Nannochloropsis sp. is one of microalgaes species with high lipid content, so it has great potential to be used as the source of biofuel. One of the microalgae cultivation system in mass scale is open raceway ponds. Problems faced in microalgae cultivation with open raceway ponds system are low productivity and the high production cost, especially high electrical energy for operating paddle wheel machine. This research studies about efficiency and effectiveness level of the cultivation system with open raceway ponds through the analysis of correlation between operational duration of the paddle wheel with growth rate and lipid content from Nannochloropsis sp.. The highest density is 530x10 6 cell/ml found in treatment of 45min/h. The highest growth rate is 0,45/days Which also found in the treatment of 45min/h but the treatment 45min/h is only able to survive until 12 days. The highest productivity of dry biomass is 0,25 g/L/day found in treatment of 45min/h. Meanwhile, the highest lipid content contained on treatment 15min/h is 5,19% dry cell weight (DCW). Dominant fatty acids for all treatments are palmitic acids. The best treatment related to the use of the paddle wheel machine is 15min/h.