Fuel and emission model for large vessels

This package allows for estimating fuel consumption (taking into account ocean currents, waves and wind) for vessels. It also allows to derive estimates of CO_2 emissions.

Model parameters

In the model the convension of SI units for all parameters is implemented. Input parameters for the model are described in the table below.

Parameter	Description , Units
Vessel design speed	maxium speed vessel reach at calm conditions [m/s]
Specific fuel consumption (SFOC)	specific fuel consumption, [kg/Wh]
Number of operational engines	Vessel number of operational engines
Load per active engine	the torque output of an engine
Maximum continuous rating (MCR)	maximum power output of engine
Conversion factor of fuel to CO_2	conversion factor from fuel to CO_2 mass [kg of fuel / kg CO_2]

Emission model description

For a single operational engine and auxiliary engine power, the total fuel consumption is estimated according to (see [1]):

$Fuel_Consumption = (CRScor \cdot MCR \cdot Engine_Power \cdot Load_Factor + FCaux) \cdot SFOC / 3600$

where $CRScor$ is a correction reduced speed factor evaluated as given:

$CRScor = ((V_{actual}/V_{design}) ^ 3 + 0.2) / 1.2,$

$V_{actual}$ and $V_{design}$ are vessel speeds operational and design.

The term $FCaux$ is an auxiliary engine power estimated according to relationship:

$FCaux = Auxiliary_Engine_Power \cdot Load_Factor$,

for simplicity in the model $FCaux = 0.63 \cdot Engine_Power$

For a case when a number of operational engines of vessel > 1 the formula for a fuel consumption recasts to [1]:

$Fuel_Consumption = (CRScor \cdot Number_Active_Engines \cdot fMCR \cdot Engine_Power \cdot Load_Factor + FCaux) \cdot SFOC / 3600$

where $fMCR$ is a fraction of maximum continuous rating which is equal to:

$fMCR = Number_Operational_Engines / Number_Active_Engines \cdot CRScor \cdot MCR$

To estimate the number of active engines, the following relationship is used:

$Number_Active_Engines = {\rm min}(Engines_Operational, {\rm ceil}(CRScor \cdot Engines_Operational \cdot MCR))$

As for total fuel-based CO_2 emission per a single voyage the formula is used:

$Emission = Conversion_Factor_Fuel_toCO2 \cdot Fuel_Consumption \cdot Sailing_Time,$

where $Sailing_Time$ is a single voyage time.

Literature

[1] D.R. Schouten, T.W.F. Hasselaar Ship emision model validation with noon reports, 2018 Marin Report No. 30799-1-TM (v3)

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License

MIT License, see LICENSE file.