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| Fig. 1: This is a close up one type of duckweed: Lemna minor. (Source: Wikimedia Commons) |
The issues posed by continued use of crude oils, natural gases, and nuclear energy are abundant. Aside from the all too clear environmental costs from their continued use, we must also take into account the relative volatility of these commodities. In the wake of these dilemmas, new alternatives have emerged, including biofuels. While first generation biofuels (such as corn and wheats) have required countries to choose between food production and energy production, second generation biofuels such as duckweed actively avoid this problem. [1] While there are abundant issues, including political and economic hurdles to overcome, the mass use of Duckweed as an energy source could have a lasting positive impact on developing countries. One such variety of duckweed is shown in Fig. 1, to the right.
In the year 2012 alone, the use of biofuels as an energy source has exceeded expectations as nearly 85.2 billion liters were produced. [2] Indeed, the United States alone made up nearly 47% of the worlds bioethanol production, with Brazil and other Latin American countries close behind. [2] As a first generation biofuel, corn has been the predominant source for bioethanol fuel. Of course, with the inevitable increase in biofuels, there will be an inevitable increase in the cultivatable land needed to produce its feedstock. As this need increases, there will exist an equally strong push against the croplands available for the production of food.
Indeed, while the effects of biofuel production limiting foodstuff production will not be felt immediately in the United States, this is not true in developing countries. According to the IMF, biofuel production was expected to be responsible for nearly 20-30% of all global food price increases in 2008. [3] This issue will only increase as the number of biofuel reliant vehicles in the European Union is expected to increase by 4x within the coming decade. It should also be noted that nearly 25% of corn grown in the United States alone is expected to be used for the production of biofuels for personal cars. [4]
Readers of this article should not expect though that the increase in first generation biofuels will create hyper-inflation in food prices. Most concerns regarding the effects of increased biofuel production on food prices stems, albeit legitimately, only from the food price surge of the early 1970s. [1]
Duckweed, unlike first generation biofuels, does not require the use of farmable land. This is because duckweed is a relatively small aquatic plant that floats on or just below the surface of the water. [1] In nature, duckweed can be found most prevalent in fresh water and wetlands. The significance of this should not be overlooked. Duckweed's ability to grow in water will allow 1) a more widespread and accessible production means, and 2) much needed farmland to be used for the production of foodstuff. Perhaps even more importantly is duckweed's ability to grow in wastewaters. One often overlooked value of wastewaters is its high nutrient concentration relative to other bodies of water, such as fresh water or wetlands. [5] In this way, industrial production of duckweed need not overtake fresh water lakes or rivers and could instead be limited to the many wastewater facilities located throughout the United States or other developed nations.
Biofuel production is based on many different properties of the source ingredient: cellulose concentration, sugar concentration, and starch concentration chief among them. Interestingly enough, duckweed has a very high starch concentration ranging anywhere from 3-75% (depending on the species and growing conditions). [5] More importantly, the starch concentration can be artificially increased by manipulating said growing conditions. Indeed, this makes the application of duckweed as an efficient source for biofuels unparalleled.
Duckweed is also unique in its superior rate of growth relative to first generation biofuels. Another major obstacle posed by the use of corn and wheat for biofuels is the time needed for these sources to grow. Fortunately, duckweed is known as one of the fastest growing plants and can effectively double biomass every twenty hours (when under appropriate environmental conditions.) [5] Indeed, the yield alone from the use of duckweed relative to first generation biofuels is exponential and could yield a large increase in energy supply and a subsequent decrease in energy costs.
However, if the use of duckweed as a biofuel is superior to existing sources of biofuel, why do we currently see a stagnation? Although there is no one easy answer, duckweed has not been as effective to reach commercialization as initially planned. Even though the United States and the European Union have extensive programs to aid the cultivation of new energy sources, new political policies from the United States Environmental Protection Agency have recently hindered those efforts by lowering the previously required levels of biofuels that should be blended into gasolines. With the requirement that only 10% of gasoline in the United States be a blended biofuel, there has been a limited market need for the increased production of more effective biofuel substances. [6]
However, government policies are not the only obstacle facing the increased use and commercialization of duckweed. According to a study conducted by The International Council on Clean Transportation, seven of the nine largest companies producing algal biofuels have a beat coefficient greater than or equal to 1. [6] In other words, the volatility of pursuing duckweed and duckweed-like biofuels is extremely high (higher than the stock market). For this reason, it is no wonder that duckweed producing biofuel companies are struggling to attain private investments as their business model is seen as a high risk venture. As such a risky venture, private companies pursuing research and development in duckweed as a biofuel simply lack the monetary incentive and financial backing.
It should be noted that my research leaves out details pertaining to questions such as: How many square meters are needed to supply the energy equivalent of today's corn ethanol, Where should duckweed farms be located, and how many kilograms of duckweed will an individual need to grow per year to pay something like their mortgage. While these are interesting questions and must be explored, they are beyond the scope of this research which is to bring about awareness to the potential positives of duckweed.
© Riley Noland. 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.
[1] J. Vidal, "EU Biofuels Significantly Harming Food Production in Developing Countries," The Guardian, 15 Feb 10.
[2] M. Balat and H. Balat, "Recent Trends in Global Production and Utilization of Bio-Ethanol Fuel," Appl. Energy 86, 2273 (2009).
[3] J. Borger, "US Biofuel Subsidies Under Attack at Food Summit," The Guardian, 3 Jun 08.
[4] J. Vidal, "One Quarter of US Grain Crops Fed to Cars - Not People, New Figures Show," The Guardian, 22 Jan 10.
[5] W. Cui and J. J. Cheng, "Growing Duckweed for Biofuel Production: A Review," Plant Biol. 17, 16 (2015).
[6] N. Miller et al., "Measuring and Addressing Investment Risk in the Second-Generation Biofuels Industry," The International Council on Clean Transportation, 2013.
