The effect of automobile weight on gasoline costs

An experimental procedure is summarized to calculate automobile fuel consumption in the work trip and to indicate the implications of evaluating alternative subdivision street layouts. The results of the Residential Area Traffic Analysis Model show that annual fuel consumption increases with vehicle weight. The paper concludes that annual cost savings in fuel consumption and other benefits are realized by commuters who drive lighter cars.     

Supply chain cost analysis of long-distance transportation of energy wood in Finland

The increasing use of bioenergy has resulted in a growing demand for long-distance transportation of energy wood. For both biofuels and traditional forest products, the importance of energy efficiency and rail use is growing. A GIS-based model for energy wood supply chains was created and used to simulate the costs for several supply chains in a study area in eastern Finland. Cost curves of ten supply chains for logging residues and full trees based on roadside, terminal and end-facility chipping were analyzed. The average procurement costs from forest to roadside storage were included. Railway transportation was compared to the most commonly used truck transportation options in long-distance transport. The potential for the development of supply chains was analyzed using a sensitivity analysis of 11 modified supply chain scenarios.For distances shorter than 60 km, truck transportation of loose residues and end-facility comminution was the most cost-competitive chain. Over longer distances, roadside chipping with chip truck transportation was the most cost-efficient option. When the transportation distance went from 135 to 165 km, depending on the fuel source, train-based transportation offered the lowest costs. The most cost-competitive alternative for long-distance transport included a combination of roadside chipping, truck transportation to the terminal and train transportation to the plant. Due to the low payload, the energy wood bundle chain with train transportation was not cost-competitive. Reduction of maximum truck weight increased the relative competitiveness of loose residue chains and train-based transportation, while reduction of fuel moisture increased competitiveness, especially of chip trucks.     

The primary forest fuel supply chain: A literature review

This paper provides a literature review of articles on the primary forest fuel supply chain which have been published in English speaking peer-reviewed journals from 1989 to 2011. The focus is on the key issues of the transportation of primary forest fuel to heat and/or power plants: (i) transportation modes, (ii) terminal types, and (iii) forest fuel supply chain management, and provides basics on the logistically relevant characteristics of wood as feedstock such as on various feedstock assortments.The analysed supply chains include the transshipment, storage, handling (e.g. chipping) and transportation of primary forest fuel from the place of harvest to energy conversion plant. Due to spatial distribution, low mass density, low energy density and low bulk density, the transportation of primary forest fuel is crucial for economic efficiency as well as for reduced CO₂ emissions. As a consequence of forests accessibility, road transportation (after hauling the biomass to the forest road) is the first step of the modern primary forest fuel supply chain. For longer transportation distances, rail or waterway is preferred because of lower transportation costs per volume transported and lower CO₂ emissions. We highlight that some experience exists in multimodal transport, including truck, train or ship. Intermodal transport, however, has not been studied in the past and, therefore, an outlook for the research requirements is made here.     

Measuring the environmental benefits of hydrogen transportation fuel cycles under uncertainty about external costs

In this paper, we attempt to measure the environmental benefits of hydrogen deployment in the transportation sector. We compare the hydrogen pathways to the conventional transportation fuel cycles in terms of external costs, estimated using the results of the most accurate methodologies available in this field. The central values of performed analysis bring us ambiguous results. The external cost of the best conventional solution (“oil to diesel hybrid internal-combustion engine”) in some cases is just higher and in others just lower than that of the best fossil fuel to hydrogen solution (“natural gas to hydrogen fuel cell”). Nevertheless, by accounting for the uncertainty about external costs, we are able to remove this ambiguity highlighting that the hydrogen pathway provides significant environmental benefits ,especially in densely populated areas, assuming 100% city driving.     

An economic analysis of energy requirements and input costs for tomato production in Turkey

The aim of this study was to examine direct and indirect input energy in per hectare in tomato (industrial type) production and compare it with production costs. The research also sought to analyse the effect of farm size. For this purpose, the data were collected from 95 tomato farmers by questionnaire method. The results indicated that tomato production consumed a total of 45.53 GJ ha⁻¹ of which diesel energy consumption was 34.82% followed by fertilizer and machinery energy. Output–input energy ratio and energy productivity were found to be 0.80 and 0.99 kg of tomato MJ⁻¹, respectively. Cost analysis revealed that the most important cost items were labour costs, machinery costs, land rent and pesticide costs. According to the benefit–cost ratio, large farms were more successful in energy use and economic performance. It was concluded that energy use management at farm level could be improved to give more efficient and economic use of energy.     

The impact of geography on energy infrastructure costs

Infrastructure planning for networked infrastructure such as grid electrification (or piped supply of water) has historically been a process of outward network expansion, either by utilities in response to immediate economic opportunity, or in response to a government mandate or subsidy intended to catalyze economic growth. While significant progress has been made in access to grid electricity in Asia, where population densities are greater and rural areas tend to have nucleated settlements, access to grid electricity in Sub-Saharan Africa remains low; a problem generally ascribed to differences in settlement patterns. The discussion, however, has remained qualitative, and hence it has been difficult for planners to understand the differing costs of carrying out grid expansion in one region as opposed to another. This paper describes a methodology to estimate the cost of local-level distribution systems for a least-cost network, and to compute additional information of interest to policymakers, such as the marginal cost of connecting additional households to a grid as a function of the penetration rate. We present several large datasets of household locations developed from satellite imagery, and examine them with our methodology, providing insight into the relationship between settlement pattern and the cost of rural electrification.     

An analysis of energy use and input costs for cotton production in Turkey

The aim of this study was to determine direct input energy and indirect energy in per hectare in cotton production and compare with input costs. The study also sought to analyse the effect of farm size. Data were collected from sixty five farmers using a face to face questionnaire. The sample farms were selected through a stratified random sampling technique. The results revealed that cotton production consumed a total of 49.73 GJha⁻¹ of which diesel energy consumption was 31.1% followed by fertilizer and machinery energy. Output–input energy ratio and energy productivity were 0.74 and 0.06 kg of cotton MJ⁻¹, respectively. Cost analysis showed that net return per kilogram of seed cotton was insufficient to cover costs of production in the research area. The most important cost items were labour, machinery costs, land rent and pesticide costs. Large farms were more successful in energy productivity, use efficiency and economic performance. It was concluded that energy management at farm level could be improved to give more efficient and economic use of energy.     

Performance investigation of a transportation PEM fuel cell system

In this study, a comprehensive performance analysis of a transportation system powered by a PEM fuel cell engine system is conducted thermodynamically both through energy and exergy approaches. This system includes system components such as a compressor, humidifiers, pressure regulator, cooling system and the fuel cell stack. The polarization curves are studied in the modeling and compared with the actual data taken from the literature works before proceeding to the performance modeling. The system performance is investigated through parametric studies on energy, exergy and work output values by changing operating temperature, operating pressure, membrane thickness, anode stoichiometry, cathode stoichiometry, humidity, reference temperature and reference pressure. The results show that the exergy efficiency increases with increase of temperature from 323 to 353 K by about 8%, pressure from 2.5 to 4 atm by about 5%, humidity from 97% to 80% by about 10%, and reference state temperature from 253 to 323 K by about 3%, respectively. In addition, the exergy efficiency increases with decrease of membrane thickness from 0.02 to 0.005 mm by about 9%, anode stoichiometry from 3 to 1.1 by about 1%, and cathode stoichiometry from 3 to 1.1 by about 35% respectively.     

PEM fuel cell degradation effects on the performance of a stand-alone solar energy system

After comparing fresh and degraded performances of Polymer Electrolyte Membrane (PEM) based components of a hydrogen cycle with the help of computational fluid dynamics simulations, recently established stand-alone solar energy system producing hydrogen for energy storage is investigated focusing on the effects of degradation of fuel cells on the overall performance of the system. A complete model of the system has been developed using TRNSYS, and a degraded PEM Fuel Cell Subsystem has been incorporated into the model. Then, the effects of the PEM fuel cell degradation on the overall performance of the energy system are estimated. After reviewing the simulation results, the model shows that the PEM Fuel Cell degradation has a substantial impact on the overall system performance causing a system down time of approximately one month in a typical simulation year. Consequently, the stand-alone system is not capable of operating continuously for a complete year when the PEM fuel cells are degraded. Furthermore, an economic analysis is performed for a project lifetime of 25 years and the Levelized Cost of Electricity (LCE) value of the degraded system is found to be 0.08 $/kWh higher than the newly established system. Nevertheless, LCE calculations that are repeated for declining PV panel costs show that the considered hybrid system may be an economically competitive alternative to conventional diesel generators, even when the degradation of PEM based components and their regular maintenance are considered.     

External costs from electricity generation of China up to 2030 in energy and abatement scenarios

This paper presents estimated external costs of electricity generation in China under different scenarios of long-term energy and environmental policies. Long-range Energy Alternatives Planning (LEAP) software is used to develop a simple model of electricity demand and to estimate gross electricity generation in China up to 2030 under these scenarios. Because external costs for unit of electricity from fossil fuel will vary in different government regulation periods, airborne pollutant external costs of SO₂, NO_x, PM₁₀, and CO₂ from fired power plants are then estimated based on emission inventories and environmental cost for unit of pollutants, while external costs of non-fossil power generation are evaluated with external cost for unit of electricity. The developed model is run to study the impact of different energy efficiency and environmental abatement policy initiatives that would reduce total energy requirement and also reduce external costs of electricity generation. It is shown that external costs of electricity generation may reduce 24–55% with three energy policies scenarios and may further reduce by 20.9–26.7% with two environmental policies scenarios. The total reduction of external costs may reach 58.2%.     

汽车节油途径及节能技术的探讨

通过节约油料可以降低运输成本、提高经济效益。汽车节能与环保技术成为汽车技术领域的热点问题。从整车轻量化、提高燃油发动机性能、采用替代燃料和采用新能源发动机等方面论述了目前主要的汽车节能技术。     

Modeling stump biomass of stands using harvester measurements for adaptive energy wood procurement systems

The value and volumes of industrial stump fuel supply are increasing for energy production. Accurate estimates of aboveground and belowground biomass of trees are important when estimating the potential of stumps as a bioenergy source. In this study two stump biomass equations were adapted and tested using them as calibrated stump biomass models computed as the cumulative sum by a local stand. In addition, variables derived from stem measurements of the forest harvester data were examined to predict stump biomass of a stand by applying regression analysis. The true stump yield (dry weight) was used as the reference data in the study. Both biomass models performed well (adjusted R² ˜ 0.84) and no advance was found in using other stem dimensions as independent variables in the model. The stand-level model can be used in innovative stump biomass prediction tools for increasing efficiency of energy wood procurement planning to stands within a certain area. In practice, wood procurement managers would need to adapt developed system and decide whether the degree of accuracy/precision provided by the models is acceptable in their local stand harvesting conditions.     

Marginal costs and co-benefits of energy efficiency investments: The case of the Swiss residential sector

Key elements of present investment decision-making regarding energy efficiency of new buildings and the refurbishment of existing buildings are the marginal costs of energy efficiency measures and incomplete knowledge of investors and architects about pricing, co-benefits and new technologies. This paper reports on a recently completed empirical study for the Swiss residential sector. It empirically quantifies the marginal costs of energy efficiency investments (i.e. additional insulation, improved window systems, ventilation and heating systems and architectural concepts). For the private sector, first results on the economic valuation of co-benefits such as improved comfort of living, improved indoor air quality, better protection against external noise, etc. may amount to the same order of magnitude as the energy-related benefits are given. The cost–benefit analysis includes newly developed technologies that show large variations in prices due to pioneer market pricing, add-on of learning costs and risk components of the installers. Based on new empirical data on the present cost-situation and past techno-economic progress, the potential of future cost reduction was estimated applying the experience curve concept. The paper shows, for the first time, co-benefits and cost dynamics of energy efficiency investments, of which decision makers in the real estate sector, politics and administrations are scarcely aware.     

Economics of producing hydrogen as transportation fuel using offshore wind energy systems

Over the past few years, hydrogen has been recognized as a suitable substitute for present vehicular fuels. This paper covers the economic analysis of one of the most promising hydrogen production methods—using wind energy for producing hydrogen through electrolysis of seawater—with a concentration on the Indian transport sector. The analysis provides insights about several questions such as the advantages of offshore plants over coastal installations, economics of large wind-machine clusters, and comparison of cost of producing hydrogen with competing gasoline. Robustness of results has been checked by developing several scenarios such as fast/slow learning rates for wind systems for determining future trends. Results of this analysis show that use of hydrogen for transportation is not likely to be attractive before 2012, and that too with considerable learning in wind, electrolyzer and hydrogen storage technology.     

Minimization of total drying costs for a continuous packed-bed biomass dryer operating at an integrated chemical pulp and paper mill

This paper presents a MILP (Mixed Integer Linear Programming) model for a continuous packed-bed biomass dryer. The model minimizes total drying costs, including both capital and operational costs, of the dryer. Heated air, which flows through a biomass bed and perforated conveyor, is used as drying gas by the dryer. We define the dryer size with the help of an experimentally-measured characteristic drying curve. The MILP model is tested in a case study where the dryer is assumed to have been installed at a Scandinavian pulp and paper mill. There are three different heat sources available for the heating of drying air: warm water at 60 °C, warm water at 80 °C and backpressure steam at the pressure of 0.4 MPa. The results indicate that, in practice, the use of only low-temperature warm water flows for heating of drying air is the most economic method when their prices are low (below 1 € MWh⁻¹ in the case study). Warm water flows are usually waste heat from pulp and paper mills and their prices are low compared to the price of back-pressure steam (typically from 10 to 15 € MWh⁻¹). The use of steam for drying may be reasonable if the price of warm water is for some reason clearly higher than the price of a typical waste-heat stream. The MILP model presented in this work can be used for minimizing drying costs of any material (not only biomass) dried in a continuous packed-bed dryer if the characteristic drying curve of the material is available.     

Thermodynamic analysis and assessment of an integrated hydrogen fuel cell system for ships

In this thermodynamic investigation, an integrated energy system based on hydrogen fuel is developed and studied energetically and exergetically. The liquefied hydrogen fueled solid oxide fuel cell (SOFC) based system is then integrated with a steam producing cycle to supply electricity and potable water to ships. The first heat recovery system, after the fuel cells provide thrust for the ship, is by means of a turbine while the second heat recovery system drives the ship's refrigeration cycle. This study includes energy and exergy performance evaluations of SOFC, refrigeration cycle and ship thrust engine systems. Furthermore, the effectiveness of SOFCs and a hydrogen fueled engine in reducing greenhouse gas emissions are assessed parametrically through a case study. The main propulsion, power generation from the solid oxide fuel cells, absorption chiller, and steam bottoming cycle systems together have the overall energy and exergy efficiencies of 41.53% and 37.13%, respectively.     

Operational characteristics of the direct methanol fuel cell stack on fuel and energy efficiency with performance and stability

This paper is presented to investigate operational characteristics of a direct methanol fuel cell (DMFC) stack with regard to fuel and energy efficiency, including its performance and stability under various operating conditions. Fuel efficiency of the DMFC stack is strongly dependent on fuel concentration, working temperature, current density, and anode channel configuration in the bipolar plates and noticeably increases due to the reduced methanol crossover through the membrane, as the current density increases and the methanol concentration, anode channel depth, and temperature decreases. It is, however, revealed that the energy efficiency of the DMFC stack is not always improved with increased fuel efficiency, since the reduced methanol crossover does not always indicate an increase in the power of the DMFC stack. Further, a lower methanol concentration and temperature sacrifice the power and operational stability of the stack with the large difference of cell voltages, even though the stack shows more than 90% of fuel efficiency in this operating condition. The energy efficiency is therefore a more important characteristic to find optimal operating conditions in the DMFC stack than fuel efficiency based on the methanol utilization and crossover, since it considers both fuel efficiency and cell electrical power. These efforts may contribute to commercialization of the highly efficient DMFC system, through reduction of the loss of energy and fuel.     

Optimization of an energy district for fuel cell electric vehicles: Cost scenarios of a real case study on a waste and recycling fleet

This paper analyses the planning and operation of an energy district that aims to integrate a hydrogen supply chain for feeding vehicles based on fuel cell technology. A model of an energy district and an optimization algorithm based on the economic parameters are presented and validated leveraging an existing energy district, simulating several scenarios depending on different economic conditions and technical parameters. The model of the energy district evaluates energy balances, distinguishing hydrogen and electrical energy flows; the districts can include an FCEV fleet, electrical loads, energy generators, storage system and an electrolyser for producing hydrogen from the green energy surplus produced in the district as well as drawing energy from the power distribution network. The algorithm, based on MILP, is used for optimizing the flows in the district; indeed, it evaluates all the technical and economic constraints at a certain timestamp and provides optimal scheduling of the energy units. Model and algorithm have been used to evaluate different scenarios that were identified by varying the economic parameters (i.e., prices of electrical energy and hydrogen) as well as district design (i.e., upgrading sizes of the generators and electrolysers). Energy district parameters have been identified exploiting real data collected in an existing district located in Terni (Italy) owned by the local multi-utility ASM Terni S.p.A. It already includes a fleet for waste management, PV plants, office buildings and warehouses. Through parameters combination, 1125 OPEX and 729 CAPEX simulated scenarios have been evaluated and reported; each scenario assesses the daily variation of variables' economic trends covering the timeframe from 2030 to 2050. Results of simulations highlight the most convenient economic contexts as well as the envisioned amount of expenditures for adopting FCEV in the presented district or similar ones. For the case study, the forecasted cost of the hydrogen district, including FCEVs, is fully comparable to current costs, resulting in some cases even cheaper.     

Feasibility of the Nordic forest energy harvesting technology in Poland and Scotland

Finland and Sweden have been forerunners in the development of wood harvesting machinery and methods. In both countries, small- and large-scale supply systems for wood chips have been in operation for several decades. More recently, the production and use of forest chips from logging residues and small diameter trees has been growing rapidly.The European Union (EU) has set ambitious targets for the use of renewable energy to mitigate climate change and to increase domestic energy security and self-sufficiency. The largest unutilised source for renewable energy in the EU is forest biomass. European forests could fulfill one third of the goal set for biomass-based energy production in the EU’s Biomass Action Plan. In addition, member countries have started national programmes to promote the use of biomass for energy.As a result, interest in Nordic forest energy technology has been increasing rapidly in other parts of the EU. The Finnish Forest Research Institute and its collaborators have been running a technology transfer project in ten European countries, with the goal of tailoring and adapting Nordic forest technology to local conditions through analysing the applicability, costs and overall competitiveness of selected feedstock supply technologies.This paper summarizes the findings of feasibility studies carried out in Poland and Scotland and gives an overview of the current situation and development trends of forest energy in the European Union.