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close this bookRenewable biological systems for alternative sustainable energy production. (FAO Agricultural Services Bulletin - 128) (1997)
close this folderChapter 1 - Biological energy production
View the document1.1 Energy and environmental issues
Open this folder and view contents1.2 Photosynthesis and biomass
View the document1.3 General problems
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1.3 General problems

Among the biomass conversion processes discussed thus far, methane and ethanol production from various wastes is economically feasible within the restraints of scale and location. Although biological processes for the production of gaseous and liquid fuels have been well demonstrated with cultured microalgal biomass, these processes must still be integrated into a system capable of meeting basic requirements for overall efficiency of converting solar energy into biofuels. Furthermore, a model system must at least in principle, be capable of easy scale-up and not be limited by either engineering or economic factors. Under the current petroleum economy, prospects for the use of H2 or oils produced by biological processes seem remote. However, future requirements for a "clean environment" necessitate fundamental research into microbial and algal physiology and genetics, together with basic engineering research on converters and total systems.

In its effort to address global warming and other environmental problems, the Research Institute of Innovative Technology for the Earth (RITE), engaged in investigating projects, including the Project for Biological CO2 Fixation and Utilization, and the Project for Biological Production of Hydrogen Through The Use of Environmentally Acceptable Technologies was established by the Japanese Government in 1990. These projects employ researchers from both national institutes and private companies who are engaged in the research and development of technologies for microbiological CO2 fixation and the production of hydrogen. At the same time, research efforts at the university level include biochemical and genetic studies on CO2-fixing and H2-producing enzymes, and the application of these enzymes to the development of more efficient energy systems.

The following Chapters, address biological and engineering aspects of alternative sustainable energy production, with emphasis on recent progress in four specific areas: (i) fuel alcohol production from cellulosic biomass, (ii) improved methane fermentation from industrial and agricultural residues, (iii) biological H2 production from water and various wastes, and (iv) oil production through thermochemical liquefaction of microalgal biomass. The final Chapter outlines prospects for the future of renewable energy systems, although this is by no means a simple task, since problems concerned with energy, the environment, population, and food, are all interrelated.