The Role of Bio-productivity on Bio-energy Yields

The principal photosynthetic pathways convert solar energy differently depending on the environmental conditions and the plant morphotype. Partitioning of energy storage within crops will vary according to environmental and seasonal conditions as well. Highest energy concentration is found in terpens like latex and, to a lesser extent, in lipids. Ideally, we want plant ingredients with high energy content easily amenable to ready-to-use bio-fuel. Generally, these crops are adapted to drier areas and tend to save on eco-volume space. Competition with food crops could be avoided by fetching energy from cheap agricultural by-products or waste products such as bagasse in the sugar cane. This would in fact mean that reducing power of agricultural residues should be extracted from the biomass through non-photosynthetic processes like animal ingestion or industrial bio-fermentation. Conversion and transformation efficiencies in the production chain are illustrated for some relevant crops in the light of the maximum power theorem.