نشریه انرژی ایران
سال بیست و سوم شماره 3 (پیاپی 88، پاییز 1399)

Growing demand for electricity and the reduction of fossil fuels have made it essential to consider alternative and renewable energy sources, such as solar and wind, to generate electricity. In this paper, by computing levelized output energy cost and levelized cost of electricity, the prices of electricity generated from the different combined cycle, wind, and photovoltaic power plants are compared. Moreover, data envelopment analysis method is used to evaluate and compare power generation technologies. The results showed that the total cost of electricity generated from fossil fuels is higher than what generated from renewable power plants and that renewable technologies have the highest compliance with sustainability criteria.

The Rebound effect refers to the reactions that occur to the advancement of technology and the increase of energy efficiency, and these reactions prevent the achievement of the desired goal completely. In this study, in order to investigate the effect of energy return on the value added of Iranchr(chr(chr('39')39chr('39'))39chr(chr('39')39chr('39')))s industrial sector, first by estimating the production function by the ordinary least squares (OLS) method and using Divarge logarithmic mean index (LMDI) return effect in industry and for years It has been calculated from 1987 to 2017. The results indicate that the energy recovery effect of industry in the period under study has been declining. In order to achieve the main goal of the research and using the distributed interruptive autoregression (ARDL) method, the effect of energy return on the value added of the industry has been investigated. The estimation results indicate that in the short and long term there is a negative and significant relationship between the return effect and value added of the industry. But the relationship between industrial capital investment and value added is positive and significant. On the other hand, the return effect has a greater effect on value added than capital, which is greater in the long run than in the short run. The error correction factor (ECM) is -0.47, which indicates that in the event of an economic shock in the current period, 0.47 will be adjusted from the imbalances of the previous period.

Anaerobic digestion can be used to convert organic waste into energy not only to provide renewable energy, but also reduce greenhouse gases. During the anaerobic digestion process, biogas is produced, which can be used for heating and electricity generation. The produced biogas contains methane and some other gases, the most destructive of which is hydrogen sulfide gas. If hydrogen sulfide gas exists, it will cause corrosion and damage to facilities. In this study, to produce energy in the form of flammable biogas, different combinations of kitchen waste and poultry manure were used to optimize and increase the amount of biogas according to the available organic matter composition. The results showed the best combination of poultry manure and kitchen waste in proportion. Equivalence and the adsorption of hydrogen sulfide gas with adsorbents (ironstone) was examined to the aim of the production of impurities reduction in gas. This indicates the removal of the gas in a different time period than the produced gas. In this study, three modified Gompertz models, modified logistics and no delay phase model were investigated to determine which model predicts the best biogas production. The first two models, Gompertz and modified logistics, well matched the data with accuracy, but the No-lag model shows some errors due to lack of the delay phase consideration in biogas production. Considering the amount of biogas produced in different digesters, the results show that the potential for biogas production for the ratio (KW + CM) with the amount of .11000ml is more than other cases.

The impact of the financial crisis on the OPEC oil market is important to us as an important member of OPEC and an oil-exporting country with an oil-dependent economy. This study examines four networks, pre-financial crisis, US financial crisis, European debt crisis and post-financial crisis, using the contagion index and complex network for the period 2007-1-2 to 26-8-2019. The results show that during the US financial crisis and the European debt crisis, the New York stock market acts as a bridge node and transmits the shock to other markets. During the US financial crisis, the OPEC oil market and the European stock market suffered the most damage, which caused the European financial crisis in the next period. This study, for the first time, examines and compares the OPEC stock and oil market network in times of financial crisis. During the European debt crisis, the OPEC oil market suffered the most in the network. This research helps policymakers to adopt appropriate policies in times of financial crisis.

Residential and commercial sectors are the main consumers of energy. According to available data, these two sectors account for more than one-third of total energy use. Moreover, heating and cooling systems contribute to the major share of energy use in a building. The current research economically evaluates the radio-frequency heating systems for use in residential buildings. A building in District 1 of Tehran was chosen as a pilot for the study and the hydro and gas usage were compared before and after installation of radio-frequency heating systems and related devices. The result showed the after 18 months, 27,896 cubic meters of gas were saved. The net saving from the installation of a descaling decalcifier device for water treatment in 2017 was 100,293,000 rials. Economic evaluation with a non-discounting method of appraisal predicts a positive net present value (NVP) with the economic discount rate of %21.4. Therefore, the utilization of radio-frequency heating systems is economically justified.

The increasing consumption of energy from fossil fuels on the one hand and the pollution created by it on the other hand has always raised the concern of replacing clean and renewable energy with fossil fuels in the human mind. Generating electricity through clean energy can be a good solution to reduce pollutants and prevent global warming. One of the most available types of renewable energy is solar energy, which can be used to generate electricity in solar chimney power plants. The purpose of this study is to detect the trend of flow velocity changes along the chimney due to changes in the chimney geometry in order to find the optimal geometry. For this purpose, Ansys Fluent software based on computational fluid dynamics has been used to solve the proposed models. The results indicate that the change of geometry will have a significant effect on the flow rate and thus the power of the power plant. Also, by considering a proportional relationship between geometry and environmental conditions, including the height of the power plant, a more desirable power can be achieved.

The role of the countrychr('39')s electricity industry is so fundamental that it is impossible to continue working in various sectors of industry, agriculture and even services. The industrychr('39')s upstream documentation plays a key role in determining the direction of its movement. In this regard, the present study aimed to analyze the content of upstream documents of Guilan Regional Electric Company. 29 upstream documents were selected and analyzed. Data analysis revealed a total of 351 focus points and 66 categories at different levels of attribution. The findings of this study show that the five indicators of "environmental protection", "attention to human resources", "satisfaction of people and society", "research and development" and "supply and demand management and secure and sustainable electricity supply" are the most important issues highlighted in the documents. A map of the relationships between multiple categories of documents at different levels is also provided in the form of a comprehensive graph of the relationships of indicators related to the electric industry.