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NIRE Annual Report
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1996

Emissions of Global Warming Substances from Coal Mines in Japan

System Safety Division
Safety Engineering Department
Objectives
Energy consumption is the main CO2 source to the global environment, however, the emission from the mining of the energy resources has not been investigated systematically. To obtain quantity of CO2 emission from coal mining, the life cycle inventory for coal mining in Japan was investigated as well as CH4 emission. All energies, materials, equipment and facilities used for the coal production in Japan are listed for the assessment.
Results
As the results, 109kg of CO2 and 15.5kg of CH4 are emitted par one ton of clean coal output. Share of each CO2 source is shown in figure 1. 92% of the total CO2 emission is generated by the process of the production of energies needed for coal mining. CO2 emission by the production of the materials used for the coal mining is around 7% of the total CO2 emission. CO2 emission by the production of machinery and buildings for the coal mining is less than 1% of the total CO2 emission each.
Since 65% of used electricity came from the domestic power generation plants of each colliery and the efficiency of the domestic plants is lower than that of commercial power generation plants, improvement of the efficiency is essential for the reduction of the CO2 emission.
By comparison with other countries' CO2 emission data including the emission by the transportation process to Japan, CO2 emission from coal mining in Japan is almost as same level as the emission by imported coal from main coal producing countries.
Considering the higher global warming performance of CH4 compared with CO2 (GWP of CH4 is 24.5 for 100 years) and the emission volume of CO2 and CH4, the results of our investigation show that CH4 gives larger effects for global warming than CO2. Though Japanese coal mines are utilising drained CH4 and the parentage is quite high, the mines which have advantages for the utilisation are closing down. Hence, Japan is facing difficult stage to reduce the amount of CH4 emission. International co-operation to utilise low level CH4 and to increase CH4 drainage percentage is important and urgent to prevent the global warming.


Selected Publication
1) Emissions of global warming substances from coal mines in Japan-A study on the life cycle assessment of coal (1st Report)-. J. MMIJ. 111(14):975-981.1995
2) Mining condition and the emissions of GHG from coal mines in Japan-A study on the life cycle assessment of coal (2nd Report)-. Printing

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