The bioeconomy has the potential to contribute significantly to sustainable development and a just transition. To ensure the sustainable production of bio-based products, it is essential to understand their potential environmental, economic, and social impact. However, the social dimension receives far less attention in sustainability literature and assessments than the environmental and economic dimensions. Especially in the Global South, where a large part of the world's biomass is produced, vulnerable communities are at higher risk of being negatively affected by the bioeconomy. These risks include food insecurity, monoculture expansion, and unequal wealth distribution. Therefore, it is crucial to understand new bio-based value chains' (potential) social impacts better. This paper contributes to this debate by developing a prospective Social Life Cycle Assessment (SLCA) for a bush-based value chain in Namibia. We assessed the existing charcoal value chain and identified potential social risks, impacts, and opportunities of a prospective value chain to produce marine biofuels from encroacher bush. We use this case study to reflect on the SLCA methodology and compare the SLCA results with our qualitative fieldwork based on interviews and a multi-stakeholder workshop. We found that the current methods for SLCA do not adequately capture salient aspects of the local context. SLCA is a good method to quantify some social impacts and to identify social risks in the value chain, such as labor conditions and existing policies. However, the methodology of SLCA currently misses a more nuanced understanding of the context and potential social issues, like issues related to gender and ethnicity, and the adherence to existing policies. We propose adding more context-specific indicators to the risk assessment. In addition, stakeholder engagement is crucial for identifying and assessing relevant social impact categories, and we advocate for incorporating local stakeholders' subjective assessments. This approach allows for the inclusion of softer social impact categories, such as gender and ethnicity-related social norms, which are not easily captured by general indicators.

Bio-based value chains (BBVCs) have often been criticized for their detrimental social and environmental effects. Existing methods such as social impact assessment do not sufficiently address these negative effects because of their limited focus and lack of attention to social justice. This paper explores the contribution of Capability Sensitive Design (CSD) to designing BBVCs for social justice. CSD is a combination of Value Sensitive Design (VSD), an approach to account for human values in a design process, and the Capability Approach (CA), a normative framework that incorporates multiple dimensions of human well-being. Three case studies demonstrate how CSD can be used to make design choices in the early stages of developing new BBVCs from waste biomass. The cases explore olive oil residues in Spain, coffee and cocoa residues in Colombia, and encroacher bush in Namibia. CSD is a relatively new approach and its contribution to social justice in BBVCs remained unexplored. We show that CSD can contribute to distributive, recognition, and procedural justice by allowing the identification of local vulnerable stakeholders and providing tools to connect their needs, knowledge, and capabilities to concrete design choices.