With the spread of environmental pollution, environmental recovery has turned into a critical goal of governments. Energy efficiency and the use of renewable energy are two essential solutions to control the emission of greenhouse gases. However, the research on these effective tools in reducing greenhouse gas emissions at macro and systemic levels in the power sector is insufficient. The present research uses the comprehensive approach of system dynamics to investigate these policies for reducing CO2 emissions in Iran’s electricity generation sector. The results show that both policies are effective in improving the country’s energy security, but the impact of the renewable development policy in reducing carbon emissions is more prominent. Furthermore, the results showed that by implementing the photovoltaic development policy, access to the 21% share of this sector of the entire Iranian electricity sector can be realized by the end of 2033. Also, improving the efficiency of thermal power plants by up to about 3.5% can be achieved by implementing the policy of increasing efficiency.