Microalgae (Scenedesmus obliquus) produced in flat panel photobioreactors were converted via supercritical water gasification. The long term aim is to gain higher process efficiency through recycling of byproducts of supercritical water gasification and waste water during the cultivation of microalgae. The first step of the project, the general feasibility of conversion of microalgae Scenedesmus obliquus via supercritical water gasification to a hydrogen-rich combustible gas is presented. The product gas had a higher heating value and consisted of hydrogen, methane, carbon dioxide, and ethane.