Greenhouse Gas Emissions

Coursework – Morpeth Northern Bypass

This coursework aimed at estimating the greenhouse gas emissions and the Net Present Value associated with it by using WebTAG. The appraisal has been done to compare 2 options. Option 1 maintaining the current existing roads A and B without building a bypass. And option 2 where a new bypass (road C) has been planned to be constructed and roads A and B still operate. For each of the two options, three years were analysed: the opening year 2014, 2029 and the end of appraisal period sixty years ahead which corresponds to the year 2073. In total, six scenarios were analysed, each one broken down to analyse two or three roads as shown in table 1.

Table 1. Six scenarios resulting from analysing two options for 3 different years.

Part a)

The total vehicle km travelled was calculated divided into the three vehicle classes: petrol, diesel and electric. In order to do this, for each scenario analysed, the AADT was multiplied by 365 days, then multiplied by the percentages of each vehicle class, number of vehicles and length in km. The percentage of vehicle class can be obtained from Table A.1.3.9. from WebTAG. This table does not extend up to the appraisal period so the values for the year 2073 have been chosen the same as the last year available which is 2035.

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Table 2. Example of results, total vehicles km travelled broken down by vehicle class and type.

Part b)

The fuel consumption per km for each vehicle category was calculated for each scenario. For this, the data of the speed of each road and the parameters (a, b, c and d) each vehicle type was needed and the equation given in the Table A.1.3.11. from WebTAG was used. The formula is as follows:

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Figure 1. Fuel consumption in l/km.

Then, these values were multiplied by the total vehicle km travelled calculated in part a), to obtain the results for total fuel consumption in litres.

Part c)

The total annual CO2 equivalent emissions in tons for each scenario was calculated, broken down into vehicle type and class: petrol, diesel and electric. For this, Table A.3.3. from WebTAG was used, which are the values of CO2 equivalent per litre of fuel burnt or kWh used. These values were multiplied by the total fuel consumption per vehicle class and type calculated from part b). The total emissions in CO2 equivalent for each scenario were then summed petrol and diesel on the one hand to get the value for non-traded and electric on the other hand for the traded. These results per scenario are shown in table 2.

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