has seen a number of proposals in the form of incentivizing shipping companies to
reduce carbon through operational changes or adoption of more carbon-efficient
vessels, the introduction of a carbon tax on shipping, or emission trading
mechanisms.
In the short term, CO 2 intensity of shipping can be reduced by a number of
measures like changes to speed, ship size and utilization, retrofit technologies, and
other efficiency measures. Slow steaming, a practice of deliberately lowering the
speed of a ship to reduce fuel costs, is one suggested response to the sulfur cap. It
proved very effective when the shipping industry was hit hard by the oil rally of
2002–2008. Slow steaming even in a lower oil-price environment can help mop up
excess capacity when the shipping markets are oversupplied. In addition to saving
energy, it has been argued that shipping carbon emissions are also reduced and
marine transport reliability is improved by reductions in bottlenecks in terminals
(Halff et al. 2019). See also Maloni et al. (2013) for a cost-benefit analysis of slow
steaming.
Energy efficiency is also an important means of reducing air pollution. One study
that considered 22 potential ship efficiency measures found that a reduction of 33%
of CO 2 emissions could be achieved by 2020 (ICCT 2011). Another study found that
energy-saving could reduce CO 2 emissions by 50% by 2030 (Alvik et al. 2010).
Energy efficiency has been promoted in the maritime transport sector through
regulatory measures in force since 2013: IMO’s Energy Efficiency Design Index
(EEDI), Energy Efficiency Operational Indicator (EEOI), and Ship Energy Efficiency Management Plan (SEEMP) (IMO 2017).
Virtually full decarbonization will be needed in the longer term that will mean
fleet-wide deployment of near-zero carbon ships. This is a great challenge given the
very short time frame (Traut et al. 2018). Bouman et al. (2017) review around
150 studies to provide a comprehensive overview of CO 2 emissions reduction
potentials and measures published in the literature and find that emissions can be
reduced by more than 75% based on current technologies (and through a combination of the proposed measures) by 2050. See Fig. 10.3 as a snapshot of CO 2
emissions reduction measures and their potential impact. Also, for a marginal
abatement cost (MAC) curve that presents the average marginal cost associated
with alternative individual measures in CO 2 emissions reduction, see Fig. 10.4.
Psaraftis and Zachariadis (2019) highlight some issue in the discussion about the
use of alternative fuels for marine use for GHG reductions. Many of what are called
“clean burning” fuels may be correctly labeled as such when focusing on SOx, NOx,
and particulate matter but not when the GHG footprint is considered. When considering the life cycle GHG footprint of nearly all proposed alternative fuels, they are
worse than conventional liquid fuels (marine gas oil (MGO), marine diesel oil
(MDO), or desulfurizer fuel oil). For instance, when taking into account its life
cycle, methane slip LNG’s global warming effect is much worse than conventional
liquid fuels and possibly even worse than coal. See Psaraftis and Zachariadis (2019)
for a discussion of the alternative fuels: natural gas (NG), liquified natural gas
10 Sustainable Shipping: Levers of Change
161
reduce carbon through operational changes or adoption of more carbon-efficient
vessels, the introduction of a carbon tax on shipping, or emission trading
mechanisms.
In the short term, CO 2 intensity of shipping can be reduced by a number of
measures like changes to speed, ship size and utilization, retrofit technologies, and
other efficiency measures. Slow steaming, a practice of deliberately lowering the
speed of a ship to reduce fuel costs, is one suggested response to the sulfur cap. It
proved very effective when the shipping industry was hit hard by the oil rally of
2002–2008. Slow steaming even in a lower oil-price environment can help mop up
excess capacity when the shipping markets are oversupplied. In addition to saving
energy, it has been argued that shipping carbon emissions are also reduced and
marine transport reliability is improved by reductions in bottlenecks in terminals
(Halff et al. 2019). See also Maloni et al. (2013) for a cost-benefit analysis of slow
steaming.
Energy efficiency is also an important means of reducing air pollution. One study
that considered 22 potential ship efficiency measures found that a reduction of 33%
of CO 2 emissions could be achieved by 2020 (ICCT 2011). Another study found that
energy-saving could reduce CO 2 emissions by 50% by 2030 (Alvik et al. 2010).
Energy efficiency has been promoted in the maritime transport sector through
regulatory measures in force since 2013: IMO’s Energy Efficiency Design Index
(EEDI), Energy Efficiency Operational Indicator (EEOI), and Ship Energy Efficiency Management Plan (SEEMP) (IMO 2017).
Virtually full decarbonization will be needed in the longer term that will mean
fleet-wide deployment of near-zero carbon ships. This is a great challenge given the
very short time frame (Traut et al. 2018). Bouman et al. (2017) review around
150 studies to provide a comprehensive overview of CO 2 emissions reduction
potentials and measures published in the literature and find that emissions can be
reduced by more than 75% based on current technologies (and through a combination of the proposed measures) by 2050. See Fig. 10.3 as a snapshot of CO 2
emissions reduction measures and their potential impact. Also, for a marginal
abatement cost (MAC) curve that presents the average marginal cost associated
with alternative individual measures in CO 2 emissions reduction, see Fig. 10.4.
Psaraftis and Zachariadis (2019) highlight some issue in the discussion about the
use of alternative fuels for marine use for GHG reductions. Many of what are called
“clean burning” fuels may be correctly labeled as such when focusing on SOx, NOx,
and particulate matter but not when the GHG footprint is considered. When considering the life cycle GHG footprint of nearly all proposed alternative fuels, they are
worse than conventional liquid fuels (marine gas oil (MGO), marine diesel oil
(MDO), or desulfurizer fuel oil). For instance, when taking into account its life
cycle, methane slip LNG’s global warming effect is much worse than conventional
liquid fuels and possibly even worse than coal. See Psaraftis and Zachariadis (2019)
for a discussion of the alternative fuels: natural gas (NG), liquified natural gas
10 Sustainable Shipping: Levers of Change
161