Coal-fired Generation Research Articles

A decade of the U.S. energy mix transitioning away from coal: historical reconstruction of the reductions in the public health burden of energy

In the last decade, the transition away from coal and to fossil gas and biomass in the U.S. has had a major influence on greenhouse gas emissions, especially from electricity generation. However, the effect of this transition on the public health burden of air pollution is not well understood. We use three reduced complexity models (RCMs) and emissions inventory data to reconstruct the changes in health impacts due to PM2.5 exposure from stationary fuel combustion sources in the U.S., from 2008 to 2017. In 2008, the health impacts of air pollution from stationary sources was largely driven by coal combustion. By 2017, the contribution of coal has dropped precipitously, and the health burden of stationary air pollution sources is shared among a mixture of source types and fuels—largely gas and biomass in buildings and industry, and the remaining coal-fired electricity generation. Nationwide, in 2017, health impacts of biomass and wood combustion are higher than combustion of coal and gas individually. Industrial boilers had the highest emissions and health impacts, followed by residential buildings, electricity, and then commercial buildings. All three RCMs indicate that biomass and wood are the leading sources of stationary source air pollution health impacts in 24 states, and that the total health impacts of gas surpass that of coal in 19 states and the District of Columbia. We develop a projection method using state-level energy consumption data for 2018 and show that these trends likely continued. The RCMs had high agreement for 2008 emissions, when sulfur dioxide emissions from coal-fired power plants were the predominant air pollution source. However there was substantial disagreement between the three RCMs on the 2017 health burden, likely due to pollutants less well-characterized by the RCMs having a higher proportionate share of total impacts.

Why coal? – The political economy of the electricity sector in the Philippines

The Philippines encounter a rapidly growing electricity demand which is planned to be met mainly with coal. The build-up of coal-fired electricity generation is the result of a complex interplay of political economy factors. This analysis follows a novel political economy framework to shed light on actors, their objectives and how they influence policy-making given the country's context factors, such as the vulnerability to climate change and the oligopoly in the power sector. It is based on 35 semi-structured expert interviews with 50 stakeholders conducted in Metro Manila in October and November 2019. We identify four main goals determining electricity sector policy: reducing energy poverty, energy security, ecological sustainability, as well as private profits. Our insights on the political economy of the electricity sector in the Philippines can help to identify possible entry points for policies to decarbonize energy production.

Correlation of Critical State Strength Properties with Particle Shape and Surface Fractal Dimension of Clinker Ash

Clinker ash is a byproduct obtained from coal-fired electrical generators. It is a type of recycled granular material with a complex particle shape and large surface roughness. Particle shape descriptors and surface fractal dimensions are effective parameters to quantify sand grain morphologies. A simple image analysis approach is employed to determine the aspect ratio, sphericity, roundness, and convexity of 12 types of clinker ash collected from thermal power plants distributed on the western island of Japan. Compared to the majority of sands with other mineralogical components, clinker ash particles have a smaller aspect ratio, sphericity, and roundness. Under similar test conditions, clinker ash exhibits higher shear resistance than natural sands at the critical state. Critical state friction angles tend to decrease with increasing aspect ratio, sphericity, roundness, and convexity. A decreased aspect ratio, roundness, and convexity enhance the slope and intercept of critical state lines in the void ratio and mean stress plane. The mean regularity, which is the average of four particle shape descriptors, is regarded as an effective index to characterize the shear strength of clinker ash at the critical state. The surface fractal dimension could also be decided from digital image analysis. The results also show that the critical state friction angle is well correlated with the surface fractal dimension for different types of clinker ash. The implication is that a rougher surface texture hinders the rotation, frustration, and interlocking of particles at the critical state, resulting in higher shear resistance.

Carbon Policy and the Emissions Implications of Electric Vehicles

Will a carbon tax improve the welfare consequences of policies to promote electric vehicles? This paper examines when a complementarity could exist between carbon pricing and high electric vehicle adoption. We analyze electricity generation in recent years to show that in several regions, carbon pricing interacts with electric vehicle adoption. Under moderate carbon prices like those in effect today, additional electric vehicles will be more likely to be charged with coal-fired generation than without carbon pricing. We confirm this finding using a detailed dynamic model that includes the transportation and power sectors. At much higher carbon prices, the effect reverses. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Elucidating long-term trends, seasonal variability, and local impacts from thirteen years of near-road particle size data (2006–2019)

Significant attention, especially in the last decade, has been focussed on elevated concentrations of ultrafine particulate matter (UFP) in urban areas and the adverse health effects associated with exposure to UFP. Despite this, there is a relative scarcity of long-term ambient UFP measurements. This study examined trends in UFP measurements made continuously near a busy roadway in downtown Toronto, Canada, between the years 2006 and 2019 using a fast mobility particle sizer (FMPS). These long-term trends were associated with other air pollutant concentrations—namely: nitric oxide (NO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and fine particulate matter mass concentrations (PM2.5)—and persistent declining trends were observed for each during the study period. From 2006 to 2019, reductions of 45%, 68%, 39%, 83%, and 41%, for UFP, NO, NO2, SO2, and PM2.5, respectively, were observed. These reductions are in part associated with a total phase-out of coal-fired electricity generation in Ontario, Canada, between 2004 and 2015, and continuous improvements in vehicle emissions control technologies. Additionally, deconvolution of the time-series yielded seasonal fluctuations which were analysed as a function of particle diameter and ambient temperature, the results from which may aid in the comparison of UFP measurements made in climates with different ambient temperature ranges in a meaningful way. Finally, the UFP data were background-subtracted and it was found that local sources (such as vehicle traffic) contributed ~45% to total concentrations and this fraction remained relatively constant throughout the study. A multilinear function regressed on these local and background concentrations better elucidated the sources contributing to UFP variability—background concentrations were largely covariate with SO2 emissions whereas local concentrations were more affected by NO emissions. The data in this study shows clear co-benefits to reducing UFP concentrations by targeting NOx and SOx emissions.

Cost–Benefit Analysis of HELE and Subcritical Coal-Fired Electricity Generation Technologies in Southeast Asia

A large potential exists in the Southeast Asia region for deployment of high-efficiency, low-emission (HELE) electricity generation technologies. A cost–benefit analysis of HELE technologies compared to the less efficient subcritical electricity generation plants is thus carried out to find a persuasive scenario supporting quicker transition from subcritical stations towards HELE technologies in the region. A levelized cost of electricity (LCOE) analysis is carried out for both technologies under four potential policy scenarios. Scenario 1 does not take into consideration any carbon pricing or costs associated with the desulphurization (deSOx) and denitrification (deNOx) facilities. Scenario 2 (Scenario 3) incorporates carbon pricing (costs associated with the deSOx and deNOx facilities), and Scenario 4 includes both carbon pricing and costs associated with the deSOx and deNOx facilities. Under each scenario, a sensitivity analysis is performed to evaluate the uncertainty affecting the future coal prices. This study demonstrates that HELE technologies are competitive against the subcritical plants under all four scenarios and both the technologies derive benefit from lifetime extensions and low coal prices. It is revealed that future deployments of HELE technologies can be best expedited by factoring in carbon pricing in LCOE costs of coal-fired power plants under Scenario 2.

The mortality impacts of current and planned coal-fired power plants in India

We examine the health implications of electricity generation from the 2018 stock of coal-fired power plants in India, as well as the health impacts of the expansion in coal-fired generation capacity expected to occur by 2030. We estimate emissions of SO2, NOX, and particulate matter 2.5 μm (PM2.5) for each plant and use a chemical transport model to estimate the impact of power plant emissions on ambient PM2.5 Concentration-response functions from the 2019 Global Burden of Disease (GBD) are used to project the impacts of changes in PM2.5 on mortality. Current plus planned plants will contribute, on average, 13% of ambient PM2.5 in India. This reflects large absolute contributions to PM2.5 in central India and parts of the Indo-Gangetic plain (up to 20 μg/m3). In the south of India, coal-fired power plants account for 20-25% of ambient PM2.5 We estimate 112,000 deaths are attributable annually to current plus planned coal-fired power plants. Not building planned plants would avoid at least 844,000 premature deaths over the life of these plants. Imposing a tax on electricity that reflects these local health benefits would incentivize the adoption of renewable energy.

Optimal Decision-Making of Vertical Relationship Governance in China’s Coal-electricity Energy Supply Chain

Coal and coal-fired electricity generation, as interdependent upstream and downstream industries, play a positive role in ensuring energy security, economic development and social stability in China. However, the strategies of coal enterprises and coal-fired power enterprises are influenced by the market structure, coal-electrical energy policies and the characteristics in the coal-electricity energy supply chain. In this paper, considering the upstream for many coal enterprises, the downstream for many coal-fired electricity generation enterprises in coal-electricity energy supply chain model, is concluded that profit calculation model for coal-electricity cooperative enterprises, independent upstream coal enterprises, and independent downstream coal-fired electricity generation enterprises were obtained. In order to maximize the profits, we construct coal enterprises and coal-fired electricity generation enterprises cooperative operation decision-making model, and the different situation of the optimal strategy is studied and analyzed. Using Matlab simulation software for numerical simulation. It is to belong to the simulation results confirm the efficiency of the model.

Конец эпохи энергетического угля

The article analyses the process of coal crowding out of the world energy balance. In developed countries, the tendency towards the rejection of using energy coal accelerated in the end of 2000s under the pressure of climatic considerations. The global COVID‑19 pandemic has led to the acceleration of the world energy balance restructuring at the expense of lowering demand for coal. Coal is crowded out from energy consumption for both climatic considerations as well as because of the strong harmful effect of coal power plants emissions on health. Developed and an increasing number of developing countries strengthen and expand complex of measures aimed at coal energy displacement: emissions trading systems and direct emissions tax, Coal Plant Directive and closures of coal mines. Decarbonisation has been accelerated after Pittsburgh Summit (2009) and Paris Agreement (2015). By 2020, developed countries have largely abandoned direct subsidies for coal consumption, and all major international development banks have limited their involvement in coal-fired generation and have stopped considering coal mining projects. Developing countries continue support coal consumption and production in order to maintain economic growth and employment. Excessive supply will lead to overstocking of the coal market, lower prices and slowdown of the decline in coal consumption after COVID‑19. Although several largest economies in the Asian-Pacific Region, primarily China, India and Indonesia, continue to increase coal generation capacities (HELE plants), the analysis in the article shows that after the accomplishment of the recovery growth in the world economy by 2025, global demand for energy coal will start to steadily decline. China announced plans to curtail coal use after 2025, G‑7 decided to stop financing coal projects. Meantime many developing countries with low level of income and modest financial capacities cannot afford to quit comparatively cheap coal quickly as a factor supporting economic growth. Increasing High-Efficiency, Low-Emissions coal plants demand is rapidly rising requirements to coal quality.

Carbon Policy and the Emissions Implications of Electric Vehicles

Will a carbon tax improve the welfare consequences of policies to promote electric vehicles? This paper examines when a complementarity could exist between carbon pricing and high electric vehicle adoption. We analyze electricity generation in recent years to show that in several regions, carbon pricing interacts with electric vehicle adoption. Under moderate carbon prices like those in effect today, additional electric vehicles will be more likely to be charged with coal-fired generation than without carbon pricing. We confirm this finding using a detailed dynamic model that includes the transportation and power sectors. At much higher carbon prices, the effect reverses.

Inland Hard Coal Transportation Costs in the European Union—A Model Based Approach

Although some EU countries have already ceased coal-fired electricity generation, coal will still be a relevant topic within the European electricity mix in the medium term. A hard coal power plant competes in the merit order mainly with other hard coal power plants and also with gas power plants. One of the main cost drivers of fuel supply is the transport costs of steam coal from import harbors to the power plant sites. These costs consist either of freight rates of the barges, charges for transport by train, or a combination of both, and additional transshipment costs that arise during transport. The resulting costs differ considerably depending on the country and the region within a country. This work aims at determining country-specific regional transport costs for hard coal to power plant sites in the European Union. The geographical resolution for this work is at the municipal level of each country, in which each municipality is characterized by specific costs, depending on distance and means of transport. In total, transport costs are modelled for 119,978 municipalities. The results show a clear ranking of preferred locations with regard to transport costs, starting with locations close to the open sea followed by inland locations near riverbanks. Locations remote from both sea and waterway access are the most expensive sites. The resulting data basis can be used as an input for energy system models.

Measuring Windfall Profits to Coal-Fired Electricity Generators from Free Emission Permit Allocations

Measuring Windfall Profits to Coal-Fired Electricity Generators from Free Emission Permit Allocations

The impacts of climate change on coal-fired power plants: evidence from China

Climate change-induced coal-fired plant generation efficiency reduction tends to cut power supply by 15.77 billion kWh/year in the 2050s under RCP8.5. The challenges could be more evident if factoring in the rapidly increasing power demand.

Performance and Flexibility Improvements of Staged Pressurized Oxy-Combustion

Staged Pressurized Oxy-Combustion (SPOC) is a low-carbon coal combustion power technology being developed by Washington University in St. Louis (WUSTL). Oxy-combustion plants enable straightforward capture of carbon dioxide (CO2) by removing most of the nitrogen in the combustion air prior to use, thereby burning fuel in near-pure oxygen instead of air, producing a flue gas containing primarily CO2 and water. CO2 capture at amounts > 90% is possible, often using cryogenic air separation. Oxy-combustion typically relies on flue gas recycle (FGR) to reduce the peak temperature and radiation that would otherwise occur in a fuel/oxygen only flame. SPOC reduces the peak temperatures of combustion by utilizing two or more pressurized boiler modules connected in series to produce fuel staging; hence, only a portion of the fuel is combusted in any given furnace module. This means that the thermal energy released at each stage can be captured and removed from the gases prior to subsequent stages, when more fuel is introduced. This allows the SPOC process to operate with minimal FGR, avoiding the associated efficiency losses and additional costs. Also, the process operates at an elevated gas-side pressure, reducing boiler size, enhancing heat transfer to achieve a compact boiler configuration as compared to an atmospheric-pressure boiler design, and allowing for recovery of the latent heat of the water from the flue gas at a temperature useful to the steam cycle. The resultant net efficiency of the system is over 3 percentage points greater than traditional atmospheric-pressure oxy-combustion, and 7 percentage points greater than the post combustion variant, representing a step-change improvement over first-generation capture technologies. To further develop the concept, WUSTL and the Electric Power Research Institute, Inc., organized a project with American Air Liquide, Inc., Doosan Babcock Limited, and the U.S. Department of Energy to investigate a practicable and workable boiler design. The team has identified the potential for enhanced process flexibility for controlling power generation over a wider load range than is normally available to conventional coal-fired power plants due to the staged nature of the heat release. With increasing intermittent renewable generator contribution, on-demand generators need to be highly flexible to participate in the future energy market, requiring extensive operation at reduced load. Conventional coal-fired steam generators typically face challenges in maintaining temperature control of the reheat steam and main steam at reduced loads. This results in inefficient operation, both in terms of the boiler efficiency and steam turbine heat rate. The results of this project show the SPOC process is capable of exceptional turndown, both on a stage basis and with the ability to bypass entire stages. Oxygen-supply flexibility was also investigated, as this is also a key consideration for the overall flexibility of the SPOC process given the operating constraints of conventional air separation units. A boiler design concept assessment was conducted and was focused on delivering compact and constructible design. The assessment checked appropriate tube operating metal temperatures at full load and at lower operating loads, balanced against the needs of efficient coal combustion, and the resultant slagging and ash environments. Combustion testing in the 100-kWth pressurized combustion test rig at WUSTL was carried out to validate the combustion, heat flux profiles and burnout at multiple loads. Combustion parameters investigated were flame stability, fuel burnout, ash composition, radiative heat flux, and temperature profiles. The results of these tests formed the basis of a full-scale boiler design that will encompass improvements in both efficiency and flexibility over conventional oxy-combustion processes. The air separation unit flexibility was investigated, and associated cost implications were addressed. Detailed economic assessment results for a 550 MWe net power block are also provided, allowing for a comparison against the baseline NETL oxy-combustion and post combustion capture cases.

Synergistic Effects of Carbon Pricing and Power Market Reform on CO <sub>2</sub> Emissions Reduction in China's Electricity Sector

China is pursuing aggressive action to reduce greenhouse gas emissions from its coal-dominated electric power system. Two key strategies are power market reform and carbon pricing. This paper investigate the synergistic effects of these two strategies in reducing CO2 emissions from power system operations. We develop an economic dispatch model to simulate hourly power supply system operation in China Southern Power Grid in 2018 under fifteen carbon pricing scenarios; these reflect a wide range of policy ambition, from today’s carbon prices to much higher ones that aim to instigate aggressive emission mitigation. Our results show that moderate carbon pricing alone is insufficient to effectively reduce CO2 emissions without concurrent power sector reform. With power sector reform and as carbon prices increase, large coal units supplemented by energy storage witness higher use rates as they supplant smaller coal-fired generators, until a carbon price of 300 RMB/TCO2 phases out coal use in favor of natural gas. Only at carbon prices higher than 300 RMB/TCO2 do emissions begin to decrease appreciably. Geographic disparities emerge among the five provinces that comprise the Southern Power Grid, with Guangdong witnessing the most CO2 emission reduction at high carbon prices, while emissions reduction in other provinces are negligible. Carbon pricing also dramatically increases total power system costs, even at low carbon prices. Our results show the necessity of introducing power sector reform and carbon pricing policies concurrently if the goal is to reduce CO2 emissions, with the ultimate goal being a carbon price significantly greater than 300 RMB/TCO2. Because both options will be necessary, our research maps a path to deep emission reductions in China Southern Power Grid for investors, analysts, and policy makers as discussions regarding both reforms accelerate.

Carbon Sequestration Potential and Environmental Impacts of Utilizing Crop Residues for Biochar Implementation in China

The carbon sequestration potential and environmental impacts of crop residue biochar implementation in China are quantified by using life cycle assessment combined with Gabi software. The results show that the annual GWP100 (global warming potential at 100-year scale) value of the biochar system can reach -921.66 kg CO2e, which can significantly improve the carbon sequestration in China; The realization of negative carbon emission mainly depends on the bio-oil and pyrolysis gas generated to offset the coal-fired generation, and the carbon storage realized by biochar in the soil. Among all the parameters, the biochar yield has the greatest influence on the carbon sequestration potential of the whole system; the biochar system can also alleviate human toxicity potential, acidification potential and other environmental problems; the environmental feasibility of biochar implementation is confirmed.

China's retrofitting measures in coal-fired power plants bring significant mercury-related health benefits

Summary China has implemented retrofitting measures in coal-fired power plants (CFPPs) to reduce air pollution through small unit shutdown, the installation of air pollution control devices (APCDs), and power generation efficiency improvement. The reductions in highly toxic Hg emissions and their related health impacts by these measures remain poorly understood. Here, we evaluated the health benefits of reduced Hg emissions via retrofitting measures during China's 12th Five-Year Plan (2011–2015) by combining plant-level Hg emission inventories with the China Hg Risk-Source-Tracking Model. We found that the measures reduced Hg emissions by 23.5 tons (approximately 1/5 of that from CFPPs in 2010), preventing 30,484.77 total points of intelligence quotient decrement and 114 deaths between 2011 and 2015. These benefits were dominated by CFPP shutdowns and APCD installations, and nearly 50% of provincial health benefits were attributable to Hg reductions in other regions. We suggest that Hg control strategies should consider various factors, such as CFPP location, population density, and trade-offs between reductions in total Hg and in Hg2+.

Life cycle assessment of pharmaceuticals: the ciprofloxacin hydrochloride case

Despite the benefits in human health from pharmaceuticals, their production has simultaneously given rise to severe environmental pollution. Using ciprofloxacin hydrochloride production as an example, the objectives of this study were to determine the key materials and stages in the life cycle of pharmaceutical production and to develop methods to prevent high materials/energy consumption and pollution. The environmental impacts were evaluated by the Eco-indicator 99 (EI 99) method built into the Ecoinvent database of the Simapro software. The functional unit was set to the annual production of 280 million ciprofloxacin hydrochloridet tablets. The data in this study regarding the process parameters, raw materials energy consumption, and the emissions of pollutants were provided by a pharmaceutical enterprise located in the Zhejiang province, China. The complete production process was classified into three stages, active pharmaceutical ingredient (API) synthesis, galenic formulation, and packaging following the product category rules (PCR) for pharmaceuticals. API synthesis had the largest environmental contribution, followed by galenic formulation, and packaging, which accounted for 42.9%, 41.9%, and 15.2%, respectively. The most important influencing factors of the first two stages were polyols which represent solvents or reaction media used and electricity (coal-fired generation). The damage categories of both factors were ranked from high to low as follows: human health, resources, and ecosystems. The ecological index points of human health in the API synthesis decreased by 8 k point (kPt) after solvent replacement, by 4 kPt after coal-based electricity generation was replaced with natural gas, and by 12 kPt after simultaneous optimization. The proposed improvements for cleaner production all proved the feasibility of environmental sustainability in pharmaceutical production. Compared with energy optimization, the solvent replacement was a more effective and convenient method to reduce the environmental impact of ciprofloxacin hydrochloride production.

Legal Pathways to Coal Phase-Out in Italy in 2025

This contribution aims to provide an in-depth outlook of the phase-out of coal-fired energy generation in Italy. In particular, this article analyzes the state-of-the-art with regard to both the current role of coal generation and the performance of the main legal and regulatory tools as implemented in Italy thus far to ensure the closure of all coal power plants by 2025 as announced in the Italian National Climate and Energy Plan. Based on existing data and scenarios on both electricity production and demand trends, this article unfolds the marginal role played by coal-fired generation in the Italian energy mix. In addition, this paper aims to highlight the outstanding technical uncertainties and regulatory hurdles in the way towards de-carbonization of energy generation in Italy. This paper argues that several remarkable improvements are needed in order to avoid over-generation (especially through natural gas), to upscale the penetration of renewable energy sources, and develop the necessary infrastructures to adequately deliver on the full phasing-out of coal within the expected timeframes.

Replacement of All Coal-fired Electricity Generation in the United States by Solar (PV) Power (from an Engineer’s Perspective)

This paper identifies the considerations that must be addressed for solar power (PV) to successfully replace coal-fired power generation in the USA. All the requirements and opportunities are discussed in detail supported by the basic engineering calculations necessary to understand the potential.