The main challenge in photobioreactor design is to create a simple, inexpensive, high-cell density, energy efficient photobioreactor which is scalable to industrial capabilities. A plastic bag photobioreactor that can meet the above requirements has been demonstrated by our research group. The photobioreactors made of floating transparent plastic bags were compared to stationary plastic bag photobioreactors in relation to microalgal biomass and oil production. Green microalga Neochloris oleoabundans was grown in these photobioreactors in batch mode for four weeks under artificial and natural illumination. The plastic bags were placed on the surface of an artificial pond. Waves were generated by electrical fans to shake and mix microalgal cells in plastic bags. Initially, we tested photobioreactors with bags placed on a rocking platform, which were used as model for floating bag photobioreactors. The bags were supplied with a gas mixture of CO2 and air (with higher CO2 concentrations compared to ambient conditions). It created an elevated pressure of CO2 in the gas phase inside of bags (exit valve will only open when gas pressure reaches a certain point). We exceeded our expectations by obtaining high volumetric productivity values in our floating bag photobioreactors (3-4 g per L per day), compared to stationary type photobioreactors and to data found in publications. We also produced a significant amount of oil from this microalga. Particular attention in this presentation will be is given to the oil separation from algal biomass and the saturation of algal culture with CO2 in a photobioreactor without losses.