25
January 2008 - International sea transport
from Danish ports contributes significantly
to air pollution with CO2, NOx and SO2.
Concerning CO2, emissions amount to 2.6
million ton adding an extra five per cent
to the Danish CO2 emissions. For NOx and
SO2 respectively the percentages are 34
and 167. None of these emissions are included
in the Danish national inventories reported
to the relevant UN bodies. This is shown
in a new NERI-report. The report also documents
a new and more accurate method to calculate
emissions from sea transport.
This report documents
the updated 11000-2005 fuel consumption
and emission inventory for navigation in
Denmark , following the UNFCCC (United Nations
Framework Convention of Climate Changes),
and the UNECE CLRTAP (United Nations Economic
Commission for Europe Convention of Long
Range Transboundary Air Pollutants) convention
rules.
The Danish inventory
covers national sea transport, fisheries
and international sea transport. For national
sea transport, the new inventory distinguishes
between regional ferries, local ferries
(small ferries) and other national sea transport,
and the fuel consumption is estimated on
the basis of fleet activity data and ferry-specific
technical information. For fisheries and
international sea transport, the new inventory
is fuel based.
This project uses new
information of the development of NOX emissions
from ship engines, starting with production
year 1949, and proceeding until the engines
of today (2005). The emission data have
been provided by the ship engine manufacturer
MAN DIESEL, which have a 75% world market
share of the ship engines produced. Emission
data from this source ensures a fine representation
of the emission factors used, and the inventory
introduction of emission factors per engine
production year is necessary for the more
accurate assessments of the emission trends.
For national sea transport
in Denmark , the fuel consumption estimates
obtained with the new model are regarded
as much more accurate as the DEA fuel sales
data used in the previous model version.
The large fluctuations in reported fuel
sales cannot be explained by the actual
development in the traffic between different
national ports. The fuel discrepancies between
estimated and reported sales are most likely
explained by inaccurate costumer specifications
made by the oil suppliers.
Concerning SO2, emissions
from all other mobile sources have been
mitigated so effectively that sea transportation
now stands out as the single significant
Danish mobile source to SO2 pollution, mostly
due to the high sulphur content in the heavy
fuel oil used in both domestic and international
sea transportation.
Concerning NOx, emissions
from the national sea transportation are
foreseen to level with emissions from road
transportation in 2020.
Recommendations
If pollution from both domestic and international
sea transportation is to follow the downward
trend from all other means of transportation,
it will be necessary to tighten regulations
for emissions from ships. The International
Maritime Organization (IMO), a UN agency,
is preparing a mandatory set of regulations
that in a two step approach aims to reduce
emissions of SO2 and NOx in 2010 and 2015
respectively.
Otherwise the report
recommends replacing the current time series
of fuel sales for national sea transport
by the new bottom-up fuel consumption estimates
calculated in this project. Such an updated
time series for fuel consumption for national
sea transport will introduce changes to
the energy statistics for fisheries and
industry, since the revealed differences
between the sales figures and bottom-up
estimates for national sea transport are
balanced out by adjusting the sales figures
for fisheries (for gas oil) and industry
(heavy fuel oil).
Moreover, it would be
very useful to implement a new project in
which the fuel consumption and emissions
for international sea transport in Denmark
are calculated based on actual vessel movements,
as has already been carried out for domestic
ferries. Such project results would strongly
support the work made by Danish policymakers
dealing with the issue of bunker emissions
allocation.
Senior advisor Morten Winther
