Biomass production from food sources has been shown to increase greenhouse gas emissions and other pollutants through necessary land use changes (Stucki et al. 2009). In order to provide a sustainable source of biofuel in the future, biomass production must be enacted that does not substantiate the climate problems or compete with food production. Microalgae have recently been targeted as great potential sources for biofuel. The two main problems for this type of production are an efficient means to grow the algae and an efficient means to convert the algae into useful energy. One potential clean energy source is methane. New technologies are currently being explored to make methane production from algae more efficient. — Alec Faggen
Stucki, S., Vogel, F., Ludwig, C., Haiduc, A., Brandenberger, M., 2009. Catalytic gasification of algae in supercritical water for biofuel production and carbon capture. Energy Environmental Science 2, 535–541.
Stucki and colleagues working at the Laboratory for Energy and Materials Cycles in Switzerland have revolutionized biofuel production via algal biomass. The authors employ a two-phase process in which they first grow the algae in a photobioreactor and later convert it into methane. The methane produced is pipeline quality synthetic natural gas.
The authors’ first process ameliorates the issue of climate change by using carbon dioxide emissions for algae cultivation. The subsequent process converts this algae into biofuel via a catalytic hydrothermal gasification process in supercritical water. The hydrothermal process also succeeds in recycling the algal organic matter back into nutrients for algae growth. These processes are experimentally designed to be sustainable whereby all heat demands are satisfied by heat recovery or by combustion of some of the methane gas product.
This methodology successfully lessens fossil fuel dependence, without disturbing food production. It is especially useful because the yields do not depend on algal products such as lipids. A challenge to the procedure and area for future study is the protection of the catalyst from the toxic effects of the heteroatoms, which are present in the algal biomass.