Accounting for well-to- wake carbon dioxide equivalent emissions in maritime transportation climate policies

This briefing paper outlines a methodology for calculating well-to-wake CO2-equivalent emissions from four fossil marine fuels: heavy fuel oil, very low sulfur fuel oil, marine gas oil, and liquefied natural gas. Well-to-wake emissions, or life-cycle emissions, are the sum of upstream (well-to-tank) and downstream (tank-to-wake) emissions. In addition to CO2, carbon dioxide equivalents include greenhouse gases such as methane and nitrous oxide, as well as particles like black carbon. While the EU Emissions Trading Scheme presents the most immediate opportunity to apply this methodology, it can also be applied to policies being developed at the International Maritime Organization and in other regions and countries that aim to reduce shipping’s climate impacts.