle, second ed. VSSD Publishers, Delft, the Netherlands. Wang, F., Huisman, J., Stevels, A., Baldé, C.P., 2013. Enhancing E-waste estimates: improving data quality by multivariate inputeoutput analysis. Waste Manage 33 (11), 2397e2407. Yu, Jinglei, Williams, Eric, Ju, Meiting, 2010. Analysis of material and energy consumption of mobile phones in China. Energy Policy 38, 4135e4141.
Contents lists available at ScienceDirect
Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro
Products that go round: exploring product life extension through design Conny Bakker a, *, Feng Wang a, b, Jaco Huisman a, b, Marcel den Hollander a a b
Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628 CE Delft, The Netherlands United Nations University, Institute for Sustainability and Peace, Hermann-Ehlers-Strasse 10, Bonn 53113, Germany
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 June 2013 Received in revised form 5 November 2013 Accepted 8 January 2014 Available online 21 January 2014
Product lifespans of electric and electronic products are in decline, with detrimental environmental consequences. This research maps the environmental impacts of refrigerators and laptops against their increasing energy efficiency over time, and finds that product life extension is the preferred strategy in both cases: refrigerators bought in 2011 should be used for 20 years instead of 14, and laptops for at least 7 years instead of 4. Designers however lack expertise to design for product life extension (through longer product life, refurbishment, remanufacturing) and product recycling. The paper explores a range of product life extension strategies and concludes that tailored approaches are needed. One of the main research challenges is to determine when to apply which product life extension strategy. Ó 2014 Elsevier Ltd. All rights reserved.
Keywords: Sustainable product design Eco design Circular economy Product life extension Life cycle optimization
1. Introduction Product lifespans in industrialized societies have steadily declined over the past decade, leading to an increased throughput of materials in society and more waste (Huisman et al., 2012). As a result, the environmental impacts of materials production and processing are rapidly becoming critical (Allwood et al., 2011). For product designers, three strategies for addressing these problems are material efficiency, product life extension and product recycling (ibid.). Material efficiency, designing products with less material, is dealt with in most design projects as it brings down costs and is considered good business practice. Product life extension (through longer product life, refurbishment and remanufacturing) and product recycling are however not routinely dealt with in most design practices (Hatcher et al., 2011). Hatcher et al. (2011), in their comprehensive review of design for remanufacture literature, conclude that although the relevance of design for remanufacture (DfRem) research has increased in recent years, this does not yet translate into an increase in OEM remanufacturing activity, nor in design for remanufacture efforts by designers and engineers.
* Corresponding author. Tel.: þ31 15 278 9822/þ31 6 2447 2323. E-mail address: [email protected] (C. Bakker). 0959-6526/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jclepro.2014.01.028
Given the rapidly changing market conditions this might however change in the near future. For instance, the prices of most raw materials have increased significantly due to growing demand from emerging economies (Rosenau-Tornow et al., 2009). For several materials supply disruptions were reported, causing concerns about long-term supply security (Erdmann and Graedel, 2011). A few forward-looking thinkers even claim a paradigm shift has occurred with increasing competition and rising prices of everscarcer resources now being the new norm (Grantham, 2012). In such volatile markets, retaining value through careful management of a product’s end-of-life makes sense. Recent developments in legislation and regulation such as (ongoing) revisions of the WEEE and EcoDesign directives in the EU and the EPEAT (Electronic Product Environmental Assessment Tool) in the USA stress the importance of design for end-of-life, product longevity and life cycle extension. The aim of this paper is to explore how product design can more proactively address product life extension (through longer product life, refurbishment and remanufacturing) and product recycling. In order to do so, it is necessary to first develop an understanding of the extent to which product lifespans have been declining, and to assess whether these shorter lifespans are indeed causing overall negative environmental impacts. This assessment will provide starting points for the development of product life scenarios in Section 7. Based on these, a research agenda for the further
C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16
development of product life extension and recycling is outlined in Section 8. The focus in this paper is on energy using products as this is one of the best-documented product categories (a result of legislation like the WEEE directive). It is also the product category where most research on product life extension was done. This paper will add to the body of knowledge by presenting novel data on product lifespans, and considering the implications of this data and the resulting product life scenarios for product design. 2. Theoretical framework and definitions According to Stahel (1998: p 29), the key to product life extension “lies in the transformation of the actual linear productionfocused industrial economy into a utilization-focused service economy operating in loops”. This is a concise summary of the concept of a circular economy that is at the basis of much current design thinking. McDonough and Braungart (2002, 2013) for instance talk about “waste equals food” and “nutrient management” in their cradle-to-cradle design methodology and the Ellen MacArthur Foundation (2013) argues for “circular products” that complement a circular economy. Stahel (1998) likens the linear economy to a river and the circular economy to a lake, creating a useful metaphor of flow and loss versus retainment and preservation of value. This circular thinking underpins the EU Waste Framework Directive (2008/98/EC), which presents a waste management hierarchy of prevention, reuse, recycling, other recovery (i.e. energy recovery) and disposal, with prevention and reuse the preferred waste management approaches. For product designers this translates into the following hierarchy of corresponding design strategies (leaving out the categories of ‘other recovery’ and ‘disposal’, as these do not contribute to a circular economy). The definitions in Table 1 (based on the Waste Framework Directive) show that prevention and reuse partially overlap, as reuse also contributes to reducing the quantity of waste. Prevention and reuse can be achieved through a range of product life extension strategies, like repair, refurbishment and remanufacturing (Den Hollander and Bakker, 2012). By including product recycling it is possible to explore the full spectrum of relevant product life scenarios in a circular economy. The British Standard BS8887-2-2009 (2009) has useful definitions of repair, refurbishment and remanufacturing. Repair is defined as “returning a faulty or broken product or component back to a usable state.” Refurbishment (or reconditioning) is to “return a used product to a satisfactory working condition by rebuilding or repairing major components that are close to failure, even where there are no reported or apparent faults in those components,” and remanufacturing is to “return a used product to at least its original performance with a warranty that is equivalent or better than that of the newly manufactured product.”
Table 1 A hierarchy of design strategies for product life extension and recycling. Hierarchy
Definition (2008/98/EC)
Design strategy
1. Prevention
Measures taken to reduce the quantity of waste.
Material efficiency Longer product life
2. Reuse
Using a product or component again for the same purpose for which it was conceived.
Product repair Product refurbishment Product remanufacturing
3. Recycling
Any recovery operation by which waste materials are reprocessed into products, materials or substances whether for the original or other purposes.
Product/material recycling
11
Table 2 Median lifespans of a selection of household products and change over time (delta), based on Dutch data (Wang et al., 2013). Refrigerators and laptops are subject of further scrutiny in the paper. Product category Lamps, compact fluorescent (CFL) Flat display panel TVs Vacuum cleaners Wash dryers and centrifuges Refrigerators Dishwashers Small IT and accessories Tools Small toys Mobile phones Washing machines Laptop PCs Hot water and coffee Printing and imaging equipment Microwaves Small consumer electronics and accessories
Median lifespan in years, 2000
Median lifespan in years, 2005
Delta in 5 years
7.4
7.7
þ3%
10 8.1 14.5
10 8.0 14.3
0% 1% 1%
14.2 10.7 4.5 9.8 3.8 4.8 12.1 4.3 7.0 9.0
14.0 10.5 4.4 9.6 3.7 4.6 11.7 4.1 6.4 8.2
1% 2% 2% 2% 3% 3% 3% 5% 9% 11%
10.9 9.4
9.4 7.8
15% 20%
3. Shorter product lifespans Central to product life extension is the concept of a product’s lifespan, which is defined in this paper as the period from product acquisition to discarding of the product by the final owner (Murakami et al., 2010). It is also referred to as a product’s domestic service lifespan. The period includes any repair, refurbishment or remanufacturing, as well as periods of storage when the product is no longer in use (also called ‘dead storage’ or ‘hibernation’). Reliable data on product lifespans is hard to find. In 2003, Van Nes complained such data was “rarely available from practice” (Nes, 2003, p. 24). In recent years increasingly accurate data is becoming available, for instance Murakami et al. (2010) for consumer durables and cars in Japan, and Wang et al. (2013) for Dutch electric and electronic products. The research of Wang et al. was used to derive Table 2. It shows that in the Netherlands between 2000 and 2005, the lifespan of most domestic appliances and consumer electronics has been in decline, with CFL lamps the only exception. The product lifespan data was obtained from two consumer surveys conducted in 2007 and 2009 in the Netherlands (Hendriksen, 2007, 2009). Each survey collected data from over 90 different product categories, focussing on current product stock (how long in use, use frequency), as well as product acquisition, dead storage, and disposal, in almost 6000 households. Face-to-face visits were conducted to quality-check and validate the responses. The results were further verified by comparison with documented end-of-life streams of Dutch recycling facilities. The lifespan distribution over the years was determined using a Weibull statistical distribution function, and multiple regression analysis was performed to find the most plausible time-varying parameters. This made it possible to determine the median lifespans from 2000 to 2005 (Table 2). For brevity, only a selection of the surveyed product categories is shown here. There are many possible reasons for the observed trend of decreasing product lifespans. In some product categories a shorter product lifespan benefits manufacturers directly and is therefore purposely built into the product’s design, so-called ‘planned obsolescence’. In others, advances in technology or changes in legislation might prematurely render a product obsolete. Also, markets can force manufacturers to change their
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C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16
products in order to keep up with the competition and with customer expectations (Bartels et al., 2012), thus adding to the business rationale for an overall shortening of product lifespans. Finally, the period 2000e2005 was an economic ‘boom’ period in the Netherlands. It is not unthinkable that product lifespans will increase in the current period of economic recession. 4. Determining the optimal product lifespan: methodology The question is to what extent decreasing product lifespans are problematic from a sustainability perspective. According to Allwood et al. (2011) and Nes and Cramer (2006), products with high use energy compared to embedded energy should be replaced frequently, provided a significantly more energy efficient alternative is available. Refrigerators, for instance, are always ‘on’ and some researchers have calculated that early replacement can be an eco-effective strategy (Kim et al., 2006). The trend of decreasing fridge lifespans might thus be a positive development. Laptops on the other hand have a high material density, a relatively short lifespan and low energy consumption. Early replacement will probably not be eco-effective, and decreasing laptop lifespans will therefore be a negative development (Prakash et al., 2012). This research set out to test these assumptions. The optimal product lifespan is the point in time where the environmental impacts that arise from using a product equal the embedded impacts of a (more energy efficient) replacement product. The optimal lifespans of fridges and laptops were calculated using a life cycle optimization model based on Kim et al. (2003, 2006). This model combines life cycle assessment and dynamic programming to analyse the impacts of replacing old, inefficient products with new ones. The inputs to the model consist of life cycle inventory data describing the materials production and manufacturing, distribution and use of the refrigerator and laptop as functions of time and product age. The changing environmental performance of refrigerators and laptops between 1980 (1990 for laptops) and 2020 was modelled, leading to an indication of optimal replacement times. This entailed the following steps: 4.1. Electricity consumption over time National statistics data from the UK and the USA were used to map the decrease in the average electricity consumption of both fridges and laptops over time. Refrigerator data was available from 1980 to 2010, laptop data from 1990 to 2010. The trend in electricity consumption between 2010 and 2020 was predicted with an exponential function (best-fit curve). 4.2. Life cycle assessment A fast track life cycle assessment (Vogtländer, 2012) was used to calculate the life cycle impact of laptops and fridges. The environmental impact data was obtained from the recently updated Idemat database (2012). The ReCiPe indicator was used, which is a composite, damage-oriented indicator that includes the impact categories of human health, ecosystem diversity and resource availability (Goedkoop et al., 2013). The score of ReCiPe is expressed in Points or Pt with higher points denoting a higher overall environmental impact. In calculating the impact score, material production and processing, transport and the use of the products were included. This led to single-year environmental profiles expressed in Pt, that were subsequently modelled as functions of product age and model year. The end-of-life phase was excluded because previous studies have shown that for fridges and laptops the environmental impacts of this phase are small compared to their production and use (Kim et al., 2006; Prakash et al., 2012).
4.3. Dynamic modelling The lifespan modelling starts from a baseline scenario, which is compared with a range of replacement scenarios. In the baseline scenario a product is used until it reaches its median lifespan of yav years. In the replacement scenarios the product is used for a certain number of years yR , and a new product is purchased for the remaining years of yav yR . For example, the baseline year for the refrigerator scenario is 1980. In 1980, the median lifespan of a fridge was 20 years (Huisman et al., 2012). In the baseline scenario, therefore, the fridge lifespan is 20 years. The replacement scenarios are: 1) use the refrigerator sold in 1980 for 1 year, and buy a new refrigerator in 1981, and use this for 19 years; 2) use the refrigerator sold in 1980 for 2 years, and buy a new refrigerator in 1982, and use this for 18 years, .; 19) use the refrigerator sold in 1980 for 19 years, and buy a new refrigerator in 1999, and use it for 1 year. It is then possible to identify the moment of lowest environmental impact by comparing the baseline scenario with the 19 replacement scenarios. The optimal lifespan (Toptimal) can then be concluded from (Kim et al., 2006) with E representing the environmental impact score in the baseline (Ebaseline) or replacement scenario (Ereplace):
Toptimal ¼
yav if Ebaseline < Ereplace ðxÞ; cx ¼ 1; .ðyav 1Þ xoptimal if Ebaseline > Ereplace ðxÞ; cx ¼ 1; .ðyav 1Þ (1)
and
n o Ereplace xoptimal ¼ min Ereplace ðxÞ ;
cx ¼ 1; .; ðyav 1Þ (2)
where minfEreplace ðxÞg is the replacement scenario, and the lowest environmental impact score is obtained in year xoptimal. In order to find the optimal level, all the environmental impacts from Ereplace ð1Þ to Ereplace ðyav 1Þ are calculated and compared, and the year with the minimum score is identified as the optimal replacement year. From Eqs. (1) and (2) follows that if the environmental impact of the baseline scenario is lower than any of the replacement scenarios, the optimal lifespan is the median lifespan (in the case of the fridge, 20 years). This suggests that replacement of the product will introduce an extra environmental burden, which is not preferable. By contrast, if the lowest environmental impact appears in one of the replacement scenarios, this supports the early replacement of the product. 5. Case studies: refrigerator and laptop Following the steps in Section 4, the results of the life cycle optimization modelling are shown for a domestic refrigeratore freezer and a laptop. 5.1. Electricity consumption over time A domestic refrigeratorefreezer (in this paper referred to as ‘refrigerator’) was used for the case study, as this is widely in use in households. The average electricity consumption in kWh/yr per unit of refrigeratorefreezer between 1990 and 2011 in the UK was used (National Statistics UK, 2012). Due to a lack of UK data for the period 1980e1990, the historical figures of refrigerator electricity consumption in the US were used to deduce UK data (AHAM, 2003; Horie, 2004). For laptops, use was made of the average electricity consumption between 1990 and 2011 in the UK (National Statistics UK, 2012). In both cases, the trend in electricity consumption from 2012 to 2020 was predicted with an exponential function.
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13
Table 3 Overview of environmental impact in points (Pt) and percentages of a refrigerator in 1980 and 2010, and of a laptop in 1990 and 2010. In both cases the impact of the (one year) use phase has declined, which shows how energy efficiency has improved. Fridge (in Pt)
Production Transport Use phase (one year)
Fig. 1. Average electricity consumption per unit of refrigeratorefreezer (1980e2020).
Figs. 1 and 2 show the considerable advances in energy efficiency in both cases. Refrigerators have on average become approximately 60% more efficient since 1980, and laptops 50% since 1990. The improvement in energy efficiency has not been a smooth process. There are for instance ‘flat’ periods when the efficiency did not improve substantially followed by sudden jumps in efficiency. The most likely reason for the sudden efficiency improvements is the introduction of new energy efficiency standards, although inconsistency of measurement data cannot be ruled out as a possible explanation. 5.2. Life cycle assessment The environmental impact per unit of refrigerator was calculated for each year between 1980 and 2020, and likewise for laptops between 1990 and 2020. The material composition data for both products was obtained from a combination of sources (Horie, 2004; Oguchi et al., 2011). According to Horie (2004), material compositions and weight of mid-sized refrigeratorefreezers have remained more or less constant over the past 36 years. To simplify the calculations it was assumed that the material compositions of both fridge and laptop stay constant over time. Also, the deterioration of the energy performance over a fridge’ lifetime (for instance because of leaking seals) or a laptop’s lifetime (battery degradation) was not taken into account, although it is acknowledged that this can in some cases have a notable influence on the product’s energy performance over time (Table 3).
Laptop (in Pt)
1980
2010
1990
2010
34 (44%) 1.5 (02%) 42.1 (54%)
34 (66%) 1.5 (03%) 15.7 (31%)
6.7 (68%) 0.07 (01%) 3.1 (31%)
6.7 (78%) 0.07 (01%) 1.9 (21%)
The laptop’s median lifespan in 1990 was 7 years (Huisman et al., 2012). The results of the LCA and the dynamic modelling are presented in graphical form, see Figs. 3 and 4. Fig. 3 shows that a refrigeratorefreezer sold in 1980 should have been replaced after 8 years. The new model, bought in 1988, should have been used for 13 years; after which the next replacement would have had to take place in 2001, with the new refrigerator to be used for 10 years; then in 2011 the old model would have had to be replaced for a new one which can last for 20 years (and will need to be replaced in 2031). Following the same approach as for the refrigeratorefreezers, Fig. 4 shows that the baseline scenario for laptops (replacement every 7 years) is in all cases the optimal replacement scenario. Had the median lifespan of a laptop been 10 years in the baseline scenario, the optimal lifespan in 2011 would have been 10 years. Prakash et al. (2012) calculated even longer replacement times for laptops, ranging from 33 to 89 years. 6. Findings from the case studies
The fridge scenario’s baseline year is 1980. In this year the median lifespan was 20 years. For the laptop, the baseline year is 1990, which is when laptop computers started to be widely used.
While the energy consumption of laptops and refrigerators has decreased substantially over time, so has their lifespan. The overall effect is negative, for it results in premature replacements where the environmental impacts of production have not been fully offset by the energy efficiency improvements in newer models. The results suggest that fridgeefreezers and laptops bought in 2011 should be used for longer than their current median lifespans of approximately 14 and 4 years respectively. This research shows that for fridges and laptops, product lifespan is the determining factor for the overall environmental impacts. In both cases, product life extension is the preferred strategy. Similar findings were reported by Bakker et al. (2012) for LED TVs, Yu et al. (2010) for mobile phones, and Prakash et al. (2012) and Deng et al. (2011) for laptop computers. Given the current trends towards decreasing energy consumption, increasing material intensity, and declining product lifespans (Table 2), one can wonder whether these findings might be valid for more electric and electronic devices. This would require further
Fig. 2. Average electricity consumption per unit of laptop computer (1990e2020).
Fig. 3. Optimal lifespans for a refrigeratorefreezer based on ReCiPe (Pt.) as a measure of environmental impacts.
5.3. Dynamic modelling
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C. Bakker et al. / Journal of Cleaner Production 69 (2014) 10e16 Table 4 Design strategies for product life extension and product recycling applied to fridges and laptops. Hierarchy
Fridge
Laptop
Given the trend towards bigger Material efficiency is already important in laptop design fridges, this might be a useful (reduction of weight, ‘thin’ approach. designs) In spite of (or because of?) To make a fridge last for 20 Longer the emotional and aesthetic years, functional as well as product appeal of laptops, early emotional and aesthetic life durability should be addressed. replacement is the norm. Reparability Self-repair and serviced repair Self-repair and serviced should be easy e but are often repair should be easy e this expensive when outside of is however not so for many warranty. laptops (trend towards unibody designs with sealed batteries) Refurbishment Possibilities for refurbishing and Refurbishment (i.e. upgrading of components upgrading might be explored (for instance mid-life efficiency such as RAM, hard drive) can be done, but is check and seal replacement) sometimes discouraged by manufacturers. Remanufacture Not likely, given 20-year Small-scale remanufacturing lifespan? is done, can be much improved (also through better design). Collection from consumers is a challenge. Recycling Most fridges are recycled at the Can be improved, also through design for recycling. moment. There might be Collection from consumers options for improvement is a challenge. through design for recycling. Material efficiency
Fig. 4. Optimal replacement time for laptop computers based on ReCiPe (Pt.).
research. Such research would have to take the limitations of the current study into account: a full LCA would need to be done, including the end-of-life of the products, and the dynamic modelling would have to take into account energy deterioration of the products over time. Also, several future scenarios should be modelled (instead of only one ‘best fit’ curve), that show different possible developments in the energy efficiency of the products. A sensitivity analysis should be performed to determine the robustness of the results. For these reasons, the results of the current life cycle optimization modelling only give an indication of the optimal replacement times. For both products, however, the results clearly point towards product life extension. 7. Design strategies for product life extension The analysis outlined in the previous sections is an example of how design researchers could start mapping product life scenarios. It is possible that the optimal product life requires a shortening of the product lifespan, however, in the case of the fridge and the laptop, product life extension was found to be the most ecoefficient scenario. Using the theoretical framework in Table 1, a range of possible design strategies for product life extension and product recycling was mapped (Table 4). Refrigeratorefreezers are low-interest products. In the Netherlands, 57% of the 6000 households surveyed keep their fridges until they break down (Hendriksen, 2007). Fridges have relatively mature technology, meaning not a lot of breakthrough technological innovation is happening in fridge engineering. Extending a fridge’s life to 20 years therefore means making it reliable and (emotionally, aesthetically and functionally) durable, and ensuring its energy efficiency doesn’t deteriorate over its lifetime due to ageing insulation foam and leaking door seals. Allwood and Cullen (2013, p. 240) suggest that it could be possible to “sell a fridge with a life-time guarantee, if we identified the likely causes of failure and designed into the original product a simple means to repair them.” Also, given the relatively large amount of materials used, the degree of fridge recycling could probably be intensified. Design for recycling might be useful here. In contrast to fridges, laptops are high-interest products subject to dynamic market conditions. The need to compete with other mobile devices drives technological development and design innovation. This creates a volatile market where rapid replacement cycles are the norm. Modular design is often suggested as a way to increase a laptop’s useful life without closing off possibilities for innovation (for instance Prakash et al., 2012) and industrial designers have developed interesting concepts (Heimbuch, 2012; Lee, 2013). Modular designs are however challenging to realize in practice with technology in such a flux. Alternative approaches
include design for (more efficient) remanufacturing and eventual recycling. One of the challenges is the collection of obsolete laptops from consumers, and here design might also make a meaningful contribution. It follows from this description that for refrigerators and laptops different product life scenarios make sense. Fridges are mature, almost sedate, products whose basic technology and layout hasn’t changed very much over the decades. Laptops, in contrast, are subject to rapid innovation cycles that inspire much excitement. Making a fridge last for 20 years is not too great a challenge, but making a laptop last for 7 years or more is currently regarded as economical suicide, which is why for laptops, recycling and remanufacturing are more likely strategies than longer product life. For most products categories, tailored product life extension approaches will be needed depending on product characteristics such as lifespan, technological maturity and resource intensity, and business constraints such as market competitiveness and regulations. All design strategies for product life extension and product recycling could be explored in more detail, and from different practical and theoretical perspectives. For refrigerators, designing for a longer product life means taking into account the functional as well as the emotional and aesthetic durability. Designers may ask, for instance, how a fridge can maintain a hygienic look and feel throughout its life, and how to ensure the fridge and its interior components wear in an acceptable (or even attractive) way. Authors like Chapman (2005) and Nes (2003) have extensively explored emotional durability and product attachment. Moving away from theories that address product-user interactions, designers could ask what constitutes a ‘normal’ lifespan for products such as fridges and laptops and why and how people accept and accommodate ever-shorter product lifespans into their everyday lives. This may provide different insights and starting points for addressing product life extension. Contributions to such questions
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are made in sociology, through for instance practice theory (Shove et al., 2012). For laptops, remanufacturing was pinpointed as a promising product life extension strategy. While remanufacturing is often understood as ‘patching up’ an old product, this is in reality an underestimation of what it could potentially offer. Gehin et al. (2008) stress that remanufacture is a dynamic and innovative strategy, as “remanufactured components can be mixed with innovative parts, making the remanufactured product more attractive than the discarded one if this one was new.” (p 571). Remanufacturing isn’t only about the (re)design of the product. The creation of viable business models and (reverse) supply chains is equally important, for without a feasible business model remanufacturing is unlikely to happen. What this brief overview shows is that product life extension and product recycling are not ‘simple’ strategies, but require and deserve much more in-depth design research. 8. Implications for design research In order to design products that fit within a circular economy (“circular products”), it is important to first of all understand how to optimize product lifespan from a sustainability perspective without compromising the product’s economic viability. The main challenge for design research therefore is to determine when to apply which product life extension strategy. The waste management hierarchy is of limited guidance, as the previous section showed. Different products require different hierarchies of product life extension and product recycling strategies, based on product characteristics (i.e. lifespan, technological maturity, resource intensity) and business constraints (i.e. market dynamics, legislation). As products and markets change dynamically, these hierarchies are not set in stone e monitoring product life and trends in resource efficiency should be an on-going process. Establishing the optimal product life scenario is the first item of a future research agenda for products in a circular economy, and the approach explored in this paper may be a useful starting point. Once the appropriate scenarios have been determined, the next challenge is to find business models that support these. A decision to go for product refurbishment, for instance, could result in the development of a lease concept where the company retains ownership of the product (Vodafone and KPN for instance introduced lease phones). Developing such business models successfully is probably beyond the expertise of product designers, but design research could play a useful role in understanding the factors that influence consumer acceptance of new ownership models and other product service systems (Catulli, 2011; Mont et al., 2006). These strategic decisions (choice of product life scenarios; choice of business model) will have considerable impact on the design of a product. Designing a product that is to be leased and refurbished several times during its life, for instance, will require designers to obtain intimate knowledge of how the product and its parts wear and tear, and of how to decide which parts should last, and which should be replaced, and when. Functional, emotional, aesthetic and economic considerations will all play a role. In the past decades a number of methods and tools were developed to assist design for remanufacturing, design for recycling, and design for end-of-life. Overviews are given in for instance Rose (2000) and Allwood et al. (2011). Most of these tools and guidelines are highly function-oriented, focussing for instance on constructions that are easy to disassemble, but they have little consideration for the emotional, aesthetic and economic consequences of design decisions. It may be worthwhile to consider developing tools that are less geared towards engineers and more towards product designers. On a very practical level, designers will need to learn about
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the different end-of-life treatment and recycling processes that are available, and about the advantages and drawbacks of the application of recycled materials in products. Lastly, it is important that design research tries to answer the question whether the new circular business models and “circular products” in the long run deliver solutions with a lower environmental impact. Leasing and refurbishing or remanufacturing products, may require a lot of extra service kilometers (for instance for reverse logistics) and new parts will need to be produced. A scenario-based life cycle assessment can help determine whether the benefits of a circular business model outweigh the negatives. Finding best practice case studies may be useful to provide models of ‘what works’, and of how environmental impacts can be minimized. 9. Conclusion This research sets out to determine the optimal product lifespans of refrigerators and laptops, with the aim to understand whether product life extension and/or product recycling is the preferred strategy from a sustainability perspective, and to explore what options there are to address these through design. The inquiry was triggered by recent research that demonstrates how product lifespans in the Netherlands have declined (sometimes by more than 10%) between 2000 and 2005, causing unsustainable throughputs of materials. The current refrigerator lifespan is 14 years in the Netherlands, and a laptop’s lifespan is approximately 4 years. After comparing the trends in electricity consumption of refrigerators and laptops against environmental impact data (through life cycle assessment), it was found that whilst the energy efficiency of both refrigerators and laptops has increased over time, the declining lifespans cause a negative overall effect e meaning that product life extension, with newly bought (energy efficient) refrigerators lasting up to 20 years and laptops at least 7 years, is the preferred approach. The conclusion that refrigerator lifespan should be prolonged runs counter to popular belief; here the paper makes an original contribution to research on product life. It could be hypothesized that these findings may be valid for other electrical and electronic products, but this would require further study. Design knowledge on product life extension strategies (longer product life, reparability, refurbishment and remanufacturing) and product recycling is currently underdeveloped. These strategies need to be tailored to the specific product at hand with the generic waste management hierarchy (prevention, reuse, recycling) providing only limited guidance. Laptops for instance need to compete in highly dynamic markets, which makes remanufacturing and recycling more feasible strategies than longer product life, turning the waste management hierarchy “upside down” in this particular case. Understanding which product life extension or recycling strategies should be applied when is one of the main challenges for design research in this field. The consequences of such strategies for new business development need to be mapped, and the current “design for X” tools and methods should be revitalized. The paper has provided a first overview of this new research field. Our research is of direct relevance for design practice. Industry, faced with increasing resource costs, increasing competition from low-wage countries and progressive environmental legislation, is already exploring product recycling and other circular business models and will be on the lookout for designers with relevant knowledge and expertise related to products that “go round”. Acknowledgements The authors gratefully acknowledge the support of the Innovation-Oriented Research Program ‘Integrated Product
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