A three-stage evaluation model for biomass co-firing combined with carbon capture and storage (in oil wells) retrofit in coal-fired power plants based on multi-criteria decision-making: An example from Hebei Province, China

Coal-fired power plants can be retrofitted by biomass co-firing combined with CO2 capture and storage, reducing carbon emissions significantly. Site selection is an important task for the entire project, but little research has been done on this. Therefore, this paper proposed a three-level evaluation model. Firstly, alternative power plants and carbon sequestration sites (set oil wells as an example) were screened by feasibility evaluations. Secondly, source-sink pairs were performed based on the shortest distance between power plants and oil wells. Finally, source-sink pairs were evaluated with suitability evaluation. Entropy weight method (EWM) and Analytic hierarchy process (AHP) were used to calculate objective and subjective weights, respectively. Lagrangian optimization method was used to combine the two weights. The ranking results of alternative source-sink pairs were obtained through Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) improved by combined weight. An example of in-service power plants in Hebei Province was conducted. Engineering geology and reservoir characteristics were the most important considerations. D5 (source: Langfang thermal power plant, sink: Bieguzhuang - Jing 11 oil well) was the best choice of the five given candidates. The results of the study provided an evaluation framework for governments and investors in retrofitting power plants.