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1.
In response to the demand for flexible and sustainable energy storage devices that exhibit high electrochemical performance, a supercapacitor system is fabricated using mulberry tree‐derived paper as a substrate and Poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) and carbon black as the active material. The mulberry paper‐based supercapacitor system demonstrates high energy density of 29.8–39.8 Wh kg?1 and power density of 2.8–13.9 kW kg?1 with 90.7% retention of its initial capacity over 15 000 charge–discharge cycles. In addition, the mulberry tree fibers are known to have superior mechanical strength and toughness and the mulberry paper‐based supercapacitor; as a result, exhibit high mechanical and chemical toughness; 99% of its initial capacity is retained after 100 repeated applications of bending strains, and twisting. 94% capacity retention is observed even after exposure to HCl and H2SO4 acid solutions. The fabrication methodology of the mulberry‐based supercapacitor is highly scalable and could be stacked to increase the energy storage capacity, where operation of light‐emitting diode lights with a drive voltage of 12 V integrated in a wearable device is demonstrated.  相似文献   

2.
Biofuels from agricultural sources are an important part of California's strategy to reduce greenhouse gas emissions and dependence on foreign oil. Land conversion for agricultural and urban uses has already imperiled many animal species in the state. This study investigated the potential impacts on wildlife of shifts in agricultural activity to increase biomass production for transportation fuels. We applied knowledge of the suitability of California's agricultural landscapes for wildlife species to evaluate wildlife effects associated with plausible scenarios of expanded production of three potential biofuel crops (sugar beets, bermudagrass, and canola). We also generated alternative, spatially explicit scenarios that minimized loss of habitat for the same level of biofuel production. We explored trade‐offs to compare the marginal changes per unit of energy for transportation costs, wildlife, land and water‐use, and total energy produced, and found that all five factors were influenced by crop choice. Sugar beet scenarios require the least land area: 3.5 times less land per liter of gasoline equivalent than bermudagrass and five times less than canola. Canola scenarios had the largest impacts on wildlife but the greatest reduction in water use. Bermudagrass scenarios resulted in a slight overall improvement for wildlife over the current situation. Relatively minor redistribution of lands converted to biofuel crops could produce the same energy yield with much less impact on wildlife and very small increases in transportation costs. This framework provides a means to systematically evaluate potential wildlife impacts of alternative production scenarios and could be a useful complement to other frameworks that assess impacts on ecosystem services and greenhouse gas emissions.  相似文献   

3.
ABSTRACT Wind turbines in the Altamont Pass Wind Resource Area (APWRA), California, USA, have caused annual fatalities of thousands of raptors and other birds. Alameda County implemented an Avian Protection Program requiring mitigation measures and eventual repowering to modern wind turbines, all intended to reduce raptor fatality rates 50% from levels estimated for 1998–2003. Two years into the 3-year program, we compared estimates of fatality rates between 1998–2003 and 2005–2007 and between a repowered wind project (Diablo Winds) and the APWRA's old-generation wind turbines. The APWRA-wide fatality rates increased significantly for multiple bird species, including 85% for all raptors and 51% for all birds. Fatality rates caused by the Diablo Winds repowering project were not lower than replaced turbines, but they were 54% and 66% lower for raptors and all birds, respectively, than those of concurrently operating old-generation turbines in 2005–2007. Because new-generation turbines can generate nearly 3 times the energy per megawatt of rated capacity compared to the APWRA's old turbines, repowering the APWRA could reduce mean annual fatality rates by 54% for raptors and 65% for all birds, while more than doubling annual wind-energy generation. Alternatively, the nameplate capacity of a repowered APWRA could be restricted to 209 megawatts to meet current energy generation (about 700 gigawatt-hr), thereby reducing mean annual fatalities by 83% for raptors and 87% for all birds. In lieu of repowering, bird fatalities could be reduced by enforcing operating permits and environmental laws and by the County requiring implementation of the Alameda County Scientific Review Committee's recommendations.  相似文献   

4.
Organic photovoltaics (OPVs) have become a potential candidate for clean and renewable photovoltaic productions. This work examines the current cost drivers and potential avenues to reduce costs for organic solar modules by constructing a comprehensive bottom‐up cost model. The direct manufacturing cost (MC) and the minimum sustainable price (MSP) for an opaque single solar module (SSM) (MC = 187 ¥ m?2, MSP = 297 ¥ m?2) and for a tandem solar module (MC = 224 ¥ m?2, MSP = 438 ¥ m?2) are analyzed in detail. Within this calculation, the most expensive layers and processing steps are identified and highlighted. Importantly, the low levelized cost of energy (LCOE) value for an SSM with a 10% power conversion efficiency in a 20‐year range from 0.185 to 0.486 ¥ kWh?1, with a national average of 0.324 ¥ kWh?1 in China under an average solar irradiance of 1200 kWh m?2 year?1. Moreover, the impact on the cost of alternative materials and constructions, process throughputs, module efficiency, and module lifetime, etc., is presented and avenues to further reduce the MSP and LCOE values are indicated. The analysis shows that OPVs can emerge as a competitive alternative to established power generation technologies if the remaining issues (e.g., active layer material cost, module efficiency, and lifetime) can be resolved.  相似文献   

5.
We studied the effects of climate change and forest management scenarios on net climate impacts (radiative forcing) of production and utilization of energy biomass, in a Norway spruce forest area over an 80‐year simulation period in Finnish boreal conditions. A stable age‐class distribution was used in model‐based analyses to identify purely the management effects under the current and changing climate (SRES B1 and A2 scenarios). The radiative forcing was calculated based on an integrated use of forest ecosystem model simulations and a life cycle assessment (LCA) tool. In this work, forest‐based energy was used to substitute coal, and current forest management (baseline management) was used as a reference management. In alternative management scenarios, the stocking was maintained 20% higher in thinning compared to the baseline management, and nitrogen fertilization was applied. Intensity of energy biomass harvest (e.g. logging residues, coarse roots and stumps) was varied in the final felling of the stands at the age of 80 years. Also, the economic profitability (NPV, 3% interest rate) of integrated production of timber and energy biomass was calculated for each management scenario. Our results showed that compared to the baseline management, climate benefits could be increased by maintaining higher stocking in thinning over rotation, using nitrogen fertilization and harvesting logging residues, stumps and coarse roots in the final felling. Under the gradually changing climate (in both SRES B1 and A2), the climate benefits were lower compared to the current climate. Trade‐offs between NPV and net climate impacts also existed.  相似文献   

6.
Bioenergy is expected to play a critical role in climate change mitigation. Most integrated assessment models assume an expansion of agricultural land for cultivation of energy crops. This study examines the suitability of land for growing a range of energy crops on areas that are not required for food production, accounting for climate change impacts and conservation requirements. A global fuzzy logic model is employed to ascertain the suitable cropping areas for a number of sugar, starch and oil crops, energy grasses and short rotation tree species that could be grown specifically for energy. Two climate change scenarios are modelled (RCP2.6 and RCP8.5), along with two scenarios representing the land which cannot be used for energy crops due to forest and biodiversity conservation, food agriculture and urban areas. Results indicate that 40% of the global area currently suitable for energy crops overlaps with food land and 31% overlaps with forested or protected areas, highlighting hotspots of potential land competition risks. Approximately 18.8 million km2 is suitable for energy crops, to some degree, and does not overlap with protected, forested, urban or food agricultural land. Under the climate change scenario RCP8.5, this increases to 19.6 million km2 by the end of the century. Broadly, climate change is projected to decrease suitable areas in southern regions and increase them in northern regions, most notably for grass crops in Russia and China, indicating that potential production areas will shift northwards which could potentially affect domestic use and trade of biomass significantly. The majority of the land which becomes suitable is in current grasslands and is just marginally or moderately suitable. This study therefore highlights the vital importance of further studies examining the carbon and ecosystem balance of this potential land‐use change, energy crop yields in sub‐optimal soil and climatic conditions and potential impacts on livelihoods.  相似文献   

7.
Forest plantations support several ecosystem services including biodiversity conservation. Establishment of a forest biomass‐based industry could significantly change the age structure of forest plantations located in its vicinity and thus, could lead to a possible loss of biodiversity. Therefore, this study assesses spatiotemporal impacts of a forest biomass‐based power plant on the age structure of surrounding forest plantations at landscape level. A cellular automata approach was adopted and interactions between economic objectives of forest landowners and a power plant owner punctuated by forest growth and management characteristics were considered. These spatiotemporal impacts were jointly assessed for four separate scenarios and four different power plant capacities using appropriate landscape‐level indices. Slash pine (Pinus elliotti L.) was selected as a representative species. Results indicate that the age structure of surrounding forest plantations continuously fluctuates with respect to each year of power plant operation. However, the age structure, once disturbed, never becomes comparable to the original age structure. We also found that the mature plantations were harvested during early years of power plant operation and were never observed again for the remaining years of power plant operation. This was particularly true for high capacity power plants. Similarly, high value of selected spatial index at the end of power plant life for a high capacity power plant relative to the original low value of the same index indicates aggregation of remaining plantation ages at landscape level. Establishment of low capacity forest biomass‐based power plants and adoption of an integrated regional level planning approach could help in maintaining original age structure characteristics of surrounding forest plantations to a large extent. This might help in sustaining various ecosystem services including biodiversity conservation obtained from forest plantations in a long run.  相似文献   

8.
Agrivoltaics describes concurrent agricultural production of crops and photovoltaic generation of electricity on the same cropland. By using tinted semi‐transparent solar panels, this study introduces a novel element to transform the concept of agrivoltaics from just solar‐sharing to selective utilization of different light wavelengths. Agrivoltaic growth of basil and spinach is tested. When compared with classical agriculture, and based on the feed‐in‐tariff of the experimental location, agrivoltaic co‐generation of biomass and electricity is calculated to result in an estimated financial gross gain up to +2.5% for basil and +35% for spinach. Marketable biomass yields do not change significantly for basil, while a statistically significant loss is observed for spinach. This is accompanied by a relative increase in the protein content for both plants grown under agrivoltaic conditions. Agrivoltaics implemented with tinted solar panels improve the biomass production per unit amount of solar radiation up to 68%, with up to 63% increase in the ratio of leaf and stem biomass to root. Agrivoltaics can enrich the portfolio of farmers, mitigate risks associated with climate, and vastly enhance global photovoltaics capacity without compromising agricultural production.  相似文献   

9.
Artificial photosynthesis provides a blueprint to harvest solar energy to sustain the future energy demands. Solar‐driven water splitting, converting solar energy into hydrogen energy, is the prototype of photosynthesis. Various systems have been designed and evaluated to understand the reaction pathways and/or to meet the requirements of potential applications. In solar‐to‐hydrogen conversion, electrocatalytic hydrogen and oxygen evolution reactions are key research areas that are meaningful both theoretically and practically. To utilize hydrogen energy, fuel cell technology has been extensively investigated because of its high efficiency in releasing chemical energy. In this review, general concepts of the photosynthesis in green plants are discussed, different strategies for the light‐driven water splitting proposed in laboratories are introduced, the progress of electrocatalytic hydrogen and oxygen evolution reactions are reviewed, and finally, the reactions in hydrogen fuel cells are briefly discussed. Overall, the mass and energy circulation in the solar‐hydrogen‐electricity circle are delineated. The authors conclude that attention from scientists and engineers of relevant research areas is still highly needed to eliminate the wide disparity between the aspirations and realities of artificial photosynthesis.  相似文献   

10.
In this study, a newly isolated strain screened from the indoxacarb‐rich agricultural soils, Bacillus cereus WZZ006, has a high stereoselectivity to racemic substrate 5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester. (S)‐5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester was obtained by bio‐enzymatic resolution. After the 36‐hour hydrolysis in 50‐mM racemic substrate under the optimized reaction conditions, the e.e.s was up to 93.0% and the conversion was nearly 53.0% with the E being 35.0. Therefore, B cereus WZZ006 performed high‐level ability to produce (S)‐5‐chloro‐1‐oxo‐2,3‐dihydro‐2‐hydroxy‐1H‐indene‐2‐carboxylic acid methyl ester. This study demonstrates a new biocatalytic process route for preparing the indoxacarb chiral intermediates and provides a theoretical basis for the application of new insecticides in agricultural production.  相似文献   

11.
This article addresses agricultural metabolism and transitions for energy, nitrogen, farm production, self‐sufficiency, and surplus from historical data since the nineteenth century. It builds on an empirical data set on agricultural production and production means in France covering 130 consecutive years (1882–2013). Agricultural transitions have increased the net production and surplus of farms by a factor of 4 and have zeroed self‐sufficiency. The energy consumption remained quasi‐stable since 1882, but the energy and nitrogen structure of agriculture fully changed. With an EROI (energy return to energy invested) of 2 until 1950, preindustrial agriculture consumed as much energy to function as it provided in exportable surplus to sustain the nonagricultural population. The EROI doubled to 4 over the last 60 years, driven, on the one hand, by efficiency improvements in traction through the replacement of draft animals by motors and, on the other hand, by the joint increase in crop yields and efficiency in nitrogen use. Agricultural energy and nitrogen transitions shifted France from a self‐sufficiency agri‐food‐energy regime to a fossil‐dependent food export regime. Knowledge of resource conversion mechanisms over the long duration highlights the effects of changing agricultural metabolism on the system's feeding capacity. Farm self‐sufficiency is an asset against fossil fuel constraints, price volatility, and greenhouse gas emissions, but it equates to lower farm surplus in support of urbanization.  相似文献   

12.
The all‐vanadium redox flow battery is a promising technology for large‐scale renewable and grid energy storage, but is limited by the low energy density and poor stability of the vanadium electrolyte solutions. A new vanadium redox flow battery with a significant improvement over the current technology is reported in this paper. This battery uses sulfate‐chloride mixed electrolytes, which are capable of dissolving 2.5 M vanadium, representing about a 70% increase in energy capacity over the current sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of ?5 to 50 °C, potentially eliminating the need for electrolyte temperature control in practical applications. This development would lead to a significant reduction in the cost of energy storage, thus accelerating its market penetration.  相似文献   

13.
Flexible batteries, seamlessly compatible with flexible and wearable electronics, attract a great deal of research attention. Current designs of flexible batteries struggle to meet one of the most extreme yet common deformation scenarios in practice, folding, while retaining high energy density. Inspired by origami folding, a novel strategy to fabricate zigzag‐like lithium ion batteries with superior foldability is proposed. The battery structure could approach zero‐gap between two adjacent energy storage segments, achieving an energy density that is 96.4% of that in a conventional stacking cell. A foldable battery thus fabricated demonstrates an energy density of 275 Wh L?1 and is resilient to fatigue over 45 000 dynamic cycles with a folding angle of 130°, while retaining stable electrochemical performance. Additionally, the power stability and resilience to nail shorting of the foldable battery are also examined.  相似文献   

14.
The aim of this study was to evaluate the biomass production potential for the Spanish Iberian Peninsula using the Populus spp. ‘I‐214’ clone under several management regimes and land availability scenarios, and to determine its future contribution to Spanish energy demands. Empirical models were fitted to the data from a network of 144 plots located at 12 sites in the continental Mediterranean climatic regions of the Iberian Peninsula, in which yield was related to climate and soil, as well as to plantation management variables. Four models were developed considering average maximum temperature of the hottest month (TMAXH, °C), length of drought (A, months), intensity of drought (K, unitless) and soil pH. Predictions were made for the irrigated agricultural land (IAL), where the value of the independent variables were within the validity range, and for two management scenarios. Energy production capacity was evaluated by considering the alternatives for transforming poplar SRC biomass: heat, bio‐ethanol and electricity. The results indicated a mean productivity for the Spanish Iberian peninsula of between 15.3 and 10.9 Mg ha?1 yr?1 for the standard management scenario and the poorly irrigated and weeded management scenario respectively. Two IAL scenarios were considered for the calculation of biomass production potential: all IAL for which it was possible to make predictions is made available for poplar SRC (TP, maximum hypothetical production capacity), and another in which only unproductive IAL is available for poplar SRC (RP, production capacity without constricting agricultural production). The TP scenario contributes up to 6.8–9.6% of total energy demands, and the RP scenario 0.7–0.9%, depending on plantation management.  相似文献   

15.
Domestic and foreign renewable energy targets and financial incentives have increased demand for woody biomass and bioenergy in the southeastern United States. This demand is expected to be met through purpose‐grown agricultural bioenergy crops, short‐rotation tree plantations, thinning and harvest of planted and natural forests, and forest harvest residues. With results from a forest economics model, spatially explicit state‐and‐transition simulation models, and species–habitat models, we projected change in habitat amount for 16 wildlife species caused by meeting a renewable fuel target and expected demand for wood pellets in North Carolina, USA. We projected changes over 40 years under a baseline ‘business‐as‐usual’ scenario without bioenergy production and five scenarios with unique feedstock portfolios. Bioenergy demand had potential to influence trends in habitat availability for some species in our study area. We found variation in impacts among species, and no scenario was the ‘best’ or ‘worst’ across all species. Our models projected that shrub‐associated species would gain habitat under some scenarios because of increases in the amount of regenerating forests on the landscape, while species restricted to mature forests would lose habitat. Some forest species could also lose habitat from the conversion of forests on marginal soils to purpose‐grown feedstocks. The conversion of agricultural lands on marginal soils to purpose‐grown feedstocks increased habitat losses for one species with strong associations with pasture, which is being lost to urbanization in our study region. Our results indicate that landscape‐scale impacts on wildlife habitat will vary among species and depend upon the bioenergy feedstock portfolio. Therefore, decisions about bioenergy and wildlife will likely involve trade‐offs among wildlife species, and the choice of focal species is likely to affect the results of landscape‐scale assessments. We offer general principals to consider when crafting lists of focal species for bioenergy impact assessments at the landscape scale.  相似文献   

16.
Given today's political targets, energy production from agricultural areas is likely to increase and therefore needs to be more sustainable. The aim of this study was thus to carry out a long‐term field trial based on the poplar short‐rotation coppice (SRC), in order to compare dry matter, energy‐use efficiency and the net energy yield obtainable from this crop in relation to different harvest frequencies (1‐, 2‐ and 3‐year cutting cycles). The results showed that poplar SRC performed very well under temperate climates as it can survive up to 12 years, providing a considerable annual biomass yield (9.9, 13.8, 16.4 t ha?1 yr?1 for annual T1, biannual T2 and triennial T3 cutting cycles, respectively). The system tested in southern Europe showed a positive energy balance characterized by a high energy efficiency. We found that the choice of harvest interval had huge consequences in terms of energy yields. In fact, the energy efficiency improved from T1 to T2 and T3, while the net energy yield increased from 172 to 299 GJ ha?1 yr?1. This study suggests that, with 3‐year harvest cycles, poplar SRC can contribute to agronomic and environmental sustainability not only in terms of its high yield and energy efficiency but also in terms of its positive influence on limiting soil tillage and on the environment, given its low pesticide and nutrient requirements.  相似文献   

17.
A life cycle assessment (LCA) of various end‐of‐life management options for construction and demolition (C&D) debris was conducted using the U.S. Environmental Protection Agency's Municipal Solid Waste Decision Support Tool. A comparative LCA evaluated seven different management scenarios using the annual production of C&D debris in New Hampshire as the functional unit. Each scenario encompassed C&D debris transport, processing, separation, and recycling, as well as varying end‐of‐life management options for the C&D debris (e.g., combustion to generate electricity versus landfilling for the wood debris stream and recycling versus landfilling for the nonwood debris stream) and different bases for the electricity generation offsets (e.g., the northeastern U.S. power grid versus coal‐fired power generation). A sensitivity analysis was also conducted by varying the energy content of the C&D wood debris and by examining the impact of basing the energy offsets on electricity generated from various fossil fuels. The results include impacts for greenhouse gas (GHG) emissions, criteria air pollutants, ancillary solid waste production, and organic and inorganic constituents in water emissions. Scenarios with nonwood C&D debris recycling coupled with combustion of C&D wood debris to generate electricity had lower impacts than other scenarios. The nonwood C&D debris recycling scenarios where C&D wood debris was landfilled resulted in less overall impact than the scenarios where all C&D debris was landfilled. The lowest impact scenario included nonwood C&D debris recycling with local combustion of the C&D wood debris to generate electricity, providing a net gain in energy production of more than 7 trillion British thermal units (BTU) per year and a 130,000 tons per year reduction in GHG emissions. The sensitivity analysis revealed that for energy consumption, the model is sensitive to the energy content of the C&D wood debris but insensitive to the basis for the energy offset, and the opposite is true for GHG emissions.  相似文献   

18.
Over the last decade, optimizing energy storage has become significantly important in the field of energy conversion and sustainability. As a result of immense progress in the field, cost‐effective and high performance batteries are imperative to meeting the future demand of sustainability. Currently, the best performing batteries are lithium‐ion based, but limited lithium (Li) resources make research into alternatives essential. In recent years, the performance of aluminium‐ion batteries has improved remarkably in all battery‐relevant metrics, which renders them a promising alternative. Compared with monovalent Li‐ion batteries, aluminium (Al) cations can carry three positive charges, which could result in higher energy densities. This review describes recent developments in Al‐based cathode materials. The major goal of this review is to highlight strengths and weaknesses of various different approaches and provide guidelines for future research.  相似文献   

19.
A novel low‐cost nanoporous polytetrafluoroethylene (PTFE)/silica composite separator has been prepared and evaluated for its use in an all‐vanadium redox flow battery (VRB). The separator consists of silica particles enmeshed in a PTFE fibril matrix. It possesses unique nanoporous structures with an average pore size of 38 nm and a porosity of 48%. These pores function as the ion transport channels during redox flow battery operation. This separator provides excellent electrochemical performance in the mixed‐acid VRB system. The VRB using this separator delivers impressive energy efficiency, rate capability, and temperature tolerance. In additon, the flow cell using the novel separator also demonstrates an exceptional capacity retention capability over extended cycling, thus offering excellent stability for long‐term operation. The characteristics of low cost, excellent electrochemical performance and proven chemical stability afford the PTFE/silica nanoporous separator great potential as a substitute for the Nafion membrane used in VRB applications.  相似文献   

20.
Diminishing fossil carbon resources, global warming, and increasing material and energy needs urge for the rapid development of a bioeconomy. Biomass feedstock from agro‐industrial value chains provides opportunities for energy and material production, potentially leading to competition with traditional food and feed production. Simulation and optimization models can support the evaluation of biomass value chains and identify bioeconomy development paths, potentials, opportunities, and risks. This study presents the linkage of a farm model (EFEM) and a techno‐economic location optimization model (BIOLOCATE) for evaluating the straw‐to‐energy and the innovative straw‐to‐chemical value chains in the German federal state of Baden‐Wuerttemberg taking into account the spatially distributed and price‐sensitive nature of straw supply. The general results reveal the basic trade‐off between economies of scale of the energy production plants and the biorefineries on the one hand and the feedstock supply costs on the other hand. The results of the farm model highlight the competition for land between traditional agricultural biomass utilization such as food and feed and innovative biomass‐to‐energy and biomass‐to‐chemical value chains. Additionally, farm‐modeling scenarios illustrate the effect of farm specialization and regional differences on straw supply for biomass value chains as well as the effect of high straw prices on crop choices. The technological modeling results show that straw combustion could cover approximately 2% of Baden‐Wuerttemberg's gross electricity consumption and approximately 35% of the district heating consumption. The lignocellulose biorefinery location and size are affected by the price sensitivity of the straw supply and are only profitable for high output prices of organosolv lignin. The location optimization results illustrate that economic and political framework conditions affect the regional distribution of biomass straw conversion plants, thus favoring decentralized value chain structures in contrast to technological economies of scale.  相似文献   

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