Foresight Brief: Seaweed & Algae as Biofuels Feedstocks

Abstract

Seaweed is a known potential carbon-dioxide (CO2) neutral source of second generation biofuels. When seaweed grows it absorbs CO2 from the atmosphere and this CO2 is released back to the atmosphere during combustion. What makes seaweed, and in particular micro algae, so promising as a fuel source is their growth rates and high lipid (oil) content. Algae are among the fastest-growing plants in the world. Energy is stored inside the cell as lipids and carbohydrates, and can be converted into fuels such as biodiesel (in the presence of oils) and ethanol (in the presence of carbohydrates). Its high protein content implies that waste from the feedstock conversion process may yield a saleable waste stream as well. The level of interest in the use of algae as a source of biofuels (primarily ethanol and biodiesel but also methane and hydrogen) is rising globally. Several factors appear to account for this. Firstly, despite earlier predictions of stability in world oil prices, such non-renewable hydrocarbon source fuels continue to spiral upwards (having closed at $100 per barrel during Feb. 2008 for the first time) and there is a heightened awareness about the contribution of fossil fuels emissions to rapid climate changes. In this context, algae-based biofuels offer potential solutions since they are known to be a CO2 sorbent and their harvesting may not have a negative CO2 balance due to loss of CO2 absorbing landmass which is the current topic of debate about first generation biofuels. The Marine Institute of Ireland has experienced a rise in interest in seaweed and algae as a potential feedstock for production of biofuels, reflected by requests for data concerning the properties and composition of algae and seaweed, from both the research and industrial communities over the past several months.