Developing a Material Flow Cost Accounting Model for Integrated Supply Chains Under the Circular Carbon Economy

In the modern world, businesses are under increasing pressure to account for more than just the money they make and spend. They are being asked to track the invisible footprint of their operations: the carbon dioxide released into the atmosphere. For decades, companies have used standard accounting methods to measure how much raw material they waste, calculating the cost of lost wood, metal, or food. However, these traditional methods often treat waste as a simple physical loss, ignoring the environmental cost of the carbon embedded in that waste. As governments begin to charge fees for carbon emissions and investors demand transparency, a new approach is needed. This approach must connect the physical weight of a discarded product with the specific amount of carbon it represents, treating the carbon cycle not just as an environmental issue, but as a financial one. The goal is to create a system where closing the loop on carbon—capturing it and using it again instead of letting it escape—is as clear and measurable as counting the coins in a register.

A researcher named Ezzaddin Hasan Kadhim has developed a new accounting model designed to solve this exact problem. The study focuses on a concept called the "closed carbon economy," which goes beyond the general idea of recycling to focus specifically on keeping carbon in use. In this system, waste carbon is not released into the sky but is recovered and fed back into the production process. To test whether this idea could work in the real world, Kadhim applied a new method called Material Flow Cost Accounting to a complex supply chain in the agrobiochemical sector. This specific chain involves growing sugarcane, turning it into raw sugar, fermenting it into bioethanol fuel, and finally using the leftover residues to generate electricity. The researcher tracked five distinct stages of this process, measuring not only the tons of material moving through each step but also the carbon density of every flow.

The investigation revealed a significant hidden cost that traditional accounting missed. Across the entire supply chain, the process generated 5,478 tonnes of material waste, which represented nearly 20% of all the inputs. While standard accounting would simply tally the cost of this wasted material, the new model added a second layer: the cost of the carbon contained within that waste. By applying a price of fifteen dollars per tonne of carbon dioxide equivalent, the study calculated that the carbon waste alone cost the supply chain 187,260 US dollars. This figure represents a substantial financial burden that was previously invisible to managers. The study also introduced a new way to measure efficiency called the Carbon Cycle Closure Index. This index acts like a scorecard, showing what percentage of the carbon entering a stage is successfully recovered and reused versus what percentage is lost. In this specific case, the average score for the entire chain was 0.79, meaning that roughly 79% of the carbon was being kept in the loop, while the rest was escaping.

The results showed that the efficiency of keeping carbon in the loop varied significantly depending on the stage of production. The initial farming and harvesting stage performed the best, with a score of 0.85, indicating that most of the carbon in the crops was successfully captured in the final products or reused. However, as the material moved through the industrial stages of refining and especially into the power generation phase, the efficiency dropped. The power generation stage, which burns residues to create electricity, had a score of 0.70, indicating that this is where the most carbon was being lost. The study suggests that this drop is due to the nature of combustion processes, which are inherently less efficient at retaining carbon compared to biological or chemical transformations. By identifying these specific weak points, the model allows companies to see exactly where they are losing money and carbon simultaneously.

To understand the potential of this new model, the researcher ran several simulations to see how the system would react to different changes. One scenario involved improving the technology in the power generation stage to capture more of the ash and residue for use as fertilizer. This change alone was projected to raise the efficiency score for that stage from 0.70 to 0.88 and save the company thousands of dollars in carbon costs. Another simulation tested the impact of raising the internal price of carbon. The study found that if the company started charging itself a higher fee for every tonne of carbon wasted, it would immediately make investments in waste-reduction technology financially attractive. The data suggested that once the price of carbon reached a certain threshold, the cost of fixing the problem would be lower than the cost of continuing to waste it.

The paper concludes that this integrated model offers a practical tool for businesses to meet global sustainability goals. By combining the measurement of physical waste with the cost of carbon, companies can make decisions that are good for both the environment and their bottom line. The study argues that without this level of detail, companies are flying blind, unable to see the true cost of their inefficiencies. The model provides a clear roadmap for improvement, showing that by closing the carbon cycle, industries can reduce their waste, lower their costs, and contribute to climate action in a way that is measurable and financially sound. This approach transforms the abstract concept of a circular economy into a concrete accounting practice, turning the recovery of carbon from a theoretical ideal into a daily operational reality.