Comparison of algae cultivation technologies

Open ponds, tubular glass photobioreactors or systems with disposable polymer materials?

Open raceway ponds are the most widespread method for the cultivation of algae and originate from natural ponds. However tubular glass photobioreactors have been reliably in operation for almost 20 years, indoors and outdoors. Additionally a broad variety of systems made of disposable polymers exist, amongst them are green wall panels, hanging and floating plastic bags, and flat panel reactors.

Deciding which method is best  for algae cultivation depends on many factors, however biomass quality and production cost tend to be the deciding factors. The consideration whether to produce in an open or a closed system usually starts with the availability of land and water, the local weather conditions, temperature range and sunshine hours.

All cultivation of algae starts in a closed system, typically in a glass flask in a laboratory. Next is the inoculation of algae, which is essentially growing enough algae for use in algae production systems. Open systems have been ruled out for inoculation due to the high risk of contamination and culture crashes. Typical inoculation systems are illuminated stainless steel tanks or tubular glass photobioreactors, or alternatively disposable polymer bags. Although there are other methods, they have not gained traction due to specific disadvantages and they are therefore scarcely encountered in industrial use.

Open raceway ponds, tubular glass photobioreactors and systems with disposable polymer materials are very different methods for algae production. Therefore, we have written a guide to provide assistance in determining the pros and cons of those different algae cultivation methods. However, the comparison in this guideline does not focus as much on technical characteristics and the resulting advantages and disadvantages. This guideline rather looks into the implications that emerge in a business assessment of the methods.

In particular, the following questions are posed:

• What is the service life of major equipment components?
• Which method has the best productivity and why?
• Which system is best for planning production and predicting output?

The statements made in this guideline are based on scientific studies and calculations made for open raceway ponds, tubular photobioreactors and green wall panels. The information on green wall panels can be applied to other systems with disposable polymer materials.

Download your free guide now: A comparison of commonly used technologies for the cultivation of algae