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1.
Understanding and properly managing risks that could potentially affect the target- and performance-based profits of energy performance contracting (EPC) projects are essential. It is particularly important for the establishment and success of energy service companies (ESCOs) acting in the vulnerable environment of the vast but highly energy-inefficient Russian market. This study systematically explores common risk factors and causes of risk associated with EPC projects executed in three Russian sectors: (1) industrial; (2) housing and communal services; and (3) public. Several interviews with the Russian EPC experts were accomplished and a qualitative risk assessment by using an analytic hierarchy process (AHP) approach. The data were obtained from a web-based questionnaire survey conducted among Russian EPC project executors. For each focus sector, a specific preference-based ranking of the identified risk factors and causes of risk was derived. The AHP results show that causes of risk related to the financial and regulatory aspects contribute most to the riskiness of EPC projects performed in all three focus sectors in Russia, calling for the special attention of EPC policy- and business-makers. Due to sectorial particularities and different actors involved, we conclude that there is a need for elaboration of sector-specific contractual schemes for EPC projects.  相似文献   

2.
Energy conservation running for vehicle has been a promising research hotspot in the many universities and research institutions. In order to improve the energy utilization rate in the vehicle running process, an optimization method of the energy consumption and recycle based on fuel cell (FC)/supercapacitor (SC) hybrid tram is proposed in this paper. In the method, a tram operation energy management strategy based on Pontriagin's minimum principle (PMP) can effectively was proposed what adjusts the output power of FC and SC and decreases hydrogen consumption. In addition, a tram breaking velocity curve with maximum energy recovery and the allocation strategy between regenerative force and mechanical braking force be also studied in this paper. According to the simulation results, it could be obtained that the Energy conservation rate is about 5% higher than the un-optimized, it will effectively decrease hydrogen consumption.  相似文献   

3.
The efficient use of energy is a key component of current efforts to reduce carbon emissions. There are two factors which are important when assessing the potential gains from energy efficiency technologies: the scale of energy flow and the technical potential for improvement. However, most efficiency analyses consider only the potential gains from known efficiency technologies, while ignoring the complex flow of energy through the chains of conversion devices. In response, this paper traces the global flow of energy, from fuels through to the final services, and focuses on the technical conversion devices and passive systems in each energy chain. By mapping the scale and complexity of global energy flow, the technical areas which are likely to deliver the largest efficiency gains can be identified. The result is a more consistent basis for directing future research and policy decisions in the area of energy efficiency.  相似文献   

4.
5.
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.  相似文献   

6.
It is necessary to have an energy management system based on one or more control strategies to sense, monitor, and control the behavior of the hybrid energy sources. In renewable hybrid power systems containing fuel cells and batteries, the hydrogen consumption reduction and battery state of charge (SOC) utilizing are the main objectives. These parameters are essential to get the maximum befits of cost reduction as well as battery and hydrogen storage lifetime increasing. In this paper, a novel hybrid energy management system (HEMS) was designed to achieve these objectives. A renewable hybrid power system combines: PV, PEMFC, SC, and Battery was designed to supply a predetermined load with its needed power. This (REHPS) depends on the PV power as a master source during the daylight. It uses the FC to support as a secondary source in the night or shading time. The battery is helping the FC when the load power is high. The supercapacitor (SC) is working at the load transient or load fast change. The proposed energy management system uses fuzzy logic and frequency decoupling and state machine control strategies working together as a hybrid strategy where the switching over between both strategies done automatically based on predetermined values to obtain the minimum value of hydrogen consumption and the maximum value of SOC at the same time. The proposed HEMS achieves 19.6% Hydrogen consumption saving and 5.4% increase in SOC value compared to the results of the same two strategies when working as a stand-alone. The load is designed to show a surplus power when the PV power is at its maximum value. This surplus power is used to charge the battery. To validate the system, the results were compared with the results of each strategy if working separately. The comparison confirms the achievement of the hybrid energy management system goal.  相似文献   

7.
This paper uses a random utility model to estimate consumers’ valuation of energy efficient insulation and ventilation systems in rental apartments. Given consumers’ limited experience in residential buildings and the perceived uncertainty about their comfort benefits and resulting energy savings, these relatively new technologies might be undervalued by risk-averse consumers. Using the concept of certainty-equivalence, this paper proposes a model to assess the consumers’ risk-aversion for adopting energy-efficient systems. These systems are treated as risky assets while conventional commodities are assumed to be risk-free. The curvature of the utility function is interpreted as a measure of aversion to perceived risks as opposed to explicit risks measured by observed variances. The proposed formulation is applicable in stated preference data with qualitative variables. The model is applied to data from a choice experiment conducted among 264 apartment tenants in Switzerland. The estimated curvatures reject the risk-neutrality hypothesis. The range of the estimated risk premiums suggests that risk considerations remain a central issue in dealing with energy efficiency in residential buildings. The analysis also indicates that assuming same risk attitudes toward new and conventional systems could bias the estimates of the willingness to pay, especially when the system is comprised of several components.  相似文献   

8.
The UK market for energy service contracts is expanding, owing in part to the emergence of intermediaries for those contracts in different parts of the public sector. These intermediaries combine a legal framework for establishing contracts with an organisational framework that facilitates contract negotiation and execution. This paper examines the nature and operation of these intermediaries in more detail, including their achievements to date and their similarities and differences. It uses ideas from transaction cost economics to develop a theoretical model of the contracting decision and shows how intermediary organisations can lower the transaction costs incurred by both clients and contractors, thereby increasing the viability of contracting. The paper argues that intermediaries can play an important role in expanding the market for energy service contracts, and hence in delivering cost-effective energy efficiency improvements throughout the public sector.  相似文献   

9.
In this paper, a method based on alternating direction method of multipliers (ADMM) algorithm is proposed to solve the energy management problem for fuel cell vehicles (FCVs). Taking the minimum hydrogen consumption as the objective function, a new fuel cell dynamical system and a whole vehicle model that conform to the property of convex function are constructed, and an augmented Lagrangian equation with its scaled dual form is established, which satisfies the standard normal form of ADMM algorithm. For the first time, the ADMM algorithm is applied to energy management system of FCVs. In the meantime, a cyclic constraint inspection strategy is introduced to have a further precise control of the power of the fuel cell system so that it can meet the dynamic change constraints of the power. Compared with dynamic programming (DP) algorithm off-line calculation results, the simulation results of the proposed method indicate that the calculation of this algorithm is approximately 20–200 times faster than the former in 9 standard driving cycles. And under the two energy management modes by power maintenance and consumption, the deviation results in terms of the hydrogen consumption derived from the proposed method and DP were 2.37% and 1.06% respectively.  相似文献   

10.
To investigate how fuel economy is valued in the Indian car market, we compute the cost to Indian consumers of purchasing a more fuel-efficient vehicle and compare it to the benefit of lower fuel costs over the life of the vehicle. We estimate hedonic price functions for four market segments (petrol hatchbacks, diesel hatchbacks, petrol sedans, and diesel sedans) to compute 95% confidence intervals for the marginal cost to the consumer for an increase in fuel economy. We find that the associated present value of fuel savings falls within the 95% confidence interval for most specifications, in all market segments, for the years 2002 through 2006. Thus, we fail to consistently reject the hypothesis that consumers appropriately value fuel economy.  相似文献   

11.
An energy management strategy (EMS) is responsible for distributing the power between the electrochemical power sources of a fuel cell hybrid electric vehicle (FCHEV) with a view to minimizing the hydrogen consumption and maximizing the lifetime of the system. However, the energetic characteristics of the electrochemical devices (fuel cell, battery, and supercapacitor) are time-varying due to the influence of ageing, and different ambient and operating conditions. Any drift in the characteristics of the power sources can lead to the mismanagement of an EMS. According to the literature, ignorance of health adaptation can increase the hydrogen consumption from almost 6.5%–24% depending on the EMS. Therefore, it is necessary to develop a strategy which is aware of the actual state of the components while conducting the power split. Health monitoring techniques are potential candidates to deal with the uncertainties arising from the mentioned factors. In this respect, this paper first puts forward a concise review of the general modeling techniques which are essential for developing precise health monitoring techniques and in turn EMSs. Subsequently, the utilized methods for prognosis, diagnosis, and health state tracking of each of the mentioned power sources in a FCHEV are introduced. Then, a new taxonomy for the classification of the EMSs based on their health-awareness is proposed based on which three categories of prognostic-based, diagnostic-based, and systemic EMSs are formed. Each category is thoroughly explained, and a state-of-the-art review of these health-aware EMSs is presented. Finally, future perspectives of this new line of research and development are discussed before drawing a conclusion.  相似文献   

12.
It is evident that future worldwide patterns of energy use will be modifications of current ones. The objective of this work is to understand the directions these modifications are taking and to assess opportunities for bringing about beneficial changes and avoiding detrimental ones.

The future will see greater deficits of conventional fuels such as oil and gas and the certainty of higher prices. Fuel and electricity prices, already at record highs, are seen to double again in the next 1–2 years. As a consequence of potential scarcity, disruption of supplies and economic pressures, the danger of a major war is greater now than it has been in the past several decades. The problem is compounded by the fact that the public, in general, is not convinced there is a serious problem and is not prepared to take decisive action.

The United States—the world's major energy user—plays a pivotal role. The consequences of an ineffective U.S. national energy policy have been that U.S. imports remain high, oil prices stay high, the world economy is less stable and less oil is available for other nations. Commensurately, increased prices for food, industrial products, and transportation are resulting.

At this time, changing energy futures is less a problem of technology and more a problem of motivation, values and social awareness. New technology is available for many industrial processes, for heating and cooling buildings, for lighting and agriculture. New technology is urgently needed for energy efficient transportation. Unresolved are the issues of how best to educate and inform the public and to instill new values appropriate for the future. The public, in general, still is not convinced that there is a serious problem and still is not prepared to take decisive actions.

New energy resources are widely sought as replacements for conventional ones, especially those which are imported. While these efforts will lead to varying degrees of success, energy use management has been established during the decade of the 1970s as an effective near-term ‘resource’. It is the most immediate, least risky, cheapest and least environmentally damaging of all the potential options for solving energy problems. National and international policies must be modified to vastly increase the priority given this resource.  相似文献   


13.
The goal that the international community has set itself is to reduce greenhouse gas (GHG) emissions in the short/medium-term, especially in Europe that committed itself to reducing GHG emissions to 80–95% below 1990 levels by 2050. Renewable energies play a fundamental role in achieving this objective. In this context, the policies of the main industrialized countries of the world are being oriented towards increasing the shares of electricity produced from renewable energy sources (RES).In recent years, the production of renewable energy has increased considerably, but given the availability of these sources, there is a mismatch between production and demand. This raises some issues as balancing the electricity grid and, in particular, the use of surplus energy, as well as the need to strengthen the electricity network.Among the various new solutions that are being evaluated, there are: the accumulation in batteries, the use of compressed air energy storage (CAES) and the production of hydrogen that appears to be the most suitable to associate with the water storage (pumped hydro). Concerning hydrogen, a recent study highlights that the efficiencies of hydrogen storage technologies are lower compared to advanced lead acid batteries on a DC-to-DC basis, but “in contrast […] the cost of hydrogen storage is competitive with batteries and could be competitive with CAES and pumped hydro in locations that are not favourable for these technologies” (Moliner et al., 2016) [1].This shows that, once the optimal efficiency rate is reached, the technologies concerning the production of hydrogen from renewable sources will be a viable and competitive solution. But, what will be the impact on the energy and fuel markets? The production of hydrogen through electrolysis will certainly have an important economic impact, especially in the transport sector, leading to the creation of a new market and a new supply chain that will change the physiognomy of the entire energy market.  相似文献   

14.
15.
The aim of this study is to introduce a comprehensive comparison of various energy management strategies of fuel cell/supercapacitor/battery storage systems. These strategies are utilized to manage the energy demand response of hybrid systems, in an optimal way, under highly fluctuating load condition. Two novel strategies based on salp swarm algorithm (SSA) and mine-blast optimization are proposed. The outcomes of these strategies are compared with commonly used strategies like fuzzy logic control, classical proportional integral control, the state machine, equivalent fuel consumption minimization, maximization, external energy maximization, and equivalent consumption minimization. Hydrogen fuel economy and overall efficiency are used for the comparison of these different strategies. Results demonstrate that the proposed SSA management strategy performed best compared with all other used strategies in terms of hydrogen fuel economy and overall efficiency. The minimum consumed hydrogen and maximum efficiency are found 19.4 gm and 85.61%, respectively.  相似文献   

16.
In this paper, we evaluate energy efficiency in the European freight transport sector over three decades, according to a variety of indicators, methodologies and databases. The aim is, on the one hand, of determining major drawbacks in energy efficiency metrics, on the other hand, identifying a possible trend in the sector. The present analysis shows that energy efficiency evaluation is generally subject to misinterpretation and distortion with regard to the methods and data source adopted. Two different indicators (energy intensity and fuel economy) were initially taken into account to select the most suitable for evaluating vehicles’ efficiency. Fuel economy was then adopted and measured according to two different methodologies (top–down and bottom–up). We then considered all the possible sources of distortion (data sources employed, methods of data detection, speed of detection, power enhancement, size factor) with the aim of accomplishing a sound estimation. Fuel economy was eventually divided with the maximum power available (adjusted fuel economy), to account for the power shift of vehicles, that represents a further efficiency improvement.  相似文献   

17.
The road transport and particularly the passenger cars are responsible for increasing the share of transport energy consumption and harmful emissions level growth. The fuel economy label is an informative tool to influence customers and manufacturers to put special care to the energy efficiency issue. The implementation of fuel economy label for motor vehicles in Malaysia will prevent the up going trend of petroleum consumption which will be beneficial to consumer and society. As a consequence, the harmful greenhouse gas (GHG) emissions that are the main causes of the global warming and air pollution will be reduced. Studies in developed countries show that implementing the fuel economy label is beneficial for society, government and the environment. This paper focused on a review of international experiences on fuel economy label. It also attempts to discuss about the energy savings possibilities that lead to reduce GHG emissions by implementing the program. The last but not least recommendation is the fact that the sooner the fuel economy label applies for the passenger cars in Malaysia will be more beneficial for the country.  相似文献   

18.
Hydrogen has a considerable potential for becoming a major factor in speeding the transition of our carbon-based global energy economy ultimately to a clean, renewable and sustainable economy. The development of hydrogen production, transportation-storage and utilization technologies can play a central role in addressing growing concerns over carbon emissions and climate change, as well as the future availability and security of energy supply. However the widespread use of hydrogen may have unknown environmental effect due to increased anthropogenic emissions of molecular hydrogen and other gases to the atmosphere, through production, transportation-storage and utilization processes. It is recognized that hydrogen participates in stratospheric chemical cycles of H2O and various greenhouse gases, and a substantial increase in its concentration might lead to changes in equilibrium concentration of constituent components of the stratosphere. More accurate modeling of the stratospheric processes as well as better understanding of several other factors such as hydrogen uptake in soil and its effect on microbial communities is required to assess potential adverse effects of hydrogen economy. It is critical for us to understand the potential adverse effect of widespread use of hydrogen and take necessary actions to understand and prevent its possible environmental impacts.  相似文献   

19.
In recent years, copula models are being used in all areas of human endeavors including energy, environment, social, natural and physical sciences. Copulas are the most powerful tools that can model dependent structures between various complex correlated variables. In this paper, we specifically examine the development of copula models and their applications in the areas of energy, fuel cells, forestry and environmental sciences. It reviews the latest literature on the types of copula models, including Gumbel, Clayton, Frank, Gaussian, vine, and the theoretical development of a mixture of bivariate and multivariate copula distributions, in terms of both static and dynamic applications. A comparative review of literature is done using ARMA, DCC, and GARCH models relative to copulas.  相似文献   

20.
The substantial subsidizing of energy prices over the years has led to high energy consumption, inefficiencies, fiscal pressures, and environmental problems in Iran. To address the increasing socio-economic problems associated with the energy subsidies, the government embarked on an aggressive energy price reform through which energy subsidies were removed and cash handouts were given to all households in 2010. In this paper, I analyze the effectiveness of the energy price reform in Iran by estimating energy demand elasticities for households in different income groups. I apply a two-stage consumer optimization model and estimate the system of energy expenditures shares using the household budget survey data for the period 2001–2008. The results show that the overall price elasticities of demand are small, but income elasticities are close to one. The results also indicate heterogeneous responses to energy price and income changes in different income groups. Specifically, the urban households show stronger response to price changes, but rural households, particularly mid-income households, to income changes. These findings suggest that the current policy of price increases would not solely be able to reduce energy consumption and, therefore, it should be geared towards increasing energy efficiency through a series of price and non-price measures.  相似文献   

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