What methane and nitrous oxide default does the Intergovernmental Panel on Climate Change give for ship fuel, and how much fuel does it say a ship burns a day?

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Accepted Answer

The Intergovernmental Panel on Climate Change (IPCC) 2006 gives one default for ships: 7 kilograms of methane (CH4) and 2 of nitrous oxide (N2O) per terajoule (TJ), for ocean-going ships on heavy fuel oil. It prints none for small craft, but lists the tonnes of fuel burnt a day by ship type. Table 3.5.3, ocean-going ships, in kilograms per TJ: CH4 7 (plus or minus 50 percent), N2O 2 (plus 140 percent, minus 40 percent). The table note says the values were derived for diesel engines using heavy fuel oil. That makes the CH4 range 3.5 to 10.5 and the N2O range 1.2 to 4.8. Carbon dioxide (CO2), in kilograms per TJ: residual fuel oil 77,400, gas or diesel oil 74,100, gasoline 69,300, liquefied petroleum gases 63,100, natural gas 56,100. Tier 1 gives these "on a very general level", with one line, for ocean-going ships. The guide gives no separate default for inland, coastal or small craft. For Tier 2 it says the factors should be country-specific, ideally from in-country testing of fuels and engines. Our reading is that, without such data, a small-vessel owner can only use the ocean-going line and say so; the guide does not endorse that, so state it as an assumption. Table 3.5.5 gives the average shares of fuel burnt by main and auxiliary engines for ships above 500 gross registered tonnage (GRT), as main then auxiliary. Bulk carriers 98 and 2 percent. Combination carriers, container vessels, roll-on roll-off vessels and tankers 99 and 1. Dry cargo vessels 95 and 5. Reefer vessels 97 and 3. Offshore vessels, ferries and passenger vessels, and miscellaneous vessels 98 and 2. All ships 98 and 2. The chapter says water-borne navigation should also account for fuel that may be used in auxiliary engines running refrigeration plants and cargo pumps, and in boilers on board. It adds that many steam tankers burn more fuel a day pumping out cargo in port than steaming at sea. Table 3.5.6 is for when the fleet by tonnage and category is known. It gives an average in tonnes a day and a full-power line as a function of GRT. Examples: inland cargo 21.3 on average, or 9.8197 + 0.00143 x GRT at full power; tugs 14.4, or 5.6511 + 0.01048 x GRT; fishing 5.5, or 1.9387 + 0.00448 x GRT; solid bulk carriers 33.8; container ships 65.9. The source is a 1997 study. Our reading: these figures are for country-level estimates. For a single vessel they can only be a sanity check against the fuel log, never a replacement for bunker delivery notes.

What methane and nitrous oxide default does the Intergovernmental Panel on Climate Change give for ship fuel, and how much fuel does it say a ship burns a day?

The one default for methane and nitrous oxide

What the table does not cover

Main engine and auxiliary engines

Fuel burnt a day, by ship type

1,000 tonnes of heavy fuel oil on an ocean-going ship (example quantity)

What Senseible does here