Methoden voor de berekening van de emissies door mobiele ... - CBS

2.5 Activity data
2.5.1 Actual and NEC emissions
Professional inland shipping
Table 2.1 shows the fuel consumption figures used for the emission calculations.
For the basis data for calculating the emissions of cargo fumes, refer to the protocol on this topic that
was established as part of the EMS Project [ref 99: Bolt, 2003].
Passenger ships and ferries
Because no data about these vessel categories are available after 1995 and no information is
available about trends, it was decided to keep the relevant usage figures constant after 1994. Of
course it is advisable in the short-term to conduct additional research into the actual consumption
beginning in 1995.
Recreational boat traffic
The activity data concerning recreational boat traffic are shown in Table 1 of the fact sheet "Engine
emissions of recreational boat traffic" [ref 108: RWS, Waterdienst, 2005]. The fuel consumption figures
derived from this fact sheet are shown in Table 2.1 of the present report.
2.5.2 IPCC emissions
2.6 Emission factors
2.6.1 Actual and NEC emissions
Professional inland shipping
The methodology for determining the emission factors in professional inland shipping is described in
the EMS protocol for inland shipping. These age-dependent emission factors are based on a TNO
report and are shown in g/kWh. Tables 2.2 through 2.6 show for each year the total derived average
emission factors for professional inland shipping expressed in grams per kg of fuel.
The average emission factor is determined by a distribution of ship engines over the various year of
construction classes to which emission factors have been linked. This distribution is calculated by
means of a Weibull function.
The general formula of the Weibull function is the following:
The values of the Weibull parameters (b and c) have been derived from sample survey by telephone
carried out by TNO among the shipmasters of 146 inland in use vessels. They were asked about the
age of the ship and the age of the ship’s engine. In the calculations the following values have been
used: x = age/10 and x has been varied between 1 en 7. By means of a smallest square estimate the
optimal values for b en c have been determined to be 1.2 and 1. 3.
The median age (the age when 50% has been replaced) can be calculated through the formula:
The result has to be multiplied with 10 as x has been entered as age/10 into the formula. In that case
the median age of the vessels, according to the formula, is 9.6 years. The median age of the engines
in the survey was 9,0 jaar and the average age was 14.9 years.
The distribution of year of construction classes calculated with the weibull function is shown in a graph:
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