This article discusses some of the challenges that beset the commercial implementation of algae as a biofuel feedstock.
Petroleum shortages and the climate implications of burning fossil fuels have driven academic research and private industry into algae-based fuels (Clarens, Resurreccion, White, & Colosi, 2010). Indeed, the use of fossil fuels as an energy resource is now considered as unsustainable due to depleting resources and the accumulation of greenhouse gases (GHG) in the environment (Demirbas, 2010). Thus, clean, secure and affordable supplies of transportation fuels using low-carbon technologies, such as algae-based fuels, are considered essential in order to alleviate global dependence on oil and to meet the GHG reduction targets originally proposed in the 1997 Kyoto protocol and subsequently revised in the 2009 Copenhagen Accord (Luque, Lovett, Datta, Clancy, Campelo, & Romero, 2010).
However, not all biofuels are created equally. In their article, Groom, Gray and Townsend emphasized that only biodiversity-friendly biofuel feedstock should be considered for biofuel production, particularly those that do not undermine environmental goals of biodiversity and natural resource sustainability. They cited algae-based biofuel production as the most efficient biofuel, both in terms of land use and energy conversion (Groom, Gray, & Townsend, 2008).
Indeed, there are several desirable characteristics that algae have over other biomass sources. First, algae tend to produce more biomass than terrestrial plants per unit area. They can also be cultivated on otherwise marginal land using freshwater or saltwater, unlike terrestrial plants. Second, algae do not compete directly with food crops. For example, the United States ethanol boom of 2008 was alleged to have contributed to a spike in corn prices worldwide, which consequently brought the food versus fuel debate to the forefront of global discussions. Third, algae, by virtue of their fast growth rates and aquatic habitat, could be cultivated in systems designed for simultaneous biomass production, uptake of anthropogenic CO2 and removal of certain water pollutants (Clarens et al., 2010).
Groom et al., however, failed to discuss some of the challenges that beset the commercial production of algae into biofuels.
Full-cost accounting through life cycle assessment (LCA) is generally employed as the major tool for evaluating the environmental sustainability of biofuels (Luque et al., 2010). It is an essential element in designing an algal biofuel pipeline, since it systematically quantifies the environmental burdens at every stage of production, from growth of the biomass through to final use of the fuel. Of particular importance are the usages of fossil fuel in the entire production process and the corresponding releases of fossil-derived CO2 (Scott, Davey, Dennis, Horst, Howe, Lea-Smith, & Smith, 2010). Verily, a comprehensive LCA of bioenergy must take into account all the major environmental matters of bioenergy production such as carbon emissions, nitrogen emissions, water use and land use (Miller, 2009).
First is the higher capital cost of production because of the low biomass concentration in the algal harvest due to the limit of light penetration and the small size of algal cells. The higher capital cost, coupled with equally high operational costs of intensive care required by a microalgal farming facility vis-à-vis a conventional agricultural farm, impede the commercial implementation of biofuels from algae (Demirbas, 2010).
Second is the energy production from algae was found to have significantly higher energy use, GHG emissions and water use. The large environmental footprint of algae cultivation is driven primarily by upstream impacts including the demand for CO2 from steam coming from fossil fuels (Clarens et al., 2010).
Third is the requirement of large quantities of fertilizers. While algae are estimated to be capable of producing ten to twenty times more biodiesel than other bioenergy crops, they need fifty five to one hundred eleven times more nitrogen fertilizer. Such quantities of nitrogen could damage the environment and could limit the economic viability of using algae (Demirbas, 2010). Interestingly, a biofuel feedstock that has low land requirements tends to have reasonably high nitrogen requirements, and vice versa. Thus, while algae have the lowest land use footprint, they have one of the highest nitrogen requirements (Miller, 2009). It is the production of nitrogen fertilizer and its consequences to the environment that contribute substantially to the external costs of nitrogen-intensive feedstocks such as algae (Kusiima & Powers, 2010).
Admittedly, the use of biofuels alone will not effectively solve the world’s energy problems. This is due in part because the production of most biofuels is still too energy intensive. Also, many well-established biofuel industries in which there is a net positive energy yield (i.e., more energy is generated than consumed during biomass production) are still beset with many technological, social and environmental problems (Sivakumar, Vail, Xu, Burner, Lay, Ge, & Weathers, 2010).
In order to have a more sustainable future in this post-Copenhagen era, governments and private industries around the world need to strategically deal with increasing global energy demand, the finite nature of fossil fuel reserves, dramatic curbs in emissions of GHG to mitigate the consequences of climate change, the volatility of oil prices especially for the transport sector, and geopolitical instability in fossil-fuel supplier regions. Indeed, with oil prices continuously fluctuating, a cost-competitive and stable solution is urgently required that can cope with the expected sixty percent increase in transport sector energy demand by 2030 (Luque et al., 2010).
Indeed, the algae-based biofuel industry is one such cost-competitive and stable solution, provided that the commercial, technological and environmental challenges discussed above are addressed effectively and immediately.
In conclusion, biofuels are projected to play a strategic role in the global portfolio of clean energy solutions in this carbon-constrained world. A variety of different biofuels will be used, each with its own regional and cultural niche, in combination with non-biological alternative energies such as wind, solar, tidal and nuclear (Sivakumar et al., 2010). Together with such other forms of renewable energy, biofuels will help address the mitigation of greenhouse gas emissions to tackle climate change while simultaneously respond to the huge energy appetite of a fast growing global population.
Clarens, A., Resurreccion, E., White, M., & Colosi, L. (2010). Environmental Life Cycle Comparison of Algae to Other Bioenergy Feedstocks. Environmental Science and Technology, 44(5), 1813-1819.
Demirbas, A. (2010). Use of algae as biofuel sources. Energy Conversion and Management, 51(12), 2738-2749.
Groom, M., Gray, E., & Townsend, P. (2008). Biofuels and Biodiversity: Principles for Creating Better Policies for Biofuel Production. Conservation Biology, 22(3) 602–609.
Kusiima, J., & Powers, S. (2010). Monetary value of the environmental and health externalities associated with production of ethanol from biomass feedstocks. Energy Policy, 38, 2785–2796.
Luque, R., Lovett, J., Datta, B., Clancy, J., Campelo, J., & Romero, A. (2010). Biodiesel as feasible petrol fuel replacement: a multidisciplinary overview. Energy & Environmental Science, Advance Article, Available online on September 9, 2010, http://pubs.rsc.org (accessed September 23, 2010).
Miller, S. (2010). Minimizing Land Use and Nitrogen Intensity of Bioenergy. Environmental Science and Technology, 44(10), 3932–3939.
Scott, S., Davey, M., Dennis, J., Horst, I., Howe, C., Lea-Smith, D., & Smith, A. (2010). Biodiesel from Algae: Challenges and Prospects. Current Opinion in Biotechnology, 21(3), 277-286.
Sivakumar, G., Vail, D., Xu, J., Burner, D., Lay, J., Ge, X., & Weathers, P. (2010). Bioethanol and biodiesel: Alternative liquid fuels for future generations. Engineering in Life Sciences, 10(1), 8–18.
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