پژوهشنامه اقتصاد انرژی ایران
پیاپی 34 (بهار 1399)

Due to the importance of economic relations and environmental potential issues, the relationship between economic growth and environmental degradation is a very important issue. Therefore, understanding the relationship between GDP growth, consumption and extraction of fossil fuels, use of renewable energy, and  emissions in the Iranian economy are very important for sustainable development. In this study, we try to investigate how  emissions (as the main cause of pollution) are affected by per capita income growth, innovation, renewable energy consumption, and extraction from non-renewable energy resources in a model with four equations (for Iran in period 1979 to 2019). By reviewing the wide range of studies, the framework developed in this paper has not been investigated in domestic or international studies. On the other hand, in this research, for estimating nonlinear simultaneous equations, the multi-objective optimization method and its application for estimating simultaneous equations in econometrics have been developed. (This method can be a way to estimate nonlinear simultaneous equations in future studies). The results showed innovation activities have not been able to have a significant effect on reducing pollution emissions for the Iranian economy. Also, we found out the consumption of renewable energy has not had a significant effect on reducing pollution emissions. Also, the existence of the Kuznets environmental hypothesis was confirmed and Iran is in the upward part of this curve.

Half a century after the oil crisis in the 1970s, there is still not any agreement among economists when it comes to the type and existence of any relationship between energy consumption and economic growth. In this regard, many studies have been conducted, and many methods have also been adopted to find this relationship, most of which are now proved to be inappropriate and inefficient. Having utilized a new causality approach proposed by Konya (2006), this study investigated the relationship between three energy carriers, natural gas, electricity, oil products, as well as considering the value-added of sixteen main industrial sub-sectors in the period 1995-2017, via the bootstrap panel approach. Comparison to the traditional methods, one of Konya's merits is paying attention to the two categories of heterogeneity of coefficients and cross-sectional correlation, making the estimation of parameters more efficient. The results show that in five sub-sectors of the industry, including “rubber and plastic”, “other non-metallic mineral products”, “manufacture of machines and unclassified equipment”, “machinery generator, electric transmission, and unclassified electrical appliances”, “manufacture of motor vehicles, trailers and semi-trailers” there is a one-way causal relationship from value-added to natural gas consumption. On the other hand, in an industrial sub-sector of “manufacture of chemical products”, this relationship is two-way. Also, there is a lack of causal relationship between electricity consumption and value-added in sixteen industrial sub-sectors. Moreover, a one-way relationship from value-added to the consumption of oil products can be seen only in the industrial sub-sector of “manufacture of other transport equipment”. According to the results of this study, it seems that energy consumption is not dominant in the economic growth of the Iranian economy, and the government can adopt necessary policies regarding energy price liberalization and demand management without worrying about its dire consequences.

Considering the critical role of energy consumption and productivity in economic growth, the central purpose of this study is to investigate the effect of some key macroeconomic variables and energy consumption on the total factor productivity of the agriculture sector in Iran. First, the Solo residual parametric method is employed to estimate the total factor productivity index. Subsequently, the quantile regression method is applied to time series data for the period 1967-2016 in order to investigate the impact of mentioned variables on the total factor productivity. The main results showed that energy consumption and lagged inflation rate have a negative and significant impact on the total factor productivity in agriculture in the 0.25 and 0.5 quantiles. On the contrary, market exchange rate, foreign investment, and lagged TFP exhibit a positive and significant impact on the total factor productivity of the agricultural sector.

Energy is one of the essential inputs in production that due to inefficient and inappropriate use of its resources, its consumption has increased significantly. In this regard, the identification of factors affecting energy consumption in the provinces is important. This study aims to investigate the effect of urbanization on energy consumption in Iranian provinces. To do so, we used the STIRPAT model to design the econometric model. The spatial error econometric model in panel data was used to estimate the effect of urbanization on energy consumption in 28 Iranian provinces from 2002 to 2015. The results show that the relationship between urbanization and energy consumption is inverted U-shaped. This finding indicates that an increase in urbanization first causes to increase and then decreases energy consumption.

Economic sanctions in the field of international relations affect the trade pattern of countries. One of the effective channels of sanctions is exports (as the most important source of foreign exchange supply for countries). In this regard, oil exports to OPEC member countries, especially Iran, are among the most important economic revenues and have a high share in the country's budget. In the present study, the effect of sanctions on the pattern of trade in Iranian crude oil and petroleum products and also the effect of these sanctions on OPEC member countries in the framework of the generalized gravity model using panel data econometric models have been investigated. The research model is based on statistical data from 1988 to 2018 in the form of four periods of sanctions, including the first period of US sanctions, EU sanctions, UN sanctions, and the second period of US sanctions. The findings show that US-era sanctions and EU sanctions have had less of an impact on Iran's oil exports, but UN sanctions have had a significant impact on these oil exports and Iran's share of OPEC exports. According to research findings, other OPEC member countries have not had a significant impact on the replacement of the Iranian oil market, and this shortage has been mainly met by countries outside the OPEC.