Two closed reactors (flat panel and tubular) and one open reactor (raceway pond) are used commercially to cultivate microalgae in a pilot scale. Capital costs for construction of these three reactors decrease in the following order: tubular > flat panel > raceway. A continuous operating system at a dilution rate of 0.1 (10% of working volume of algal suspension is harvested daily) is a typical configuration of full-scale production, which generally yields 1 g lutein/1L biomass when cultivated outdoors. The lowest amount of energy needed to maintain a microalgal suspension in flat panel reactors, tubular reactors and in raceway reactors is 50 W/m3, 500–3000 W/m3, and 4W/m3, respectively