فصلنامه نظریه های کاربردی اقتصاد
سال دهم شماره 3 (پیاپی 38، پاییز 1402)

The purpose of this paper is to find the ratio of the domestic price of natural gas to the export price that maximizes the welfare function of households. To achieve this goal, The administrative regulation of domestic gas prices is explicitly modelled in CGE Model. Regional gas markets can be characterised as being imperfectly competitive, so strategic behavior in a regional gas market modelled Cournot oligopoly structure. The database in this paper is the Social Accounting Matrix (SAM) of Iran 2013, which was prepared by the Majlis Research Center. The results show that the increase in the price of domestic natural gas under certain assumptions increases the level of economic efficiency and export demand function with a higher elasticity create a higher welfare level. Finally The optimal domestic gas price should be approximately 45% of the export price which is a lower ratio compared to the proposed ratio of 65% in the Law of the Fifth Development Plan of IRAN.

The main objective of this study is to assess the impacts of financial sanction on combination of the factors of production in Iran. This analysis was performed using the computable general equilibrium (CGE) model and it focused on investment, employment, production, and price levels. After calibrating the CGE model and measuring the values of exogenous parameters and variables, the study assessed the economic impacts of sanctions on Iran’s economy using the 2016 input-output table (IO) and other statistical information based on scenario building. The results obtained using GAMS 34 revealed that Financial sanctions change the composition of production inputs in Iran and lead to an increase in the share of labor, compared to the capital factor in the economy. These changes lead to a decrease in production and an increase in the general level of prices, so that in the first and second scenarios, 4.42 and 11.11 percent, respectively, reduce economic growth and 1.84 and 4.72 percent, increase the general level of production prices

One of the most vital concerns of economists and policymakers is finding the root of economic fluctuations and minimizing them. The political situation in Iran, the existence of economic sanctions, and uncertainty in the economy have caused severe fluctuations in the exchange rate market during the last few decades. The main goal of this research is to investigate the effect of macroeconomic uncertainty and political risk on the fluctuations of the foreign exchange market in Iran from 1991 to 2020 using the vector autoregression method with time-varying parameters (TVP-VAR). To achieve this goal, the macroeconomic uncertainty index was first measured using seven economic sectors, including production, energy, price, monetary and credit variables, currency and foreign trade, and financial and stock market variables. The results of this research indicate an increasing and very strong effect of the macroeconomic uncertainty index on exchange rate fluctuations in Iran. On the other hand, political risk has had an increasing effect on exchange rate fluctuations in Iran, except during the nuclear agreement period (2014 - 2017). Moreover, other results of the research indicate the increasing and very strong effect of housing price fluctuations and gold price fluctuations on exchange rate fluctuations in Iran, while stock market fluctuations have a decreasing effect on currency market fluctuations in Iran.

The purpose of this study is to investigate the multi-period optimization model of capacity expansion planning in the electricity industry considering different scenarios of carbon dioxide emissions. In this study, using interperiod dynamic linear programming model, the capacity development of power plants has been designed and modeled in GAMS software.
The objective function of the model has been to minimize the total discounted present value of investment cost, operation and maintenance cost, fuel cost and environmental cost in a 30-year horizon and with the constraints of supply and demand balance, power system security operation, the upper boundary of newly installed capacity, resource potential and grid stability. The proposed model was evaluated in different scenarios and sensitivity analysis.
The results of the study showed that in the basic scenario without environmental considerations (reduction of production costs), only the capacity of fossil power plants should be expanded. Meanwhile, in the basic scenario with environmental considerations, the capacity of combined cycle, solar, atomic and wind power plants have been expanded by reducing production costs and environmental costs. Considering the environmental considerations, the generation share of steam and gas power plants in the planning horizon has decreased from 27.7 and 22.7 percent to 9.5 and 4 percent compared to the base year, but the generation share of combined cycle, nuclear, solar and wind power plants have increased from 41.8, 2.3, 0.1 and 0.1 percent to 72.7, 6.5, 2 and 2.3 percent. The investment cost (capacity expansion) of the basic scenario with environmental considerations compared to the basic scenario without environmental considerations will reach 183 billion dollars in the planning horizon with an increase of 60%, and the basic scenario with environmental considerations significantly increases the development costs. Also, in the scenario of the continuation of sanctions, when the maximum annual capacity of renewable power plants decreases, the environmental goals will not be met, and there is a need to invest in expanding the production capacity through fossil power plants. In the sensitivity analysis of the model, the results indicate that there is a need to invest in expanding the capacity of renewable power plants in the three cases of reducing the investment cost, increasing the carbon price, and fuel price.

Uncertainty in the key variables of macroeconomics with disruptions in the decision-making of economic agents and distortions in the resource allocation mechanism is considered an important challenge for Iran's economy.  Therefore, it is necessary to adopt appropriate policies to reduce uncertainty. So, the current research examines the effectiveness of monetary policy in reducing macroeconomic uncertainties during the period of 1989-2021. For this purpose, continuous wavelet transformation was used to discover the dynamics of the relationship between monetary policy and inflation uncertainty, economic growth uncertainty and foreign currency market uncertainty. The results show that the uncertainty of inflation only in the medium run and long run in the period of 1993-1997 has resulted in the aggressive reaction of the monetary policy. The monetary policy tool in Iran’s economy is not functioning effectively in reducing the uncertainty of the real sector. So that it cannot play a role in the medium and long run. The results show a strong relationship between uncertainty in the currency market and monetary policy instruments. So that in the long run, uncertainty in the foreign currency market leads to a greater growth of the monetary base.The mentioned process occurs due to the suppression of the exchange rate by the policy maker to anchor the Inflation expectations and gain credit. This procedure leads to the growth of monetary totals and the intensification of uncertainty in the foreign currency market, which results in the monetary policy becoming irrelevant. This article tries to provide useful information and policy suggestions by analyzing the relationship between variables in the time-frequency domain

Economic stability is important for economic performance and achieving sustainable economic growth. One concept related to the subject of economic instability is uncertainty and fluctuations in macroeconomic variables. Uncertainty in the money and exchange markets may cause fluctuations in other markets and affect the result of policies toward economic stability. In this study, output and inflation variability are used as measures of economic instability. Additionally, uncertainty of money and foreign exchange markets are obtained as volatilities of liquidity volume and exchange rate using the GARCH model. Finally, the relationship between volatilities of money and exchange rate market and economic instability index has been estimated during the period of the first quarter of 1990 to the fourth quarter of 2021, using the dynamic conditional correlation model. The results indicate that over time, the correlation between exchange rate volatilities and inflation variability is often positive, although the coefficient of this relationship varies in some periods. Furthermore, the volatilities of liquidity volume in the long term are associated with economic instability from both production and inflation aspects. Therefore, reducing macroeconomic instability caused by variability of inflation and production requires addressing uncertainty and fluctuations in the exchange market and implementing appropriate monetary policy shocks

A delay in finalizing a company's tax file causes a decrease in the real value of the government's tax revenues, an increase in the cost of tax collection, and the destruction of the business environment for companies. Therefore, in this article, the factors influencing this delay were investigated by using the data of 45 companies from the three petrochemical, chemical and food industries of Iran and analyzing their tax files during the financial years of 2015 to 2015 using the combined data regression method. The results show that 62% of the cases were decided in authorities outside the tax organization and the average time for the companies' tax cases to be decided was more than 4 years. The results show that the size of the company, tax complexity, the difference in the diagnostic-expressive tax rate and the change in the tax laws have a positive and significant effect on the delay in the finalization of the tax in all companies, but the results are somewhat different in the petrochemical industry, chemical industry and food industry

Uncertainty of exchange rate is one of the factors that has faced Iran's economy with many challenges and has caused instability in macroeconomic variables. In the meantime, the variable of indirect taxes can be affected by the uncertainty of the exchange rate due to the two important sub-sectors of import tax and transaction tax. Because the expected fluctuations in the exchange rate can change the amount of imports or the volume of transactions. On the other hand, the change in indirect taxes, in turn, will affect the government budget and the consequences of the budget deficit will cause problems for the entire economy. Therefore, in this research, the effect of exchange rate uncertainty on indirect taxes has been investigated. For this purpose, the fuzzy regression method has been used for the time period of 1991-2021. The results showed that the uncertainty of the exchange rate has a significant negative effect on the absorption of indirect taxes in Iran's economy. The average value of the impact factor is -0.0431, which is between the upper and lower limits of -0.0338 and -0.0524. Also, the results show that the inflation rate has the most negative effect and oil revenues have the most positive effect on the absorption of indirect taxes in Iran's economy