پژوهشنامه اقتصاد انرژی ایران
پیاپی 47 (تابستان 1402)

There is good reason to expect crude oil prices to follow nonlinear models. However, previous research has considered the linear assumption to investigate the existence of a unit root. Unit root linear tests such as ADF, PP, and KPSS are provided for linear models. These tests are not suitable for nonlinear time series. Because the model deviation from the linear state may be considered as a random permanent deviation. The purpose of this article is to test the nonlinear unit root of crude oil prices, specifically Brent and WTI oil in the period 2019-2020 daily. For several decades now, various classes of nonlinear models have been introduced. These models introduce a wider range of dynamics than linear models in time series. A special type of these models that economists pay attention to are TAR models. In these models, as in linear models, valid statistical analysis requires distinguishing between the deterministic trend and the stochastic trend. In this study, the Bayesian unit root test for the general SETAR (1) model has been used with respect to the necessary and sufficient conditions for the maintenance of SETAR processes based on the article by Petrocyl and Wolford (1984). A nonlinear unit root test was performed using Bayesian validity interval. The results show that Brent crude oil prices in both regimes contain a unit root that is consistent with similar findings for the production or consumption of crude oil..

Energy supply and ensuring energy security for countries is a vital goal to achieve growth and sustainable development. Energy security provides a country's ability to meet current and future energy demand, resilience, and responsiveness to minimize systematic shocks to supply disruptions. This study uses five dimensions; Availability, Accessibility, Affordability, Acceptability, and Develop-ability, as well as by using entropy-weight and TOPSIS method, the composite index of Iran's energy security for the period 1980-2019 has been measured. The results show that Iran's energy security has decreased in the period under review. The highest level of energy security was 0.716 in 1982 and the lowest level was 0.272 in 2018. Also, the level of energy security was higher than 0.5 in the periods 1980 to 1987 and 1991 to 1993, and lower than 0.5 in the periods 1988 to 1990 and 1994 to 2019.

The purpose of this research is to investigate different levels of country risk and its role in the relationship between renewable energy consumption and economic growth in Iran, during the period (1997-2021). In terms of purpose, this research is of applied type and in terms of causal-analytical method, and the method of collecting information is of documentary-library type. After calculating the threshold value of each variable, we analyzed the effect of renewable energy consumption on economic growth using the threshold distance of different country risks. The results indicate the non-linear effect of renewable energy consumption on economic growth under different risks in the country. This research is one of the first studies in Iran that analyzed the relationship between renewable energy consumption and economic growth based on a risk-based approach. According to the regression model described in the current research, this research provides suggestions for developing a suitable strategic plan with the aim of specifying short-term and long-term goals, and future vision, as a road map for those involved.
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The purpose of this paper is to evaluate the role of ICT due to ecological footprint from the perspective of individual effect and the trend of the 113 countries' reserves and land production in selected developing countries using the data panel method in the period 1992-2018. The results showed that increasing the mobile penetration rate increased greenhouse gas and carbon dioxide emissions and increased the ecological footprint effect. However, increasing the Internet penetration rate has reduced carbon dioxide emissions, increased greenhouse gases, and increased ecological footprint. Therefore, ICT use in these countries has not yet been effective in improving the environment. In the short term, there is a positive relationship between economic growth and environmental degradation in these countries, and economic growth worsens the quality of the environment. And in the long term, there is evidence of the Kuznets hypothesis being correct. Dynamic analysis showed that the use of ICT has been effective in improving the environment and this effect lasts for at least a decade. Technology shocks have an immediate effect on improving some environmental indicators and the range of effects on some indicators appears in the long term. In these countries, the production of ICT has no relative advantage, but they can benefit from the economic and environmental benefits of ICT.

Despite the decrease in the share of oil in the world's energy basket, the absolute amount of oil consumption is still increasing. Oil is at the center of the economic and political developments and countries with the oil and gas deposits are trying to maximize their benefit from these reserves. In Iran, there have been many policies and legislations related to optimizing the value and volume of the oil and gas reserve. The term "conservation production" has been mentioned several times in several legislations and guidelines however, it is still ambiguous as to how to implement this framework. This research has sought to use the real data of an oil reservoir (with periods of natural depletion, primary production, secondary and tertiary recovery), different objective functions (reservoir net present value and final recovery factor), and the effect of changes in the optimization period to model the concept of conservation production. The results show that the changes in the objective function and the optimization periods would have a significant effect on the production path.

The development of Underground Gas Storage (UGS) in depleted hydrocarbon reservoirs has always been a priority for industrialized countries. This is mainly because UGS helps in balancing the seasonal supply and demand of gas, managing reservoirs efficiently over time, ensuring the security of gas supply, and fulfilling international contractual obligations. Providing a legal platform and an attractive contract model is crucial to encourage private sector participation in this strategic industry and accelerate UGS development. Concession arrangements are one of the most commonly used and attractive models for UGS development. However, the main question of this research is whether the use of concessional agreements faces any legal prohibitions. To answer this question, the legal challenges facing the application of this contractual model in the oil fields development have been investigated. In this regard, the research verifies whether this industry is upstream or downstream from the legal point of view, and considers the opinions of prominent jurists. After analyzing the unique features of the storage industry, the essential differences between UGS and the traditional development of oil fields, and especially the governmental ownership of the gas that is injected, the conclusion is that the use of concession agreements is allowed