For capture link, the model needs CO₂ emissions amount (also as capture demand) and CO₂ capture cost data for different industries and capture methods.

The CO₂ capture demand data under the fossil energy continuation scenario is mainly based on the report “The Road to China's Carbon Neutrality” published by the Global Energy Interconnection Development and Cooperation Organization (GEIDCO) ^[22]. According to the predicted annual carbon emissions of major carbon-emitting industries (including energy, chemical, metallurgy, and building materials) in China and their location distribution ^[9], considering factors such as population growth, economic development, industrial scale, and future planning layout, the total CO₂ emissions demand of different industries in seven regions of China will reach 27.33×10⁸ t in 2060, involving the petroleum and chemical industry, thermal power, steel and cement industry. The CO₂ reduction amount of CCUS in China in 2060 is roughly equivalent to the upper limit of CCUS reduction amount in the United States in 2050 predicted by the US Department of Treasury, i.e., 24.5×10⁸ t ^[9]. Based on the development trend and application potential of different technical routes of CO₂ capture ^[4], the capture amount of specific technical routes used in different industries has also been divided.

Different technical routes are used for different application scenarios (industries, facility conditions, CO₂ concentration, etc.), and different technical routes have different technological maturity, applicability, economic feasibility, and corresponding facility construction processes. The economic cost of carbon capture is also different. The technical scenarios considered by the model include exhaust gas capture from chemical plants and heating boilers in the petrochemical industry; pre-combustion capture, post-combustion capture and oxygen-enriched combustion capture in the thermal power industry; carbon capture in the steel industry; and carbon capture in the building cement industry. The unit carbon capture cost in 2060 under different scenarios ranges from 70 to 170 RMB/t ^[4,9].

For storage method, the model needs the location, capacity and cost data of the storage target area.

The storage data is mainly based on the research of the “National Evaluation and Demonstration Project of CO₂ Geological Storage Potential” led by the China Geological Survey Bureau ^[23]. The research shows that the regions in China with large CO₂ storage potential include onshore regions such as the Ordos Basin, the Junggar Basin, the Tuha Basin, the Songliao Basin and the Sichuan Basin, and offshore regions such as the Pearl River Mouth Basin, the East China Sea Basin, and the North Jiangsu-South Yellow Sea Basin. According to the suitability evaluation results, the storage basins are divided into five levels: suitable, relatively suitable, general, relatively unsuitable, and unsuitable. The higher the suitability level, the better the geological safety, storage environmental risk and economic suitability conditions are. The model only considers the storage target areas of the first three levels and reflects the suitability levels in the storage cost.

Based on the geological conditions and suitability evaluation of different target areas ^{[9,23⇓ -25]}, we have sorted out the cost of CO₂ storage in different regions and the maximum capacity corresponding to each cost. The costs of different storage technical routes are 35 RMB/t for depleted gas reservoirs, 50-150 RMB/t for onshore enhanced saline aquifers and 100-200 RMB/t offshore saline aquifers respectively ^[9,18,23].

For utilization method, the model needs the data on the distribution, development potential, and utilization benefit of relevant industries. The utilization scenarios include biological, chemical and geological utilization, specifically including gas fertilizer, methanol-ethylene, methanol-traditional raw materials, urea, methane, methanol-aromatic hydrocarbons, enhanced oil and gas exploitation, involving chemical industry, agriculture, oil and gas, and other industries. The economic attributes of each link of CCUS in the model are expressed as costs. Therefore, the benefits brought by the utilization link are expressed as negative values for the cost.

Chemical utilization is the field with the greatest potential for CO₂ utilization, especially for ethylene, traditional raw materials and urea. Synthesizing CO₂ and hydrogen gas into chemical products by using the power to raw materials (P2X) technology is an inevitable trend for increasing electrification rate and promoting clean development in the future ^[26]. In this model, the geographical distribution of CO₂ utilization potential for different types is predicted based on the current distribution of chemical product industry across the country ^[27⇓-29]. Based on the difference between electricity production costs and fossil fuel prices, the benefit of chemical utilization is 7-350 RMB/t ^[26,29].

Biological utilization mainly considers the use of CO₂ as gaseous fertilizers. The development potential of microorganism utilization to produce high value-added products is limited for its high cost. According to relevant research and technological progress, the model assumes that CO₂ gas fertilizer will bring an average yield increase of 30% to greenhouse crops ^[32], and the economic benefit of each ton of CO₂ is about 455 RMB. Based on the survey of China's greenhouse planting scale, it is estimated that the national CO₂ utilization potential is about 21 million tons per year ^[22]. Considering the limitation of land area and the expected slight population decline in 2060 compared with the current ^[30], the gas fertilizer utilization potential in 2060 is calculated based on the current utilization potential.

Geological utilization mainly includes EOR and EGR (enhanced gas recovery), mainly in large oil and gas fields in North China, Northeast China and Northwest China. About 13 billion tons of OOIP in China are suitable for EOR, which can increase the recovery factor by 15%, increase recoverable reserves by 1.92 billion tons, and store about 4.7-5.5 billion tons of CO₂ ^[9,31]. China's gas reservoirs are mainly distributed in the Ordos Basin, the Sichuan Basin, the Bohai Bay Basin and the Tarim Basin. Studies have shown that about 90 million tons of CO₂ can be stored through EGR ^[9]. In this model, considering a utilization period of 100 years, it is assumed that the yearly geological utilization potential of each oil and gas reservoir does not exceed 1% of the total utilization potential. The total equipment investment and project operation cost of EOR and EGR are about 25-30 RMB/t CO₂, and it is expected that the injection cost in 2060 will drop to about 10 RMB/t CO₂ ^[4,9]. Considering that fossil energy will become increasingly scarce in the future and that oil and gas energy attributes will decline due to the development of clean energy, it is estimated that the oil price during the carbon neutrality stage is about 700 dollars/t ^[33], and the average oil exchange ratio will improve from 1:7 to 1:3 with technological progress ^[31,34]. EGR technology is currently under research, and its commercialization is expected to realize after 2040. The average gas exchange ratio will reach 1:5 by 2060 ^{[4,31,35 -36]}. The economic benefit of EOR technology is expected to be about 1580 RMB/t CO₂ based on the yield increase benefit per unit weight of CO₂ minus input cost; while for EGR technology it is expected to be about 160 RMB/t CO₂.

Transportation methods include road and rail tank transport, pipeline, ship transport. Among them, pipeline is the most economical and safe way. This link involves the progress of pipeline system construction, the economy of different methods, and the global optimization scheduling of CO₂.

According to the roadmap planning of CCUS technology by the Department of Science and Technology for Social Development of the Ministry of Science and Technology of China, China will build more than 20 000 km of land pipelines with an annual transportation capacity exceeding 1 billion tons by 2050 ^[4]. Offshore pipelines will enter the commercial application stage ^[4]. It is expected that by 2060, China's land pipelines will meet the transportation demands between major industrial agglomeration areas and storage target areas. Tank truck transportation can be used within local areas. Considering the scale effect and equipment investment, the transportation prices of land pipelines, road tank trucks, rail tank trucks, and offshore pipelines are 0.3, 1.2, 1.0, and 1.0 RMB/(t•km), respectively ^[4-5,9].

The target of the model is to minimize the total cost of the CCUS entire process. With data of the CO₂ capture demand of different industries in each region and the distribution of utilization/storage resources, appropriate transportation methods and paths are used to match the capture link with the utilization/storage link to form a CCUS whole-process processing process. The whole-process cost and corresponding scale are calculated by recording the matching process. Based on the calculation results of seven regions including East China, North China, Central China, South China, Southwest China, Northeast China, and Northwest China, the cost and corresponding scale of CCUS technology in China can be obtained.

The basic structure of the calculation model for each region is shown in Fig. 1. According to the CCUS process, the model takes CO₂ capture location as the geographical starting point (blue box), and CO₂ utilization/storage resource site as the destination (orange box). Based on the location and scale capacity of capture and utilization/storage, reasonable transportation methods and routes (green box) are planned, connecting the starting point and the destination. Corresponding to the planned three links, the cost is summed up (as shown by dotted arrow). Thus the whole-process cost and corresponding scale are obtained (red box). The cost prediction of each link needs to consider factors such as technological progress, policy support, and scale effect, while the maximum scale prediction needs to consider current industry scale and future development affecting factors.

Due to limited forecast data and planning materials, we make the following assumptions: (1) For channels with transportation demand exceeding 1.0×10⁸ t/a, it is assumed that a mature pipeline has been constructed, and the transportation cost is calculated according to pipeline method. (2) Compared with CO₂ storage, CO₂ utilization has a smaller scale and a better economic benefit, and is the preferred processing method considered in each region. Considering China's plan to build a CCUS industry cluster, the CO₂ utilization in the model first meets the CO₂ processing demands of the local area, and the transportation distance is calculated based on an average of 50 km. (3) Considering the difference in storage difficulty of saline aquifer, the annual storage amount of each target area is divided according to 1:3:3:3 in injection sequence, and the cost is calculated at 50, 80, 100, and 150 RMB/t respectively.

In the model, the whole country is divided into seven regions, namely East China, North China, Central China, South China, Southwest China, Northeast China, and Northwest China, the costs and scales of different links in each region are sorted out respectively. The typical curve diagram of the model (Fig. 2) is only used to illustrate the modeling method, and the curve drawing does not completely correspond to the above data.

The research results can be applied to the national CO₂ transportation pipeline planning and the cost prediction of CCUS-based thermal power generation.

The construction of the CO₂ transportation pipeline network mainly supports two situations: one is that the local area has insufficient storage resources and needs to transport a large amount of CO₂ over long distances to other areas; the other is that the industrial agglomeration area and storage resources in the local area are far away and large-scale transportation within the region is needed. Based on the calculation results, routes with such transportation demands are statistically calculated as recommended transportation pipeline planning channels.

The combination of “thermal power generation + CCUS” is an important path for the power industry to achieve smooth carbon reduction. The model calculation results provide support for cost analysis of thermal power generation based on CCUS. By taking a weighted average cost of three CO₂ capture methods of thermal power (i.e., pre-combustion capture, post-combustion capture and oxygen-enriched combustion capture), plus the national average transportation + utilization/storage cost, the CCUS whole-process cost is obtained, which can be converted into the cost per kilowatt hour of CCUS according to the carbon emission per kilowatt hour of power generation.

Three transportation schemes, namely local on-site storage, long-distance off-site storage, and on-site and off-site combined storage, are used to construct models.

China has a vast territory, with storage areas concentrated in the northern regions, but a considerable portion of capture demand in the central and southern regions. Moreover, China's CO₂ storage potential is much greater than its utilization potential. Among 3 links in the whole process of CCUS, the scale and location of CO₂ capture link is determined according to capture demand, while the storage target areas need to be scientifically planned according to the distribution of CO₂ capture locations and national storage target area resources. If a nearby storage target area is selected, transportation costs can be saved, but storage conditions may not be good, costs may be high, and geological risks may be high. If a faraway storage target area with good conditions is selected, storage costs can be saved and geological risks can be reduced, but distance may be long and transportation costs may be high.

In some areas, there are suitable storage target areas, so off-site transportation is not needed in three schemes. In some area, however, there are no suitable storage target areas, so off-site transportation is needed in all the three schemes.

This scheme focuses on the geological safety and storage environmental risks, only using the basin resources with the first 2 levels of suitable and relatively suitable storage conditions. These target areas are mainly concentrated in the northern regions. In the southern regions, however, there are scattered suitable storage target areas only in the Sichuan Basin and the Jianghan Basin. Therefore, most of the CO₂ in the south needs to be transported to the north for storage. Table 3 lists the model calculation results of 7 regions and the whole country.

The calculation results show that the CCUS economic cost of this scheme is relatively high, with an average cost of 388 RMB/t and a maximum of 671 RMB/t. The average transportation distance is 720 km. Captured CO₂ of the eastern, central and southern regions need to be transported across regions for storage. When the CO₂ price in carbon market is set at 100 RMB/t, 14% of the CO₂ in the country is reduced by CCUS, of which only about 10% are in North China, East China, Central China and Southern China. If the price is increased to 300 RMB/t, the percentage is risen to 22%, with the highest in Northwest China (about 68%), and Central China and Southern China less than 10% where storage resources are poorer. Under this scheme, if all CO₂ in the country is reduced by CCUS, the CO₂ price needs to be set at 671 RMB/t or above. With CO₂ price of 600 RMB/t, 72% CO₂ (19.8×10⁸ t) in the country will be reduced by CCUS technology.

This scheme simulates the situation of poor cross-regional transportation pipeline conditions, and relies on CO₂ storage targets nearby, using storage resources with 3 levels of suitable, relatively suitable and general conditions. Table 4 lists the results of 7 regions and the whole country.

The calculation results show that the CCUS economic cost of this scheme is lower than that of the long-distance off-site storage scheme, with an average cost of 252 RMB/t and a maximum cost of 571 RMB/t. The average transportation distance is 168 km, and all seven regions in the country achieve local storage. When the CO₂ price is set at 100 RMB/t, about 18% CO₂ in the country is reduced by CCUS, with a lower proportion in North China, Central China and Southern China (about 10%). If the price is increased to 300 RMB/t, half of CO₂ in the country is reduced by CCUS, with Northwest China 100%, but Southern China less than 10%. If all CO₂ in the country is reduced by CCUS, the CO₂ price needs to be set at 571 RMB/t or above. With CO₂ price of 500 RMB/t, 90% CO₂ (24.6×10⁸ t) in the country will be reduced by CCUS technology.

This scheme comprehensively considers the optimal economic cost and the suitability of storage targets. It gives priority to the use of storage resources with suitable and relatively suitable conditions, and reasonably selects on-site or off-site storage methods to achieve CO₂ storage. Table 5 lists the model calculation results of 7 regions and the whole country.

The calculation results show that the CCUS economic cost of the scheme is lower than that of both the 2 above schemes, with an average cost of 225 RMB/t and a maximum of 451 RMB/t. The average transportation distance is 256 km. On-site storage can be realized in all regions except East China and Southern China, where cross-regional transportation is needed for CO₂ storage.When the CO₂ price is set at 100 RMB/t, about 18% CO₂ in the country is reduced by CCUS, with a lower proportion in North China, Central China and Southern China (about 10%). If the CO₂ price is increased to 300 RMB/t, over half of the CO₂ in the country is reduced by CCUS, with Northwest China 100%, but Southern China less than 10%. If all CO₂ in the country is reduced by CCUS, the CO₂ price needs to be set at 451 RMB/t or above. With CO₂ price of 400 RMB/t, 86% CO₂ (23.51×10⁸ t) in the country will be reduced by CCUS technology.

Each scheme has its advantages and disadvantages, and different requirements for the construction of CO₂ transport pipelines. The on-site storage scheme does not require large-scale construction of cross-regional transport pipelines, so its transportation costs are low, but poor storage conditions in some southern regions lead to high storage costs and high environmental risks in the later period. The off-site storage scheme can make full use of geological resources with better storage conditions throughout the country and realize carbon flow optimization and configuration on a national scale, and has low storage costs and low environmental risks in the later period, but it requires support from a relatively complete pipeline network, so it has relatively high transportation costs. The combined on-site and off-site scheme integrates the advantages of the above 2 schemes, comprehensively considers the utilization of high-quality storage resources and the whole-process economic cost, optimizes pipeline topology structure, and realizes global optimal allocation of CO₂. Under the scenario of fossil energy continuation, the average whole-process CO₂ emission reduction costs of the 3 schemes are 388, 252, and 225 RMB/t respectively. The CO₂ prices to cover all the CO₂ reduction demand by CCUS in China are 671, 571, and 451 RMB/t respectively, which intuitively reflects the superiority of the combined on-site and off-site scheme from an economic perspective. In addition, due to fewer geological storage resources, poorer conditions and longer transportation distance, the emission reduction costs in the southern regions such as South, East and Southwest China are generally higher than those in the northern regions.

The national CCUS technology cost is distributed in the range of -1432-451 RMB/t, with about 50% distributed around 300 RMB/t (Fig. 4). Of the total emission reduction demand of 27×10⁸ t in China, CO₂ utilization can consume about 5×10⁸ t, accounting for 18%, and its whole-process cost is generally below 200 RMB/t. CO₂ storage processes about 22×10⁸ t, accounting for 82%, and its whole-process cost is above 200 RMB/t. The proportion of biological, chemical and geological utilization is about 1:17:7. Among them, about 4×10⁸ t CO₂ utilization creates economic value that exceeds processing costs and achieves benefits, corresponding to the part where the ordinate is less than zero in Fig. 4, which is the preferred CO₂ emission reduction method. Among the three utilization methods, EOR has the best economic benefits, and CCUS whole-process of unit mass CO₂ can bring about 1400 RMB/t benefit (as shown by the red dotted line part in Fig. 4 expressed as a negative value from a cost perspective). Onshore saline aquifer storage is the main method of CO₂ geological storage. It processes about 21×10⁸ t CO₂, which accounts for more than 76% of total emission reduction demand. The whole-process cost of storage part is generally higher than that of utilization part. South China and East China have higher storage costs than other regions due to their large CO₂ emissions and scarce storage resources. An analysis of the composition ratio of storage costs shows that for on-site storage part, capture costs and transportation + storage costs are approximately equal; while for cross-regional storage part, transportation costs increase significantly with a ratio of approximately 1:2.

Different regions have their own characteristics in terms of emission reduction demands and geological conditions. (1) The South and East China need to transport CO₂ to the storage target areas in Central China, and the transportation cost is high. (2) The Northwest China has abundant storage resources, but the storage demand is small. Also, due to the long distance of the storage target area (concentrated in Xinjiang) from other capture locations, it is difficult to provide storage support to other regions. (3) Northeast, North, Central, and Southwest China can basically realize local storage. Taking the East China with high emission reduction demand as an example, the local biological and chemical utilization potentials are 0.64×10⁸ t and 1.15×10⁸ t respectively, and there are no geological utilization conditions. Among them, 1.12×10⁸ t of utilization can achieve benefits (Fig. 3). The adjacent Jianghan Basin in Central China has suitable geological storage conditions and low environmental risks, and CO₂ can be transported by pipeline at a cost of about 400 RMB/t to realize about 3×10⁸ t saline aquifer storage. Secondly, CO₂ can be transported to the North Jiangsu-South Yellow Sea Basin with general geological storage conditions to realize about 2×10⁸ t saline aquifer storage at a cost of about 450 RMB/t.

In the whole process of CCUS, the capture and transportation links are pure cost links, and the utilization/storage link is potentially profitable link. Taking the on-site and off-site combined storage scheme as an example, cost sensitivity analysis is carried out without considering the effects of subsidies and carbon taxes.

The cost difference of the capture and transportation links is small for different scenarios and methods, and the total cost is 148-341 RMB/t. The cost of the capture link is 73-171 RMB/t, with an average cost of 123-151 RMB/t in each region, a national average cost of 140 RMB/t, and a standard deviation of 37 RMB/t. The transportation cost is distributed between 75 and 200 RMB/t, with an average cost of 75-170 RMB/t in each region, a national average cost of 109 RMB/t, and a standard deviation of 50 RMB/t. Transportation costs are mainly affected by local and remote factors. Local utilization or storage mainly uses tank trucks or small-scale pipelines for transportation, with transportation costs basically around 80 RMB/t. Remote transportation mainly uses pipeline with costs generally exceeding 150 RMB/t.

The cost (benefit) difference of the utilization/storage link is large, ranging from −1580 RMB/t to 80 RMB/t. CO₂ utilization can bring profits, but different utilization methods have large differences in profits. The profit generated per unit mass of CO₂ ranges from 7 RMB/t to 1580 RMB/t. CO₂ storage is an investment link with a cost distribution range of 35-80 RMB/t. The total difference of utilization/storage links is larger. Its national average cost is −24 RMB/t (that is, the link is profitable after all), and the standard deviation is as high as 435 RMB/t. Among them, the standard deviation of CO₂ utilization methods is as high as 453 RMB/t.

In summary, the main cost-influencing link in the entire CCUS process is the utilization/storage link, especially CO₂ utilization. The potential for high-value-added utilization methods is great, the overall economic value of the CCUS industry is high.

(1) Develop chemical utilization related industries based on P2X technology. CO₂ utilization is the only profitable technology among all CCUS links, among which chemical utilization is the field with the greatest development potential, but it needs to transform traditional chemical industry based on fossil energy into P2X industry based on clean energy ^[26]. China is the world's largest CO₂ emitter, as well as the largest country in power generation fields including hydropower, wind power, solar power, and biomass ^[37], with sufficient CO₂ resources and clean energy ^[38]. P2X technology uses clean electricity to produce hydrogen, which is then chemically combined with CO₂ to prepare fuels and raw materials, realizing the production of high value-added industrial products while reducing CO₂ emissions ^[38]. It is suggested to encourage R&D of key technologies such as electric hydrogen production and electrochemistry, and explore win-win commercial models for electrochemical related industries involving power generation, transmission, chemical industry and CCUS. Enterprises and institutes are encouraged to actively participate and invest to form P2X industrialization technological conditions by 2030 and promote its application in the post-peak phase after 2030, which enhances the cost competitiveness and builds good investment ecology of CCUS industry.

(2) Plan a CCUS industrial cluster in the Jianghan Basin and its surrounding areas. Building an industrial cluster after 2030 is a national long-term development plan of CCUS industry, which can reduce costs and improve emission reduction benefits ^[4-5,9]. Model results show that both East and South China are regions with high emission reduction demand and scarce storage resources. The Jianghan Basin is located at the junction of these two regions with certain storage potential ^[23] and traditional chemical industry foundation ^[27⇓-29], which can provide storage and utilization conditions for Yangtze River Delta and Pearl River Delta regions. It is suggested to carry out relevant industrial layout and infrastructure planning before 2030, enters into the implementation construction stage after carbon peak, and coordinate and complement different links of CCUS between different regions, which will give full play to regional advantages.

(3) Explore multi-party collaborative win-win business cooperation models. The CCUS industry chain is long involving many industries. Cross-border cooperation between industries such as petroleum, chemical industry, energy, construction, is an inevitable trend. At present, commercial development of CCUS technology is still in its early stage ^[9], requiring policy guidance to explore and construct healthy and benign commercial cooperation models, attract multi-party investment, improve operation efficiency and reduce docking costs. It is suggested to guide and support demonstration projects landing and commercial model exploration through policy support and funding support before 2030. After accumulating certain operation experience by 2030, promote application on a large scale and form a benign operating investment profit environment to support CCUS industrialization and large-scale development.

Based on the model calculation results, in the scenario of fossil energy continuation, about 80% of China's CO₂ needs to be stored in onshore saline aquifers to realize emission reduction, so it is necessary to search for suitable storage targets. The geological storage potential screening indicates that areas with better saline aquifer storage conditions are mainly concentrated in northern regions such as Inner Mongolia, Xinjiang and Heilongjiang ^{[9,18,23⇓ -25]}, while areas with developed industry, dense population and large emission reduction demand are mainly concentrated in South China and East China ^[9,22]. Storage targets and CO₂ sources show a trend of deviation in space, so China's large-scale CO₂ transportation demand generally shows a trend from south to north. In addition, although there are storage targets with relatively suitable conditions within some regions such as Northwest, North and Northeast China, industrial agglomeration areas with large CO₂ emission demand are often far from storage targets, so it is necessary to construct transportation pipelines within the regions to realize CO₂ storage.

Based on the paths with larger-scale CO₂ transportation demand in the on-site and off-site combined storage scheme, the 2060 CO₂ transportation pipeline paths are selected to meet the global optimization allocation needs. The main pipeline paths include Guangdong-Jiangxi, Yunnan-Sichuan-Chongqing, Shanghai-Zhejiang-Jiangxi- Hunan-Guangxi, Shanxi-Shanxi-Inner Mongolia, Shandong-Hebei-Beijing, Hebei-Liaoning-Jilin-Heilongjiang.

In the scenario of fossil energy continuation, the national CO₂ capture demand of coal-fired power industry reaches 9.5×10⁸ t, including 0.5×10⁸, 8.5×10⁸ and 0.5×10⁸ t for pre-combustion capture, post-combustion capture, and oxygen-enriched combustion capture, respectively. China's thermal power generation is mainly based on coal combustion (also known as coal-fired power generation), and its CCUS average cost is calculated by summing the average CO₂ capture cost of thermal power and the whole-society average cost of transportation and utilization/storage links. The average CO₂ capture cost of thermal power is 126 RMB/t (it is the weighted average cost of three capture methods of thermal power, and the capture link is not influenced by the scheme selection). The whole-society average cost of transportation and utilization/storage links is the weighted average of total costs of transportation and utilization/storage links in 7 regions (different schemes have different costs). The calculation results show that in 3 three schemes, the CCUS average cost of coal-fired power generation is 365, 231, and 203 RMB/t respectively, and correspondingly the increase in electricity price is about 0.29, 0.18, and 0.16 RMB/(kW·h) (based on the CO₂ emission intensity of coal-fired power generation: 890 g/(kW·h) ^[39]). In southern China, great CO₂ capture demand and poor storage conditions makes its economic cost the highest of 7 regions, which reaches 460, 460, and 352 RMB/t respectively in all 3 schemes, corresponding to an increase in electricity price of 0.36, 0.36, and 0.28 RMB/(kW·h). In Northwest China, the capture demand is small, the economic cost is low, and there are abundant local storage target areas with suitable conditions, so on-site storage is adopted in 3 schemes, and the economic cost is as low as 34 RMB/t with a corresponding increase in electricity price of only 0.03 RMB/(kW·h). Due to its resource endowment characteristics, China's natural gas power generation scale is small. If gas power generation is developed in the future, it is expected that its CCUS cost in 2060 will be about 247 RMB/t with a corresponding increase in electricity price of about 0.10 RMB/(kW·h) (based on CO₂ emission intensity of gas power generation: 390 g/(kW·h) ^[38]).

Among 3 schemes, the long-distance off-site storage scheme has higher CCUS cost of coal-fired power generation, and the cost of the local on-site storage scheme is basically the same as that of the on-site and off-site combined storage scheme, which are 0.18 and 0.16 RMB/(kW·h), respectively. The local on-site storage scheme makes more use of salt aquifer resources with poorer storage conditions in the southern regions, which may bring the risk of CO₂ leakage. What's more, the maximum cost in local on-site storage scheme is higher, and the national cost variance is larger, so the carbon price for carbon neutrality completely by CCUS is be higher. Therefore, form the perspective of emission reduction of coal-fired power generation, it is recommended to adopt the on-site and off-site combined storage scheme for CCUS technology.

As the national transmission pipeline system is completed, the CO₂ emission reduction cost of coal-fired power generation based on CCUS can be controlled at 0.16 RMB/(kW·h), and its LCOE (Levelized Cost of Energy) is expected as 0.6 RMB/(kW·h).