This paper aims to examine energy use efficiency and economic analysis in different microalgae production systems (open space and greenhouse method) using Data Envelopment Analysis (DEA) method. The data gathered from the laboratory of Islamic Azad University, Arak branch was a place to conduct microalgae production experiments in different systems. The number of samples in each system production of microalgae was estimated to equal 20. The energy result showed that the average total input energy was 15920.40 and 17691.60 MJ kg-1 in the open space and greenhouse conditions, respectively. Also, the energy ratio for the open space and greenhouse conditions was estimated at 0.89 and 0.80, and the energy productivity index at 0.06 and 0.02 kg MJ−1, respectively. According to the economic analysis, the net return of the open space and greenhouse methods were 204376.59 and 269276.06 $ kg-1, respectively. The economic productivity of the open space and greenhouse cultivation methods were determined to be 0.17 and 0.16 kg $−1, respectively. The result of DEA demonstrated that the total optimized consumption of energy in the open space method was 14476.93 MJ kg-1. About 16355.21 MJ kg-1 was saved in the greenhouse method (7.55%) compared to the current cultivation conditions by converting inefficient to efficient cultivation. According to the investigations, it was found that open space cultivation consumes less energy and is more economical than greenhouse cultivation. As a result, promoting microalgae cultivation outdoors is preferable to greenhouse cultivation. تفاصيل المقالة