the idea was to place the towers on positions of existing petrol stations in cities. their research led them to the conclusion that algae and bamboo would give best production results; max. amount of bio-fuels per unit of surface (or spatial unit), also considering other factors, like cost of technologies required for cultivation and processing, growth rate, annual input-to-yield ratio, etc.
they envisioned this system and applied it to their immediate environment, cities in croatia, however it is applicable to any urban area in the world. by applying the bio towers we would reduce the amount of valuable agricultural land used for production of bio-fuel plants, reduce transportation costs and related air pollution. this kind of crop production also has advantages over farming in open spaces, because it's not weather-dependant, and you can create artificial conditions which enhance the plant growth (conditions that can't be achieved in the natural environment). the visual identity of the towers is a symbol and result of their function. beside the benefits of bio-fuel and oxygen production, they consider the towers architectural appearance as an added value primarily to the conscience of the city inhabitants.
