Energy consumptions to produce 1 MJ energy were compared between biomass and fossil fuel (coal) (Table 6.2.6). For both cases, the transportation stages from production site to utilization site are omitted for simplification.

Fig. 6.2.2 shows energy consumption and CO2 emission of biomass and fossil fuel respectively, then the part of ®+® and ®’+®’ indicate the boundary here. In the case of biomass, ®+® means energy consumption for the stage of afforestation, crushing, and drying. Coal mining data were obtained from the data of Australia.

Fig. 6.2.3 shows the results of comparison. Energy consumptions of biomass production in North America, Indonesia and Brazil are 0.182 MJ/MJ-biomass, 0.200 MJ/MJ-biomass and 0.132 MJ/MJ-biomass, respectively, and energy consumption of coal production is 0.008 MJ/MJ — coal. The result shows that biomass production process requires much larger energy than coal production process in order to obtain equivalent energy.

On the LCA, energy consumption evaluation target is determined based on the use of exhaustible energy resources. So biomass energy consumption is not counted as energy

consumption, if the biomass is obtained from sustainable afforestation. In addition to this energy consumption for production, 1 MJ of exhaustible energy resource is consumed at energy usage stage for coal. As a result, life cycle energy consumption becomes lower for biomass than for fossil fuel.

Fig. 6.2.2. Energy Consumption and CO2 Emisssion image on Biomass and Fossil Fuel.

Fig. 6.2.3. Comparison Between Biomass and Coal on Energy Consumption and CO2

Further information

Turhollow, A. F. and R. D. Perlack, Biomass and Bioenergy, 1(3), pp.129-135, 1991

NEDO, “Investigation of forest from a viewpoint of global environment (the 2nd) (a case study of planting)”, NEDO-GET-9603, 1996 (in Japanese)

Yokoyama, S., “Eucalyptus Plantation in Brazil, Resources and Environment”, Shigen to Kankyo, pp.431-436, 1996 (in Japanese)

IEEJ (Institute of Energy and Economics in Japan), “Life Cycle Inventory Analysis of Fossil Energies in Japan, IEEJ, 1999 (in Japanese)