Bilevel Optimization Framework Guides Circular Economy Policies for Coffee Packaging

Why It Matters

Understanding the interplay between government policy and corporate cost-minimization is crucial for designing effective circular economy strategies. This research provides a quantitative method to assess policy impacts, enabling designers and businesses to make informed decisions about resource management and waste reduction within product supply chains.

Key Finding

The study found that financial incentives like subsidies are more impactful in encouraging businesses to adopt greener practices within their supply chains compared to solely imposing carbon taxes. Factors like the cost of reprocessing materials also significantly affect how well these policies work.

Key Findings

• Subsidies are more effective than carbon taxes alone in driving supply chain shifts towards low-emission and high-circularity configurations.
• The effectiveness of policies is influenced by parameters such as glass washing distance and loss rates.

Research Evidence

Aim: To develop and demonstrate a bilevel optimization framework for evaluating the combined use of carbon taxes and subsidies in promoting circular supply chains, considering environmental impact minimization and cost minimization.

Method: Bilevel Optimization, Mixed-Integer Linear Programming (MILP), Life Cycle Assessment (LCA), Techno-Economic Assessment (TEA), Circularity Assessment

Procedure: A bilevel optimization model was formulated to represent the hierarchical decision-making between a regional government and coffee companies. The model integrates LCA, TEA, and circularity assessment to evaluate two environmental objectives: GHG emission minimization and circularity maximization. The framework was applied to a case study of coffee packaging supply chains.

Context: Supply chain management, environmental policy, circular economy, packaging design

Design Principle

Incentivize circularity through a combination of policy and design choices that align corporate cost-minimization with environmental objectives.

How to Apply

When developing a new product or redesigning an existing one with sustainability goals, use this framework to model the potential impact of different policy interventions (e.g., subsidies for recycled content) on the product's supply chain and overall environmental footprint.

Limitations

The model's applicability may vary depending on the specific product, industry, and regional context. Sensitivity analysis results are dependent on the accuracy of input data.

Student Guide (IB Design Technology)

Simple Explanation: This research shows that giving companies money (subsidies) to be more eco-friendly works better than just taxing them for being polluting, especially for things like coffee packaging. It uses a smart computer model to figure this out.

Why This Matters: This research is important for design projects focused on sustainability because it provides a method to quantitatively assess how different policy approaches can encourage the adoption of circular economy principles in real-world product systems.

Critical Thinking: How might the 'cost minimization' objective for companies in this model conflict with truly innovative or radical sustainable design solutions that might initially have higher upfront costs?

IA-Ready Paragraph: This research by Munoz Briones et al. (2026) offers a valuable framework for understanding how policy interventions can shape sustainable supply chains. Their use of bilevel optimization to model the interaction between government objectives (environmental impact) and corporate objectives (cost minimization) highlights that subsidies can be more effective than carbon taxes in promoting circularity within product systems, a finding relevant to any design project aiming for a circular economy.

Project Tips

• When researching sustainable design, look for studies that quantify the impact of different policies or interventions.
• Consider how your design choices might be influenced by or influence broader economic or environmental policies.

How to Use in IA

• Reference this study when discussing the effectiveness of different policy levers (e.g., taxes vs. subsidies) in promoting sustainable design choices within your design project.

Examiner Tips

• Demonstrate an understanding of how economic incentives can drive design decisions towards sustainability goals.

Independent Variable: ["Type of policy intervention (carbon tax, subsidy)","Budget levels for government intervention","Specific parameters like glass washing distance and loss rates"]

Dependent Variable: ["Greenhouse gas (GHG) emissions","Circularity of the supply chain","Supply chain configuration (e.g., material choices, processing methods)"]

Controlled Variables: ["Product type (coffee packaging)","Extended Producer Responsibility scenario","Regional government and coffee company interaction"]

Strengths

• Integrates multiple assessment methods (LCA, TEA, circularity assessment).
• Provides a quantitative framework for policy evaluation.

Critical Questions

• What are the ethical implications of government intervention in corporate supply chains?
• How can the 'circularity' metric be standardized across different product types?

Extended Essay Application

• Investigate the potential for a similar optimization framework to assess the impact of different material choices on a product's circularity and associated policy incentives.
• Explore how user behavior (e.g., consumer recycling habits) could be incorporated as another layer in a multilevel optimization model for product end-of-life.

Source

Incorporating circular economy policies into product supply chains using bilevel optimization -- A case study on coffee packaging · arXiv preprint · 2026