- • Capacity evaluation model of coal power is established.
- • Quantitative analysis is provided for each regional power grid of China.
- • The coal power overcapacity of China exceeds 170 GW in 2019.
- • The overcapacity situation may further deteriorate during the 14th FYP period.
- • A reasonable scale of coal power is 950–1000 GW at 2025.
Since the beginning of 2020, the weak domestic power demand caused by the COVID-19 pandemic and the large-scale advancement of coal power construction projects may have further aggravated the coal power overcapacity in China. Given the new situation, this study collected the data on China’s installed electricity capacity and electricity demand during the 13th Five-Year Plan period. Moreover, a reasonable capacity evaluation model of coal power was established based on the energy and electric power balance to analyze China’s coal power overcapacity in 2019 and determine the reasonable capacity for 2025. The internal reasons of unreasonable energy structure and regional difference of energy structure are systematically discussed. Results show that the overcapacity in 2019 was approximately 170 GW, and the overcapacity situation in North, Northwest, and South China was particularly serious. The reasonable coal power capacity for 2025 under the basic situation is 950 GW, indicating that if all the coal power units under construction and planning are operated, the overcapacity in 2025 will be 300 GW. Sensitivity and comprehensive scenario analyses show that under different scenarios, the upper and lower limits of the reasonable coal power capacity in 2025 are 1083 and 794 GW, respectively. Finally, this paper proposes relevant policy recommendations to cope with China’s serious coal power overcapacity problem.
China’s power development is subject to strong policies and resource and environmental constraints. The resource endowment indicates that China’s electricity supply and consumption structure rely highly on coal power (Yuan et al., 2015). However, high coal consumption inevitably harms the environment (Yang et al., 2019, 2020; Han et al., 2019, 2020, 2021; (Wang et al., 2021)) (Wang et al., 2016) and exacerbates climate change (Xu et al., 2014). Worse, the unreasonable large-scale construction of coal power has led to serious coal power overcapacity in China (Yuan and Zhang, 2019; Na et al., 2018).
Since the delegation of the approval of coal power projects from the central government to the provincial government in November 2014, the enthusiasm for coal power investment in different regions of China has increased rapidly. According to the statistics of China Electricity Council (CEC), the newly approved coal power projects in China exceeded 150 GW in 2015, and the newly-added installed capacity of coal power reached 59 GW (CEC, 2016). By the end of 2019, the installed capacity of China’s coal power had reached 1045 GW, indicating an increase of approximately 160 GW from that in 2014 (CEC, 2020a). Behind the rapid growth of the installed capacity is the annual decrease in utilization hours. In 2019, China’s coal power utilization hours were only 4416 h (CEC, 2020b), which caused losses for many coal power companies (Lin et al., 2019). Facing the increasingly severe overcapacity situation, the Chinese government has issued a series of coal power regulation documents since 2016. In October 2016, the National Energy Administration (NEA) issued a document requesting the suspension of 110 GW coal power projects under construction (NEA, 2016a). The goal of the 13th Five-Year Plan (FYP) electricity development plan released in November 2016 is to control the installed capacity of coal power within 1100 GW and cancel or postpone coal power construction projects exceeding 150 GW (NEA, 2016b). Subsequently, NEA issued a list to postpone the 102 GW coal power projects until the 14th FYP (NEA, 2017a).
In this context, China’s coal power has become a popular research topic. Yuan et al. (Yuan and Zhang, 2019) analyzed the development path of coal power in China based on macro policies and resource and environmental constraints, and pointed out the necessity of controlling the coal power capacity. Xu et al. (2012) conducted scenario analysis based on electricity demand and carbon emission constraints, and concluded that the coal power capacity in China should be controlled within 1000 GW by 2020. Lin et al. (2019) analyzed the challenges faced by coal power development from the perspective of China’s power market reform, and proposed countermeasures. Meanwhile, various planning models for China’s power system have also been developed and applied. Hu et al. (2010) proposed an integrated resource systematic planning (IRSP) model to analyze the electricity saving potential of China’s power system from 2009 to 2020. Yuan et al. (2016) used the IRSP model to calculate the overcapacity of China’s coal power from 2015 to 2020. Zheng et al. (2014) expanded the model to include more elements like demand response and transmission network (IRSP-sgs). Wang et al., 2020a, Wang et al., 2020b) proposed the scientific coal production capacity (SCPC) model to evaluate the rationality of China’s coal power development from 2000 to 2016. However, the above models are all data-intensive, even requiring input of load profile and unit output characteristic data, which are usually unavailable (Yuan et al., 2016). Therefore, empirical values are often used to replace actual parameters that are difficult to obtain. Moreover, this type of model often takes the lowest cost as the planning goal, which underestimates the development of China’s power system restricted by political and environmental factors, so the accuracy of medium- and long-term planning is difficult to guarantee (Feng et al., 2018). Therefore, some researchers believe that using simplified indicators to directly assess the coal power overcapacity can ensure the reliability of the conclusion (Lin et al., 2018; Feng et al., 2018; Zhang et al., 2020).
Currently, two main indicators are used to evaluate coal power overcapacity. One is the utilization hours, which reflect the economic benefits and utilization rate of coal power units (Zeng et al., 2017; Liu et al., 2020; Wang et al., 2020a, Wang et al., 2020b); the other is the installed reserve margin, which reflects the reliability or redundancy of the power system (Laleman and Albrecht, 2016; Ibanez-Lopez et al., 2017; Zhang et al., 2020; Lin et al., 2018). By combining these two indicators, an evaluation model based on energy and electric power is proposed to quantitatively calculate the coal power overcapacity of China (Yuan and Zhang, 2017; Feng et al., 2018; Zhang et al., 2020). This model is simple, the required data is available, the calculation process is direct and transparent, and the results are often convincing.
The literature review shows that previous studies on China’s coal power overcapacity focused on the 13th FYP. However, the situation has changed significantly. Under the impact of the COVID-19 pandemic, China’s electricity consumption growth rate declined sharply in 2020 (CEC, 2020c). As the pandemic situation around the world worsens, the economies of most countries continue to weaken. Standing alone as a major trading country is difficult for China, and the electricity demand may also drop during the 14th FYP. Meanwhile, having undergone strict control since 2016, China’s coal power project construction has begun to show a trend of recovery. From 2020 January to May, the newly promoted coal power projects in China reached 48 GW, which is 2.8 times that in the entire year of 2019 (Jiang, 2020). Local governments have regained enthusiasm for coal power investment.
The central and local governments have started to draft the 14th FYP electricity development plan. The setting of coal power targets will have a significant impact on the future development trend of coal power. Therefore, scientifically quantifying the current coal power overcapacity and reasonably setting coal power development goals are urgent problems to be solved. On the basis of the new domestic and international situation, this study quantitatively calculates the current overcapacity of coal power in China through energy and electric power balance and evaluates the reasonable scale of coal power in 2025 for reference by policymakers. The research framework is shown in Fig. 1, and the rest of this paper is organized as follows. Section 2 presents the model, the key parameter settings, the scenario settings, and the data sources. Section 3 analyzes China’s coal power overcapacity in 2019 and the reasonable capacity in 2025. Section 4 is present the conclusions and policy recommendations.
Fig. 1. Research framework.
2.1. Evaluation model for reasonable coal power capacity
According to the research of Feng et al. (2018), an evaluation model for reasonable coal power capacity was established. The model is based on energy and electric power balance and selects the installed reserve margin, the reasonable scale of coal power, and the utilization hour of coal-fired units as evaluation indicators.
2.1.1. Energy and electric power balance
Electric power and energy balance are calculated by (1), (2), respectively (Feng et al., 2018), and the rationality of the calculation results is verified by Formula (3).(1)(2)(3)where.
: Reasonable installed capacity of coal power;
: Reasonable installed reserve margin;
and : Reasonable and upper limit of utilization hours of coal power, respectively;
and : Maximum power load and electricity consumption, respectively;
and : Equivalent capacity input and output of inter-regional exchange, respectively;
and : Energy input and output of inter-regional exchange, respectively;
: Installed capacity of different power supplies, including coal power, gas power, hydropower, pumped storage hydropower, nuclear power, photovoltaics, wind power, biomass and other power supplies, which are denoted as ;
: Capacity factor of different power supplies, including coal power, gas power, hydropower, pumped storage hydropower, nuclear power, photovoltaics, wind power, biomass, and other power supplies, which are denoted as ; the capacity factor here is defined as the ratio of the power generation capacity to its installed capacity at the peak load;
: Utilization hours of different power supplies, including coal power, gas power, hydropower, pumped storage hydropower, nuclear power, photovoltaics, wind power, biomass and other power supplies, which are denoted as .
2.1.2. Evaluation index
184.108.40.206. Installed reserve margin
The installed reserve margin refers to the ratio of the additional power supply capacity to the maximum power load, which ensure the power supply safety in the event of equipment maintenance and emergencies. A low installed reserve margin will reduce the reliability of the entire power system, while an extremely high installed reserve margin may lead to waste of resource and a reduction in economic benefits. Generally, the reasonable installed reserve rate of China’s power system is 12%–15%. The actual installed reserve margin can be calculated using Formula (4) (Feng et al., 2018).(4)
220.127.116.11. Reasonable scale of coal power
The reasonable scale of coal power refers to the coal power installed capacity when the power system is maintained at a reasonable installed reserve margin. After calculating the reasonable scale of coal power according to Formula (1), the coal power overcapacity () can be calculated using Formula (5).(5)
18.104.22.168. Utilization hours of coal power
The utilization hours of coal power reflect the economic efficiency of coal power plants. The designed annual utilization of China’s coal power plants is 5500 h. Generally, if the actual annual utilization is less than 5000 h, then the installed capacity is excessive (Yuan and Zhang, 2017). The reasonable utilization hours of coal power () in hours refers to the utilization hours corresponding to the reasonable installed capacity of coal power (), which is calculated using Formula (2).
First, the reasonable installed capacity of coal power () is calculated according to the electric power balance (Equation (1)). Then, the corresponding reasonable utilization () is calculated in hours according to the energy balance (Equation (2)). When is higher than , energy balance is the main constraint. At this time, priority should be given to energy balance to correct . Considering the actual operation of coal power plants in China, the upper limit of the utilization hours of coal power () is set to 6700 h (Yuan and Zhang, 2017).
2.2. Regional power grids in China
The main analysis object of this study is the seven regional power grids of China. Since the power system reform in 2002, power system in China has been operated by the State Grid Corporation and the Southern Grid Corporation. The state grid is further divided into six regional power grids (Fig. 2).
Fig. 2. Regional power grids in China.
2.3. Key parameter settings
First, several key parameters in our model must be set, including the capacity factor of different power supplies and the reasonable installed reserve margins of each province and the regional power grid.
2.3.1. Capacity factor
The capacity factor represents the output level of the power supply at peak load. According to previous studies (Yuan and Zhang, 2017; Feng et al., 2018; Lin et al., 2018; Zhang et al., 2020), the capacity factor of different power supplies is set as shown in Table 1. The capacity factors of photovoltaics and hydroelectric in different studies notably vary, and the determination of these factors is discussed in Section 2.4.
Table 1. Capacity factor of different power supplies.
|Type of power supply||Capacity factor|
|Pumped storage of hydropower||1.0|
2.3.2. Reasonable installed reserve margin
Given the different power structures in different regions of China, the reasonable installed reserve margin also varies. With reference to the documents issued by the NEA in 2017 (NEA, 2017b), the reasonable installed reserve margins of various provinces and the regional power grids are shown in Table 2, Table 3.
Table 2. Reasonable installed reserve margin of different provinces.
|Provinces||Reasonable reserve margin||Province||Reasonable reserve margin|
Table 3. Reasonable installed reserve margin of different regional power grids.
|Regional power grids||Reasonable reserve margin|
|Northeast China Power Grid||13%|
|North China Power Grid||14%|
|East China Power Grid||13%|
|Central China Power Grid||14%|
|Northwest China Power Grid||14%|
|Southwest China Power Grid||15%|
|South China Power Grid||13%|
2.4. Scenario setting
The power development of China is affected by many factors. In this paper, scenarios are determined by key influencing factors, including the growth rate of electricity demand, the development of renewable energy, and the capacity factor of hydropower and photovoltaics. The reasonable coal power capacity decreases in a high scenario and increases in a low scenario.
2.4.1. Electricity demand
Affected by the COVID-19 pandemic, the electricity consumption of China from January 2020 to June 2020 dropped by 1.3% (CEC, 2020c). According to the forecast of the State Grid Energy Research Institute (State Grid Energy Research Institute, 2020), the growth rate of the electricity consumption of China in 2020 is expected to be 1.5%–3.5%, and the growth rates of the electricity consumption in different regions in the neutral scenario are 2.3% (northeast), 2.6% (north), 1.3% (east), 1.2% (central), 4.4% (northwest), 3.6% (southwest), and 3.6% (south). On the basis of the electricity consumption growth rate setting, the maximum power load growth rate is set according to its historical relationship during the 13th FYP, as shown in Table 4.
Table 4. The growth rate of electricity demand in 2020.
|Region||Electricity consumption growth||Maximum power load growth|
The national electricity consumption growth rate during the 14th FYP is set to 3.5% in the basic scenario and to 4.0% and 3.0% in the low and high scenarios, respectively. Then, the electricity consumption and maximum power load growth rate of each province during the 14th FYP period are calculated according to (7), (8).(7)where.
: Electricity consumption growth rate of province i during the 13th FYP;
: National electricity consumption growth rate during the 13th FYP;
: Electricity consumption growth rate of province i during the 14th FYP;
: National electricity consumption growth rate during the 13th FYP.
: Maximum power load growth rate of province i during the 13th FYP;
: Maximum power load growth rate of province i during the 14th FYP.
Finally, the electricity consumption and maximum power load growth rate of each regional power grid during the 14th FYP are obtained by adding the data of various provinces, as shown in Table 5.
Table 5. Electricity demand growth rate of different regions during the 14th FYP.
|Region||Electricity consumption growth||Maximum power load growth|
2.4.2. Installed capacity
The power installed capacity of each region in 2019 was obtained by China Power Knowledge (China Power Knowledge, 2020) (Table 6). According to the development potential and policy planning of each regional power source, the development trend during the 14th FYP period is estimated (Table 7). For hydropower, the abundance of hydropower resources and the construction progress of hydropower stations are comprehensively considered. For pumped-storage hydropower, the existing resource points, the approval, and the construction progress are used as references (Jiang, 2019). For nuclear power, the scale in 2025 is estimated through the existing and under construction nuclear power units (China National Nuclear Safety Administration, 2020). For wind power and photovoltaics, the resource endowments of each region and the development speed during the 13th FYP are considered (Li, 2020).
Table 6. Regional power installed capacity in 2019.
|Unit: GW||Coal power||Hydropower||Pumped hydropower||Nuclear power||Wind power||photoelectric||Gas power||Biomass and others|
Table 7. Regional power installed capacity in 2025.
|Unit: GW||Hydropower||Pumped hydropower||Nuclear power||Wind power||photoelectric||Gas power||Biomass and others|
The renewable energy of China is rapidly developed, and great uncertainties affected by future policy changes. For example, according to the 13th FYP electricity development plan, the installed capacity target of optoelectronics in 2020 is 110 GW (NEA, 2016b). However, as of the end of 2019, the actual installed capacity of optoelectronics has reached 204.68 GW (CEC, 2020a). Therefore, we set different scenarios for the development speed of renewable energy. The basic scenario is shown in Table 7, and the low and high scenarios fluctuate at 15% (Table 8).
Table 8. Renewable energy installed capacity in 2025 under different scenarios.
|Unit: GW||Wind power||Optoelectronics|
2.4.3. Capacity factor of photoelectric
The photoelectric capacity factor represents the output level of a photovoltaic unit at the peak load, which depends on the solar resource endowment and peak load period of a specific area. Feng et al. (2018) and Lin et al. (2018) set this factor at 0.25–0.3, which is a typical value in North America. However, this value may lead to an overestimation of the output level of China’s optoelectronics, and affect the calculation results. Zhang et al. (Zhang, 2017) believe that the photoelectric capacity factor of China is 0.1. Some provincial energy administrations (Energy Administration of Shandong Province, 2019) also set this factor to 0.1 when formulating the plan for summer load peak. In addition, the State Grid Energy Research Institute (State Grid Energy Research Institute, 2017) points out that the daily load curve in most areas of China shows double peaks at noon and night, and photovoltaics cannot participate in electricity power balance at night peak load. Therefore, the value of the photoelectric capacity coefficient should be as conservative as possible. In this study, we set the value to 0.1 in the basic scenario, 0.2 in the high scenario, and 0.05 in the low scenario.
2.4.4. Capacity factor of hydropower
The hydropower capacity factor is affected by the abundance of upstream water. Lin et al. (2018) set this factor to 0.4–0.5, Feng et al. set it to 0.5, and Zhang et al. (Zhang, 2017) and the State Grid Energy Research Institute (State Grid Energy Research Institute, 2017) believe that the hydropower capacity factor of China is 0.6–0.7. We set the hydropower capacity factors of the basic, low, and high scenarios to 0.5, 0.4, and 0.6, respectively.
2.5. Data sources
The electricity demand data of various provinces during the 13th FYP come from the provincial statistical yearbook and statistical data released by the provincial energy administration, and the national data come from the CEC (CEC, 2016; CEC, 2017; CEC, 2018; CEC, 2019; CEC, 2020a; CEC, 2020b; CEC, 2020c). The power installed capacity data of each province during 2015–2019 come from China Power Knowledge (China Power Knowledge, 2020), and the coal power unit data come from COALSWARM (COALSWARM, 2020). The electric power transmission information between provinces/regions in 2019 come from the reports of the CEC and the NEA (China Electricity Council, 2020d, China Electricity Council, 2020c, China Electricity Council, 2020b, China Electricity Council, 2020a; NEA, 2020d). Tibet is not included due to insufficient data. Tibet’s electricity consumption in 2019 was 7760 GWh, and its power installed capacity was 3.23 GW (China Power Knowledge, 2020), respectively accounting for only 0.11% and 0.16% of the national total, imposing a negligible impact on the calculation results is negligible.
3. Results and discussion
First, the coal power overcapacity in different regions of China in 2019 is analyzed. Then, the reasonable coal power capacity in 2025 under the basic scenario is calculated. Furthermore, sensitivity analysis is performed on key influencing factors, including the growth rate of electricity demand, the scale of renewable energy, and the capacity factor of photoelectric and hydropower. Finally, through a comprehensive scenario analysis, the upper and lower limits of the reasonable coal power capacity in 2025 are provided.
3.1. Coal power overcapacity in 2019
The analysis results show varying degrees of excess coal power installed capacity in different regional power grids in 2019. As shown in Fig. 3, except for the Central China Power Grid, the installed reserve margins of the other regional power grids exceeded 20%. This phenomenon can be attributed to the insufficient fossil energy, photovoltaic, and wind power resources of Central China, coupled with the large-scale hydropower transmitted to other regions represented by the Three Gorges, which result in a relatively tight local power supply and a relatively low installed reserve rate (18.50%). The Northwest China Power Grid has the highest installed reserve margin (48.41%), which is more than three times its reasonable value (14%), followed by the North China Power Grid (33.76%) and the South China Power Grid (31.20%). Northwest China has abundant coal, photovoltaic, and wind power resources; During the 13th FYP, the scale of photovoltaic and wind power also ushered in explosive growth, and many local coal power projects were launched. In 2019, the installed capacity of photovoltaic and wind power reached 103.44 GW, accounted for 24.94% of the national total. Thus, the power installed capacity in Northwest China greatly exceeds its own electricity demand and delivery demand, resulting in the highest installed reserve margin (48.41%). According to calculations, the average installed reserve margin of China’s power system in 2019 reached 27.89%, which is much higher than the reasonable value of 13%–15%.
Fig. 3. Reserve margin of each regional power grid in 2019.
The reasonable and actual coal power installed capacities of each region in 2019 are shown in Fig. 4. North China had the largest installed capacity and the second-highest installed reserve margin, so its coal power overcapacity (52.11 GW) was much higher than those of the other regions; while the South and Northwest China had small installed capacities, but excessively high installed reserve margin, with the coal power overcapacity reaching 34.53 and 30.82 GW, respectively. The situation in East China is quite the opposite. Although the region’s installed reserve margin was not high, its second large installed capacity still led to a significant overcapacity (25.26 GW). The situation in other regions was relatively better. Especially in Southwest China, the power supply structure was dominated by hydropower (the hydropower installed capacity accounted for 69% in 2019), and only a small amount of coal power was used as peak shaving units, so the excess coal power capacity was only 6.06 GW. In general, the reasonable scale of coal power in China in 2019 was 865.63 GW, indicating that the national coal power overcapacity exceeded 170 GW.
Fig. 4. Actual and reasonable coal power capacity in each regional power grid in 2019.