Microalgae for biofuels can be grown on land unsuitable for most other uses.
Microalgae biofuel is an alternative fuel source made from the oils and carbohydrates found in algae. The biofuel production process from algae is adapted from similar biodiesel production methods using processes such as transesterification and fermentation to create fuel from plants such as corn and soybeans. Using algae for biodiesel and crude oil production is often more economical because hydroponically grown algae produce more oil than similar amounts of plants growing in soil.
As algae are a renewable resource, biofuels produced from them are very close to carbon neutrality.
The process of manufacturing biofuels from microalgae is quite simple. The algae are grown in open tanks, closed-loop systems, or photobioreactors. These algae are harvested and dried for use in the microalgae biofuel manufacturing process. The oils are then extracted from the algae and converted into biodiesel or a green form of crude oil by transesterification. The remaining material is used to create bioethanol or biobutanol through a fermentation process.
Lipids represent up to 50% of the weight of some types of algae.
Algae farming methods have been an area of great concern for biofuel producers. Algae grow rapidly compared to other fuel crops, with an average harvest cycle of one to ten days. Although algae can be successfully grown and harvested in open ponds, these ponds are subject to contamination. Closed-loop systems and photobioreactors are designed to avoid the possibility of external contamination, but they offer their own drawbacks in the form of harvesting difficulties, operating cost, and initial investment.
Due to the demand for a constant supply of sterile carbon dioxide (CO2), many closed-loop systems and photobioreactors are designed to have a symbiotic relationship with industrial smokestacks. In this project, the algae farming team reuses the plant’s CO2 emissions to fuel algae growth for biofuel production. It should be noted that while microalgae biofuel is considered a green alternative fuel, it is only CO2 neutral because the CO2 captured during the growth phase is released when the biofuel is burned. The benefit of using biofuels lies in the fact that these CO2-neutral fuels can remove additional atmospheric CO2 caused by burning CO2-positive fossil fuels.
The use of microalgae biofuels offers several different benefits for industries and consumers. By growing algae for biofuel production, industries can lessen their impact on the environment, often gaining tax breaks and government subsidies that are passed on to the consumer in the form of lower prices. In some cases, industries can use and generate biofuels from microalgae in the same vicinity, providing fuel for the factory and generating the CO2 needed for the algae cultivation process. The advantages of using biofuels can also be seen in reduced dependency on fossil fuels and lower fuel costs, particularly in the aviation and transportation industries.