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Algae as a Biofuel: The Chemistry Behind Algae’s Energy Potential

Author: Derek Yang

Editors: Jonathan Chen, Suri Liu

Artist: Rachel Zhou


As climate change continues to worsen, experts are desperately looking to decrease fossil fuel burning—the most significant cause of global warming. This effort has led to the discovery of algae as a possible solution. Let’s say your AP Environmental Science teacher asked you to talk about algae: what would you say? Most likely something along the lines of green, gooey, mucky,-- maybe eutrophication, right? But perhaps most amazingly, you might not know that algae is an excellent source of 'green' biofuel. In this regard, it could end the burning of fossil fuels and significantly reduce global warming.

Algae are aquatic plants that capture sunlight and store it as chemical energy through photosynthesis. Certain varieties of the algae store chemical energy in the form of vegetable oils, known as triacylglycerol, or TAG. The TAG is extracted from the algae and then treated through a chemical reaction called transesterification. Transesterification involves mixing the TAG with a type of alcohol–usually methanol–which creates a byproduct of biodiesel, glycerol, and fatty acid methyl esters. 

Algae also employ a process called photolysis. They use sunlight to break down water into hydrogen and oxygen ions. The hydrogen ions can then be processed using pressure swing adsorption or cryogenic distillation—methods that separate pure hydrogen gas from impurities and other gas species— and compressed and then stored as biofuel that can run most modern, everyday cars, planes, and trucks.

Utilizing algae as an energy source is a great opportunity due to its numerous benefits. Algae grow extremely fast, and research has discovered that certain algae species double in population every six hours. Additionally, algae can be grown in numerous different types of environments, from freshwater to seawater, making it easy to grow and harvest. This allows for large-scale algae farms all around the world that can efficiently collect biofuel from algae with minimal environmental concerns. Furthermore, algae mitigate global warming by absorbing carbon dioxide for their photosynthetic reactions, being responsible for over 40% of the world’s carbon fixation—in which plant matter converts atmospheric carbon into organic matter usable by living organisms. These benefits of algae prove its feasibility in addressing climate issues by simultaneously acting as clean biofuel while also decreasing the amount of carbon dioxide in the atmosphere.

However, all these advantages of algae also come with disadvantages. In the United States, fossil fuel demand has increased so much that it was estimated that more than 30 million out of the 640 million acres of federally owned land would have to be allocated to algae farms to meet America’s significant fuel demands. Pursuing algae farming to this scale would not be practical. Distributing that much land to grow algae would undermine economic opportunities as it could limit the amount of land for agriculture, decrease crop yield, force the importing of foreign crops, and harm the overall economy. Without sufficient political and public support, constructing these algae farms would be a great struggle.

Algae biofuel is a very popular topic among environmentalists, as its energy potential could address climate change. Despite the extensive land requirements and economic and logical issues, with further research in this field, we can hope to find a viable way to utilize algae biofuel in the future.

 

Citations:

“Energy 101 Video: Algae-to-Fuel | Department of Energy.” Energy Saver, Energy.gov

2024.

Farm-Energy. “Algae for Biofuel Production.” Farm Energy, WordPress, 12 Apr. 2019, 

Hannon, Michael. “Biofuels from Algae: Challenges and Potential.” Biofuels from Algae:

Challenges and Potential, U.S. National Library of Medicine, Sept. 2010, 

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