Multi-objective optimization for hydrogen-mixed combined heat and power (CHP) plants considering economic and environmental factors based on MILP

Abstract

In this study, a mixed integer linear programming (MILP) model is built to analyze the operating strategy of the combined heat and power (CHP) units, and the impact of the hydrogen ratio on the cost and carbon emissions of the DES. The influence of the discontinuous working conditions of the CHP on the economy evaluation of the DES is investigated. The relationship between the energy consumption and the environmental benefits of the system under different hydrogen ratios is investigated and the optimal trade-off strategy is given. The results show that the electricity sales dominate the income influence considering electricity sales revenue, power generation subsidies, and carbon trading. The costs could save 60% at most. For the DES with hydrogen, the environmental benefits obtained by further increasing the proportion of hydrogen was not enough to compensate for the cost of hydrogen, resulting in an increase in the unit energy cost from 1.32 to 4.8 yuan/kWe. With the improvement of economic optimization satisfaction from 0 to 1(NG: H2 =1:1), electricity imported from the utility grid and carbon emissions increase by 24.11% and 22.61%, respectively. The low price advantage of grid electricity no longer expands when the economic satisfaction is greater than 0.7.