Raceway is a vessel for outdoor algae cultivation in large volumes. In this system algal solution is propelled and simultaneously mixed by means of a paddle wheel and flows in a path like a raceway. The surface of the solution is illuminated from the top and due to the mixing all the cells have a chance to capture energy from the light source. Growth parameters such as biomass density, dissolved oxygen, pH, and bicarbonate ion can be measured. All the liquid surface is subject to oxygen release and the speed of paddle rotation is adjustable. Surface illumination is adjusted and light intensity can be changed across culture.