Gasification of coal and biomass as a net carbon-negative power source for environment-friendly electricity generation in China

Significance

Deploying coal-bioenergy gasification systems with carbon capture and storage (CBECCS) provides a promising opportunity for China to realize its carbon mitigation and air pollution abatement goals simultaneously. We conducted a comprehensive assessment of CBECCS technology for China, with a focus on plant and fuel configurations (e.g., biomass ratios) and economics, as well as CO ₂ and greenhouse gas emissions and cobenefits for air quality. We find significant opportunities for carbon mitigation with air quality cobenefits from deployment of CBECCS systems in regions that are both rich in crop residues and facing urgent needs to curb serious air pollution. The study thus provides critical information for policy makers seeking to exploit the carbon-negative energy opportunities of CBECCS technology.

Abstract

Realizing the goal of the Paris Agreement to limit global warming to 2 °C by the end of this century will most likely require deployment of carbon-negative technologies. It is particularly important that China, as the world’s top carbon emitter, avoids being locked into carbon-intensive, coal-fired power-generation technologies and undertakes a smooth transition from high- to negative-carbon electricity production. We focus here on deploying a combination of coal and biomass energy to produce electricity in China using an integrated gasification cycle system combined with carbon capture and storage (CBECCS). Such a system will also reduce air pollutant emissions, thus contributing to China’s near-term goal of improving air quality. We evaluate the bus-bar electricity-generation prices for CBECCS with mixing ratios of crop residues varying from 0 to 100%, as well as associated costs for carbon mitigation and cobenefits for air quality. We find that CBECCS systems employing a crop residue ratio of 35% could produce electricity with net-zero life-cycle emissions of greenhouse gases, with a levelized cost of electricity of no more than 9.2 US cents per kilowatt hour. A carbon price of approximately $52.0 per ton would make CBECCS cost-competitive with pulverized coal power plants. Therefore, our results provide critical insights for designing a CBECCS strategy in China to harness near-term air-quality cobenefits while laying the foundation for achieving negative carbon emissions in the long run.