Search

Climate change is forecasted to drastically alter freshwater fish and mussel species distribution. Hydropower dam reservoirs, which modify downstream thermal regimes, may interact with climate change's impact on species distribution. This distribution shift may feedback, affecting hydropower operation costs through environmental compliance. We investigated how freshwater species distribution will shift due to climate change and hydropower reservoirs in the conterminous United States (CONUS), and how this will affect biodiversity mitigation costs for privately-owned hydropower plants. In general, using environmental niche modeling, we found that climate change increased the range of both freshwater fish and mussel species on average. For fish, this was mainly due to the expanded habitat for warm-water and cool-water fish species despite the diminish in habitat for cold-water species. Compared to climate change, thermal stratification of hydropower reservoirs had a small impact on the future range changes of these species in the tailwaters but showed an interaction with the effect of climate change on species range. Geographically, we projected an increase of species richness in the west and a decrease in the central and east of CONUS for fish, while projecting uniform increase for mussels. With this shift in species distribution, we estimated that the Northwest region will face the largest increase in mitigation cost, while the majority of plants in the Southeast will experience a decrease in cost., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Hydroelectric power facilities can generate episodic total dissolved gas supersaturation (TDGS), which is harmful to aquatic life. We developed a decision tree-based risk assessment to identify the potential for TDGS at hydropower plants and conducted validation measurements at selected facilities. Applying the risk model to Norway's hydropower plants (n = 1696) identified 473 (28 %) high-risk plants characterized by secondary intakes and Francis or Kaplan turbines, which are prone to generating TDGS when air is entrained. More than half of them discharge directly to rivers (283, 17 % of total). Measurements at 11 high-risk plants showed that 8 of them exhibited biologically relevant TDGS (120 % to 229 %). In Austria and Germany, the analysis of hydropower plants was limited due to significant data constraints. Out of 153 hydropower plants in Austria, 80 % were categorized at moderate risk for TDGS. Two Austrian plants were monitored, revealing instances of TDGS in both (up to 125 %). In Germany, out of 403 hydropower plants, 265 (66 %) fell into the moderate risk, with none in the high-risk category. At a dam in the Rhine River, TDGS up to 118 % were observed. Given the uncertainty due to limited data access and the prevalence of run-of-river plants in Austria and Germany, there remains an unclarified risk of TDGS generation in these countries, especially at spillways of dams and below aerated turbines. The results indicate a previously overlooked potential for the generation of biologically harmful TDGS at hydropower installations. It is recommended to systematically screen for TDGS at hydropower installations through risk assessment, monitoring, and, where needed, the implementation of mitigation measures. This is increasingly critical considering the expanding global initiatives in hydropower and efforts to maintain the ecological status of freshwater ecosystems., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Martin Schletterer reports a relationship with TIWAG Tyrolean Hydropower that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Biomass and waste power generation holds the promise to secure electricity supply for a growing population and mitigate global warming simultaneously. Along with the increasing commission and installation of biomass/waste power units (BWPUs) across the globe, some BWPUs failures have been observed, including the cancellation of planned/commissioned BWPUs and the termination of those in operation before reaching their natural retirement. While empirical evidence suggests that factors like feedstock accessibility and policy instruments might affect the feasibility and performance of BWPUs, there is a lack of comprehensive investigation about why some BWPUs failed at the global scale. To fill this knowledge gap, this study quantifies the hazard ratio of BWPUs via a parametric survival analysis using a panel dataset covering a total of 12,829 BWPUs (relying on woody, non-woody, and waste biomass as raw feedstocks) located in 164 countries/regions worldwide for the period of 2001-2021. The analytical results suggest that large unit size is conducive to BWPUs failure, while feedstock accessibility and the implementation of policy instruments (including Feed-in-Tariff and carbon pricing) could largely reduce the hazard ratio of BWPUs, with varying impacts on BWPUs at the planned/commissioned stage or the operation stage, located in developed or developing countries. Our findings not only shed additional light on the fate of BWPUs, which is crucial to enriching our understanding about the development of the bioenergy sector worldwide, but also provide salient empirical evidence for policy-making in terms of ensuring feedstock accessibility, overcoming diseconomies of scale, and making fiscal instruments available and transparent to boost the confidence of investors and entrepreneurs in support of BWPUs development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In light of the pressing need to reduce carbon emissions, the biomass power generation industry has gained significant attention and has increasingly become a crucial focus in China. However, there are still considerable gaps in the historical background, status, and prospects of biomass power generation. Herein, the historical and current status of biomass power generation in China are systematically reviewed, with a particular emphasis on supportive policies, environmental impacts, and future projections. By 2022, the newly installed capacity for biomass power generation reached 3.34 MW with a total installed capacity of 41 MW. The power produced from biomass power generation is 182.4 billion kWh in China. The total installed capacity and generated power in 2022 were 1652 and 1139 folds higher than in 2006 when the first biomass generation plant was established. However, disparities in the distribution of biomass resources and power generation were observed. Key drivers of the industry development include tax, finance, and subsidy policies. Under the implementation of the 14th Five-Year Plan for renewable energy development and the goal of carbon neutrality, biomass power generation may achieve great success through more targeted policy support and advanced technologies that reduce air pollutant emissions. If combined with Bioenergy with Carbon Capture and Storage (BECCS) technology, biomass power generation will make its contribution to carbon neutrality in China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nuclear power plants, recognized for their extended operational life, minimal greenhouse gas emissions, and high-power density, are deemed as reliable energy sources. Nonetheless, concerns persist regarding the radioactive discharges from these plants and their potential impact on health and the environment. To comprehend the radiological implications of such releases, this study presents, for the first time, an analysis of radiological data from 7 Indian nuclear power plants (NPPs), collected by Indian environmental survey laboratories (ESL) over the past two decades (2000-2020). This dataset encompasses radioactivity concentrations in the atmospheric, aquatic, and terrestrial environments within a 30 km radius of each NPP, as well as the annual cumulative external gamma doses recorded by environmental thermoluminescence dosimeters (TLDs). The analysis yielded several key findings: (i) Radioactivity concentrations around the NPPs were low and comparable to values measured at other nuclear power plant sites worldwide; (ii) Tritium concentrations in receiving water bodies were <1 % of the internationally recommended limit of 10,000 Bq/l; (iii) The estimated total radiation doses to the public were at most 10 % of the stipulated regulatory dose limit of 1000 μSv and consistently decreased over the study period and (iv) Variations in doses among the NPP sites were primarily attributed to legacy technology used in specific reactors. These results indicate efficient and secure reactor operations and the minimal contribution of Indian nuclear power plants to anthropogenic doses in the country. The findings hold potential significance for reinforcing India's commitment to advancing its nuclear power program., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Incineration technology is an effective treatment method for municipal solid waste (MSW). In this study, fine particulate matter emissions from two waste incineration power plants (WIPP) were characterized. Both filterable particulate matter (FPM 2.5 ) and condensable particulate matter (CPM 2.5 ) were collected using a direct sampling method. The FPM 2.5 concentrations from stacks #1 and #2 in WIPP A were 0.87 ± 0.10 and 0.68 ± 0.19 mg/m 3 , respectively, and 3.30 ± 0.65 mg/m 3 was measured at stack #3 in WIPP B. Fe was the most abundant elemental component in the FPM 2.5 , followed by Na, Ca, Al, and K. Ca 2+ , SO 4 2− , Cl − , and NH 4 + accounted for the largest fraction of the total detected water-soluble ions in the FPM 2.5 . In the CPM 2.5 , Na was the most abundant elemental component, followed by Ca, Mg, and K. The total detected water-soluble ions accounted for 22.2% and 27.3% of the CPM 2.5 collected from stack #1 and #2, respectively. High concentrations of NH 4 + and NO 3 − were found in CPM 2.5 , which could be derived from the escape of excessive NH 3 in the denitrification unit and that of the NOx in the flue gas, respectively. Alcohols, aromatic compounds, and ketones were the major organic species in the CPM 2.5 . Both fly ash and bottom ash were collected from WIPP A. Ca was the dominant element, followed by K, Mg, Na, and Fe. The enrichment of elements in the fly ash and bottom ash were analyzed. The enrichment factors of most elements were higher than 1, except for the Ti and Sn in the bottom ash. The fly ash had a higher enrichment of Cd, As, and Ti than the bottom ash. In contrast, Cu, Ni, and Cr had higher enrichments in the bottom ash because of their low volatility. [ABSTRACT FROM AUTHOR]

Source contributions to fine airborne particulate matter with aerodynamic diameters < 2.5 μm (PM 2.5 ) during 2013 were determined for 25 Chinese provincial capitals and municipalities using a source-oriented version of the Community Multiscale Air Quality (CMAQ) model. Based on the hierarchical clustering analysis of the observed PM 2.5 concentrations, the 25 cities were categorized into nine groups. Generally, annual PM 2.5 concentrations were highest in the cities in the north (81–154 μg m − 3 ) and lowest in the cities close to seas in the south and east (27–57 μg m − 3 ). Seasonal PM 2.5 observations in the cities were generally higher in winter than in the other seasons. Industrial or residential sources were predicted to be the largest contributor to PM 2.5 for all the city groups, with annually fractional contributions of 25.0%–38.6% and 9.6%–27%, respectively. The annual contributions from power plants, agriculture NH 3 , windblown dust, and secondary organic aerosol (SOA) for the city groups were 8.7%–12.7%, 9.5%–12%, 6.1%–12.5%, and 5.4%–15.5%, respectively. Meanwhile, the annual contributions from transportation, sea salt, and open burning were relatively low (< 8%, < 2%, and < 6%, respectively). Secondary PM 2.5 accounted for 47%–63% of total annual PM 2.5 concentrations in the cities and contributed to as much as 70% of daily PM 2.5 concentrations on PM 2.5 pollution days (daily concentrations > 75 μg m − 3 ). Industrial or residential sources were generally the largest contributor on PM 2.5 pollution days for all the city groups in each season, except that open burning, SOA, and windblown dust could be more important on some days, particularly in spring. The results of this study would be helpful to develop measures to reduce annual PM 2.5 concentrations and the number of PM 2.5 pollution days for different regions of China. [ABSTRACT FROM AUTHOR]

Samples of size-fractionated particles were collected from local natural and anthropogenic sources in two industrial cities in the Yangtze River Delta, using either grab/resuspension sampling or ambient air sampling. The chemical characterizations of twenty one source profiles were obtained, based on elements (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn), soluble ions (Cl − , NO 3 − , SO 4 2 − , NH 4 + , K + , Na + and Ca 2 + ) and carbonaceous material such as organic carbon (OC) and elemental carbon (EC). The profiles vary between sources from different areas, as well as between different particulate sizes. Results show that particulate matter that originated as soil dust, construction dust and fugitive dust is typically rich in crustal elements, especially Al, Ca, Fe and Mg, while the presence of calcium is found to be a hallmark of the cement industry and ceramic industry. Dominant compositions of particles from coal-fired power plants are variable, with OC ranging from 2.2%–27%. Garbage-fired power plant and cooking smoke particulate emissions are enriched in Na, Cl − , OC and K due to the presence of salty and organic matter. The element Fe, ranging from 6.1% to 26.0%, is found to be an important marker for steel production dust. Vehicle exhaust profiles are characterized by high abundances of OC (12.1%–53.6%) and EC (3.9%–20.0%). Burning of straw results in K (1.6%–7.2%) and OC (12.4%–25.9%) being the dominant composition. Preliminary work has also been done on establishing local industrial profiles such as textile, ceramic and electroplating industries. This work could be used in receptor model studies to estimate the contributions of different sources to the size-fractionated particulate matter in the Yangtze River Delta. [ABSTRACT FROM AUTHOR]

China is the world's top carbon emitter and suffers from severe air pollution. We examine near-term air quality and CO 2 co-benefits of various current sector-based policies in China. Using a 2015 base case, we evaluate the potential benefits of four sectoral mitigation strategies. All scenarios include a 20% increase in conventional air pollution controls as well as the following sector-specific fuel switching or technology upgrade strategies. Power sector (POW): 80% replacement of small coal power plants with larger more efficient ones; Industry sector (IND): 10% improvement in energy efficiency; Transport sector (TRA): replacement of high emitters with average vehicle fleet emissions; and Residential sector (RES): replacement of 20% of coal-based stoves with stoves using liquefied petroleum gas (LPG). Conducting an integrated assessment using the regional air pollution model WRF-Chem, we find that the IND scenario reduces national air-pollution-related deaths the most of the four scenarios examined (27,000, 24,000, 13,000 and 23,000 deaths reduced annually in IND, POW, TRA and RES, respectively). In addition, the IND scenario reduces CO 2 emissions more than 8 times as much as any other scenario (440, 53, 0 and 52 Mt CO 2 reduced in IND, POW, TRA and RES, respectively). We also examine the benefits of an industrial efficiency improvement of just 5%. We find the resulting air quality and health benefits are still among the largest of the sectoral scenarios, while the carbon mitigation benefits remain more than 3 times larger than any other scenario. Our analysis hence highlights the importance of even modest industrial energy efficiency improvements and air pollution control technology upgrades for air quality, health and climate benefits in China. [ABSTRACT FROM AUTHOR]

Freshwater heat emissions from power plants with once-through cooling systems constitute one of many environmental pressures related to the thermoelectric power industry. The objective of this work was to obtain high resolution, operational characterization factors (CF) for the impact of heat emissions on ecosystem quality, and carry out a comprehensive, spatially, temporally and technologically differentiated damage-based environmental assessment of global freshwater thermal pollution. The aggregation of CFs on a watershed level results in 12.5% lower annual impacts globally and even smaller differences for the most crucial watersheds and months, so watershed level CFs are recommended when the exact emission site within the basin is unknown. Long-range impacts account for almost 90% of the total global impacts. The Great Lakes, several Mississippi subbasins, the Danube, and the Yangtze are among the most thermally impacted watersheds globally, receiving heat emissions from predominantly coal-fuelled and nuclear power plants. Globally, over 80% of the global annual impacts come from power plants constructed during or before the 1980s. While the impact-weighted mean age of the power plants in the Mississippi ranges from 38 to 51 years, in Chinese watersheds including the Yangtze, the equivalent range is only 15 to 22 years, reflecting a stark contrast in thermal pollution mitigation approaches. With relatively high shares of total capacity from power plants with once-through freshwater cooling, and tracing a large part of the Danube, 1 kWh of net electricity mix is the most impactful in Hungary, Bulgaria and Serbia. Monthly CFs are provided on a grid cell level and on a watershed level for use in Life Cycle Assessment. The impacts per generating unit are also provided, as part of our effort to make available a global dataset of thermoelectric power plant emissions and impacts. [ABSTRACT FROM AUTHOR]

Past studies on the impacts of climate change (CC) on Alpine hydropower production have focused on high-head accumulation power plants. We provide one of the first comprehensive, simulation-based studies on CC impacts on Alpine Run-of-River (RoR) production, also considering effects of environmental flow requirements and technical increase potential. We simulate future electricity production under three emissions scenarios for 21 Swiss RoR plants with a total production of 5.9 TWh a -1 . The simulations show an increase in winter production (4 % to 9 %) and a decrease in summer production (-2 % to -22 %), which together lead to an annual decrease of about -2 % to -7 % by the end of the century. The production loss due to environmental flow requirements is estimated at 3.5 % of the annual production; the largest low-elevation RoR power plants show little loss, while small and medium-sized power plants are most affected. The potential for increasing production by optimising the design discharge amounts to 8 % of the annual production. The largest increase potential is related to small and medium-sized power plants at high elevations. The key results are: i) there is no linear relationship between CC impacts on streamflow and on RoR production; the impacts depend on the usable streamflow volume, which is influenced by the Flow Duration Curve, environmental flow requirements, and design discharge; ii), the simulated production impacts show a strong correlation (>0.68) with the mean catchment elevation. The plants at the highest elevations even show an increase in annual production of 3 % to 23 %, due to larger shares of precipitation falling as rain instead of snow. These general results are transferable to RoR production in similar settings in other Alpine locations and should be considered in future assessments. Future work could focus on further technical optimisation potential, considering detailed operational data., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Replacing coal energy with biomass energy in power plants is important in reducing air pollutants and CO 2 emissions in China. We first calculated the optimal economic transport radius (OETR) to evaluate the optimally available biomass (OAB) and the potentially available biomass (PAB) for the year 2018. The OAB and PAB of power plants are estimated to be 423-1013 Mt, with higher values found in the provinces with higher population and crop yields. Unlike crop and forestry residue, the PAB can access to OAB for waste, mainly because the waste is easier to collect and transfer to a power plant. When all the PAB were consumed, the NOx, SO 2 , PM 10 , PM 2.5 , and CO 2 emissions would decrease by 41.7 kt, 115.3 kt, 117.6 kt, 26.0 kt, and 701.2 Mt, respectively. The scenario analysis results showed that the PAB will not be sufficient to meet the biomass power growth estimated for 2040, 2035, and 2030 under the baseline scenario (BS), policy scenario (PS), and reinforcement scenario (RS), respectively, whereas the CO 2 emission will dramatically decrease by 1473 Mt in 2040 under the BS, 1271 Mt in 2035 under the PS, and 1096 Mt in 2030 under the RS. Our findings indicate that the abundant biomass resources in China will bring significant co-benefits, reducing air pollutants and CO 2 emissions, if biomass energy can be applied in power plants. Furthermore, more advanced technologies, such as bioenergy with carbon capture and storage (BECCS), are expected to be used in power plants in the future, which will probably result in significantly lower CO 2 emissions and promote the achievement of the CO 2 emission peaking target and carbon neutrality. Our results provide useful information for developing a strategy for the coordinated reduction of air pollutants and CO 2 emissions from power plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Hydropeaking is one of the major hydropower-related disturbances of natural processes in river systems. The artificial flow fluctuations that are caused by the on-demand production of electricity are known for their severe impacts on aquatic ecosystems. These particularly affect those species and life stages that are not able to adjust their habitat selection to rapid up- and downramping rates. To date, the stranding risk has both experimentally and numerically mainly been investigated with variable hydropeaking graphs over stable river bathymetries. There is a lack of knowledge on how single, discrete peaking events vary concerning their impact on the stranding risk when the river morphology changes in the long-term perspective. The present study precisely addresses this knowledge gap by investigating morphological changes on the reach scale over a period of 20 years and the related variability of the lateral ramping velocity as a proxy for stranding risk. Two alpine gravel bed rivers impacted by hydropeaking over decades were tested by applying a one-dimensional and two-dimensional unsteady modelling approach. Both the Bregenzerach River and the Inn River exhibit alternating gravel bars on the reach scale. The results of the morphological development, however, showed different developments in the period 1995-2015. The Bregenzerach River displayed continuous aggradation (uplift of river bed) over the various selected submonitoring periods. In contrast, the Inn River showed continuous incision (erosion of river bed). The stranding risk exhibited high variability on a single cross-sectional basis. However, on the reach scale, no significant changes in stranding risk were calculated for either river reach. In addition, the impacts of river incision on the substrate composition were investigated. Here, in line with preceding studies, the results show that the coarsening of substrate increases the stranding risk and that especially the d 90 (90 % finer of the grain size distribution) must be considered. The present study reveals that the quantified stranding risk of aquatic organisms is a function of the general morphological (bar) characteristics of the impacted river and both the morphological and grain size development have an impact on the potential stranding risk of aquatic organisms and should be considered in the revision of licences in the management of multi-stressed river systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The prospective impacts of electric vehicle (EV) penetration on the air quality in Taiwan were evaluated using an air quality model with the assumption of an ambitious replacement of current light-duty vehicles under different power generation scenarios. With full EV penetration (i.e., the replacement of all light-duty vehicles), CO, VOCs, NO x and PM 2.5 emissions in Taiwan from a fleet of 20.6 million vehicles would be reduced by 1500, 165, 33.9 and 7.2 Gg yr − 1 , respectively, while electric sector NO x and SO 2 emissions would be increased by up to 20.3 and 12.9 Gg yr − 1 , respectively, if the electricity to power EVs were provided by thermal power plants. The net impacts of these emission changes would be to reduce the annual mean surface concentrations of CO, VOCs, NO x and PM 2.5 by about 260, 11.3, 3.3 ppb and 2.1 μg m − 3 , respectively, but to increase SO 2 by 0.1 ppb. Larger reductions tend to occur at time and place of higher ambient concentrations and during high pollution events. Greater benefits would clearly be attained if clean energy sources were fully encouraged. EV penetration would also reduce the mean peak-time surface O 3 concentrations by up to 7 ppb across Taiwan with the exception of the center of metropolitan Taipei where the concentration increased by < 2 ppb. Furthermore, full EV penetration would reduce annual days of O 3 pollution episodes by ~ 40% and PM 2.5 pollution episodes by 6–10%. Our findings offer important insights into the air quality impacts of EV and can provide useful information for potential mitigation actions. [ABSTRACT FROM AUTHOR]

Emissions of SO 2 and NO 2 from coal-fired power plants are a significant source of air pollution. In order to typify the power plants' plumes dynamics and quantify their contribution to air quality, a comprehensive characterisation of seven coal-fired power plant plumes has been performed under six representative circulation types (CTs) identified by means of a synoptic classification over the Iberian Peninsula. The emission and the transport of SO 2 and NO 2 have been simulated with the CALIOPE air quality forecasting system that couples the HERMES emission model for Spain and WRF and CMAQ models. For the facilities located in continental and Atlantic areas (As Pontes, Aboño, and Compostilla) the synoptic advection controls pollutant transport, however for power plants located along the Mediterranean or over complex-terrains (Guardo, Andorra, Carboneras, and Los Barrios), plume dynamics are driven by a combination of synoptic and mesoscale mountain–valley and sea–land breezes. The contribution of power plants to surface concentration occurs mainly close to the source (< 20 km) related to a fumigation process when the emission injection takes place within the planetary boundary layer reaching up to 55 μg SO 2 m − 3 and 32 μg NO 2 m − 3 . However, the SO 2 and NO 2 plumes can reach long distances (> 250 km from the sources) especially for CTs characterised by Atlantic advection. [ABSTRACT FROM AUTHOR]

Condensable particulate matter (CPM), as an air pollutant that has received wide attention in recent years, has a high emission concentration compared to filterable particulate matter (FPM), yet there is not a well-developed removal method. Air pollution control devices (APCDs) with a condensation process have a certain effect on CPM removal, which inspired us to study the condensation behavior of CPM. During the condensation process, the condensed CPM may exist in two final forms: one was collected by the cold surface that caused the condensation; the other was converted to fine particles and suspended in the space of the flue. In a sense, the surface collection form can reflect the removal of CPM, while the CPM in the space suspension form should be further separated with the aim of removal. In this work, we adopted a CPM sampling system based on EPA Method 202 to reveal the distribution of the condensation behavior of CPM. In this sampling system, the CPM collected by all the cooling surfaces, including the cooling coil and impingers, can be counted as the surface collection form, while those collected by the terminal CPM filter can be regarded as the space suspension form. It was found that about 75 % of CPM was collected by the cooling surfaces, which suggested that CPM preferred to be in the surface collection form than the space suspension form. This preference characteristic also could be observed in the inorganic (CPM i ) and organic components of the CPM (CPM o ). Among the CPM i , almost all NH 4 + and SO 4 2- condensed in the form of surface collection. The preference characteristics in CPM's (and its components') condensation behavior are similar under every temperature reduction condition. In this work, the interference of CPM measurement error was resolved by the statistical method of ANOVA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

As treatments for mainstream pollutants in coal-fired power plants have been established, the control of non-conventional pollutants, such as SO 3 and HCl, is gradually gaining attention. In this study, combined SO 3 and HCl removal is proposed based on SO 3 removal by absorber injection. However, it is challenging to selectively absorb SO 3 and HCl from SO 2 -rich atmospheres. Therefore, Ca(OH) 2 was modified via ball milling and doping with CuO for the combined removal of SO 3 and HCl. The results showed that ball milling reduced the particle and grain sizes of Ca(OH) 2 , which increased the active sites of Ca(OH) 2 and prolonged reaction time. After modification by ball milling, SO 3 absorption per mg of Ca(OH) 2 increased by 40 %. However, HCl removal efficiency was difficult to improve by modifying Ca(OH) 2 using only ball milling under SO 3 and SO 2 atmospheres. Therefore, the dechlorination capacity of Ca(OH) 2 was improved by adding ions during the ball milling process. Doping of Ca(OH) 2 with Cu 2+ changed its crystal structure, weakened the diffusion resistance of HCl, and improved Ca(OH) 2 utilization. Additionally, it increased the energy of Ca(OH) 2 to adsorb HCl., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Evaluating the embodied environmental impact of solar photovoltaic (PV) technology has been an important topic in addressing the sustainable development of renewable energy. While monetization of environmental externality is a remaining issue, which should be carried out in order to allow for an easy-to-understand comparison between direct economic and external cost. In this study, the environmental impact of solar PV power is monetized through conversion factors between midpoint and endpoint categories of life cycle analysis and the monetization weighting factor. Then, the power generation capacity and generation life of PV and coal-fired power plants are assumed to be consistent in order to compare the total cost of PV and coal-fired power generation. Results show that the cost of PV technology is higher than coal-fired form the base year from 2026 until 2030, taking into account environmental external costs and production costs. However, by 2030, the total cost of coal-fired power will be higher than that of solar PV. The life span cost per kWh is $3.55 for solar PV and $116.25 for coal-fired power. Although solar PV power seems more environmentally effective than coal-fired power in the life span, our results reveal the high environmental external cost of producing solar photovoltaic modules, which reminds us to pay more attention to the environmental impact when conducting cost-benefit analysis of renewable technologies. Without incorporating the environmental cost, the real cost of renewable technology will be underestimated., Competing Interests: Declaration of competing interest Authors have no conflict of interest to declare., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Even though water-energy systems and ecosystems have complex relationships, regional energy policies seldom consider this connection. The current regional energy policies are developed primarily based on technical and socio-economical aspects and lack ecological considerations that may deteriorate the ecosystems and sustainability of these policies. Hence, considering the water-energy-ecosystem nexus in the development stage of the energy policies can aid decision-makers in initiating successful multi-dimensional energy policies. This study proposes a novel approach to develop an environmental index to support the regional energy policies that rely on Run-of-river (RoR) hydroelectric power plants (HEPPs) with a nexus approach. First, significant environmental impacts of RoR HEPPs are identified as environmental flows, impacts on ecologically valuable areas such as heritage sites, wetlands, national parks, river water quality degradation, modification of habitat, and impact on ecosystems and biodiversity loss. Then these impacts are represented through indicators and are aggregated into an overall environmental performance index through a fuzzy multi-criteria decision-making approach. The proposed approach allows the integration of ecological dimensions into the evaluation of RoR HEPPs through easy-to-measure indicators, among which environmental flow is a critical component., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this study, two top-down methods-mass balance and Gaussian footprint-were used to determine SO 2 emissions rates via three airborne sampling studies over Korea's largest coal power plant in October 2019 and 2020. During the first two flights in October 2019, mass balance approaches significantly underestimated the SO 2 emissions rates by 75 % and 28 %, respectively, as obtained from the real-time stack monitoring system. Notably, this large discrepancy accounted for the insufficient number of transects altitudes and high levels of background SO 2 along the upwind side. Alternatively, the estimated SO 2 emissions rates of the third flight (October 2020) displayed a difference of <10 % from rea-time monitoring data (630 vs. 690 kg·hr -1 ), owing to the enhanced vertical resolution with increased transects and lower background SO 2 levels. In contrast to the mass balance method, Gaussian footprints offered significantly improved accuracy (relative error: 41 %, 32 %, and 2 % for Flights 1, 2, and 3, respectively). This relatively good performance was attributed to prior emissions knowledge via the Clean Air Policy Support System (CAPSS) emissions inventory and its unique ability to accurately estimate stack-level SO 2 emissions rates. Theoretically, the Gaussian footprint was less prone to sparse transects and upwind background levels. However, it can be substantially influenced by atmospheric stability and consequently by effective stack heights and dispersion parameters; basically, all factors with minimal-to-no influence on the mass balance approach. Conversely, the mass balance method was the only plausible approach to estimate unidentified source emissions rates when well-defined prior emission information was unknown. Here, the footprint approach supplemented the mass balance method when the emission inventories were known, and employing both strategies approaches greatly enhanced the integrity of top-down emissions inventories from the power plant sources, thus, supporting their potential for ensuring operational compliance with SO 2 emissions regulation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Hazard element contamination coming from coal power plants is something obvious, but when this contamination is accompanied by other contamination sources, such as, urban, coal mining and farming activities the study gets complicated. This is the case of an area comprised in the southern part of Santa Catarina state (Brazil) with the largest private power plant generator. After the elemental analysis of 41 agricultural soils collected in an extensive area around the thermoelectric (from 0 to 47 km), the high presence of As, Co, Cr, Cu, Fe, Mn, Mo, Pb, Sb, Sn, Tl, V and Zn was found in some specific areas around the power plant. Nevertheless, as the NWAC (Normalized-and-Weighted Average Concentration) confirmed, only soils from one site were classified as of very high concern due to the presence of potential toxic elements. This site was located within the sedimentation basin of the power plant. The spatial distribution obtained by kriging in combination with the analysis of the data by Principal Component Analysis (PCA) revealed three important hotspots in the area according to soil uses and geographic localization: the thermoelectric, its area of influence due to volatile compound deposition, and the area comprised between two urban areas. Farming practice turn out to be an important factor too for the quantity of hazard element stored in soils. [ABSTRACT FROM AUTHOR]

The elemental composition of water-soluble and acid-soluble fractions of PM2.5 samples from two different Greek cities (Patras and Megalopolis) was investigated. Patras and Megalopolis represent different environments. Specifically, Patras is an urban environment with proximity to a large port, while Megalopolis is a small city located close to lignite power plants. Both cities can serve as a representative example of European cities with similar characteristics. The concentration of 14 elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Fe, Sr, Ti, V and Zn) was determined in each fraction by ICP-MS. Microwave assisted digestion was used to digest the samples using a mixture of HNO3 and HF. For the determination of the water soluble fraction, water was chosen as the simplest and most universal extraction solvent. For the validation of the extraction procedure, the recoveries were tested on two certified reference materials (NIST SRM 1648 Urban Particulate Matter and NIST 1649a Urban Dust). Results showed that Zn has the highest total concentration (273 and 186 ng/m³) and Co the lowest (0.48 and 0.23 ng/m³) for Patras and Megalopolis samples, respectively. Nickel with 65% for Patras and As with 49% for Megalopolis displayed the highest solubility, whereas Fe (10%) and Ti (2%) the lowest ones, respectively. [ABSTRACT FROM AUTHOR]

This paper provides a synthesis and comparison of methodologies and results obtained in several studies devoted to the impact of climate change on hydropower. By putting into perspective various case studies, we provide a broader context and improved understanding of climate changes on energy production. We also underline the strengths and weaknesses of the approaches used as far as technical, physical and economical aspects are concerned. Although the catchments under investigation are located close to each other in geographic terms (Swiss and Italian Alps), they represent a wide variety of situations which may be affected by differing evolutions for instance in terms of annual runoff. In this study, we also differentiate between run-of-river, storage and pumping-storage power plants. By integrating and comparing various analyses carried out in the framework of the EU-FP7 ACQWA project, this paper discusses the complexity as well as current and future issues of hydropower management in the entire Alpine region. [ABSTRACT FROM AUTHOR]

The technology of flue gas CO 2 fixation by microalgae is highly attractive in the era of CO 2 neutrality. However, CO 2 emission along the whole process has yet to be sufficiently evaluated. Here, a life-cycle assessment was performed to evaluate the energy conversion characteristics and environmental impacts of flue gas CO 2 fixation from coal-fired power plant (Case 1) and coal chemical plant (Case 2) by microalgae. The results show that total energy consumption and CO 2 gas emissions for Case 1 are 27.5-38.0 MJ/kg microalgae power (MP) and 5.7-7.7 kg CO 2 equiv/kg MP, respectively, which are lower than that for Case 2 (122.5-181.3 MJ/kg MP and 32.7-48.6 kg CO 2 equiv/kg MP). The CO 2 gas aeration rate and microalgae growth rate are the two most sensitive parameters for the energy conversion and net CO 2 emission. Therefore, increasing the CO 2 aeration efficiency and microalgae growth rate are key to advance the technology of flue gas CO 2 fixation by microalgae which will contribute to carbon naturality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The selective catalytic reduction (SCR) denitration technology is widely used in coal-fired generating units. The NOx concentration of boiler outlet is an important parameter in the feedforward control of SCR denitration. However, its measurement lag leads to a large range fluctuation of NOx emission, which affects the safe and economic operation of the unit. In order to solve the problem of boiler outlet NOx concentration measurement lag in denitration control, and improve the timeliness of fluctuation response for denitration control. Many studies have reported on NOx concentration prediction models based on the long short-term memory (LSTM) algorithm, support vector machines (SVM) algorithm, et al. However, there are no reports on online modeling, particularly none on predictive values of boiler outlet NOx concentration ahead of the measured values. Thus, in this study, a 1000 MW ultra-supercritical coal-fired boiler was selected, and 2404 sets of measured samples were collected to predict NOx concentration. A novel online modeling method for NOx concentration of boiler outlet was proposed. For the first time, a high-precision online real-time prediction model of boiler outlet NOx concentration was innovatively established based on improved long short-term memory network (ILSTM). A feature quantity weight analysis method based on the RRelieff algorithm is adopted, and the change rates of feature quantities were used as input in the model. The results showed that the root mean square error (δ R ) and computation time of ILSTMN reduced relatively by 17.97 % and 1.97 s, respectively. The online model with satisfied accuracy is trained in 1 s, which uses the latest recent data from decentralized control system (DCS). The NOx concentration of boiler outlet predicted by the online model is 22 s ahead of the measurement NOx concentration, and the prediction accuracy is still as high as 96 % without the intervention after two years of operation. As a feedforward of SCR denitration control system, NOx concentration predicted by the model can significantly improve the timeliness of control response. The online model provides theoretical support for suppressing large fluctuations of NOx emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Hydropeaking has become a global issue because of extensive hydropower dam construction worldwide. Yet, its ecological impacts on riverine ecosystems are not well studied. We explored the effects of hydropeaking on riverine plants, based on data from a ~300 km reach downstream of the world's largest hydropower dam, the Three Gorges Dam. We tested three hypotheses relating to hydropeaking impacts on species elevational distributions, assemblage structure and species-specific biomass patterns by generalized linear mixed modelling and joint species distribution modelling. We found that, first, hydropeaking greatly shaped species elevational ranges, leading to expansions of herbs to high elevations and shifting species dominance at low elevations. Secondly, we detected contrasting effects of hydropeaking on assemblage-level characteristics of herbs. The inundation induced by hydropeaking had strong effects on assemblage composition and biomass allocation, where more biomass was allocated to belowground part. Hydropeaking blurred the species richness-biomass relationship, although it had little effect on species richness or plot-level biomass. Thirdly, hydropeaking induced inundation was the most important covariate driving species biomass patterns of riverine plants, although complex species-specific effects were identified, and random effects were often large in fitted models. We concluded that hydropeaking likely acted as a major driver of plant community assembly in rivers with a hydropower dam. Conservation and restoration of riverine plants can benefit from the inclusion of water level management in operational schemes of hydropower dams, especially during the early life history stages., Competing Interests: Declaration of competing interest Xueqin Liu reports financial support was provided by National Key Research and Development Program of China., (Copyright © 2022 Elsevier B.V. All rights reserved.)

This study assesses the energy and environmental performances of electricity produced from Italian anaerobic digestion coupled with combined heat and power plants. The Life Cycle Assessment methodology is applied to a set of plants characterised by different power sizes (from 100 to 999 kW) and feedstock compositions (variable rates of agricultural products and by-products). Then, the average eco-profile of the produced electricity is compared with electricity produced by the national grid and photovoltaic panels. The analysis allows detection of the combinations of size and feedstock with the lowest impacts. They correspond to small and medium plants mainly fed by organic by-products. In addition, compared to electricity from the grid, the average biogas electricity is characterised by the lowest contribution in impacts categories, such as abiotic depletion potential and ozone layer depletion potential, while largest in acidification and eutrophication. Focusing on global warming potential and cumulative energy demand fossil, the impacts of average biogas electricity (155 kgCO 2eq /MWh and 172 MJ/MWh) are about 35 % and 38 % of that generated by the grid. Furthermore, it could generate 47 % less of the impact in the abiotic depletion elements category of the solar system. To enhance the farms' environmental and economic sustainability and balance the electric grid, these outcomes point out that biogas electricity produced from the agriculture and livestock sector can contribute to the decarbonisation and self-sufficiency of European countries. The results strictly depend on the operative conditions and can aid policymakers at the global level in improving the energy supply security and sustainability. Further, they provide reliable information to stakeholders to select the most sustainable solution, according to the feedstock type, power supply, and management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Abstract: Little is known about the intensity and extension of subsurface urban heat islands (UHI), and the individual role of the driving factors has not been revealed either. In this study, we compare groundwater temperatures in shallow aquifers beneath six German cities of different size (Berlin, Munich, Cologne, Frankfurt, Karlsruhe and Darmstadt). It is revealed that hotspots of up to +20K often exist, which stem from very local heat sources, such as insufficiently insulated power plants, landfills or open geothermal systems. When visualizing the regional conditions in isotherm maps, mostly a concentric picture is found with the highest temperatures in the city centers. This reflects the long-term accumulation of thermal energy over several centuries and the interplay of various factors, particularly in heat loss from basements, elevated ground surface temperatures (GST) and subsurface infrastructure. As a primary indicator to quantify and compare large-scale UHI intensity the 10–90%-quantile range UHII10–90 of the temperature distribution is introduced. The latter reveals, in comparison to annual atmospheric UHI intensities, an even more pronounced heating of the shallow subsurface. [Copyright &y& Elsevier]

Coal combustion is considered an important source of atmospheric nanoparticles (NPs). However, the underlying information on the emission of NPs from coal-fired power plants (CFPPs) is still lacking. Along these lines, in this study, coal fly ashes (CFAs) were collected from different multi-stage particulate emission control devices (PECDs) in three representative CFPPs in China. The particle size and particle number concentration (PNC) of typical metal-containing NPs (Fe- and Ti-containing NPs) were analyzed by using the single-particle inductively coupled plasma mass (SP-ICP-MS) technology. By increasing the stage of PECDs, the mean particle sizes of NPs gradually declined and the PNCs of Fe- and Ti-containing NPs increased significantly. Specifically, the PNC of final-stage CFA was 3 - 8 times that of the first-stage CFA. A comparison of the electrostatic precipitators (ESPs), fabric filters (FFs), and electrostatic-fabric-integrated precipitators (EFIPs) showed that the state-of-the-art EFIPs exhibited a relatively good NP-removal efficiency with the highest PNCs. In addition, NP hourly emissions in all coal combustion by-products (CCPs) were further calculated in a typical CFPP. The total emissions of Fe- and Ti-containing NPs in all CCPs were 1.87 × 10 18 and 1.57 × 10 18 particles/h, respectively. NPs were mainly enriched in CFA trapped by PECDs (80% of total emissions). Although the mass of the CFA that escaped through the stack was extremely low, it contained the highest PNCs of Fe- and Ti-containing NPs of all CCPs, accounting for 3.41% and 1.67% of the corresponding total NP emissions. These NPs may also coexist with various toxic metals, such as Zn and Pb, and be released directly into the atmosphere, where they pose a potential risk to human health., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The dry impinger method is commonly used for the determination of condensable particulate matter (CPM) emissions. The coil and chamber condenser is used to build different dry impinger methods for CPM sampling. The comparative analysis of coil and chamber condenser is performed in a laboratory experiment to evaluate the deviation caused by SO 2 . Results showed that the positive deviation caused by SO 2 in the chamber condenser is lower than that in the coil condenser under the same sampling conditions, especially under high humidity flue gas. The CPM emission characteristics from Hanchuan coal-fired power plant (CFPP) determined by both dry impinger methods are also investigated as well. The CPM and its most water-soluble ions (e.g., F - , Cl - , NO 3 - , SO 4 2- , Na + , Ca 2+ and NH 4 + ) measured by method #2 (chamber condenser) are higher than that of method #1 (coil condenser). In addition, the esters in the CPM also increased with the CPM concentrations. Based on above evidences, it can be inferred that the dry impinger method with chamber condenser, will be recommended as the appropriate method for measuring CPM emitted from stationary sources, especially under the high humidity flue gas conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Hydropower production is a key electricity generation technology in many parts of the world which can play a significant role in the transition towards a green and clean energy system. Hydropower can mobilize flexible energy on demand (hydropeaking) to balance out intermittent electricity from wind and photovoltaics. Adoption of hydropower as a peaking power source could lead to increased frequency of flow ramping in rivers downstream hydropower tailraces, which is one of the main stressors for riverine biota in alpine rivers. Both planned and accidental shutdowns of hydropower turbines need ecological mitigation. Our survey revealed that >3000 km of rivers downstream ca 800 hydropower plants in Norway may be ecologically impacted by non-natural flow fluctuations, and few have appropriate mitigation thresholds. A considerable eco-friendly peaking service may come from the Norwegian hydropower portfolio of over 19 GW installed capacity, with outlets into fjords, reservoirs or other large water bodies which normally dampen the ecological impacts of flow ramping. Intensive flow ramping occurs with irregular intervals from most types of hydropower. Although the highest frequency of stops were revealed in hydropower turbines not impacting river flow from storage hydropower, a significant number of turbine flow stops lasting over half a day in most types and categories of diversion hydropower. We suggest that further emerging ecosystem-based mitigations need to be adapted in hydropower licenses. This includes operational thresholds for both up and down ramping, constructional measures like by-pass valves, retention basins and increased base-flow or flow cap to ensure sustainability for hydropower operations. Our data reveal some of the most intensive hydropeaking operations from hydropower impacting longer rivers. Hence, our data underpins the potential for restoring downstream modified flow by ecosystem based measures related to both up and down ramping events in many regulated rivers., Competing Interests: Declaration of competing interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, although both JHH and JHL-L have been working with river and hydropower management at national level in Norway., (Copyright © 2022. Published by Elsevier B.V.)