Abstract: A model for minimizing power generation costs in the power industry was established based on linear programming duality theory, and the shadow price of carbon dioxide in the power industry from 2014 to 2020 was measured and analyzed by taking Tianjin as an example, and the influencing factors were studied. The results indicate that the reduction of photovoltaic power generation costs in Tianjin's power sector will lead to a decrease in its carbon dioxide shadow price: for every 0.1 yuan per kWh reduction in photovoltaic power generation cost, the carbon dioxide shadow price decreases by an average of 13.66 yuan per ton, alongside a reduction in the average power generation cost. Under the condition of tightening carbon emission constraints, the shadow price of carbon dioxide in Tianjin's power industry did not show significant changes, but its power generation structure was continuously optimized, indicating that Tianjin can adjust the power generation structure to meet carbon quota requirements while keeping the marginal abatement cost unchanged. High carbon intensity thermal power generation can reduce the shadow price of CO₂ in the power sector by implementing CCS technology, though the average cost of power generation will rise.