Algal Technology. Algae are present in all existing habitats where light is available. ... Photoautotrophic cultivation occurs when algae use light as the energy source, and inorganic carbon (e.g. carbon dioxide) as the carbon source to form chemical energy through photosynthesis. Algae fuel, algal biofuel, or algal oil is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Also, algae fuels are an alternative to commonly known biofuel sources, such as corn and sugarcane. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil.