3.1. Model Validation with PSS Experts
The following sections present the results from the statistical analysis, where Section 3.1.1
shows the described analysis, while Section 3.1.2
presents the results of the factor analysis.
3.1.1. Descriptive Analysis
presents the results of the descriptive analysis, where the average (
) and standard deviation (σ) of the model variables were calculated.
The results indicate that, in the dimension “Re” (regenerate), the variable that best describes the observed phenomenon is the “Re7”, since it presented the highest average and lowest standard deviation of this dimension. Thus, it is inferred that there is a high index of convergence in the respondents’ opinions, in addition to the fact that this variable presented the highest mean and lowest standard deviation of the entire statistical analysis, demonstrating the importance of adopting measures aimed at socio-environmental balance in the early stages of the life cycle.
In dimension “S” (sharing), there was also a high convergence index, since dimension S2 (extension of the product’s life cycle; intensified use) obtained the highest average and lowest standard deviation. The interviewees stressed this variable’s importance as a way to reduce the disposal and pollution caused by the product. In the “O” dimension (optimize), the variable O3 (ease of disassembly of parts) showed the highest average and lowest standard deviation, demonstrating that there is a high index of convergence and appreciation of dimensions based on preventive behavior towards sustainable development.
The analyses of dimension “L” (cycling) presented the lowest convergence index of the statistical analysis, since variable L6 (remanufacturing) presented the highest average, and L2 (circular design) the lowest standard deviation. Although the result of this dimension is the least valued, the model generally presents high averages and low standard deviation values, contributing to the validation of the analyzed phenomenon.
The final dimensions of the model, “V” (virtualize) and “E” (exchange), presented converging results, since the variable V5 (operational support, advise on the efficient use) and E5 (rethink) presented the highest means and lowest standard deviations of their respective dimensions. Both variables emphasize the need to support the customer regarding socio-environmental balance, since an organizational awareness of sustainable production is not enough if there is no mobilization on the part of the consumer.
3.1.2. Factorial Analysis
presents the factorial analysis’ results, where the variance (V) is calculated for each variable in the model.
The variables that contribute the most to the dimensions’ significance were identified through the analysis of variance. Thus, it is inferred that the variables Re3 (ecodesign or Design for X (DfX)), S3 (redistribution), O5 (maintenance), L1 (cradle to cradle approach), V1 (advisory and consulting) and E6 (replace non-renewable materials by more sustainable alternatives) were the variables that best represent the construct. These are the ones that contribute the most to significance and summarize the information of the other variables. For example, variable Re3 (ecodesign or Design for X (DfX)) best represents the “Regenerate” dimension.
These variables (Re3, S3, O5, L1, V2 and E6), which have the most significant impact on each dimension’s significance based on the sample analyzed, are suggested to receive the most prioritization. However, analyses with a larger sample are necessary to validate this assertion.
3.2. Case Study—Life Cycle Analysis (LCA)
Conducting a Life Cycle Analysis of products makes it possible to act before the occurrence of environmental and human health impacts, and Haupt (2017) points out that Life Cycle Analysis supports the transition to a circular economy [47
]. Thus, Table 6
presents how this approach (LCA) is interrelated with the structure used in the generic model developed (ReSOLVE).
shows that the literature highlights the LCA potential in the face of circular economy, making it possible to affirm that the LCA is related to the generic model developed (Figure 2
). Thus, a Life Cycle Analysis was conducted to quantify the environmental and human health impacts caused by a bike, enabling to outline an action plan to mitigate them.
Although bicycles represent a means of transportation aligned with sustainable development, the product must be planned to balance the environmental, social and economic spheres in order to transition to a PSS proposal [13
]. In view of this, Figure 5
shows a mapping of the main impacts caused by a bike, where it can be seen that the production stage is responsible for the main negative externalities on the environment and human health.
In this phase, high energy consumption and different materials usage (such as aluminum, steel, and rubber [19
]) cause an environmental burden. Moreover, the Simapro®
software highlights that the main impacts are the carcinogenic toxicity of the production process of a bicycle and the contribution to the scarcity of mineral resources. Henriques et al. (2013) point out that the main materials that make up a bike, such as aluminum, contribute to the context of resource scarcity, in addition to contributing to the emission of chlorofluorocarbons (CFCs), thus potentiating harmful effects on health, such as the incidence of skin cancer, sunburn and genetic changes in humans, animals and vegetation [22
Given the result presented in Figure 5
, this research performs the Life Cycle Analysis (LCA) of the production of a bike, measuring its impacts on the environment and human health (midpoint and endpoint). Table 7
presents the steps of the first phase of the LCA (definition of scope and objective), where we highlight that the goal of this Life Cycle Analysis is to analyze the environmental impacts caused by the production of a bicycle in Brazil, aiming to identify the main negative externalities. This makes it possible to draw a strategy to mitigate them, making the product aligned with the principles of a product-service system.
In the second and third stages of the Life Cycle Analysis, the SimaPro®
software was used, which enabled the construction of the inventory (LCI) [41
], where the inputs, processes and outputs of the system were represented, in order to correlate the inventory data with the functional unit (production of 1 bicycle) (stage 2: Life Cycle Inventory). In stage 3, the life cycle impacts assessment (LCA) took place, which supports the interpretation of an LCA study [56
]. Table 8
presents the main procedures of these steps.
In the fourth step of the Life Cycle Analysis, the results were interpreted, so that Figure 6
presents the negative externalities caused by the production of a bike. These impacts are presented according to the raw materials used for the production of bicycles, such as aluminum, chrome, steel, and polymers (direct materials). In addition, the externalities caused indirectly by the manufacturing processes are also analyzed, such as electricity consumption, the impacts caused by the injection molding process, the extrusion of aluminum bars, among others. All the impacts of these materials, both direct and indirect, are analyzed, in order to measure how they interfere with global warming, the emission of ionizing radiation, ozone emissions (impacts on human health and terrestrial ecosystems), and the degradation of the stratospheric ozone layer, among others.
The results of the application of this tool indicate that aluminum, chrome steel, and low alloy steel cause the greatest impacts on human health and the environment, contributing 45.17%, 31.86%, and 10.23% of negative externalities, respectively. When analyzing the impact categories, the Life Cycle Analysis highlights that the main burdens of bike production considering the Brazilian context are terrestrial acidification (79%), impacts of ozone emissions on human health (75%) and terrestrial ecosystems (74%).
The results obtained are theoretical and generic, but the work of Matos et al. (2020) corroborates the software data, highlighting the impact of the aluminum production process through a case study carried out in Pará, Brazil. The authors highlight the contribution of aluminum to the alteration of the physical and chemical properties of the soil, since the removal of the upper layers of soil for the extraction of bauxite (the raw material base of alumina, and subsequent aluminum) exposes the lower layers to the loss of nutrients and erosion. There is also high water consumption during this process (data in Figure 6
corroborates this assertion), used in the bauxite extraction process, its processing and other steps until aluminum is obtained.
The study by Erkoyuncu (2019) corroborates this analysis, highlighting that the aluminum used for the production of the bike frame is the main responsible agent for the impacts at the stages of production, use and maintenance [57
]. Therefore, it is essential to avoid the aluminum frame, and replace it with another material aligned with sustainable development. The Life Cycle Analysis by [57
] was conducted in Bangladesh, also aiming to measure the impacts of producing a bicycle. The study by [57
] points out that among the main negative externalities of aluminum, climate change stands out, since it is responsible for 67.3% of the impacts related to this category, as presented in Figure 7
This research corroborates with the study of Erkoyuncu, extending the analysis to the Brazilian context, in which Figure 8
complements this investigation through a Pareto diagram, which points out that the three main sources of impacts are aluminum, chrome steel and low alloy steel. By applying the 80/20 Pareto rule, these variables represent the activities (approximately 20%) responsible for approximately 80% of the impacts, i.e., these are the main factors to consider when developing an action plan aiming to mitigate the impacts on the environment and human health caused by the production of a bike.
The higher impact caused by aluminum can be explained because its production depends mainly on the electrolytic method (Hall–Héroult process, in which igneous electrolysis of alumina fused into cryolite is performed), which consumes high rates of electricity [58
]. Although aluminum in the transportation sector is widely used due to its light weight, its production causes greater environmental impacts compared to other materials, such as steel [59
]. According to Cullen (2013), aluminum production uses more than 3.5% of global electricity, contributing significantly to greenhouse gas (GHG) emissions [60
]. Thus, aluminum consumption and production drives coal consumption, as well as sulfur dioxide (SO2
) and carbon dioxide (CO2
) emissions [8
Among the components of a bike that use aluminum, the frame stands out, followed by the chain, rims, spokes, among others. Considering the sustainable development, it becomes attractive to change this material for others that cause less impact, such as the replacement of the aluminum chain with a more ecological steel chain that ensures the same degree of wear and useful life [14
Given the environmental impacts caused by aluminum and that the annual demand for this material grows exponentially (30-fold increase since 1950) [60
], the identification and use of alternative materials becomes an imperative measure. Thus, in order to mitigate the main negative externalities caused by bicycle production, especially aluminum (responsible for approximately 45.17% of the impacts), the following section presents alternatives aimed at replacing the aluminum frame with more sustainable proposals, in order to apply them in the proposed model to analyze their effectiveness.
3.3. Applying the Model in the Case Study
Aiming to mitigate the impacts pointed out by the LCA, this subsection presents a proposal that seeks to align the production of a bike with the principles of a product linked to a PSS proposal. Since the Life Cycle Analysis pointed out that aluminum generates high environmental and human health impacts, this work analyzes the substitution of this material with a bamboo fiber polypropylene composite. According to Scherer (2020), composites reinforced with natural fibers, besides being aligned with sustainable development, present the advantages of low cost, abundance and low weight [61
To measure the effectiveness of the alternative facing the transition to a PSS proposal, the proposed model was applied (Table 9
), in order to analyze how many characteristics of a PSS product the materials meet (aluminum and bamboo fiber).
The application of the model shows that the alternative of using bamboo fiber is 37.5% more aligned with sustainable development than aluminum, proving the viability of the proposal aiming at the transition to a PSS business model. According to Scherer (2021), bamboo’s high strength and durability, as well as its rapid growth and wide availability, allows for a high range of high-performance applications [20
Thus, Table 9
presents a comparative analysis, based on bibliographic data, between using aluminum and developing a biocomposite with bamboo fiber. Among the advantages of substitution, it can be highlighted that bamboo is a renewable resource, of rapid growth, that helps prevent soil erosion, absorbs carbon dioxide (CO2
) and releases oxygen into the atmosphere, contributing to the minimization of the greenhouse effect, a factor considered critical in the Life Cycle Analysis of aluminum as one of the main negative externalities caused by this element.
Thus, managers and industries can benefit from this substitution given the benefits mentioned above, in addition to being an alternative aimed at sustainability, which has been arousing business interest given the pressure in the face of environmental commitments such as Agenda 2030. Thus, proposals with sustainable alignment gain greater visibility in the market, enabling companies to perform the green marketing of the proposal.
Scherer, Bom and Barbieri (2020) reinforce this notion, highlighting that bamboo reconciles the benefits of being a sustainable alternative with low cost, abundance in nature and low weight, an essential characteristic for a bike frame [61
]. Thus, this step contributes to propose an alternative to the main impacts of the production of a bicycle, pointed out by the Life Cycle Analysis (LCA). In this way, the next steps of this research will focus on mechanical tests of the polypropylene and bamboo fiber biocomposite, to perform a comparative study with the aluminum, in order to validate in a practical way the contributions pointed out in Table 9