As a producer and also exporter of energy, Iran has a great potential for reducing the use of fossil fuels and thus reduce greenhouse gas emissions. One of the most important efforts to save energy is identifiying CDM projects in the industrial, energy, and other sectors. Therefore, the country will be able to devote a large part of the emission reduction market and it would also save energy in various industrial sectors. In this paper, at first, emission reduction projects in all sectors are detected. Then, two indexes, i.e. the emissions reductions per dollar invested and the amount of energy production per dollar invested, have been estimated for each project. Finally, a mathematical optimization model has been proposed and implemented for optimal project selection which considers pollution caused by carbon emissions and also financial goals. Moreover, a sensitivity analysis has been conducted over different parameters of the model.