Third IMO Greenhouse Gas Study 2014

128 Third IMO GHG Study 2014
Business as usual and policy scenarios
The Second IMO GHG Study 2009 presented a multitude of scenarios but did not consider any of them to be
BAU. All scenarios presented in this study are combinations of trade scenarios, ship efficiency scenarios and
emissions scenarios. The trade scenarios are based on combinations of RCPs and SSPs and, as discussed in
detail in Section 3.2.2, all four are equally likely to occur. Their differences reflect either inherent uncertainties
about the future (e.g. economic development, demographics and technological development), or uncertainties
related to policy choices outside the remit of IMO (e.g. climate, energy efficiency or trade policies). In many
cases, these uncertainties are interrelated and cannot be disentangled.
The ship efficiency and emissions scenarios can be classified in two groups. Each of the scenarios has an
option in which no policies are assumed beyond the policies that are currently in place, and one in which
IMO continues to adopt policies to address air emissions or the energy efficiency of ships. The first type is
labelled BAU, as it does not require policy interventions. In this way, each of the four trade scenarios has
one BAU variant and three policy intervention variants. As both policy interventions result in lower GHG
emissions, all policy intervention scenarios have emissions below the BAU scenario. These lower emission
scenarios require additional policies beyond those that are currently adopted.
Marginal abatement cost curves
This study employs MACCs containing 22 measures in 15 groups (measures within the same group are
mutually exclusive), taking into account the fact that measures may be applicable to certain ship types only.
The benefit of using MACCs over holistic efficiency improvement assumptions is that they allow for feedback
between fuel prices and improvements in efficiency.
MARPOL Annex VI revisions (EEDI, SEEMP)
After the publication of the Second IMO GHG Study 2009, State Parties adopted a new chapter for MARPOL
Annex VI on energy efficiency for ships, mandating EEDI for new ships and SEEMP for all ships. The impact of
these regulations on the energy efficiency of ships is analysed and included in the model.
Ship types
Since the Second IMO GHG Study 2009, there has been a remarkable increase in ship size, especially for
container ships. The earlier study assumes that all container ships over 8,000 TEU would have an average
size of 100,000 dwt, but in 2011 the size of the average new-build ship had increased to 125,000 dwt, while
ships of 165,000 dwt have entered the fleet and larger ones are being studied. Larger ships are more efficient,
i.e. they require less energy to move an amount of cargo over an amount of distance. In response, this study
analyses the development of ship types in the last year and includes new categories for the largest ships.
3.1.2 Outline
The remainder of this chapter is organized as follows. Section 3.2 provides a brief description of the methods
and data used to project emissions. It begins by presenting the emissions model, the factors taken into account
in our projections and the long-term scenarios used as a basis for our projections. All the relevant factors of the
projections are then discussed individually, showing which assumptions are made in each case and the basis
on which they are made. Section 3.3 presents the projections of international maritime transport demand and
associated emissions of CO 2 and of other relevant substances up to 2050.
3.2 Methods and data
3.2.1 The emissions projection model
The model used to project emissions starts with a projection of transport demand, building on long-term
socioeconomic scenarios developed for IPCC (see Section 3.2.2). Taking into account developments in fleet
productivity (see Section 3.2.4) and ship size (see Section 3.2.5), it projects the fleet composition in each year.
Subsequently, it projects energy demand, taking into account regulatory and autonomous improvements in
efficiency (see Section 3.2.6). Fuel consumption is calculated together with the fuel mix (see Section 3.2.7);