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Written by: Melissa Owens
Written on: May 1st, 2009
Tags: energy & sustainability, chemical engineering
Thumbnail by: Sagdejev/Wikimedia Commons
About the Author
Melissa Owens is from Sugar Land, Texas. She majored in chemical engineering with an environmental focus and graduated from the University of Southern California in May 2011.
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Volume XI Issue I > The Power of Pond Scum: Algae Biofuels
Our world is facing a global energy crisis. As we continue to deplete non-renewable energy resources, we must seek to develop alternative renewable resources to meet our energy demands. Scientists and engineers are currently researching algae as a potential source of biofuel that might replace fossil fuels as a main source of energy. Compared to other biofuel options, algae have a much higher yield of energy per area per time, a greater speed of proliferation, and an ability to proliferate successfully in many different environments. Further, because algae grow through photosynthesis, which consumes carbon dioxide, algal growth could be fed by industrial carbon emissions, thus reducing overall emissions and thereby slowing global warming. Deterrents to large-scale algae cultivation for use as fuel are its highly expensive production and comparatively high costs of the fuel after it is processed. If its production and sale could be made to be economically competitive with other forms of energy, algae biofuel would certainly become an important energy source that will fuel the world to a greener future.

The Power of Pond Scum

Could oil ever become green? The domestic and global energy crisis has accelerated alternative energy research; scientists and engineers are currently scrambling to develop realistic substitutes for current non-sustainable energy sources. One largely unpublicized option among proposed clean, renewable energy sources are algae. With developing technology and increasing public interest, pond and pool scum may be the key to pulling out of our energy crisis, saving our planet, and preserving our lifestyles.

"That goo in my pool has a name?"

Yes, and it is called algae. Algae are a large and diverse group of eukaryotic (nucleus-containing)​ organisms. It is estimated that there are over 30,000 species of algae, ranging in color from lime green to black [1]. Like plants, algae are photosynthetic, meaning they use solar energy to convert carbon dioxide into organic compounds. Requiring only water, carbon dioxide, and light to grow, algae readily proliferate; thus, ponds and swimming pools often fall victim to unwanted colonies of these visitors (see Fig. 1). Though the algae we often refer to as scum may seem to be no more than a slimy nuisance, they have immense potential to be developed into usable energy.
Sagdejev/Wikimedia Commons
Figure 1: Algae blooms in a North Carolina pond. Similar microorganisms have the potential to be processed into valuable biofuel in photobioreactors.
To begin, there are three general classes of algae: emergents (which grow in swamps), macroalgae (like seaweed), and microalgae, (which are the type that can be manipulated to produce the kinds of oil that could potentially solve our energy problems) [2]. More specifically, the National Renewable Energy Laboratory (NREL) considers about 300 species of microalgae as potentially good sources for harvesting oil. There are 4 main groups of microalgae: diatoms, green algae, blue-green algae, and golden algae. Besides creating a diverse color palette, each of these microalgae groups has advantages that make it uniquely useful when considering it a fuel source.