Brochure

Table 1 and Table 2 use the probabilities
of the dierent wind speeds to produce
a weighted mean gure, which reects
the average fuel and NOx rates over a
one year period.
From Table 2 the mean fuel saving
by using “Energy Ecient mode -
xed heading” is estimated as 11%
of total, while in “Energy Ecient
mode - optimum heading” the saving
is estimated at 12%. This equates to
either 2664 kg or 2880 kg of fuel per
day. The estimated annualised fuel
saving equates to around $ 0.8 million
a year based on a bunker price of
$ 0.8/kg.
From Table 2 the NOx emissions are
estimated as being reduced by about
5 kg/hr which equates to between
21% and 23%.
Simulated drillship example of fuel usage
and NOx emissions
Wind speed (m/s)
NOx in “Normal DP”
(kg/hr)
NOx in Energy Ecient
mode - xed head (kg/hr)
NOx in Energy Ecient mode
- optimum head” (kg/hr)
5 24.5 18.8 18.7
10 24.8 19.5 19.3
15 27.3 22.2 21.2
20 32.9 29.4 26.3
Weighted mean 25.4 20.0 19.6
Table 2: Simulated NOx emissions at different wind speed. 3600kW non DP load included
Wind speed (m/s)
Fuel used in
“Normal DP” (kg/hr)
Fuel used in Energy Ecient
mode - xed heading (kg/hr)
Fuel used in Energy Ecient
mode - optimum head” (kg/hr)
5 947 835 834
10 966 852 848
15 1011 905 887
20 1115 1017 970
Weighted mean 971 860 854
Table 1: Simulated fuel usage at different wind speeds. 3600kW non DP load included
7
GE I A new direction for DP