Evaluation of cost reduction potential for a coal based polygeneration system with CO₂ capture

The coal based polygeneration with CO₂ capture (PG + CC) technology is expected as one of the possible options to mitigate CO₂ emissions with low cost and low energy. This work assesses the cost reduction potential of PG + CC technology based on learning curve method, and finds out what factors and how they influence the cost curve.Results show that the unit investment of PG + CC can decrease to around 600-900$/kW from current 1500$/kW by means of capacity increment, technology further localization and plant efficiency upgrade. Localization and plant efficiency upgrade will play an important role in PG + CC cost reduction. 45%∼55% of the unit investment reduction originates from the capacity increment, 20%∼35% from technology localization, and 10%∼20% from plant efficiency upgrade.Compared with IGCC technology with CO₂ capture (IGCC + CC), the unit investment of PG + CC is 25%∼30% lower. Compared with coal-pulverized supercritical plant with CO₂ capture (PC + CC), in short term PG + CC is less economically competitive; In medium term, when the total installed capacity reaches several to ten GWs, the unit investment of PG + CC technology can compete with that of PC + CC and will be lower afterwards; In long term, the PG + CC technology will be more economically competitive than PC + CC. Moreover, PG + CC is more energy efficient than the other two technologies. The results indicate that the coal based PG + CC is more acceptable for China and may act as a significant part in CO₂ capture technologies.