The problem the researchers set out to solve is one that lurks inside nearly every eco-design effort. When a manufacturer wants to extend a product’s useful life, the temptation is to modify the part most responsible for wear and tear, and to consider that part in isolation. But products are not collections of independent components; they are webs of coupled functional chains in which one part’s behavior constrains another’s. The study shows that many lifespan-extension practices overlook this interdependence, along with the environmental impacts that design changes themselves introduce. The result is that engineers often cannot identify which parts are truly critical to both longevity and environmental performance, and cannot guarantee that a longer-lived product actually delivers net sustainability benefits rather than simply shifting burdens elsewhere in the life cycle.

To close this gap, the team built a framework that links part-level design changes directly to three outcomes: lifespan, environmental impact, and cost. The approach begins by mapping how components depend on one another functionally, borrowing concepts from design structure matrix methods that have long been used in systems engineering to untangle complex products. Reliability engineering then enters the picture through Weibull-based lifetime modeling, a statistical approach widely used to predict how long a component will survive under given operating conditions. By combining coupling analysis with lifetime modeling, the framework can identify which components must be redesigned together, and how changes to one ripple through the durability of the whole.

The air circuit breaker served as a rigorous test bed. These devices protect electrical circuits in industrial settings, and their lifespan is typically measured not in years of service but in switching cycles, the number of times they can open and close safely. Two components emerged as central: the contact tip, which endures the physical stress of each switching operation, and the rear connection, which anchors the assembly and is vulnerable to the mechanical and thermal conditions created by the moving contact. The analysis found that these two parts are strongly coupled. In practical terms, any effort to thicken or toughen the contact tip must be coordinated with the choice of materials for the rear connection, because the two components interact in ways that jointly determine whether the breaker meets its lifespan target and its environmental requirements.

The team then applied the framework to a concrete design target: a breaker capable of enduring 6,000 switching cycles at 90 percent reliability. Using their coupled analysis, they identified a feasible design space before any optimization took place: a contact tip thickness range of roughly 2.0 to 2.5 millimeters. This step matters because it treats lifespan as a prior constraint rather than as one objective to be traded away later. Within that lifespan-secured space, the remaining decision was which material to use for the rear connection, and here the framework exposed a genuine trade-off between carbon and cost. Choosing copper delivered the larger environmental payoff, cutting the carbon emissions associated with the equipment by 34 to 36 percent, while recycled aluminum limited any increase in production cost to less than 2 percent but offered a smaller carbon benefit. Neither choice dominates; the framework’s contribution is making the trade-off visible and quantifiable at the design stage, when decisions are still cheap to change.

Perhaps the most counterintuitive finding concerns reliability itself. Designers often assume that demanding higher reliability is unambiguously good, since it means fewer failures in the field. But the study shows that reliability requirements and product lifespan interact in complex ways. When the researchers raised the reliability level from 78 to 90 percent, the projected lifespan fell by 15 percent while carbon emissions rose by 1.9 percent. The mechanism is subtle: requiring a component to survive under stricter statistical guarantees changes the way lifetime must be modeled and can push designs toward configurations that are, in aggregate, shorter-lived and more emissions-intensive. The implication is that environmental impact assessments of electronic equipment cannot treat lifespan as a fixed number; they must always state the reliability level that lifespan corresponds to, otherwise comparisons between designs are meaningless.

These results arrive at a moment when the policy landscape is shifting rapidly. The European Union’s Ecodesign for Sustainable Products Regulation, which entered into force in 2024, pushes manufacturers to design for durability, repairability, and circularity, while international standards such as IEC 62271 for switchgear and NF EN 45552 for assessing durability of energy-related products increasingly require quantitative methods for product longevity. Meanwhile, the Global E-waste Monitor 2024 documented that only a fraction of the world’s discarded electronics is formally collected and recycled, leaving vast quantities of embodied materials and emissions to leak into landfills and informal waste streams. Tools that let designers see, early on, how lifespan, emissions, and cost interact could therefore shape products far more effectively than end-of-pipe recycling alone.

The study distills its findings into three guiding principles. First, eco-design should evaluate coupled functional chains rather than isolated parts, because the components that govern longevity frequently interact and cannot be optimized one at a time. Second, lifespan should be established as a prior design constraint before multi-objective optimization begins; if durability is merely one objective among many, optimization algorithms may sacrifice it in favor of cost or weight, quietly undermining the circularity goal. Third, environmental impact assessment should consider product lifespan together with the reliability level at which that lifespan is defined, ensuring that reported lifetimes are statistically meaningful and comparable across designs. Taken together, these principles shift eco-design from a part-by-part checklist exercise toward a systems view of product sustainability.

The framework’s significance extends beyond circuit breakers. Electrical and electronic equipment spans everything from consumer devices to grid infrastructure, and the authors’ earlier work, including a knowledge-graph-based method for green design evaluation of such equipment published in ACS Sustainable Chemistry & Engineering in 2023, has been building toward exactly this kind of integrated, quantitative approach. The new study, funded by the Fujian Provincial Science and Technology Department, the Chinese Academy of Sciences, and the National Natural Science Foundation of China, demonstrates the method on real industrial data provided by a partner company under confidentiality, lending it practical credibility. As regulators tighten durability requirements and manufacturers confront both climate targets and cost pressures, the message of this research is likely to resonate: the greenest product is not simply the one built with the cleanest material or the thickest part, but the one whose designers understood how every component’s fate is bound to every other’s, and who defined, from the start, how long the product should last and with what statistical confidence.

Subject of Research: Eco-design and environmental impact assessment of electrical and electronic equipment incorporating product lifespan and component interdependencies

Article Title: Incorporating product lifespan into eco-design and environmental impact assessment of electrical and electronic equipment

Article References: Liu, G.-G., Wang, Q.-C., Fan, L., Wang, J.-Y., & Chen, W.-Q. (2026). Incorporating product lifespan into eco-design and environmental impact assessment of electrical and electronic equipment. Journal of Industrial Ecology. https://doi.org/10.1007/s44498-026-00181-2

Image Credits: AI Generated

DOI: 10.1007/s44498-026-00181-2

Keywords: eco-design, electronic waste, product lifespan, life cycle assessment, reliability engineering, Weibull model, air circuit breaker, circular economy, carbon emissions, multi-objective optimization, electrical equipment, sustainability