فصلنامه مطالعات اقتصاد انرژی
پیاپی 39 (زمستان 1392)

In this paper، we evaluate the performance of parametric models in forecasting the value at risk for the OPEC basket price. We compute VAR [2] for 3 Arch/Garch- type models، including FIGARCH، HYGARCH and FIEGARCH for one day and 10 day periods. These models are estimated for three alternative distributions، namely: normal، student and skewed student. Our results show that long-range memory and fat tails are present in the volatility of price returns of the OPEC basket. Moreover skewed distribution performs better in predicting one and ten day ahead value at risk. The FIEGARCH model outperforms the other models in terms of predicting the value at risk for both time frames.

The main goal in this paper is introducing a DSGE model to evaluate the effects of an energy price shock on macroeconomic variables in Iran. The results indicate deviation in production، labor supply، and inflation from their steady state due to an energy price shock. The most important deviation from optimal levels relates to an 11% deviance in relation to long term investment growth rates. The results further indicate that the lower the share of energy and the higher the share of labor in the production function، the more quickly investment returns to its steady state rate and the less GDP will deviate from optimal levels. In addition، the more energy revenues are neutralized in the national budget، the less production and government expenditure will deviate from their steady state.

Subsidized energy carriers’ prices has lead to increasing demand for them specially in transport sector. Due to enforcement of targeting subsidies plan، price of energy carriers and also gasoil price will increase. Economic analysis of this increase need to modeling energy consumption reaction to price changes. In this paper gasoil demand function has been estimated for Iranian road transport subsector. For modeling the gasoil demand function Engle-Granger، Johansen and ARDL cointegration approaches and structural time series modeling (STSM) has been used. Results showed that gasoil demand is price inelastic. Price and Income elasticities of gasoil demand has been estimated -0. 5 and 0. 93 respectively. Estimated elasticities throught different techniques are not very different. Besides STSM results showed that gasoil underlying demand trend isn’t stochastic and estimated elasticities by STSM are lower than cointegration approaches. Because gasoil demand is price inelastic، in order to reducing gasoil demand، relying on price policies would not be effective.

Energy، as an important factor of production and final product، has a special role in the economic growth and development of any country. Financial development is also recognized as a factor that can influence economic growth and energy consumption. In this paper we investigate the short and long run causal relations amongst energy consumption، financial development، GDP per capita and urban population in Iran، for the period 1971-2008 based on Autoregressive Distributed Lag (ARDL) bounds testing approach of co integration and Vector Error-Correction Models. In order to test for structural breaks in the time series data we use the Zivot Andrews unit root test. The results indicated that all variables meet the initial condition for the ARDL model. The result of F-test and Gregory- Hansen cointegration test confirmed the existence of a long term relationship between the considered variables. The ARDL long- term results suggest a positive effect of financial development، GDP per capita and urban population on energy consumption over the study period. Causality test results indicate that there is bi-directional causality between financial development and energy consumption as well as urban population and energy consumption in the long-term. There is also a unidirectional causal relationship from GDP per capita to energy consumption in the long and short -term.

Transport is one of the most effective economic activities linking su. ly with demand. Transport have direct impact in reduction production costs and available to market and finally increase competitiveness in international trade. This paper optimizes the transport network of Fuel oil of entry points to consumption Centers، by using the transshipment model with minimize transport expenses. Optimum results show 66% in cost of saving Fuel oil transport expenses.

More activate of privatization in energy market in Iran، led to pay more attention on profitability of power plants، and movement to competition rather than governance monopolistic. The process of profit maximization in energy market contains some implicit factors، which، has to be considered in optimization models. This article deals with production programming in Shariati Power Plant by using Fuzzy logic and methodology. Based on، the methodology of NSGA11 is utilized to end among a set of optimal. Optimal production during 24 hours at different generators is determined on the basis of restrictions which، considered tow important elements، demand for plant power at any hour، type of allocation comprising maximum profit. Results show profit maximization on the basis of fuzzy methodology، implies more profit comparing current methodology.

Analysis of substitution between energy carriers is an important topic in economics and energy policy. Substitution between energy carriers could create radical changes in energy balance and combinationofenergy supply. Substitution between fuels is often caused by changes in relative prices. The information about the possibility of substitution between fuels in evaluating the effects of government policies، particularly energy pricing policy is very effective. Meanwhile، energy demand in the industrial sector has great potential for substitution between fuels. In this study we analyze the substitution between various energy carriers in Iranian industerial sector during 1367-88 using the linear logit model. Logistic function by entering lagedvalues، well illustrates the dynamic adjustment mechanism. Estimation of dynamic linear logit model shows that the elasticity of gas demand in the industry with respect to its price changes is-1. 25 that is high. In contrast، electricity demandhaslower elasticity (-0. 25) and demand for petroleum products has almost zero elasticity (-0. 008). Petroleum products and electricity are complement، and petroleum products and gas are substitue by each other. Allen partial elasticity of substitution between electricity and petroleum products and petroleum products and natural gas are -0. 775 and 1. 096 respectively. Furthermore، electricity and gas with Allen elasticity of substitution equal 0. 395 are moderate substitutes for each other.

This research is a model of CHP system which used energy for Parand City, produced by Gas Turbine from Parand power plant. At first, the structures are simulated base on the type of materials and the usage of structures by data gathering & simulation software such as HAP, Carrier & E-Quest software. Subsequently the Thermal Energy consumption for the City is estimated. And optimization point for production of energy is found.Retrievable energy potential from Power Plant Gas Turbines is obtained by Thermo-flow software. Then with respect to the retrievable energy potential & average demand of Thermal energy usage of City, the steam produced capacity from simulation of HRSG by Thermo-flex is calculated. Finally, the project is economically evaluated by excel software.

It is clear that excessive consumption of energy has irreparable adverse effects on the environment. Therefore energy management، education and awareness of human resources in the field of efficiency، will gradually change internal behavior of human resources. Today، computers and their accessories such as monitors، scanners and printers are one of the main causes of electrical energy consumption in offices. So is it necessary to train human resources about energy management and usage of computers and their accessories. The purpose of this article is to check of energy consumption of computers and their accessories in the Iranian gas transmission company in four different positions، and also assessment of saving energy. At the end some ways are offered for human resources to save energy and performance optimization in computers.