Grenergy has already performed several experiments at lab scale and field scale in Dubai, and identified the optimal parameters for algae production. Those parameters are the type of algae species, the proper nutrition and aqua environment that will determine their reproduction rates. We believe that we have reached reproduction rates up to 4-5 times a day. Our harvesting technique is also energy efficient and environmental friendly. Traditionally, photobioreactors suffer from the problems of scalability, especially in terms of mixing and gas exchange (both CO2 and O2). Open ponds are, however, subject to daily and seasonal changes in temperature, humidity, evaporation rate and presence of impurities. Our hybrid system that is combining the benefits of both is also enhanced with a method of rapid, automated or semi-automated biological and chemical monitoring in the production settings. During summer, thermophilic or thermo-tolerant strains of algae will be cultivated at temperatures above 40°C.
Since algae growth requires CO2 input, productivity can be enhanced by supplementing the CO2 from concentrated sources such as flue gas from fossil-fuel burning power plants, as well as from other CO2-emitting industrial sources. Due to our industrial experience in water treatment, we can inject CO2 into open pond water without covering the entire ponds.
Most of the challenges faced at the time of extraction are associated with the industrial scale-up of the integrated extraction systems. Many analytical techniques exist for optimizing the extraction systems to consume less energy than that contained in the algal products. That poses a challenge owing to the high energy needs associated with handling and drying algal biomass, as well as separating out the desirable co-products. We have combined several processes into this one step, at the same time expediting the process through mechanical disruption of the algal cells for oil extraction. Thus, economical production of biofuels from oleaginous microalgae via supercritical processing is achieved through this technology. Subcritical water extraction from the algae, through filtration during the conversion process, will make it possible to return the recycled water to the ponds, eliminating any negative environmental impact.
Anaerobic digestion can be effectively used as a means of producing biogas from algae and the algal remnants, after extraction. In particular, the organic fractions of the algae that remain after oil extraction are amenable to anaerobic digestion. Further, once the algae are harvested, little if any pre-treatment is required. The biogas product typically contains 60% methane, and 40% CO2, by volume. Methane will be used in the system to generate power, and CO2 will be re-injected into the ponds to stimulate algae production.