Figure 1: Subitec GmBH Microalgae Flat-Panel-Airlift Photobioreactors
Continued use of fossil fuels as an energy source is now widely viewed as unsustainable method due to its finite resources and the build up of carbon dioxide in the atmosphere. A new developing technology is the use a microalgae bioreactor to capture CO2 from the atmosphere through the process of photosynthesis. The microalgae are unicellular biofactories (individual organisms) that can then be harvested and used in the production biomass or biofuels. The microalgae can be grown through a variety of methods (that are explored later on), but has basic requirements such as sunlight, carbon dioxide and a variety of nutrients.
There are plenty of reasons for using microalgae, most notably it captures about 100 times more CO2 per hectare than a hectare of trees. As well as this productivity per hectare is 5 to 10 times greater than other plants or crops meaning it requires much less space and removes any direct competition for arable land with the production of food. Due to the wide varieties of microalgae and the ability of the manufacturer to choose specific species of algae, the biomass can be ‘designed’ to suit what is required of it. This is primarily dependant on what the user needs, either a high lipid content (primarily for biofuel) or a high carbohydrate content (primarily for biomass). For this investigation the species focused on was designed to produce a large amount of biomass. The biomass reactor can be bolted onto a combined heat and power plant or alternatively to the Tennants factory, to increase the efficiency of the process.