Coal-fired Generation Research Articles

From 30- to 5-minute settlement rule in the NEM: An early evaluation

Australia’s National Electricity Market has shifted from 30- to 5-minute settlement (5MS)— a major regulatory reform since its inception. Using a Bayesian structural time-series model over the period 1 October 2021 to 31 May 2022, we demonstrate that despite having no immediate impact on price dynamics, 5MS eventually exerts upward pressure on spot prices over time. Price volatility remains essentially unchanged. Moreover, dispatch-weighted prices (DWPs) for flexible battery generators increase. DWPs for aggregated gas generators barely change, while DWPs for incumbent black coal-fired generators unexpectedly increase. These findings support the notion that the market is gradually adapting to 5MS. For a more effective adaptation, energy policies must be in place to lower entry barriers for flexible, dispatchable generation capacity and reduce market concentrations.

Substantial differences in source contributions to carbon emissions and health damage necessitate balanced synergistic control plans in China

China’s strategy to concurrently address climate change and air pollution mitigation is hindered by a lack of comprehensive information on source contributions to health damage and carbon emissions. Here we show notable discrepancies between source contributions to CO2 emissions and fine particulate matter (PM2.5)-related mortality by using adjoint emission sensitivity modeling to attribute premature mortality in 2017 to 53 sector and fuel/process combinations with high spatial resolution. Our findings reveal that monetized PM2.5 health damage exceeds climate impacts in over half of the analyzed subsectors. In addition to coal-fired energy generators and industrial boilers, the combined health and climate costs from energy-intensive processes, diesel-powered vehicles, domestic coal combustion, and agricultural activities exceed 100 billion US dollars, with health-related costs predominating. This research highlights the critical need to integrate the social costs of health damage with climate impacts to develop more balanced mitigation strategies toward these dual goals, particularly during fuel transition and industrial structure upgrading.

Возможности и проблемы энергогенерации в Республике Тыва

RELEVANCE. The energy sector forms the basis for functioning of other economic sectors and social services. Presentday technologies of energy generation are based on using coal, gas, oil, hydro, nuclear and renewable sources. PURPOSE. Analysis of the current state of energy generation in the Republic of Tyva, identification of drivers for development and optimization of its structure. RESULTS. A review is made of the current global trends in energy generation. Directions for diversifying energy generation sources are proposed, e.g. using both imported and coal seam gas as well as hydro resources along with coal. CONCLUSIONS. Focusing on only one energy source reduces the energy security of the region. Energy shortages and the presence of costly diesel-based power generation hinder the economic development of the Republic of Tyva. In the republic that has extensive coal reserves, coal generation has to introduce modern “clean coal” technologies. A high share of thermal power plants in the structure of the coal-fired generation capacity will allow the development of cogeneration using innovative, environmentally friendly Russian technologies. Options for solving the challenge of energy shortage in Tuva in the future until 2035 are proposed.

Early warning and proactive control strategies for power blackouts caused by gas network malfunctions

There is growing consensus that gas-fired generators will play a crucial role during the transition to net-zero energy systems, both as an alternative to coal-fired generators and as a flexibility service provider for power systems. However, malfunctions of gas networks have caused several large-scale power blackouts. The transition from coal and oil to gas fuels significantly increases the interdependence between gas networks and electric power systems, raising the risks of more frequent and widespread power blackouts due to the malfunction of gas networks. In a coupled gas–electricity system, the identification and transmission of gas network malfunction information, followed by the redispatch of electric power generation, occur notably faster than the propagation and escalation of the malfunction itself, e.g., significantly diminished pressure. On this basis, we propose a gas-electric early warning system that can reduce the negative impacts of gas network malfunctions on the power system. A proactive control strategy of the power system is also formulated based on the early warning indicators. The effectiveness of this method is demonstrated via case studies of a real coupled gas–electricity system in China.

Numerical modeling of hydrodynamics of spouted bed in solid fuel boiler

The issues of numerical modeling of hydrodynamics of a spouted fuel bed in the furnace of a solid-fuel boiler are considered. At present, solid-fuel boilers are widely used in the power industry of the Russian Federation, with the share of coal-fired generation to remain significant in the projected terms. Therefore, the study of the efficiency of thermal and hydrodynamic processes that ensure the implementation of clean coal technologies is a relevant task both today and in the long term. The article presents the following main stages of numerical modelling of the hydrodynamics of the spouted bed: problem formulation with selection of boundary and initial conditions, methods of solving the Navier-Stokes and continuity equations for the air flow, Newton's equations and diffusion equations for particles. The k-omega turbulence model was used in the calculations that is described by means of two partial differential equations for the variables k (kinetic energy of turbulence) and omega (specific dissipation rate). A comparative analysis of environmental advantages and disadvantages of existing methods of combustion of low-grade coal in schemes with in-cycle gasification (ICG) is carried out. Advantages and difficulties of switching to structures with CFB in the spouted bed mode are shown. Numerical modeling of the cold spouted bed created by means of particle injection is performed, a set of initial settings and boundary conditions is presented, the adequacy of the obtained results is verified by hydrodynamic characteristics of the isothermal process. The obtained results allow us to proceed to the next stages with non-isothermal models, with heat exchange and combustion reactions in the spouted bed of coal taken into account. The following refinement of the physical model will allow to achieve more accurate and reliable results and to ensure their correct scaling.

Modeling of Unburned Carbon in Pulverized Coal-Fired Supercritical Steam Generators

ABSTRACT In coal-fired boilers, one of the most important metrics for optimizing combustion is the proportion of unburned carbon (UC) in the ash. In most Indian power plants, it is still assessed offline through manual sample collection and laboratory analysis. The laborious processes of sample collection, preparation, analysis, and reporting require at least five to eight hours of work. The delayed results may not be useful to optimize combustion in the boiler furnace, as the boiler operating conditions may be completely different from the conditions when the samples were collected. Instead, the use of prediction algorithms may bring timely corrective action if the UC goes high. The present experimental study is taken up to obtain a correlation between UC and corresponding relevant boiler operational parameters and on the residence time of coal particles in the boiler furnace. Multiple regression analysis is performed using ANOVA tools. One hundred and ninety-four sets of coal, ash samples and boiler operating parameters are collected from 07 supercritical units. Coal proximate, coal fineness and ash UC analysis are carried out. The analyzed results and collected boiler operational data are statistically analyzed using Microsoft Excel’s ANOVA tool to understand the dependent behavior of UC on the boiler operational parameters and fired coal characteristics. The empirical equations are proposed for the prediction of UC in bottom and fly ash for supercritical boilers. Additionally, fresh 20 sets of coal, ash samples, and related operating data are gathered for the validation of the proposed empirical equations. For additionally collected samples, the predicted results are compared with the offline measured laboratory results. The maximum deviation between the predicted and laboratory results are within the range of ± 0.40% and ± 0.24% for bottom and fly ash samples, respectively.

Air pollution mortality from India’s coal power plants: unit-level estimates for targeted policy

Air pollution from coal-fired electricity generation is an important cause of premature mortality in India. Although pollution-related mortality from the sector has been extensively studied, the relative contribution of individual coal-fired units to the fleet-wide mortality burden remains unclear. Here, we find that emissions from a small number of units drive overall mortality. Units producing just 3.5% of total generation and constituting less than 3% of total capacity result in 25% of annual premature mortality from coal-fired generation. This is a direct consequence of the 200-fold variation that we find in the mortality intensity of electricity generation across units. We use a detailed emissions inventory, a reduced complexity air quality model, and non-linear PM2.5 concentration-response functions to estimate marginal premature mortality for over 500 units operational in 2019. Absolute annual mortality ranges from less than 1 to over 650 deaths/year across units, and the mortality intensity of generation varies from under 0.002 to 0.43 deaths/GWh. Our findings suggest the potential for large social benefits in the form of reduced PM2.5-related premature mortality in India if the highest mortality intensity units are prioritized for the implementation of pollution control technologies or accelerated retirement.

Canary in a Coal Mine: Infant Mortality and Tradeoffs Associated with Mid-20th Century Air Pollution

Abstract This paper examines the health tradeoffs associated with the historical expansion in coal-fired electricity generation in the United States. We combine newly digitized data on all major coal-fired power plants for the period 1938–1962 with two complementary difference-in-differences strategies. Coal-fired plants imposed large negative health externalities that were partially offset by the benefits of local electricity generation. The health impacts varied widely according to initial electricity access and evolved as the stock of generating capacity expanded over the sample period. These findings highlight the importance of accounting for both current and future payoffs when designing environmental regulation.

Optimizing High-Voltage Direct Current Transmission Corridors: Dynamic Thermal Line Rating for Enhanced Renewable Generation and Greenhouse Gas Emission Reductions

Recently, significant attention has been paid to the large-scale use of renewable energy through high-voltage direct current (HVDC) because of its economic feasibility. At the same time, the growing demand for electricity and the increasing penetration of renewable energy sources have prompted the electric power industry to explore methods to optimize the use of the existing grid infrastructure. Dynamic thermal line rating (DTLR) is a technique that allows transmission lines to operate at their maximum capacity, considering their real-time operating conditions. The majority of existing research on this topic has focused predominantly on employing DTLR in alternating current systems and exploring their applications. This study presents a novel approach by applying DTLR to HVDC transmission corridors, with the aim of maximizing the utilization of their capacity and facilitating increased integration of renewable energy. The performance of the proposed approach is evaluated by conducting a case study for an HVDC transmission line in Alberta, Canada. On average, the mean increase in ampacity above the static rating is 64% during winter and 34% during summer. This additional capacity can be used to integrate wind energy, replacing coal-fired generation. This leads to a significant reduction in greenhouse gas emissions, also quantified in this contribution.

Transition obstructionism and ‘embodied energy injustice:’ a Wyoming case study

ABSTRACT Wyoming is the epicentre of the coal transition in the United States. The coal industry is critical to the state’s economy, both in terms of jobs and a state revenue model dependent on federal coal leasing payments, mineral royalties, and mining severance taxes. However, due to economic, regulatory, and political pressures, the U.S. is currently on track to retire half of its coal-fired electricity generation capacity by 2026. Accordingly, Wyoming faces an uncertain future. Despite the difficult path ahead, many Wyoming policymakers, industry officials, and residents express hostility toward the idea of transition. This often manifests in opposition to renewable energy through policies that double down on investments in fossil fuel energy, despite the increased availability of federal resources and programmes to ease the burden of change. I refer to this phenomenon as transition obstructionism. While transition obstructionism is detrimental to residents across the state, harm is also distributed downstream in the fossil fuel lifecycle, particularly in historically marginalised communities. This article reviews recent efforts by state lawmakers and institutions to actively disincentivize transition and prolong the fossil fuel economy in Wyoming. It then considers how transition obstructionism contributes to ‘embodied energy injustices’ both within and beyond Wyoming.

The reliability pricing model and coal-fired generators in PJM

We study the interplay between coal-fired electric power generator retirements, capacity markets, and environmental policies. We focus on the Reliability Pricing Model (RPM) electricity capacity market in PJM Interconnection L.L.C. (PJM). We find that RPM acts as a channel through which environmental regulations affect the supply mix. Surprisingly, increases in RPM prices lead to more coal retirements even when we control directly for increases in generator profitability induced by higher capacity payments. Increases in RPM prices signal the need for expensive capital improvements and increase the probability of coal retirement.

China’s Zero-Coal Power System Future

Facing the challenges of climate deterioration, environmental pollution, and energy shortages, China has put forward the goals of “carbon dioxide peaking and carbon neutrality”, and the electricity sector will be the key area and the main direction of carbon emissions reduction. To prospect China’s power system and explore the potential for establishing China’s zero-coal power system in the future, this paper proposes a forecasting-test framework for long-term power system planning. We predict, evaluate, and analyze China’s power system from 2025 to 2060 using the proposed forecasting-test framework. During this process, the power capacity mix and the electricity generation mix of China’s power system will gradually transition from coal-fired generators dominated to wind and solar generators dominated. Moreover, the roles of different generators and energy storages are illustrated through the seasonal comparison and sensitivity analysis of the installed capacity of generators. The results indicate that coal-fired generators can be completely withdrawn from the power system, confirming the feasibility and possibility of achieving China’s zero-coal power system by 2060. Although the timing may be advanced or delayed in different scenarios, achieving China’s zero-coal power system will require exercising nationwide planning and making joint efforts of various sectors from now on.

Multi-stage planning of integrated electricity-gas-heating system in the context of carbon emission reduction

In order to facilitate the carbon emission reduction to mitigate climate change, this paper proposes a coordinated multi-stage planning strategy for the transmission-level integrated electricity-gas-heating system. The strategy coordinates installations of gas-fired generation plants, renewable energy plants, gas wells, power-to-gas plants, transmission lines and pipelines, considering retirements of coal-fired generation plants. It can help facilitate carbon emission reduction of the electricity system as well as the integrated energy system. The objective is to minimize the total present value of the investment and the operation economic cost, with consideration of constraints from each sub-system and carbon emission restriction. In the case studies, the proposed planning strategy is verified to be able to obtain the installation plan of the related facilities. With which the system can reduce the proportion of fossil fuel energy utilization and increase renewable energy utilization. Hence, carbon emission reduction is achieved. In addition, it has demonstrated that integrating the multi-energy systems can help reduce the economic cost in the planning result.

Перспективы угольной генерации

The article provides overview information on the state and problems of coal generation in Russia and the world. The main problem of coal energy is the environmental safety of the industry. Tightening environmental requirements for air purity from pollutants emitted by coal-fired thermal power plants has led to many countries beginning to abandon coal-fired generation in favor of alternative energy sources. The volume of investments in coal industry projects began to decline, and in a number of countries they planned to completely abandon it in the medium term. The prospect for the development of coal generation in Russia and the world is one of the most pressing topics for discussion, which has been repeatedly discussed on various information platforms, including in the international context. Experts from many countries in Russia and the world regularly present their researches on the importance of coal generation, coal reserves and energy consumption of coal fuel, and the environmental safety of the industry. The object of the study is the problems of coal generation in Russia and the world. The purpose of the work is to analyze and quantify the distribution of coal power generation capacity, assess the environmental problems associated with coal generation. The objective of the research is to obtain reliable information to assess the quantitative characteristics of energy consumption and environmental safety of the industry. The methods in the study consisted in analyzing information data from analytical agencies and publicly available materials. The results of analytical studies presented in the article indicate that in the near future, thermal energy will remain predominant in the energy balance of individual countries of the world. However, solving problems of environmental safety of fuel energy requires a centralized approach, significant financial investments and the creation of an appropriate regulatory framework.

Regional Differences in Willingness to Pay for Mitigation of Air Pollution from Coal-Fired Power Plants in South Korea

This study examined whether people who reside in different regions of South Korea exhibit different WTP for the mitigation of PM2.5 emissions from coal-fired power plants by restricting their operation during the winter and spring when air pollution becomes severe. The eastern portions of the country are relatively insulated from the harmful effects of PM2.5 emissions due to northwest winds which cause air pollutants generated from coal-fired power plants to be carried out to the East Sea (Sea of Japan). Consequently, our sample group was divided into central, western, eastern, and southern regions, and a contingent valuation method, combined with a double-bounded dichotomous choice, was used to derive people’s WTP for the mitigation of PM2.5 emissions. Our estimation results indicated that respondents who live in eastern regions showed a significantly lower WTP (about KRW 1280/month) than the mean WTP of other regions (above KRW 1337/month). Thus, we suggest that the current Seasonal Management System of PM2.5 emissions should be modified to consider regional differences. Statistical results from this study reinforce our suggestions—almost 78 percent of survey respondents support a revision of the current SMS policy and are in favor of a revised SMS policy—one that exempts eastern regions from a nationwide shutdown of coal-fired generation from December to March. Exempting coal-fired power plants in eastern regions from the Seasonal Management System might result in significant fiscal savings without a corresponding increase in nationwide PM2.5 concentrations.

Referendum as a policy instrument to enhance energy democracy in formulating energy transition path, agenda, and policies: A case study of Taiwan's referendums in 2018 and 2021

This study explores whether energy policy-related referendum initiatives in Taiwan can serve as effective policy instruments for the public to participate democratically in the formulation of energy policy and transition. Taiwan's conventional energy policy-making process is top-down, determined by the government, politicians, and experts. This process was challenged by five bottom-up energy-related referendum initiatives in 2018 and 2021, demanding a reduction in coal-fired electricity generation, electricity generation from nuclear energy instead, and an end to the expansion of large-scale fossil fuel energy infrastructure. The preferences of the general public and government for the energy transition agenda were in conflict. The results show that referendum is an effective and socially integrated policy instrument for enhancing energy democracy and guiding governmental energy transition in Taiwan, particularly by resisting the government's dominant coal-based energy agenda and facilitating a restructuring of the energy sector against various social and contextual pressures on energy preferences and contested policy goals. This bottom-up, exogenous rather than endogenous, and forced rather than voluntary energy policy formulation model corresponds to the international discussion on how energy democracy can change traditional structural power relations between the government and citizens in energy policy formulation and transition.

Emission intensities in the Australian National Electricity Market – An econometric analysis

This study examines the evolution of CO2 emission intensities in the wholesale electricity sector for the National Electricity Market (NEM) in Australia. Using daily data, we examine the impact of demand, changes in the generation mix, as well as the closure of major coal-fired power plants on emission intensities in the four largest regional markets of the NEM. Particular emphasis is also placed on the assessment of any potential association between the examined driving factors and major Australian climate and energy policies such as the 2012–2014 Carbon Pricing Mechanism (CPM) or the Renewable Energy Target (RET) scheme. Our results suggest that changes in renewable deployment can be considered as the principal factor affecting emission intensities of all regional markets. Moreover, the fossil fuel mixture effect, more precisely the reduction in coal-fired generation combined with the increase in generation from gas and renewables, also played a significant role in reducing emission intensities in the Australian power sector. Interestingly, our findings suggest that the influence of the implemented CPM was not too substantial and had only temporary effects on emission intensities.

Cooperation Mode and Operation Strategy for the Union of Thermal Generating Unit and Battery Storage to Improve AGC Performance

With the growing penetration of intermittent renewable energy resources in power systems, it is a challenge for automatic generation control (AGC) to maintain the required control performance. In recent years, battery energy storage systems (BESSs) have been installed in thermal power plants to provide frequency regulation service bundled with the traditional thermal generating units (TGUs). However, in real projects, the installed BESS typically works as parasitic equipment of the generating unit, which limits the coordination between the TGU and the BESS. In this paper, a complementary cooperation pattern is proposed for the TGU-BESS union to improve the dispatchability of its response to the AGC signal. Then, the correlation between the BESS's energy demand and the TGU's operation states is described by a data-driven method, which combines fuzzy c-means cluster, r-vine copula, and random forest. Finally, a rolling-horizon energy balance strategy is developed to make the control decisions for the TGU-BESS union in response to the stochastic AGC signal. The effectiveness of the proposed method is demonstrated using the historical data from a real union with a 9MW/4.5MWh BESS and a 350MW coal-fired generator.

Hybrid MWCNT/TiO2 nanoparticles based high-temperature quinary nitrate salt mixture for thermal energy storage applications

This study developed an advanced thermal energy storage (TES) material consisting of a quinary nitrate salt mixture doped with hybrid MWCNT/TiO2 nanoparticles. The structural, morphology, and thermophysical properties of hybrid MWCNT/TiO2 and hybrid MWCNT/TiO2 doped quinary nitrate salt mixture was characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), laser flash analysis (LFA), viscosity measurement, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy and Field environmental scanning electron microscopy and Energy dispersive X-ray (FESEM-EDX) analysis. Furthermore, levelized cost of electricity (LCOE) of concentrated solar power (CSP)-parabolic trough collector (PTC) power plant using the optimized sample as the TES materials were calculated using the “physical trough model” in system advisor model (SAM) software. Based on the result, 0.05 wt% dosage of hybrid MWCNT/TiO2 nanoparticles in the quinary nitrate salt mixture has the most favorable thermophysical properties, with 17.655 % enhancement in average specific heat capacity, 37.769 % enhancement in latent heat, 25.412 % enhancement in average thermal conductivity and 94.77 % decrement in viscosity. Furthermore, SAM simulation studies also showed that the developed TES material could reduce LCOE of the CSP power plant by 1.29 % to 0.1687 USD/kWh. Therefore, in the efforts of replacing the coal-fired electricity generation with the CSP-PTC power plants, it is also possible to achieve a potential annual saving of up to 552 million USD compared to commercial TES materials.

A Flexibility-oriented robust transmission expansion planning approach under high renewable energy resource penetration

High penetrations of renewable energy sources incorporated into transmission systems pose a substantial challenge to transmission expansion planning operations due to both the strong uncertainty of these sources and their high variability. However, most current robust transmission expansion planning studies focus exclusively on the issue of uncertainty, and neglect to optimize system flexibility in an effort to cope with the high variability of these sources. The present work addresses this critical issue by proposing a flexibility-oriented robust transmission expansion planning method developed according to the unit commitment characteristics of coal-fired and gas-fired generation units that fully considers the short-term flexibility requirements of electric power systems while maintaining high robustness to the uncertainties of RES outputs in long-term transmission expansion planning problems. The proposed complex model with unit commitment constraints containing massive binary variables is solved by first reducing the number of binary variables via the application of clustering techniques to identify generator units with similar generation properties, and then decreasing the complexity of the model further by relaxing the integer variables in the unit-clustered model. Finally, we develop generalized column-and-constraint generation algorithms that can solve the clustered model and the relaxed simplified model with greatly enhanced efficiency. Comparisons of the numerical results obtained by the proposed approach with existing state-of-the-art methods when applied to a simple Garver 6-node system and a realistically-sized power system demonstrate that the proposed method produces optimal RTEP solutions that account for both the uncertainty and variability of RES outputs. Moreover, the total cost of the proposed approach is 2.22×106$ less than that of the other state-of-the-art methods considered, which is of great significance in guiding practical transmission expansion planning applications.