Once again it is a great day for my research group since Kersti Johansson and Karin Liljequist will defend their Masters research project, “Can agriculture provide us with both food and fuel?”. Note that what they have calculated is not how much energy is required to produce food rather than the energy content of the products. The results of this work will be made available in a few weeks.
The objective of this study is to build a database on the global agricultural primary production and its energy content. The database is further used to estimate losses within the agricultural system, and possible biofuel production, to answer the question; can agriculture provide the world with both food and fuel? To better be able to answer this question, the basic conditions for agriculture and plant growth are accounted for and the expansion potential of agriculture is discussed.
The energy available for food was found to be 9370 TWh if rest products from processing are considered edible and 7320 TWh if they are considered inedible. Assuming a food demand of 2500 kcal per day and person for the 6.7 billion world population gives a global food demand of 7092 TWh.
To be able to estimate the potential of biofuel production using feedstock from agriculture, the energy exchange was calculated for different crops and biofuels. It was concluded that, if all wasted organic matter and all residues was used as feedstock in biogas production, the biogas produced would be able to replace one fourth of the consumption of fossil fuels, which was 25 000 TWh in year 2006, in terms of energy.
The expansion potential for global agriculture is limited by availability of land, water and energy input. A future decrease in supply of fossil energy and ongoing land degradation in combination with a growing world population further enforces that the energy potential lies in using inedible organic waste and residues.