• Energy Research

Abstract In the process of energy transformation in China, the potential competitiveness of natural gas power plants and coal-fired power plants equipped with carbon capture and storage (CCS) technology should be considered. In this study, the levelized cost of electricity (LCOE) method is used to compare the competitiveness of these two types of power plants. The results show that regardless of whether a carbon pricing mechanism is included, the LCOE is lower for coal-fired power plants with CCS than for natural gas power plants if the coal-fired power plants have the same level of emission reduction as the natural gas power plants or ensure deep emission reductions. When the coal price reaches 750 CNY/t, the coal-fired power plants with the CCS technology lose their competitive advantage when the carbon price is less than 158 CNY/t. In Shanxi province, the coal-fired power plants with CCS technology have a greater competitive advantage than the natural gas power plants.

As an effective emission reduction approach, CO2 capture and storage (CCS) combined with enhanced water recovery (EWR) technology can not only reduce CO2 emissions, but can also recover deep saline water resources to relieve pressure on regional water resources, and can ensure the energy supply and both social and economic development. However, the environmental benefits and application costs of CCS-EWR are uncertain, and are determined by the technology level, geological conditions, and other physical factors. In this study, an optimal source-sink matching model and a techno-economic assessment model were developed to evaluate the contributions of CCS-EWR to carbon emission reduction and the increase of the water supply by considering various uncertain factors, as well as the corresponding costs. In addition, the Yellow River Basin (YRB) in China was selected as the research region because, while there are abundant coal-fired power plants (CFPPs) in the YRB, the water resources are scarce. The results revealed the following. (1) The maximum CO2 capture capacity of the 236 CFPPs in the YRB is about 738.77 Mt/a, and nearly 13.14 Gt of fresh water could be provided until the 236 CFPPs in the YRB retire, which can partially relieve the pressure on the supply of water resources. (2) With the consideration of the CCS-EWR benefits, the average cost of the 236 CFPPs in the YRB in their residual lifetime to reduce their CO2 emissions by 90% will be no more than 180 CNY/t. (3) The incentive effect of the increase of the industrial water price on the profits of CCS-EWR projects is not significant. CCS-EWR technology has better application prospects in China under the dual constraints of carbon-neutral targets and water shortages, and more policy support is required for its deployment.

To implement strict environmental targets in China's cement industry into small regions, one should evaluate the city-level eco-efficiency that provides comprehensive instruction. This study establishes a plant-level database with 4000+ production lines located in 341 cities, calculates the energy consumption and CO2, SO2, NOx, and PM emissions, evaluates the eco-efficiency in each city via Slacks-based Measure, and verifies the spatial features of these indicators. Results show that the energy consumption and emissions of the industry are highly concentrated, with ~10 % of the land area contributing to 28.4 %-34.6 % of the total amounts in 2019. The average eco-efficiency value of the clinker calcination and cement grinding processes are 0.761 and 0.714, but the city clusters having low eco-efficiency values are inconsistent with the ones having large energy consumption and emission amounts. The results can contribute to the implementation of the targets such as carbon peaking and pollution cap in China's cement industry.

Abstract Carbon capture, utilization, and storage (CCUS) is regarded as an important option to reduce the CO2 emission of the electricity industry, especially in China. But emissions reduction potential of CCUS within each special administrative region needs to be identified. We explored the near-term CO2 storage potential of coal-fired power plants in China from the county perspective. According to the results of emissions sources and storage sites within counties, the following findings were reached: 1) Coal-fired power plants are distributed in 441 counties, the oil fields are in 149 counties, and the deep saline aquifers are in 561 counties. The spatial distribution of storage sites and coal-fired power plants is not consistent across counties. 2) Considering the injection capacity of single well, the CO2 storage potential decreased by more than 50%. Thirty counties have emission reduction potential through CCUS, with a total of 99.01Mt/y. 3) The CCUS emission reduction of counties in the top five provinces accounts for 83.9% of the total. Hebei, Xinjiang, Tianjin, Jiangsu, and Anhui provinces can be regarded as demonstration provinces for near term project deployment.

Carbon Capture, Utilization, and Storage (CCUS) technology has emerged as the bottom-line technology for achieving carbon neutrality goals in China. The development of Carbon Dioxide Enhanced Oil Recovery (CO2-EOR) not only increases revenue for high-investment CCUS projects but also enables permanent CO2storage in the oil reservoir. However, the basin is used as the research object to evaluate the CO2storage potential of the oil reservoir. The evaluation results are inaccurate and unable to support the implementation of later CCUS projects. Here, more accurate oil reservoir data is employed as the evaluation object. It is the first time at the national level to screen oil reservoirs to distinguish between CO2miscible and immiscible, and evaluate the potential of CO2-EOR and CO2storage in the reservoir. The research results show a total of 2570 suitable oil reservoirs in 4386 candidate oil reservoirs nationwide. About 1.26 billion tons of additional crude oil can be produced by CO2-EOR technology. This includes approximately 580 million tons of additional oil from CO2miscible flooding and 680 million tons from CO2immiscible flooding. The study further refines the CO2geological utilization data and provides a theoretical basis for CCUS project site selection in China.

Abstract Carbon capture utilization and storage (CCUS) technologies are crucial for achieving long-term climate change goals in China. Drawing on the 45Q tax credit provisions enacted by the U.S., three subsidy modes, two scenarios and two carbon emission reduction options are developed in this study, in which the real options approach combined with a trinomial tree model is employed to evaluate investment decisions made by coal-fired power plants (CFPP) in China. The results show that offering a 12-year CO2 storage subsidy to full-chain CCUS CFPP provides the motivation needed for CCUS investment during the 12-year subsidy period; however the economic benefits of such investment cannot be sustained over the 40-year lifetime. It's economically viable for CFPP to capture 90% CO2 emissions and sell them to oil enterprises for enhanced oil recovery (EOR) over a 40-year period. Besides, for full-chain CCUS CFPP the incentive effects of the 45Q subsidy mode and the full initial investment plus operation and maintenance (I + O&M) subsidy mode are much more suited to the 40-year emission reduction option, whereas the simple O&M subsidy mode is more suitable for the 12-year emission reduction option. However, for CO2-EOR projects, there is no significant difference between the three subsidy modes.

Abstract A trinomial tree model based on the delay real option is developed to evaluate the carbon capture and storage (CCS) retrofitting investment for existing coal-fired power plants in the context of the 45Q tax credit. The uncertainties regarding the carbon price, the CCS retrofitting investment cost, the operation and maintenance (O&M) cost, the CCS investment subsidy scenarios, and the allocation ratio of the carbon dioxide (CO2) storage subsidy between the coal-fired power plants and CO2 storage enterprises are taken into consideration. The results show that if the allocation ratio of the CO2 storage subsidy for coal-fired power plants is zero, the full government subsidy for the initial CCS investment cost and clean electricity tariff (0.015 CNY/kWh) are not sufficiently attractive for the coal-fired power plants to invest in CCS and the critical allocation ratio is 17.8% in this case. The critical allocation ratio increases to 26.4% if the government subsidy for the initial CCS investment cost is zero. Moreover, if the government subsidy for the initial CCS investment cost and clean electricity tariff are both canceled, the coal-fired power plants need to receive at least 33.3% of the CO2 storage subsidy to invest in CCS. The results provide theoretical support for the decision-making regarding CCS retrofitting investment and CCS subsidy policy-making.

Abstract Traditional policy incentives for carbon capture and storage (CCS) mainly rely on fiscal subsidies, which tend to put an inordinate strain on public finances. This study attempts to explore a non-fiscal incentive policy, granting a time extension (extra electricity quota), to finance early CCS demonstration projects in China. We find that coal-fired power plant (CFPP) operate at a loss even without CCS retrofitting under the current electricity quota (4000 h per year), while it can make profits with CCS retrofitting if extra electricity quotas are provided. Specifically, the electricity quota needs to be roughly 4709–7260 h per year with the CO2 capture level ranging from 0.1 to 1 Mt per year in the demonstration stage. In particular, the levelized cost of electricity (LCOE) of CFPP with a capture level of 1 Mt per year is estimated at 298.8 CNY/MWh if the electricity quota reaches 7000 h per year, which is approximately equal to that of CFPP without CCS retrofitting and extra electricity quota (292.2 CNY/MWh). Thus, the extra electricity quota can be considered as an economically feasible policy incentive, and related results are able to provide useful information for electric power enterprises and government decision-makers.

Carbon Capture, Utilization, and Storage (CCUS) technology plays a crucial role in China’s journey toward achieving “carbon neutrality”. To ensure the optimal efficiency and risk mitigation of CO2-EOR projects, it is imperative to enhance the safety system. This study develops a comprehensive safety evaluation system for the CO2-EOR project at Dagang Oilfield, employing a combination of the Analytic Hierarchy Process (AHP) and expert scoring. The AHP method is used to analyze the relative importance of various safety factors, while expert scoring is employed to determine the weight of each factor. The system establishes four primary evaluation indexes and 17 secondary evaluation indexes. This score indicates the relative safety of the blocks, with a lower score reflecting higher safety. A safety assessment is conducted on the Ye 21 and Ye 22 blocks using this system, which results in an assessment score of 1.2721 (less risky), indicating a relatively low overall risk. The study aims to provide a practical framework for the safety evaluation of CO2-EOR projects, and the proposed method can be applied to other CCUS projects globally to enhance safety and risk management.