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1.
Promoting renewable energy sources is one policy response to climate change. Not only is there currently a debate over the best policy instrument, it is also discussed whether the renewable energy production should be expanded centralized at locations with the highest production potential or decentralized close to load. It is yet not fully understood what influences the spatial distribution of renewable energy installation.I assess the effect of subsidy scheme and market design on the spatial distribution of wind energy installations by comparing (a) feed-in tariffs versus market premiums and (b) uniform versus nodal pricing. The analysis is based on theoretical considerations and using a six-node test model that reflects the consumption and renewable resource distribution in several countries and regions.The institutional setting has great influence on the spatial distribution and resulting system costs. With uniform pricing, a market premium only leads to a more decentralized expansion of renewable energy production than a tariff when sites share similar wind conditions. Spatially more distributed expansion of wind power performs better in terms of total costs and share of wind power in final demand when networks are restricted.  相似文献   

2.
Many studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil–50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil–80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 °C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO’s viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 °C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil.  相似文献   

3.
Strazicich and List (Are CO2 Emission Levels Converging among Industrial Countries? Environmental and Resource Economics 2003; 24: 263–271) examine whether CO2 emissions converge among the twenty-one industrial countries from 1960 to 1997. This study replicates their main results and performs a similar analysis on a more recent dataset and a new econometric method. Their findings are confirmed to a large extent.  相似文献   

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The effects of the microstructural factors of electrodes, such as the porosity and pore size of anode supports and the thickness of cathodes, on the performance of an anode-supported thin film solid oxide fuel cell (TF-SOFC) are investigated. The performance of the TF-SOFC with a 1 μm-thick yttria-stabilized zirconia (YSZ) electrolyte is significantly improved by employing anode supports with increased porosity and pore size. The maximum power density of the TF-SOFCs increases from 370 mW cm−2 to 624 mW cm−2 and then to over 900 mW cm−2 at 600 °C with increasing gas transport at the anode support. Thicker cathodes also improve cell performance by increasing the active reaction sites. The maximum power density of the cell increases from 624 mW cm−2 to over 830 mW cm−2 at 600 °C by changing the thickness of the lanthanum strontium cobaltite (LSC) cathode from 1 to 2-3 μm.  相似文献   

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This paper replicates the Diebold and Yilmaz (2012) study on the connectedness of the commodity market and three other financial markets: the stock market, the bond market, and the FX market, based on the Generalized Forecast Error Variance Decomposition, GEFVD. We show that the net spillover indices (of directional connectedness), used to assess the net contribution of one market to overall risk in the system, are sensitive to the normalization scheme applied to the GEFVD. We show that, considering data generating processes characterized by different degrees of persistence and covariance, a scalar-based normalization of the Generalized Forecast Error Variance Decomposition is preferable to the row normalization suggested by Diebold and Yilmaz since it yields net spillovers free of sign and ranking errors.  相似文献   

8.
This paper examines the multiple benefits of the adoption of Solar Home Systems (SHS) and discusses the dissemination potential for sustainable rural livelihoods in developing countries. Based on a household survey conducted in rural Bangladesh, we first identify the impact of SHS on the reduction in energy costs and compare purchasing costs. We then examine household lifestyle changes following the adoption of SHS. Finally, we consider several price-reduction scenarios to examine the potential demand for SHS and to evaluate its future dissemination potential. The results of the analysis indicate that households with SHS successfully reduce their consumption of kerosene and dependency on rechargeable batteries, with the cost reductions accounting for some 20–30% of monthly expenditures on SHS. Moreover, most households with SHS can enjoy its benefits, including electric lighting, watching television, and the ease of mobile phone recharging at home. Further, the price reduction can make possible potential demand in more than 60% of households without SHS, while additional price reductions promote the purchase of even larger SHS packages. This study concludes that even though the scale of single SHS is small, the micro-benefits for each household and the dissemination potential are substantial.  相似文献   

9.
The GERG-2008 equation of state is the approved ISO standard (ISO 20765-2) for the calculation of thermophysical properties of natural gas mixtures. The composition of natural gas can vary considerably due to the diversity of origin. Further diversification was generated by adding hydrogen, biogas, or other non-conventional energy gases. In this work, high-precision experimental (p, ρ, T) data for two gravimetrically prepared synthetic natural gas mixtures are reported. One mixture resembled a conventional natural gas of 11 components (11 M) with a nominal mixture composition (amount-of-substance fraction) of 0.8845 for methane as the matrix compound with the other compounds being 0.005 for oxygen, 0.04 for nitrogen, 0.015 for carbon dioxide, 0.04 for ethane, 0.01 for propane, 0.002 each for n- and isobutane, and ultimately 0.0005 each for isopentane, n-pentane, and n-hexane. The other mixture was a 13-component hydrogen-enriched natural gas with a low calorific value featuring a nominal composition of 0.7885 for methane, 0.03 for hydrogen, 0.005 for helium, 0.12 for nitrogen, 0.04 for carbon dioxide, 0.0075 for ethane, 0.003 for propane, 0.002 each for n- and isobutane, and 0.0005 each for neopentane, isopentane, n-pentane, and n-hexane. Density measurements were performed in an isothermal operational mode at temperatures between 260 and 350 K and at pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. The data were compared with the corresponding densities calculated from both GERG-2008 and AGA8-DC92 equations of state to test their performance on real mixtures. The average absolute deviation from GERG-2008 (AGA8-DC92) is 0.027% (0.078%) for 11 M and 0.095% (0.062%) for the 13-component H2-enriched mixture, respectively. The corresponding maximum relative deviation from GERG-2008 (AGA8-DC92) amounts to 0.095% (0.127%) for 11 M and 0.291% (0.193%) for the H2-enriched mixture.  相似文献   

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Alloying is an effective method for improving the resistance of V metals to hydrogen embrittlement. The effects of the doping with a third element (Pd, Ru, Ta) on the structure and hydrogen permeation properties of V–10Mo solid solutions have been investigated in this study. As-prepared V–5Mo-5TM (TM = Mo, Pd, Ru, Ta) alloy samples composed of V-based solid solution with a bcc structure are hydrogenated into their corresponding solid solutions (α-phase). Structural changes caused by TM-doping have notable effects on the hydrogen permeation properties (particularly the hydrogen solubility) of V–10Mo alloy, and the ability of the doping element in decreasing the hydrogen solubility of the V–10Mo alloy follows the sequence: Pd > Ru > Ta. Their doping causes a slight decrease in the hydrogen diffusion coefficient as well as an increase in the Vickers hardness of the resulting alloys. This work demonstrates that the mechanical property of V–10Mo alloy can be improved via suitable structure control caused by alloying it with an appropriate element. In addition, this approach might be suitable for improving properties of other relevant binary alloys.  相似文献   

13.
《Energy》2002,27(1):47-63
The National Programme on Improved Cookstoves (NPIC) was started by the Ministry of Non-conventional Energy Sources (MNES), Government of India, in 1985 to achieve the twin objectives of fuelwood conservation and smoke reduction in kitchens. NPIC has overseen the installation of 28 million improved cookstoves, saving nearly 20 million tons of firewood per year. These achievements, though seemingly impressive, are not realistic as they are based on certain assumptions, particularly regarding the life expectancy of stoves. This paper examines the various assumptions made in such calculations and tries to arrive at some realistic numbers regarding fuelwood savings, which can be used to evolve a policy for refining the NPIC further.  相似文献   

14.
The growth of the Spanish photovoltaic (PV) sector in the period 2004–2008 rendered Spain a prominent place among top worldwide countries. Yet, this growth was rather uneven across the different Spanish regions which raised the interest on the drivers ultimately effecting these disparities. Especially controversial were the arguments about the influence of the administrative procedure and the landscape policy on the development of GCPVS on-floor. This study therefore discloses both two elements and evaluates their impact in a group of PV prominent Spanish regions and Catalonia, the latter used as a benchmark because of its comprehensive and stringent regulation on landscape protection, which was accused by the PV industry of thwarting the development of the GCPVS on-floor. Both quantitative and qualitative analyses were carried out. In particular two indexes were elaborated to determine the consistency of the arguments pointing to the landscape protection policy as a decisive barrier to GCPVS growth. First, when the analysis is made in relative terms, the ranking of PV prominent regions changes and many of the differences vanish. Second, rather than the preeminence of a landscape protection policy what really matters for GCPVS on-floor growth is the administrative procedure and the processing enabling its implementation.  相似文献   

15.
In this work, anode supported solid oxide fuel cells based on Ni/YSZ anode, 8YSZ electrolyte and (La, Sr)(Co, Fe)O3−δ cathode were analyzed by Electrochemical Impedance Spectroscopy (EIS) with the aim to identify the main electrochemical mechanism contributing to the polarization resistance. The method was validated by performing EIS analyses on reference samples at different temperatures and overvoltages. In order to investigate the different electrochemical contributions to the polarization resistance, the study was carried out by testing the cells at different operating conditions (gas partial pressure, occurrence of H2S impurities, temperature) and considering different cells materials and microstructure (current collecting layer, diffusion barrier layer). The comparison of the different Nyquist plots, Bode plots and fitting results allows identifying the main electrochemical mechanisms occurring at the anode and the cathode and contributing to the polarization resistance of the cell. The main mechanisms associated to the anode were observed at ca. 0.1 Hz (fuel partial pressure) and ca. 600 Hz (anode charge transfer reaction). The anode contribution at low frequency (0.01–0.1 Hz) is particularly noticeable under methane internal steam reforming condition. Cathode contributions such as oxygen gas conversion and oxygen surface diffusion have been identified at ca. 0.02 Hz and 2–4 Hz, respectively.  相似文献   

16.
Between 1954 and 1996, more than 200 nuclear power projects were publicly announced in the USA. Barely half of these projects were completed and generated power commercially. Existing research has highlighted a number of potential explanations for the varying siting outcomes of these projects, including contentious political protests, socioeconomic and political conditions within potential host communities, regulatory changes (‘ratcheting’), and cost overruns. However, questions remain about which of these factors, if any, had an impact on these outcomes. This article uses a new data set of 228 host communities where siting was attempted to illuminate the factors that led projects towards either completion or cancelation. Controlling for factors highlighted by past studies, we find that regulatory, site‐ and reactor‐specific factors predict the outcomes of attempts to site nuclear reactors over this time period. These findings have important implications in the post‐Fukushima ‘nuclear renaissance’ era when many still hope to revitalize the nuclear industry in the USA. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

17.
To design an efficient and cost-effective electrocatalyst based on Prussian blue and its analogs are a promising choice to realize energy transformation and storage via water-splitting. Herein, a facile and practical method is developed to in-situ grow Fe–Co Prussian-blue-analog (PBA) nanocages with an open hole in each face center on Ni(OH)2/NF substrate to form the hierarchical cage-on-plate structure. Furthermore, the Fe–Co PBA nanocages attached to Ni(OH)2/NF plates are hydrogenated and nitrogenized into FeCoNi/NF and FeCoNiN/NF electrodes, respectively. As-prepared electrodes successfully retain the 3D hierarchical micro-nano structures of Fe–Co PBA@Ni(OH)2/NF precursor and can be used as a bifunctional water-splitting catalyst for overall water splitting. Compared to FeCoNi/NF, FeCoNiN/NF shows more efficiency and durability in the electrolytic water splitting tests in alkaline media. For the FeCoNiN/NF electrocatalyst, ultralow overpotentials for hydrogen evolution reaction (HER) are only 56 and 290 mV at current densities of 10 and 500 mA cm?2. Meanwhile, overpotentials for oxygen evolution reaction (OER) are 267 and 374 mV at current densities of 50 and 500 mA cm?2. The FeCoNiN/NF electrode can act both the cathode and the anode for overall water splitting, this electrolyzer only requires a cell voltage of 1.492 V to afford a current density of 10 mA cm?2. This electrolyzer can stably deliver a viable high current density of 625 mA cm?2 for 40 h to meet the condition of industrial application.  相似文献   

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Probable reaction intermediates and mechanistic steps involved for the selective oxidation of methane (CH4) with nitrous oxide (N2O) forming synthesis gas (CO + H2) over Co-ZSM-5 was examined. To assess the reaction kinetics reactions were conducted within a temperature range of 300 °C–550 °C and at atmospheric pressure, and the composition of reactant feed (N2O/CH4) was varied between three fixed ratios (5, 3, and 1). TPD, XRD, TEM and FT-IR techniques were used for catalyst characterization and mechanistic studies. It was found, that H2 selectivity is higher for feeds with lower N2O concentration. Furthermore, CO formation commences at lower temperatures in comparison to H2 gas which is a result of the formation of methanol (CH3OH) and carbon oxides (CO and CO2) at low CH4 conversions.Based on the reaction conditions, the literature proposes direct and an indirect mechanistic route for synthesis gas formation. Our catalytic study suggests a direct route for the synthesis gas formation; i.e. H2 gas is formed by the decomposition of intermediate species (methoxy and CH2O). This is supported by spectroscopic investigation. Under favourable reaction conditions and over the Co-ZSM-5 catalyst, N2O first oxidizes CH4 to CH3OH, an active reaction intermediate, which then subsequently is converted into (formaldehyde) CH2O and H2. CH2O is highly reactive and decomposes into CO and H2.  相似文献   

20.
The environmental and social sustainability of biofuel production and use is today the most critical issue for the development of support policies in this sector.The Life Cycle Assessment (LCA) methodology is commonly agreed as the main tool for the estimation of the impact of biofuel chains, even in quantitative terms. This is also reflected in the recently issued EU Directive (Renewable Energy Directive, RED) on the promotion of the use of energy from renewable sources. However, the results of Life Cycle Assessment works largely depend on the quality of the information given as input to the study, as also very recent research works started to investigate: in addition, the comparison of a large number of very different (technically, geographically, agronomically) biofuel chains, as some Life Cycle Assessments and reviews tried to do, is a very difficult task due to the extremely large number of variable conditions and parameters. This paper, by considering a very specific biofuel chain (production and use of Pure/Straight Sunflower Oil in North-Central Italy), discuss some limits and constraints of the application of the LCA method. The work investigated within which boundaries Life Cycle Assessment could be implemented to perform quantitative assessments, as requested by the current supporting policies in the biofuel area. Results showed very large variations in the calculation of the CO2 equivalent emissions, thus illustrating how achievable results depends on the local agricultural practices and performances, even for such a small and well defined biofuel chain. The adoption of the present standardized Life Cycle Assessment approach for generalized evaluations in the bioenergy sector and, in particular, for quantitative assessments should therefore be reconsidered. Concluding, LCA studies, even while addressing very specific and well defined chains, should always provide the bias of the calculations, as this range of variation of Life Cycle Assessment results could be significantly greater than the initially set quantitative targets and therefore the whole investigation would be at risks of inconsistency. Proposals are finally given for small scale projects, with the aim of developing sound but realistic processes to assess biofuel sustainability.  相似文献   

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