Gas or electricity? Regional pathway selection under carbon neutrality target: A case study of industrial boilers

Scattered coal combustion in industrial boilers is one of the main sources of CO2 emissions in China. With their lower emission intensity, electric and gas-fired boilers are recognized as effective alternatives to coal-fired boilers. Therefore, with the promise of reaching a peak in carbon emissions and attaining carbon neutrality, due to the differences in power structures, fuel prices, and energy resources in different regions, it is significant to identify the most suitable regional alternatives for coal-fired boiler retrofitting and the influences of policy on the effect of CO2 emission mitigation. In this paper, an optimization model combined with power structures, fuel prices, and energy resources is developed to analyze the CO2 emission mitigation performances of coal-to-gas (C2G) and coal-to-electricity (C2E) retrofits for coal-fired industrial boilers in regions of China. Based on life-cycle data, the regional substitution portfolio of C2G and C2E in each region in 2017 is optimized with the objective of maximizing the CO2 emission reduction efficiency, and the policy effects of fuel price subsidies and CO2 emission fees are discussed by scenario analysis. Based on the perspective of the local electricity structure, the optimized future pathway of low-carbon development for industrial boilers in various regions is studied. The results indicate that, in 2017, C2G retrofitting is suitable for most regions in China, while both C2G and C2E retrofits are suitable for Fujian, Guangxi, Hubei, Yunnan, Sichuan, and Qinghai. Only Yunnan's optimal portfolio is suitable for a 100% C2E retrofit without any supporting policies. “Thresholds” of electricity price subsidy exist for enterprises to adopt a C2E retrofit. It is easier to implement C2E in Fujian with a relatively low electricity price subsidy, while it is difficult to implement C2E in Qinghai as it requires a high electricity price subsidy. The effect of CO2 emission fees on improving CO2 emission reduction efficiency is only remarkable for Qinghai. Until 2050, 100% C2G retrofitting is still suitable in Henan, Hunan, and Jiangxi; in contrast, Yunnan, Fujian, Guangdong, Shaanxi, Guangxi, and Xinjing could benefit from a 100% C2E retrofit. If carbon capture and storage (CCS) is implemented, Beijing and Henan would also benefit from a 100% C2E retrofit. This study not only could help decision-makers to formulate a detailed policy for CO2 reduction but also could provide a suggested pathway for CO2 reducti