Textos de Apoio (pdf)

Bunker price, US$/tonne
380cSt HFO
500
400
300
200
100
2004 2005 2006 2007 2008
Fig. 5: Bunker prices have considerably increased in recent times. The chart shows the average price of 380 cSt heavy fuel oil (HFO)
from various ports around the world from 2004 to 2008. The green bars indicate the mean price for each year.
[08#045]
lower fuel consumption.
However, under the pressure of first costs and
softening bunker prices the strategy was changed and
the selected power/speed combination has, during
the past 15 years or so, been selected to be closer to
the R1 rating (Fig. 4).
Yet, more recently, bunker prices have steadily
climbed, rising by some 85 per cent in the course of
2007 from US$ 270 to US$ 500 per tonne (Fig. 5).
The result is that bunkers are now the dominant part
of ship operating costs.
Such drastic increases in bunker prices give a
strong impetus to reduce fuel costs. They can also
justify additional investment cost such as selecting
an engine with an extra cylinder. The consequent
fuel saving may make for an acceptable payback time
on the additional investment cost. It would justify
any efforts to increase the overall efficiency of the
complete propulsion system.
Further impetus to implementing such changes
in engine selection strategy will come from a future
need to cut CO 2
emissions. If a carbon trading
scheme is imposed on shipping it would give further
economic advantage to reducing fuel consumption
and further help to pay for any necessary extra
investment costs.
In addition it is important to bear in mind that
the fuel savings measures discussed here will also
result in lower NO X
emissions in absolute terms.
Derating engines for greater fuel savings
In the following pages are some case studies for ship
installations for which an engine is selected with an
extra cylinder without increasing the engine’s power.
These cases demonstrate that such engine derating
can be an advantageous solution with remarkable
saving potential. Depending on bunker costs, such a
strategy can have a very attractive pay-back time.
The four case studies are for a Suezmax tanker,
a Capesize bulk carrier, a Panamax container ship
and a Post-Panamax container ship. They include
estimations of the respective pay-back times for the
additional engine costs.
— 3 — © Wärtsilä Corporation, June 2008