<p>In the context of the gradual maturation of electricity and carbon trading markets, the "value" and "carbon emission" attributes of energy products have received increasing attention. However, traditional analytical methods often treat these two attributes separately, lacking an integrated perspective or modeling method. To fill this gap, this paper proposes a joint value–carbon emission flow modeling method applicable to various energy systems. The method begins by tracing the carbon emissions flow throughout the energy system. It then integrates the carbon trading mechanism to calculate carbon costs and total operational costs. Based on value chain theory, it allocates energy product value based on these costs, thereby determining the value increment at each process within the system, which achieves a joint model of value and carbon emissions flow. The results demonstrate that the proposed carbon emission flow modeling method provides traceability while maintaining a calculation error of only 0.5% compared to traditional methods. Based on this, the proposed value modeling method effectively captures how different shares of renewable energy, participation in carbon trading, and variations in energy product parameters influence the creation and transfer of value within the system. This method provides robust theoretical support for energy product pricing and carbon quota allocation in the face of market fluctuations.</p>