Converting Algae to Energy

Benefits of using Algae as a Sustainable Energy

Fig. 1: Algae being harvested. (Source: Wikimedia Commons)

Converting algae into energy through biofuel is an increasingly popular form of renewable energy. Using algae is arguably one of the best solutions to the worlds growing energy demand because it is one of the fasting growing plants and much faster than most terrestrial crops. [1] Fig. 1 shows large quantities of algae being harvested. Algae is a particularly environmentally friendly source of renewable energy because it uses an enormous amount of CO₂ through photosynthesis removing it from the atmosphere and releasing oxygen. Additionally algae depollutes the water through absorbing and removing contaminants. Algae is most commonly converted to bioethanol and biodiesel fuels which are two bio liquid transportation fuels. Biodiesel fuel is more popular than bioethanol because it holds more environmental benefits mainly being its smaller impact on air pollution. This lesser environmental impact is also because of the CO₂ consumed and oxygen released by the algae that was used to create this fuel. [1]

Importance of Algae Oil as a Source of Biodiesel

Algae is an effective source of energy because around 50% of its weight is oil. This lipid oil in their biomass can be used to make biodiesel for cars, trucks, and airplanes. Current research is focused on how to most efficiently create biodiesel specifically because of its lesser environmental impact as mentioned above. Different species of algae may be better suited for different types of fuel. Algae are simple organisms that are mainly aquatic and microscopic. Both algae and micro algae (unicellular photosynthetic microorganisms) are used and converted to biodiesel fuel. [2] Algae uses photosynthesis to convert solar energy into chemical energy which is stored in fatty or lipid oils. One challenge of converting algae into biodiesel fuel is that production costs are uncertain and vary because of feedstock availability, prior claims to land, and regulations based on environmental affects of large areas of monoculture. Both types of algae are currently mainly used for food in animal feed, aquaculture feed and as a bio fertilizer. [2]

Challenges of Using Algae as a Biofuel

According to some, algae could potentially produce between 47,000 and 308,000 liters/hectare of oil with current technology. This would require using a large scale to optimize production [3]. However these numbers have not been verified, as algae has not yet been implemented in a large scale production. Additionally this number remains unsubstantiated due to concerns of authors exaggerating the benefits of algae biodiesel production. Algae requires a large amount of sunlight for its process of photosynthesis. When farming algae, light only reaches to a depth of a few centimeters requiring algae ponds to maximize surface area over volume to give the algae maximum exposure to the sun. Because of this, algae farms require a substantial amount of land. Using this large amount of land creates other challenges in the form of increased risk of waste products affecting the surrounding environment. Current technology in creating facilities to convert algae into biofuel at a large commercial scale are still not developed. [3] Other challenges include algae fuel having a lower energy content than petroleum fuels as well as algae fuels producing less engine power and speed. If algae fuel hopes to compete with traditional fuels than technology and facilities to create it need to be advanced. [4]

There seems to be speculation across sources as to whether algae can be successfully implemented as a renewable source of energy. Claims for seemingly impossible benefits of algae production could be a result of authors who have vested interests in the success of algae as a renewable energy. [1,3]

© Nathaniel Morris. The author warrants that the work is the author''s own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

References

[1] M. F. Demirbas, "Biofuels From Agae For Sustainable Development" Appl. Energy 88, 3473 (2011).

[2] A. Demirbas and M. F. Demirbas, Importance of Algae Oil as a Source of Biodiesel," Energy Convers. Manage. 52, 163 (2011).

[3] A. Noll, "The Future of Algae Biofuel," Physics 240, Stanford University, Fall 2015.

[4] S. Kumar, "Algae Fuels," Physics 240, Stanford University, Fall 2012.