Researchers from Utah State University have developed a model that simulates algae growth and their lipid productivity at various global locations using photobioreactors, which are closed outdoor installations that create an artificial environment for algae.

The microscopic algae produce significant amounts of lipids mainly in the form of triacylglycerol which can be utilized to generate biofuels.

To assess the biofuel-generating potential of algae at various global locations, the researchers grew Nannochloropsis — oculata — microscopic algae found in freshwater and marine systems — in photobioreactors exposed to a constant temperature and ambient light. They simulated the algae growth and lipid content at 4,388 global locations by tweaking the variables hourly according to location-specific metrological data.

The study found that the algae yielded maximum annual average lipid between 24 and 27 cubic metres per hectare per year for Egypt, Saudi Arabia, Ethiopia, Australia, Brazil, Colombia and India. The major advantage of growing microalgae is that it does not require quality land like traditional terrestrial crops, such as soybeans, which required 27 times more agricultural land to give the same output.

Besides Egypt and Saudi Arabia, countries like Kuwait, Qatar and the United Arab Emirates can use this knowledge to utilize non-arable land and supplement 30% of their yearly consumption of transportation fuel by microalgae-based biofuel, suggests the study, which was published in the Proceedings of the National Academy of Sciences.

But despite its promise in facilitating pilot studies and providing a uniform way of testing algae strains across different locations, the use of photobioreactor models has its limitations.

It cannot for instance address how an algal strain will deal with contamination and invasion of grazers when grown in fields, outside the protective cover of the photobioreactor.

For this model to be really useful, it must include data on the economic costs and available resources, and these could change the results entirely.