Microalgae are cultivated in open and closed systems. The open systems are often referred to as raceway ponds due to their oval shape. A paddle wheel ensures that the microalgae culture is constantly kept moving. These systems have considerable disadvantages: They bring both lower yields, and are at a greater risk of contamination. In addition, the water loss due to evaporation is very high.

The production costs of these systems are cheaper than photobioreactors. Most microalgae produced in Asia are produced in open systems. The microalgae produced in these systems must be viewed with caution in terms of purity and contamination. In contrast to Europe, more open systems are used in North America. This is mainly due to the historical focus on the production of biofuel.

In the meantime, the focus in microalgae cultivation has shifted to high-quality substances for food, cosmetic, pharmaceutical and animal feed additives. As a direct result, the use of closed systems has increased disproportionately.

The clear price advantages of the Algoliner plants will further accelerate the shift to closed photobioreactors.