Lecture 7-10: EXAMple Questions

Question 1

Q1: Differentiate between weak and strong sustainability.

Answer 1

Weak Sustainability believes that natural capital (like forests and biodiversity) can be replaced by human capital (like infrastructure or knowledge). As long as total capital (natural + human) does not decrease, the system is considered sustainable, even if the environment is harmed.

Strong Sustainability argues that natural capital is irreplaceable and must be preserved because it’s the foundation for all other forms of capital. Without it, a truly sustainable system is not possible. It prioritises environmental protection and limits resource use to what nature can regenerate or absorb.

Ref.: Lecture 7

Question 2

Q2: What is the Triple Bottom Line?

Answer 2

The TBL framework evaluates performance on three dimensions:

1. People (social)
2. Planet (environmental/ecological)
3. Profit (economic)

It aims to guide businesses toward holistic sustainability, beyond profit maximisation.

Ref.: Lecture 7

Question 3

Q3: How does the Jevons Paradox influence the impact of product groups?

Answer 3

In short: Increased efficiency in resource use can paradoxically lead to higher overall consumption due to higher demand from lower costs, thus negating environmental benefits.

In economics, the Jevons paradox occurs when technological progress or government policy increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the falling cost of use increases its demand, negating reductions in resource use.

Ref.: Lecture 9

Question 4

Q4: How can companies implement sustainability in their supply chains? Please refer to the models we have discussed in class.

Answer 4

To implement sustainability, companies must:

1. Integrate TBL thinking into strategic goals and supply chain KPIs for holistic sustainability.
2. Choose a strategy of SSCM (Seuring & Müller, 2008) based on their maturity and industry: Supplier management to enforce sustainability and avoid risks (audits and certifications), or product management to design and deliver sustainable products (LCA, eco-design etc.)
3. Adopt circular strategies of CSCM (Batista et al., 2018), like reverse logistics and the 10Rs (Circularise, 2023), to move beyond linear “take-make-dispose” to integrated closed- and open-loop systems.
4. Collaborate across the supply chain, invest in transparency, and use LCA/MFA tools for decision-making - LCA helps firms evaluate product impacts across all life stages, and MFA tracks physical flows (inputs and outputs) in supply chains.
5. Draw from circular economy schools of thought to guide systemic transformation, including:

• Cradle to Cradle: Design for endless cycles, such that all materials either return safely to nature (biological cycle) or can be reused in industrial processes (technical cycle) -> Butterfly Diagram as visualisation (e.g. a biodegradable shoe sole that enriches soil when composted).
• Industrial Ecology: Treat supply chains like ecosystems - waste from one process becomes input for another (e.g. Kalundborg Symbiosis, where companies share by-products, water, and energy).
• Performance Economy: Sell product functions (services), not ownership (e.g. Philips Pay-per-Lux model, where light bulbs are offered as a service).
• Blue Economy, Biomimicry, Natural Capitalism: Innovation through nature and resource optimisation (e.g. Using coffee grounds to grow mushrooms, and composting the leftovers as fertiliser).

Ref.: All lectures.

Question 5

Q5: What are the key differences between ‘normal’ and ‘sustainable’ supply chains?

Answer 5

Focus:

• Normal: Cost, speed, and efficiency.
• Sustainable: Integrate economic, environmental, and social goals (Triple Bottom Line).

Time:

• Normal: Prioritise short-term profitability.
• Sustainable: Aim for long-term value creation, including societal and ecological well-being.

Suppliers:

• Normal: Limited visibility beyond first-tier suppliers.
• Sustainable: Extend responsibility across multi-tier suppliers.

Approach:

• Normal: Often reactive to regulations or risks.
• Sustainable: Take a proactive and strategic approach to sustainability.

Mindset:

• Normal: Product-centric.
• Sustainable: Include life-cycle thinking and stakeholder engagement.

Ref.: All lectures.

Question 6

Q6: Differentiate between Eco-efficiency and Eco-effectiveness? How are both related to Circular Economy?

Answer 6

In short:

• Eco-efficiency = Doing less bad by optimising and reducing to improve existing systems.
• Eco-effectiveness = Doing more good (actively) by redesigning to design truly circular (sustainable) systems.

Eco-efficiency: Doing more with less (minimising/reducing harm) - doing things right!

• Reduce raw material and energy use
• Use fewer harmful materials
• Improve durability and utilisation
• Maximise renewable energy use

Problem: Increasing the efficiency of resource use will decrease its cost of use (less needed), which then increases demand, ultimately resulting in higher overall resource consumption (Jevons’ paradox).

Eco-effectiveness: Designing systems where waste becomes input, inspired by the Cradle to Cradle principle, and where products are designed for loops, i.e. Butterfly Diagram (actively doing good) - doing the right things!

Relation to Circular Economy:

• Eco-efficiency: To optimise resource use and reduce waste/emissions by focusing on minimising input/output inefficiencies in linear systems.
• Eco-effectiveness: To design circular systems by creating products that feed back into the system through reuse or recycling.

Eco-effectiveness is core to Circular Economy thinking.

Ref.: Lecture 9

Question 7

Q7: Describe the Schools of Thought for Circular Economy, as we discussed in class.

Answer 7

Includes:

• Biomimicry: Learning from and imitating nature’s designs, systems and processes to solve human sustainability challenges - e.g. Tokyo’s transport network is inspired by an experiment with moulds to create networks between food sources.
• Industrial Ecology: Applying principles of natural ecosystems to industrial systems, treating industries as part of a larger ecosystem, where waste from one process becomes input for another - e.g. Kalundborg Symbiosis, where industries share steam, water, waste heat, and by-products to reduce waste, save costs, and lower emissions.
• Performance Economy: Shifting the business model from selling products to selling services. Instead of customers owning a product, they pay for the performance or function it provides - e.g. Philips ‘Pay-per-Lux’, where customers pay for light and not fixtures.
• Regenerative Design: Going beyond reducing harm or minimising waste by focusing on actively restoring and improving natural ecosystems through how products and systems are designed and used - e.g. BioPanel’s biodegradable material instead of plastics for coffee cups, which can return to earth after use.
• Blue Economy: An economic model that mimics natural ecosystems, transforming waste into valuable resources while supporting environmental regeneration and local economic development - e.g. growing mushrooms on coffee waste.
• Natural Capitalism: Emphasising that economic success and environmental sustainability must go hand-in-hand by recognising the value of natural capital - e.g. Interface’s carbon negative flooring, which uses recycled and carbon-sequestering materials.
• Cradle to Cradle (C2C): A design philosophy that aims to eliminate the concept of waste by designing products so that all materials can be safely and continuously cycled in either the biological or technical cycle - e.g. *DESSO EcoBase carpet tiles**.

Each offers a unique perspective on design, production, and resource use - essential to the Circular Economy.

Ref.: Lecture 9

Question 8

Q8: What are the ’10 Rs’ and how do they relate to the Circular Economy? How can companies use them to develop circular strategies?

Answer 8

The 10Rs are organised from the linear economy to the circular economy:

1. Refuse (R0): Avoid using a product or material altogether; prevent waste at the source - e.g. avoid packaging or single-use items.
2. Rethink (R1): Use products more intensively through shared use or multifunctional designs - e.g. product-as-a-service models like car sharing.
3. Reduce (R2): Use fewer resources and materials in production and consumption - e.g. material efficiency.
4. Reuse (R3): Use a product again for its original purpose without major repair - e.g. refillable containers.
5. Repair (R4): Fix a broken product to extend its useful life - e.g. repairing laptops with a new battery.
6. Refurbish (R5): Restore an old product to good working condition with minor updates - e.g. refurbished smartphones.
7. Remanufacture (R6): Rebuild a product to like-new condition using reused and new parts - e.g. remanufactured car engines.
8. Repurpose (R7): Use a product or its components for a different function - e.g. turning old clothes into new.
9. Recycle (R8): Process materials to obtain raw materials for new products - e.g. melting plastic into pellets.
10. Recover (R9): Extract energy or materials from waste that cannot be reused or recycled - e.g. incineration with energy recovery.

Relation to Circular Economy:

• The 10 Rs represent practical strategies that align with the Circular Economy’s goal of keeping resources in use for as long as possible.
• They encourage businesses to shift away from the linear model of “take–make–dispose” toward systems that retain value, reduce waste, and regenerate natural systems.

How companies use the 10Rs to develop circular strategies

• Design Phase: Apply Refuse, Rethink, Reduce by minimising material use and designing modular, Repairable, and Recyclable products.
• Business Model Innovation: Integrate Rethink through Product-as-a-Service or sharing platforms to increase product use per unit.
• Operational Strategy: Develop infrastructure for Reuse, Repair, Refurbish, Remanufacture, and Recycle, including take-back programs and reverse logistics.

Ref.: Lecture 9

Question 9

Q9: Please use a product of your choice to explain the Butterfly Diagram.

Answer 9

A Circular Economy aims to:

• Keep products, materials, and components in use at their highest value for as long as possible.
• Decouple economic growth from resource consumption.

The Butterfly Diagram consists of:

• Body: Linear production
• Wings: Cycles

The Butterfly Diagram identifies two cycles in a Circular Economy:

1. Technical Cycle: Applies to non-biodegradable materials (e.g., metals, plastics, electronics), and the goal is to retain value by circulating products and parts.

Strategies - Laptop:

• Share: Increase product use by multiple users through sharing models - e.g. shared pool of laptops at the library.
• Maintain/Prolong: Extend a product’s life through maintenance/repair - e.g. replacing a laptop battery.
• Reuse/Redistribute: Use the product again as-is by the same or a different user - e.g. donating/selling a laptop.
• Refurbish/Remanufacture: Restore to working condition or rebuild to like-new condition by using reused or new parts - e.g. factory-refurbished laptops through “buy-back” programs.
• Recycle: Recover raw materials from a product after end of life, which is a last resort since materials are retained, but product value is lost - e.g. recovering lithium from the battery or gold from the circuit board of a laptop.

2. Biological Cycle: Applies to biodegradable materials (e.g., food, wood, organic waste), and the goal is to return nutrients to the biosphere and rebuild natural capital.

Strategies:

• Farming/Collection: Harvesting renewable biological resources such as plants, fish, and animals from nature.
• Extraction of Biochemical Feedstock: Processing organic materials to extract useful substances like oils, enzymes, or bio-based chemicals.
• Cascades: Sequential use of a material in different applications to maximise its value before disposal.
• Anaerobic Digestion: Biological process that breaks down organic waste in the absence of oxygen.
• Biogas: A renewable fuel generated during anaerobic digestion.
• Regeneration: The process of returning nutrients to the biosphere, helping to rebuild natural capital (e.g., improving soil quality for future farming).

Circular economy seeks to minimise waste and systemic leakage, and focuses on maximising utility and value from resources throughout their lifecycle.

Question 10

Q10: What differentiates linear from circular supply chains?

Answer 10

In short:

• Material Flow: One-way vs. Closed-loop / regenerative.
• Waste Generation: High vs. Minimised or eliminated.
• Resource Use: Extractive vs. Restorative and regenerative.
• Value Retention: Lost at end-of-life vs. Maintained or increased.
• Collaboration: Limited vs. High (reverse logistics and partnerships)

Flow of materials:

• Linear: Take-Make-Dispose model - one-way flow, no recovery.
• Circular: Closed-loop model - multi-way flow where materials cycle back into the economy through reuse, repair, refurbishment, remanufacturing, and recycling to retain product/material value.

Resource use and waste:

• Linear: Relies heavily on virgin resource extraction, and ends in waste generation.
• Circular: Aims to minimize resource input and eliminate waste by regenerating and circulating materials.

Value retention:

• Linear: Product value is lost at the end of its life.
• Circular: Product and material value is preserved or even enhanced through strategies like remanufacturing or product-as-a-service models.

System thinking

• Linear: Operates in isolated stages, with little coordination beyond immediate suppliers or customers.
• Circular: Requires systemic collaboration across industries, often forming eco-industrial networks and symbiotic relationships.

Ref.: Lecture 9

Question 11

Q11: What framework can companies use to design circular supply chains?

Answer 11

The Circular Supply Chain Management (CSCM) Framework to design and implement circular supply chains. This framework integrates restorative and regenerative principles from the Circular Economy and supports both closed- and open-loop flows of materials.

Key components:

• Establishing a closed-loop system (materials return to the same supply chain) or open-loop system (materials flow into other supply chains).
• Defining circular strategies using the Five types of restorative loops: Reuse, Repair, Refurbish, Remanufacture, and Recycle.
• Designing products for Circularity for disassembly, material separation, and durability, enabling effective loop closure (Cradle to Cradle principle).
• Collaborating across the supply chain by engaging suppliers, logistics providers, customers, and even competitors in material recovery and loop creation (e.g. reverse logistics).
• Integrating lifecycle thinking by using Life Cycle Assessment (LCA) and Material Flow Analysis (MFA) to map impacts and material use, enabling better circular decision-making.

Question 12

Q12: How do the five different categories of ‘loops’ relate to supply chain strategies?

Answer 12

Five loops that influence supply chain design by encouraging strategies that reduce resource input, extend product life, and recover value, aligning with Circular Economy principles.

Five loops:

1. Closing: Reusing materials through e.g. recycling and remanufacturing to create a closed-loop system that minimises waste by turning it into raw materials.

• Strategy: Design reverse logistics and recovery systems.
• Goal: To minimise waste.

2. Slowing: Extending the life of a product/material through durable design and PLC extensions like repairing, maintaining and refurbishing.

• Strategy: Design for circularity.
• Goal: To delay product disposal.

3. Narrowing: Using fewer resources per product by optimising production processes and improving design to reduce raw materials needed.

• Strategy: Optimise production and design for less material.
• Goal: To reduce the total volume of materials entering the supply chain.

4. Intensifying: Introducing a more value-intensive use-phase to promote the idea of pooled or shared product use over individual consumption.

• Strategy: Enable shared use or pooled consumption models.
• Goal: To maximise the utility of each product across users/use cycles.

5. Dematerialising: Substituting products for services to increase the utility and longevity of products (materials), as seen in the shift from product ownership to product service systems (PSS).

• Strategy: Shift to product-as-a-service models.
• Goal: To reduce materials throughput by substituting services.

Ref.: Lecture 10

Question 13

Q13: How do the supply chain processes change if we consider circularity?

Answer 13

In a circular economy context, supply chain processes shift from a traditional linear “take–make–dispose” model to a closed-loop system designed to retain the value of products, components, and materials for as long as possible.

Changes include:

• Strategy: Component price vs. Leasing and service
• Structure: Linear and open vs. Cascaded loops and closed
• Flow: Input-Output vs. Biological and technical cycles
• Focus: Efficiency vs. Collaborative value capture
• Scale: High volume vs. Medium-low volume
• Scope: Global vs. Regional and local

Explained:

1. Integration of reverse logistics, i.e. flow forwards (downstream) and backwards (upstream), to enable processes like repairing, remanufacturing and recycling.
2. Support for restorative loops that demand new processing steps, logistics and collaboration.
3. Lifecycle-based product design for durability, modularity, disassembly and recyclability to align with the supply chain capabilities for loop closure.
4. Enhanced collaboration across stakeholders is required, including improved information sharing (e.g. via Digital Product Passports).
5. New business models and flows like product-as-a-service.
6. Waste becomes a resource to close the loop, which redefines procurement and production planning strategies.

Question 14

Q14: What performance measurements we discussed in class are relevant for sustainable and circular supply chains?

Answer 14

Circularity metrics include:

• Amount of recovered materials
• Amount of renewable energy used
• Percentage of recyclability of product
• Percentage of virgin materials content
• Percentage of recycled content

Other:

• Environmental impact (e.g., carbon footprint)
• Resource efficiency
• Life Cycle Costing

Problem: Tendency to only improve what can be measured.

Ref.: Lecture 10

Question 15

Q15: How are MFA and LCA related?

Answer 15

Material Flow Analysis (MFA): Quantifies physical material flows.

Life Cycle Assessment (LCA): Evaluates the environmental impacts of products.

The two analyses are complementary tools used to support sustainability and circular economy strategies.

1. Both use systems thinking to define boundaries for analysis, and both track inputs, outputs and transformations across the defined system over time.
2. MFA provides the quantitative material data for LCA:
3. Use in CE: MFA helps identify where materials are lost, stockpiled, or reused (useful for designing closed-loop systems), and LCA evaluates how different reuse or recycling scenarios impact the environmental footprint.

Ref.: Lecture 10

Question 16

Q16: How does a LCA support the transition to a Circular Economy?

Answer 16

In short: LCA identifies hotspots in the life cycle where improvements can maximise resource efficiency and reduce negative impacts, enabling informed CE strategies.

Explained:

1. Identifies environmental hotspots, which can help companies prioritise circular strategies most effectively.
2. Supports eco-design and circular product development by helping material selection.
3. Evaluates and compares circular strategies, like new vs. recycled materials, to enable the choice of solutions that reduce carbin footprint.

Ref.: Lecture 10 (+ 11 and 12)