Evaluation of supply potential of energy crops in Japan considering cases of improvement of crop productivity

In addition, the authors analyze the supply potential of energy crops produced on surplus arable land in Japan in cases of biomass productivity increment. The supply potential of energy crops is formulated into 0.12A (EJ yr−1), where A means the index of productivity increment (A=1.0 at present). On the other hand, in the case of every crop productivity increment, the supply potential of energy crops is formulated into 1.44A-1.32 (EJ yr−1). When it is assumed that the ratio is 2.0, the supply potential in the latter case is 1.44 EJ yr−1, which is equivalent to about 7% of the total primary energy supply in Japan. When it is assumed that the ratio is 2.0 in the latter case in the world, the supply potential of energy crops is 435 EJ yr−1, which exceeds the total primary energy supply in the world. It is difficult to improve the productivity of every crop. However, if the improvement is realized, energy crops will become one of the major energy resources in Japan and in the world.