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

With an increasing pressure on climate change, China is actively looking for low-cost and lowenergy CO₂ capture technologies to mitigate CO₂ emissions aiming at its high-carbon economy. The coal-based PG+CCS (polygeneration technology with CO₂ capture) technology is expected as one of the possible options to reach the target China can afford both in economy and in energy consumption. This work is to assess the potential cost reduction of PG+CCS technology based on the learning curve method and to find out what factors and how they can influence the cost curve. Results show that with continuous maturity of the technology, the unit investment of PG+CCS can fall to around 600~900$/kW from current 1400$/kW by means of capacity increment, further localization of technology and plant efficiency upgrade. It is revealed that localization and thermal efficiency upgrade will play an important role in cost reduction of PG+CCS system. 45%~55% of the unit investment reduction originates from the capacity increment, 20%~35% from technology localization, and 10%~20% from the efficiency upgrade of the system. Compared with IGCC+CCS (IGCC technology with CO₂ capture), the unit investment of PG+CCS is 25%~30% lower. Compared with PC+CCS (coal-pulverized supercritical plant with CO₂ capture), in short term PG+CCS is less economically competitive; In medium term, when the total installed capacity reaches 4GW, the unit investment of PG+CCS technology can compete with that of PC+CCS technology, and will be lower afterwards; In long term, the PG+CCS technology will be more economically competitive than PC+CCS in the future. Moreover, PG+CCS is more energy efficient than the other two technologies. The results indicate that PG+CCS is more suitable for high-carbon energy and may act as a significant part in CCS technologies in China.