5. Estimation of CO₂ Emission from Ships

　

In order to estimate the CO₂ emission from ships, S&O Committee has performed in 1998 an estimation of total volume of CO₂ emission from ships in Japan and also in all over the world based on their fuel oil consumption.

Table 1 shows the estimated results for the internal navigation vessels based on various statistics of the Ministry of Transport, of the Ministry of International Trade and Industry, and also of the Fisheries Agency of Japan. For example, there are statistics of the fuel oil consumption in the category of cargo, oil or passenger transport, and also of fisheries. For the other categories, there are 712 tug boats, 354,689 fisherboats and about 208,000 pleasure boats, in 1996. The data for the average horsepower of the main engines, average working days in a year and the load factor, and the average specific fuel consumption of the engines in each category have been used for the estimation.

Table 2 shows the estimated results for the international vessels within 200-mile Japanese territory. In 1996, 114,868 vessels have been incoming into harbours in Japan. From the statistics, the rated horsepower of the main engines of the vessels in each category of Gross Tonnage and also the fuel oil consumption was estimated by using the empirical formulas. The load factor was assumed as 0.8, and the average cruising speed was assumed as 10 to 20 knots depending on Gross Tonnage.

Also the fuel oil consumption during the stay at the harbours has been estimated as that the anchoring time is assumed as 12 to 40 hours according to the Gross Tonnage and the load factor and fuel consumption of the auxiliaries is assumed from the data available. The figures in Table 2 are the sum of the values of 200 miles sailing and of anchoring.

The amount of CO₂ emission is calculated from the figures shown in Tables 1 & 2 multiplied by the emission intensity shown in Tables 3 & 4. The calculated values are shown in the last column of Table 1 & 2 for each category of ships, and the total sum of the CO₂ emission from ships within Japan becomes 34,206 x 10³ t in 1996, which is also integrated in Table 5 with other values of pollutants.

　

Table 1. Estimated Fuel Oil Consumption of Internal Navigation Vessels within Japan (1996)

　

Table 2. Estimated Fuel Oil Consumption of International Vessels within 200-mile Japanese Territory Including Stay in Port (1996)

　

Table 3. Emission Intensity for Internal Navigation Vessels

　

Table 4. Emission Intensity for International Vessels within 200-mile Japanese Territory

　

　

　

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