Coal Power Units Research Articles

Optimization of coal power phaseout pathways ensuring energy security: Evidence from Shandong, China's largest coal power province

China has committed to peak carbon emissions before 2030 and achieve carbon neutrality before 2060. As the province with the country's largest coal power installed capacity, with soaring electricity and heating demands, Shandong has unique pathways to gradually phase out coal power. However, thus far, no studies have investigated coal power phaseout pathways at the provincial or national level with thorough consideration of energy security, encompassing both power and heating supply security. Here, we established five-dimensional criteria based on unit efficiency and environmental and technical attributes to evaluate unit-level coal power retirement priority and used an integrated resource strategic planning model to explore coal power phaseout pathways in Shandong. Overall, as many as 144 coal power units, which account for 6% of the total installed capacity, should have the highest retirement priority. Shandong could retire 100,000 MW of coal power by 2050 without compromising energy security through the ambitious development of low-carbon heating technologies. The evaluation criteria are applicable to various regions globally to assess coal power retirement priority. Shandong's case demonstrates the importance of low-carbon heating technology deployment in accelerating coal power phaseout to address climate change and facilitate energy transition.

Optimal coal power phase-out pathway considering high renewable energy proportion: A provincial example

Since the announcement of the “carbon neutrality” goal, China has actively promoted the low-carbon transition across various industries. Controversy surrounds the fate of existing coal power units as, despite their carbon emissions, they remain integral to meeting the escalating power demand. Simultaneously, the integration of renewable energy sources (RES) underscores the need for coal power to provide flexible services, ensuring the safety and stability of the power grid. This study takes a province as example, establishing a comprehensive simulation model that considers a high share of RES to evaluate the optimal phase-out pathway for coal power in China. The analysis incorporates factors such as Carbon Capture and Storage (CCS), Battery Energy Storage System (BESS), and power demand growth. Results suggest that an immediate reduction in coal power capacity is not viable due to concerns about power supply safety. Recommendations emphasize the importance of maintaining a steady coal power capacity in the short term while concurrently developing RES, BESS, and CCS technologies. This approach facilitates a judicious withdrawal of coal power, contributing to cost reduction and ensuring a balanced transition. Furthermore, effective demand-side management emerges as a crucial.

Analysis of the Operating Characteristics of a Photothermal Storage Coupled Power Station Based on the Life-Cycle-Extending Renovation of Retired Thermal Power Units

Analysis of the Operating Characteristics of a Photothermal Storage Coupled Power Station Based on the Life-Cycle-Extending Renovation of Retired Thermal Power Units

Optimal scheduling of deep peaking compensation for electric utilities considering multiple types of adjustable resources

Abstract This paper first analyzes the peak compensation process of electric power units in electric power enterprises, studies the carbon emission model of unit operation and the cost calculation method, then constructs an optimized dispatch model of deep peak compensation in electric power enterprises based on the factors of peaking subject and object and multiple types of adjustable resources, determines the critical peaking rate, and calculates the coefficient of the unit’s peaking capacity and the coefficient of the system’s peaking demand. Finally, based on the model, single-day and multi-day data from the regional power grid were analyzed, and the energy losses of the system units in summer and spring were compared before and after optimization. The results show that the average load factor of coal power units after the optimal dispatch of regional grid peak compensation is increased from 62%-68% before optimization to more than 91%, and the overall energy consumption of the system is reduced by 30.95% in the summer and 39.93% in the spring, which is of theoretical and practical significance for alleviating the scheduling pressure on the grid and the control problems of the power units.

Social and Economic Impact Assessment of Coal Power Phase-Down at the Provincial Level: An Entropy-Based TOPSIS Approach

With the rollout of the carbon peak and neutrality targets, conventional coal-fired power plants will gradually be phased down in China’s power system in an orderly manner. The economic and social impact of the energy transition is a vital topic that requires scientific measurements and evaluation. In this paper, we establish a comprehensive approach to assess the impact of provincial coal power phase-down with 11 indicators covering dimensions of economy, society, and industry. An entropy-based Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS) approach is adopted to calculate entropy weight, relative closeness, and other evaluation benchmark data. Then, the influence degree in 30 provinces is ranked based on the assessment. The results show that there is a significant regional imbalance in the process of coal power phase-down, among which Shanxi, Inner Mongolia, and other coal base provinces are the most vulnerable regions bound by their huge raw coal production and coal industry employment. Although the coal power industry is less affected than the coal industry, it will face pressure from the optimization of coal power units, followed by the dual impact of taxation and employment issues. Finally, the potential impacts of coal power phase-down and policy implications are proposed.

Multifactor configurations of coal power technology in China substantially differ in life-cycle environmental impacts

The expansion of coal power in China has led to a coexistence of multiple technologies, whereas differences in environmental impacts of each other remain hitherto unclear. This gap is largely a result of the difficulty of fully covering the factors that significantly affect environmental performances and the lack of fine data inventory. The limitation welcomes an approach that can go well beyond characterizing coal power technology with a single factor. To this end, we surveyed the information data for all coal power units in China to couple four factors (viz. operating parameter, boiler type, cooling approach, and turbine mode) into 22 types of multifactor technology configurations, as well as the first-hand operating data of nearly half of all coal power units in China to compile an elaborate data inventory that each configuration includes 88 input and output data. These fine data were modeled by the life cycle assessment method of CML 2016 to quantify twelve environmental impact categories. The results show substantial differences in environmental impacts exist for different technology configurations. High operating parameters gain environmental friendliness but the diversification of boiler type and cooling approach to improve the applicability of coal quality and water resources increases environmental impacts. The insignificant impact of the turbine mode is owning to the exergy allocation that eliminates the quality gap in electrical and thermal energy. The technology-level differences are aggregated into the provincial level by various configuration structures, which show markedly spatial heterogeneity varying by impact categories. This implies a great potential for structural adjustment and an overall improvement requires cleaner production beyond that, focused on the coal power generation process and its upstream coal supply process. Our modeling shows a majority of results with an uncertainty of lower than 10 %, which is robust for the proposal of policy suggestions.

Cost Analysis of the Boiler Unit of Coal Power Units Depending on the Initial Steam Pressure and the Availability оf Flue Gas Purification Systems

When designing power plants of a new type or equipping them with new generation equipment, the problem of estimating capital investments is solved with the uncertainty of information on its cost. The lack of reliable methods suitable for use in engineering setting complicates decision-making on the technical development of power units and thermal power plants. When evaluating investments in the equipment of power plant units, it is convenient to use continuous functions. Their use makes it possible to carry out the analysis without cost restrictions. The article proposes a method for estimating capital investments in the boiler island of power units of power plants based on a power parametric function. The method includes an assessment of the cost of a boiler unit with fuel preparation systems within the boiler shop, draught and blast. A specific feature of the method is that the cost of the boiler includes the cost of flue gas purification systems from harmful combustion products in the form of ash, sulfur oxides and nitrogen oxides. The method was developed in an engineering setting. The methodological section demonstrates the performance of the method in assessing capital investments in a boiler island in comparison with the same indicator for the EU countries, the USA and China. When discussing the results of the study, it was found that capital investments in a coal-fired boiler with flue gas purification systems is in the range of US$ 25–200 million, depending on the power and initial steam parameters. The share of the cost of environmental flue gas purification systems is 28–50 % of the total cost of the boiler unit. It is demonstrated that the design of coal-fired power units with flue gas purification systems for supercritical parameters with a capacity of less than 300 MW is inefficient due to low competitiveness in terms of specific investments in the boiler.

Research Progress of Flexible Peak Shaving Technology for Coal-Fired Boilers

In the face of the pressing challenges of climate change and carbon emissions, China's energy and power sectors are actively working towards the strategic goal of establishing a new power system, where wind and solar energy will constitute a rapidly expanding portion of grid-connected power generation. Nevertheless, the inherent characteristics of these renewable energy sources, such as their randomness, intermittency, and volatility, pose significant challenges to ensuring the secure and stable operation of the power grid. Presently, China heavily relies on pulverized coal power plants, which lack the flexibility required to accommodate the fluctuating demands posed by renewable energy generation. Overcoming this technical obstacle and enabling efficient grid integration of renewable energy necessitates a thorough exploration of the potential of existing pulverized coal furnaces for flexible peaking operations, especially under extreme peak shaving conditions. To address this challenge, coal self-preheating combustion technology has emerged as a pioneering solution developed by the Institute of Engineering Thermophysics, Chinese Academy of Sciences. By implementing preheating modification activation, this innovative approach alters the traditional combustion reaction path of pulverized coal, significantly enhancing its reaction activity. This advancement holds immense promise for achieving efficient and stable combustion, as well as facilitating rapid load changes in pulverized coal boilers operating at low loads. This study primarily focuses on discussing prevalent means of peaking technology, including low-load stable combustion technology, rapid load regulation technology, coupled peaking technology, and the development status of peaking technology for coal power units. Through in-depth research and innovation, it is anticipated that the effectiveness and viability of peaking technology will be further enhanced, promoting the sustainable development of pulverized coal boiler generating units and optimizing the operation of energy systems. Furthermore, the self-preheating combustion technology will increasingly play a pivotal role in multiple sectors and directions, such as flexible and deep peaking of coal power, driving the advancement and adoption of clean and effective coal utilization technology.

Research on Coordinated Control Strategy of Thermal Heating and Melting Depth of Steam Heating and Melting Salt Reservoir

The implementation of the upgrading of the national coal electric power unit has provided a clear proposal to promote the clean and low-carbon transformation of the power industry. With the power of large-scale intermittent renewable energy and power generation, the electric crew should be flexible enough to adjust resources to achieve a depth of 35% THA. This article aims to propose a heat extracting and heat storage system for fire power plants, to realize the coordinated control strategy of the deep peak, and to explore the coordinated control strategy of the steam–molten salt heat exchanger, molten salt and water exchanger, and the turbine’s main control. The simulation results reveal that the coordinated control of the steam–molten salt heat exchanger, molten salt and water heat exchanger, and steam turbine control could reduce the depth of the fire power unit by 10% THA. The output power response speed of the thermal power unit is enhanced by utilizing the heat turbine, which could effectively enhance the output power response speed of the thermal power unit and increase the output power response speed pertinent to 302.55 s by 75.60%.

Analysis of China’s power system transformation

China is the largest CO2 emitter, and thermal power units are the main source of CO2 emissions. The low-carbon transformation of thermal power units is the key to carbon emission reduction. China is rich in wind and solar energy resources; wind power and photovoltaic power generation technologies are mature and have good economic prospects. Significantly increasing the proportion of installed wind power and photovoltaic power is the main idea of the power system low-carbon transformation. Biomass fuel blending is the only solution for thermal power units to reduce carbon emissions. Drawing on the large proportion of biomass blending technology in large foreign coal power units, the low-carbon transformation of thermal power units will be completed, and eventually, together with wind power and photovoltaic power generation, China’s renewable energy-based low-carbon power system will be formed. The process of low-carbon transformation of the power system reduces the use of fossil energy, reduces external energy dependence, and improves national energy security. The low-carbon transformation of the power system should be steadily promoted to prevent large adverse impacts on society and the economy.

Can Inner Mongolia Learn from Zhejiang’s Low-Carbon Policy?—Comparative Analysis Based on the EPS Model

Based on the energy policy simulation model (EPS model) and the reality of Zhejiang Province and Inner Mongolia Autonomous Region, the carbon pricing policy scenario and the early retirement policy scenario of coal power generation units were constructed, respectively, and the policy effects simulated. The study explored whether Inner Mongolia Autonomous Region can learn from the low-carbon policies that have played a good role in Zhejiang Province in the process of achieving a carbon peak. The research found that: (1) Under the baseline scenario, both Zhejiang Province and Inner Mongolia Autonomous Region failed to achieve a carbon peak by 2030. (2) Under the scenarios of carbon pricing and early retirement of coal power generation units, the peak time of carbon in Zhejiang Province and Inner Mongolia Autonomous Region has been advanced, which shows the effectiveness of carbon pricing and early retirement of coal power generation units. (3) The above two policies have achieved good results in the overall implementation process of Zhejiang Province, but the carbon pricing policy has caused dramatic fluctuations in the power generation in Inner Mongolia Autonomous Region, and the early retirement policy of coal power units has failed to achieve the goal of reaching the peak carbon in Inner Mongolia Autonomous Region on schedule.

The challenge of just transition in China’s coal power sector: a city-level employment vulnerability assessment

ABSTRACT China’s target to achieve carbon neutrality by 2060 entails the phase-out of high-emissions coal power. However, a just transition policy must be implemented, given that coal power and its upstream coal mining industry provide many employment opportunities. Leveraging a bottom-up tabular analysis, we assessed the impact on employment of coal-fired power plant closures in China’s 330 prefecture-level cities. We identify vulnerable areas for employment in the transition and propose a customized employment incentive policy through a vulnerability assessment framework. Results show that in 2020, the direct employment in the coal power industry was 1.68 million, among which 16.76% will be affected by the 2045 net-zero deadline for the power sector. This number will increase to 36.90% if coal power capacity increases to 1300GW by 2030. However, 92% of Chinese cities will not suffer from unemployment risks since cities with high employment vulnerability are mostly concentrated in coal resource-based cities like Shuozhou (Shanxi Province), Huainan (Anhui Province), and Yulin (Shaanxi Province). In addition, the contraction of China's coal power-related employment will emerge only after 2035; a transition management framework focusing on highly vulnerable areas should be established as soon as possible to protect the well-being of affected workers and facilitate a just transition. Key policy insights New coal power projects should be cut back as much as possible, and instead the service life of incumbent coal power units should be extended where necessary. If no new coal power plants are built after 2020, only 16.76% of existing employment will be affected by 2045, but the share would double if new units were added. In order to effectively manage a just transition, it is necessary to plan early and establish a comprehensive policy system that takes regional differences fully into account.

Analysis and research on the impact of carbon market on the clearing price of coal-fired power units

The coal power industry accounts for the largest proportion of carbon dioxide emissions, and is first included in the national carbon market, while the cost of carbon emissions has a certain impact on the coal power clearing price. Based on this, this paper constructs a bidding model of coal-fired power units considering the cost of carbon emissions; Taking Guangdong Province as an example, this paper simulates the change of the clearing price of the spot market of coal power units in the light, medium and heavy carbon market scenarios, and provides relevant suggestions for the construction of the electricity market and carbon market.

Key problems of gas‐fired power plants participating in peak load regulation: A review

AbstractThe peak regulation capacity of gas‐fired power plants has always been an important flexibility resource of the power grid. Under the guidance of carbon emission reduction, the coal power units are gradually shut down, making the role of gas‐fired power plants more important. However, in practice, gas‐fired power plants often fail to show satisfactory flexibility. The main reasons are as follows: (1) Part of the capacity mechanism fails to effectively encourage gas‐fired power plants to provide reliable flexibility and (2) the unreliability of fuel supply for gas‐fired power plants. Aiming at these problems, the current capacity mechanism in different countries is first summarised and the applicability of the capacity mechanism for gas‐fired power plants under the government regulation and market‐oriented environment is analysed, respectively. Then, the characteristics of power dispatching and gas dispatching are analysed to explore the internal reasons for the unreliable fuel supply in gas‐fired power plants. Based on the above analysis, the gas‐electric coordination mechanism adapted to different development stages is proposed to solve the problem that the flexibility of gas‐fired power plants cannot be guaranteed. In summary, through the research of this study, it is found that the main reason for the limited flexibility of gas‐fired power plants is the lack of coordination among multiple entities belonging to different energy systems, such as electricity and gas. The cooperation mechanism proposed is an attempt to realise the cooperation between the electric system and the gas system, which provides the reference for closer collaboration among multiple energy systems in the future.

Analysis of Unit Commitment of Coal-fired Units in a Power Base of Cross-area DC Transmission Lines Under Dual Carbon Targets

China has announced achieving a carbon peak before 2030 and neutralization by 2060. Cross-area UHVDC transmission provides a feasible way for the new energy base to transmit power to the load center on a large scale. Usually, the dispatching of coal power units of DC transmission line power base is divided according to the equal proportion of unit capacity, this paper takes all the units as a group and proposes a unit commitment solution to realize lower carbon emission. As the capacity of new energy in the power base increases, this paper also considers the generation margin for new energy to do the optimization simulation. The results show that by operating coal-fired units as a group, it operates in a more economic and environmentally friendly way.

Alternative Pathway to Phase Down Coal Power and Achieve Negative Emission in China.

Although widely recognized as the key to climate goals, coal "phase down" has long been argued for its side effects on energy security and social development. Retrofitting coal power units with biomass and coal co-firing with a carbon capture and storage approach provides an alternative way to avoid these side effects and make deep carbon dioxide emission cuts or even achieve negative emission. However, there is a lack of clear answers to how much the maximum emission reduction potential this approach can unlock, which is the key information to promote this technology on a large scale. Here, we focus on helping China's 4536 coal power units make differentiated retrofit choices based on unit-level heterogeneity information and resource spatial matching results. We found that China's coal power units have the potential to achieve 0.4 Gt of negative CO2 emission in 2025, and the cumulative negative CO2 emission would reach 10.32 Gt by 2060. To achieve negative CO2 emission, the biomass resource amount should be 1.65 times the existing agricultural and forestry residues, and the biomass and coal co-firing ratio should exceed 70%. Coal power units should grasp their time window; otherwise, the maximum negative potential would decrease at a rate of 0.35 Gt per year.

Optimizing Operation Strategy in a Simulated High-Proportion Wind Power Wind–Coal Combined Base Load Power Generation System under Multiple Scenes

In order to accommodate more intermittent renewable energy in coal-dominated power systems, conventional thermal power plants need to improve their operational flexibility to balance the energy system at all times. However, flexible operation of coal-fired power plants could reduce energy efficiency and increase CO2 and pollutant emission, so it is important to consider environmental implications and optimize the dispatch of wind and coal power units in the system. In this paper, based on the output profile of wind power, a wind power peak (T, H) simulation model based on Gaussian distribution was established. Using a high-proportion wind power wind–coal combined base load power generation system as an example, the economical and environmentally friendly unit operation based on different wind power penetration was studied by simulation, and the decision strategy was established. Wind energy curtailment boundary was determined with power generation cost, energy consumption, CO2 and pollutant emissions as decision targets, respectively. Weekly scale results indicate that incorporating energy consumption and pollutant emissions into consideration will lead to different decision-making strategies compared with only targeting minimizing wind curtailment. This paper established a decision-making model of wind–coal system operation strategy based on economy and environmental criteria. This work directly contributes to real system operation and is of great significance for future scheduling/dispatch studies of actual power systems.

Optimal Dispatch of Multi-Type CHP Units Integrated with Flexibility Renovations for Renewable Energy Accommodation

Driven by the goals of carbon neutral and carbon peak, coal power units need increased flexibility in peak shaving to accommodate intermittent renewables, especially for a region with a large proportion of combined heat and power (CHP) units in China. In this study, the data-mining-based method is proposed for revealing and utilizing the heat–power coupling mechanism of CHP units, which can be used to solve the mentioned issues. Specifically, extraction-condensing (EC) units, high-back-pressure (HBP) units and low-pressure turbine zero power output (LZPO) units are introduced into the proposed dispatch model for maximizing renewable energy accommodation. The operation schemes and the feasible minimum output power of the CHP system under one certain heat load are obtained via the genetic algorithm. Results show that the CHP system is capable of reducing its output power by 18.7% to 41.7% in the heating season, compared with the actual operation data. Furthermore, the influence of multi-type units’ combination on peak-shaving flexibility is discussed. This study can be utilized for the optimal load dispatch scheme of multiple CHP units and guide the power dispatching department in making reasonable generation plans.

Repowering a Coal Power Unit with Small Modular Reactors and Thermal Energy Storage

In the first months of 2022, there was a sharp turn in the energy policy of the European Union, initially spurred by increasing energy prices and further escalated by Russia’s invasion of the Ukraine. Further transformation of the energy system will likely be accompanied by the gradual abandonment of natural gas from Russia and an increase of renewable and nuclear energy. Such a transition will not only increase energy security, but also accelerate the pace at which greenhouse gas emissions are reduced in Europe. This could be achieved more effectively if some of the new nuclear energy capacity is optimized to play an increased balancing role in the energy system, thus allowing for deeper market penetration of intermittent renewable energy sources with a reduced need for flexible fossil backup power and storage. A double effect of decarbonization can be achieved by investments in nuclear repowering of coal-fired units, with the replacement of coal boiler islands with nuclear reactor systems. Repowered plants, in turn, operate flexibly via integration with thermal energy storage systems using molten salt. This paper presents the results of a technoeconomic analysis for three cases of nuclear repowering of a 460 MW supercritical coal-fired unit in Poland. The first reference case assumes that three reactors are replacing the existing coal boilers, while the second reference leverages two reactors. The third uses two nuclear reactors equipped with a molten salt thermal energy storage system as a buffer for the heat produced by the reactor system. The analysis of the third case demonstrates how the TES system’s capacity varies from 200 to 1200 MWh, highlighting the possibility of obtaining a high degree of flexibility of the nuclear unit due to TES system without significant drops in the efficiency of electricity production. The economic analysis demonstrates that integration with TES systems may be beneficial if the current levels of daily variation in electricity prices are maintained. For current market conditions, the most attractive investment is a case with two reactors and a TES system capacity of 800 MWh; however, with the increasing price volatility, this grows to a larger capacity of 1000 or 1200 MWh.

Estimating stranded coal assets in China's power sector

China has suffered overcapacity in coal power since 2016. With growing electricity demand and an economic crisis due to the Covid-19 pandemic, China faces a dilemma between easing restrictive policies for short-term growth in coal-fired power production and keeping restrictions in place for long-term sustainability. In this paper, we measure the risks faced by China's coal power units to become stranded in the next decade and estimate the associated economic costs for different shareholders. By implementing restrictive policies on coal power expansion, China can avoid 90% of stranded coal assets by 2025.