Remanufacturing of Energy Using Products Makes Sense Only When Technology Is Mature

Hummen, Torsten; Wege, Elena

doi:10.1007/978-3-030-50519-6_6

Cited by 1 publication

(5 citation statements)

References 29 publications

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“…In this case study, the generic dynamic programming method is applied to three exemplary impact assessment methods, which lead to different results. The cost optimization results deviate considerably from the environmental assessment, as already shown in other studies, e.g., [31,64,82]. Environmental and financial impact dimensions should be aligned further possibly by pricing in all external effects and not only cost estimates for damages from climate change.…”

Section: Methodological Aspectsmentioning

confidence: 61%

“…In contrast, if a boiler is installed for the first time in 2020 (Case 2020 ), solely efficiency degradation influences the optimized replacement scheme, resulting in replacements with re-manufactured products every two years (D 0.5 ) or every year (D 1.5 ) as the OEL (Figure 5b,d,f). In this case, replacement with new products is of less advantage because the technology is already mature [64]. : no or seldom maintenance) and two replacement options (Ω = 3; O1: further use of the product; O2: newly evolved gas boiler; O3: re-manufactured gas boiler).…”

Section: Resultsmentioning

confidence: 99%

“…As a result, production-related resources are saved, and production costs are reduced. Therefore, production impacts can be assumed to be similar or even smaller than those caused by normal production [64,65], which may be expressed as a fraction of the impacts for a new product, P reman = f r • P new .…”

Section: Re-manufacturingmentioning

confidence: 99%

“…To estimate the impact saving for re-manufacturing, we adapt the figures from Hummen and Wege [64], which analyze the re-manufacturing of a circulation pump used in gas boilers, to calculate the fraction, f r , of production impacts for a new boiler caused in re-manufacturing (see Supplementary Material Table S11). It is assumed that the initial effi-ciency of the core product is fully restored and that it is like new.…”

Section: Re-manufacturingmentioning

confidence: 99%

“…Re-manufacturing these components and upgrading them, if technically possible [12], to the best available technology could also reduce resource-related environmental impacts during production. With our case study, we specify that re-manufacturing is environmentally beneficial not only when the technology is mature [64,94] but, more precisely, if the efficiency progression of a cohort of products is only minor within a specific period. Therefore, the approach might support defining a time scale and efficiency progression range in which EuPs can be considered mature.…”

Section: Case Study Implicationsmentioning

confidence: 99%

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Optimizing Lifespan of Circular Products: A Generic Dynamic Programming Approach for Energy-Using Products

Hummen,

Hellweg,

Roshandel

2023

Energies

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Slowing down replacement cycles to reduce resource depletion and prevent waste generation is a promising path toward a circular economy (CE). However, an obligation to longevity only sometimes makes sense. It could sometimes even backfire if one focuses exclusively on material resource efficiency measures of the production phase and neglects implications on the use phase. The (environmental) lifespan of circular products should, therefore, be optimized, not maximized, considering all life cycle phases. In this paper, a generic method for determining the optimal environmental lifespan (OEL) of energy-using products (EuPs) in a CE is developed, allowing the simultaneous inclusion of various replacement options and lifetime extension processes, like re-manufacturing, in the assessment. A dynamic programming approach is used to minimize the cumulative environmental impact or costs over a specific time horizon, which allows considering an unordered sequence of replacement decisions with various sets of products. The method further accounts for technology improvement as well as efficiency degradation due to usage and a dynamic energy supply over the use phase. To illustrate the application, the OEL of gas heating appliances in Germany is calculated considering newly evolved products and re-manufactured products as replacement options. The case-study results show that with an average heat demand of a dwelling in Germany, the OEL is just 7 years for climate change impacts and 11 years for the aggregated environmental indicator, ReCiPeendpoint(total). If efficiency degradation during use is considered, the OEL for both environmental impact assessment methods even lowers to 1 year. Products are frequently replaced with re-manufactured products to completely restore efficiency at low investment cost, resulting in higher savings potential. This not only implies that an early replacement before the product breaks down is recommended but also that it is essential to maintain the system and, thus, to prevent potential efficiency degradation. The results for cost optimization, as well as currently observed lifespans, vary considerably from this.

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Section: Methodological Aspectsmentioning

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Section: Re-manufacturingmentioning

confidence: 99%

Section: Re-manufacturingmentioning

confidence: 99%