The ultimate and ideal energy carrier for durable technologies is solar irradiation. The most efficient method to benefit from solar irradiation to produce biomass is growing microalgae. Microalgal biotechnology is a relatively young field and presently the market is mainly determined by a few species (Spirulina, Chlorella and Dunaliella). It is expected that the commercial market will expand with other promising species for valuable and more diverse products. The biodiversity of microalgae is enormous and each species produces its own unique product(s). Because only 10% of the species are identified microalgae represent an almost untapped resource. It has been estimated that there are  between 200,000 and several million species, compared with about 250,000 species of higher plants.

Microalgae have an enormous potential. This is supported by the comparison, in terms of development, with both microbial fermentations and agriculture. Due to the development in both technology and strains (in case of fermentation) and crops (in agriculture), the productivity of present systems is about 5000 times higher than the original natural production systems. Production of microalgae is still based on traditional technologies with wild type strains. It is a great challenge to realize breakthroughs in both photobioreactor technology and strain development.

Especially marine microalgae are rich in high-value bioactive components like vitamins, ω-3 fatty acids, pigments, antioxidants and sterols. Only a small number of these compounds have been commercialized at large scale. Development of new products from microalgae has always been limited by the technology, as described above. Especially for products for which algae need to be grown as monocultures, the available technology is seen as a bottleneck. Most of the commercial systems applied are open ponds for the production of Spirulina, Chlorella and Dunaliella. Apart from that, microalgae are produced at aquaculture sites in which they serve as feed.

Sunlight striking on Stow Lake in Golden Gate Park, San Francisco.