Green Steaming: A Methodology for Estimating Carbon Emissions Avoided

Commercial shipping cannot readily reduce its dependency on fossil fuels. Ships are large energy consumers and need to carry sufficient fuel for a voyage. The principle of green steaming, when ships travel at slower speeds to arrive just-in-time, is discussed and a methodology developed to estimate the carbon savings resulting if the industry were to adopt this practice. The method is based on public automatic identification system (AIS) data generated by commercial vessels. A speed profile is estimated for each ship, and based on observed anchoring times, potential savings are computed by back propagating the distance a ship could travel at its slowest observed speed. The methodology is demonstrated for the Port of Gothenburg. There is a discussion of how the methodology can estimate carbon emissions avoided by the global shipping industry. Also considered are the actions needed, particularly regarding digital collaboration, to realize the benefits.