22 October 2009 - In
2020, shipping in Danish waters is expected
to have reduced its emission of SO2 by 91
% in relation to 2007. The reduction is
a result of the
requirements adopted in the international
shipping organisation, IMO. On the other
hand, the emission of NOx is expected to
rise by 2 %, because the IMO requirements
in this area are more than outweighed by
the expected growth in shipping traffic.
These figures come from a new report that
the National Environmental Research Institute
(NERI), Aarhus University has prepared for
the Ministry of the Environment.
The project is based
on new and more precise information on shipping
traffic in Danish waters, the routes sailed
by individual ships, engine load and emissions,
combined with advanced air pollution dispersion
models.
Assumptions for scenarios
The main assumptions underlying the scenario
calculations are as follows:
The IMO regulations for sulphur and NOX
are implemented as planned. In particular,
it is assumed that the marine waters around
Denmark will be designated a NOX Emission
Control Area (NECA) as defined by IMO. The
countries around the Baltic Sea are preparing
an application with this purpose. The status
as NECA implies additional NOX emission
restrictions for new ships from 2016.
Concerning the amount
of ship traffic, an annual increase of 3.5
percent has been assumed for transport of
goods from 2011 and onwards, while passenger
traffic is assumed unchanged.
Concerning land-based emissions, a specific
set of assumptions have been used.
Main conclusions concerning emissions
One of the main results of the project is
that a new, improved emission inventory
for national and international ship emissions
in Danish marine waters has been established.
The inventory has a spatial resolution of
1 x 1 km.
Between 2007 and 2020
an emission reduction as large as 91% is
envisaged in the marine waters around Denmark,
in respect to sulphur dioxide from ship
traffic - despite an increase of traffic.
This is due to the IMO regulations.
Within the same period a marginal increase
is expected in total emissions of nitrogen
oxides (NOX) from ship traffic, namely by
2 % from 2007 to 2020. Without stricter
emission standards the increase would have
corresponded to the increase in fuel consumption,
i.e. 15 %. The IMO requirements imply large
NOX reductions for new ships from 2016.
As a consequence, the ship fleet will gradually
experience a reduction in its average NOX
emission factor from 2016 onwards; this
development will continue after 2020.
Main conclusions concerning
concentrations
Since 11000, SO2 emissions from land-based
sources have been substantially reduced,
and in the years to come a continued large
reduction from ship traffic is expected,
along with an expected reduction for land-based
sources. Based on scenario calculations
the SO2 concentration level as an average
for Denmark will decrease considerably in
the period up to 2020, so in 2020 it will
reach a level of 0.3 µg/m3, which
is only 6 % of what it was in 11000, and
corresponds to 1.5 % of the EU limit values.
In 2007 around 33 % of the SO2 concentration
level in Denmark was due to ship emissions,
this number will be reduced to about 11
% in 2020.
The concentration of
nitrogen dioxide (NO2) in urban background
air in Copenhagen is expected to be reduced
from 16 to 9 µg/m3 in the period up
to 2020. The reduction is due to expected
reductions in NOX emissions from land-based
sources. For ship traffic, however, the
contribution is essentially unchanged, because
increase in ship traffic and stricter emission
requirements balance each other. For Denmark
as a whole the NO2 concentration level is
considerably lower than in Copenhagen, and
it will decrease from 5.5 to around 3.5
µg/m3 from 2007 up to 2020. Presently,
as an average for Denmark, 21 % of NO2 can
be attributed to ship traffic, but the relative
share from ships will increase in the years
up to 2020 due to reductions for the land-based
sources.
Calculations point to
a slight decrease by approximately 0.2 µg/m3
during the period to 2020. Compared to total
PM2.5, the contribution in urban background
air in Copenhagen will be on the order of
7 %.
A comparison between
concentration results based on the previous
(EMEP) and the new (NERI) inventories show
that the new inventory results in concentrations
that are lower by, respectively, 46 % for
SO2, 14 % for NO2 and 10 % for mPM2.5 (average
concentrations over Denmark).
According to the new
inventory the amount of ship traffic through
the Øresund is larger than according
to the previous (EMEP). As a consequence,
emissions in the Øresund are larger
than previously assessed. On the other hand,
in the Storebælt and Kattegat ship
emissions are substantially smaller than
previously estimated. In the case of sulphur
dioxide, the emission in Storebælt
was previously assessed to be 11 times larger
than that of Øresund; now, the emission
in Storebælt is assessed to be only
2.3 times larger. Altogether, the emissions
around Zealand are smaller than previously
assessed, and the resulting level of sulphur
dioxide in ambient air is smaller than previously
assessed. For the Copenhagen region the
average SO2 concentration is estimated at
1 µg/m3, to be contrasted with the
previous estimate of 1.6 µg/m3.Conclusions
concerning ships at port
In the port of Copenhagen cruise ships are
responsible for 55 % of the total NOX emission
from ships at port. Anyhow, this does not
lead to problems related to NO2 limit values
around the docks, and neither does it create
problems with respect to limit values for
PM2.5 and SO2.
When considering conditions at high rise
buildings close to berths with very heavy
ship traffic, there may potentially be problems
with NO2 exceedances very close to the berth
(within the nearest hundred or few hundred
meters). In such cases it can be wise to
conduct detailed studies.
The report’s chapter on ships in ports indicates
some further conclusions.
