Emission source

Scope of Emission

Uncertainties

Petrol for vehicles

Scope 1

It is assumed that records supplied by contracted fuel supplier are correct, and that quantities of fuel purchased by other means are not material.

Diesel for vehicles

Scope 1

It is assumed that records supplied by contracted fuel supplier are correct, and that quantities of fuel purchased by other means are not material.

All purchased electricity in owned buildings and leased buildings where the agency is the sole tenant

Scope 2

It is assumed that records provided by suppliers and collating agency are correct. Where data gaps exist, electricity consumption has been calculated by multiplying the average consumption per person by the known average number of staff on the site, over the period of occupancy.

Purchased electricity for lighting and utility/appliance power in leased space where the agency is not the sole tenant

Scope 2

It is assumed that records provided by suppliers and collating agency are correct. Where data gaps exist, electricity consumption has been calculated by multiplying the average consumption per person by the known average number of staff on the site, over the period of occupancy.

Transmission and distribution line losses for all purchased electricity

Scope 3

It is assumed that records provided by suppliers and collating agency are correct. Where data gaps exist, electricity consumption has been calculated by multiplying the average consumption per person by the known average number of staff on the site, over the period of occupancy.

Domestic air travel

Scope 3

It is assumed that records provided by contracted suppliers are correct, and that any incompleteness is not material.

International air travel

Scope 3

It is assumed that records provided by contracted suppliers are correct, and that any incompleteness is not material.

Business travel in rental cars

Scope 3

It is assumed that records provided by contracted suppliers are correct, and that any incompleteness is not material.

Business travel in employee owned cars

Scope 3

Ministry of Education has two separate processes for reclaimed mileage for business travel in employee owned cars. Special Education field staff claim through their local office, and these claims are held at local level. Most of this data was not available for this year's report. However, with approximately 900 field staff, the emissions figure is likely to be material, so has been estimated from the small amount of data available. Other staff claim through the payroll process, so more complete data was available for this portion of the reclaimed mileage. It is assumed to be complete and accurate.

Waste to landfill

Scope 3

Only one waste audit has been carried out, for the largest of the ministry's sites. The resulting weight of waste to landfill per FTE per annum has been used to calculate waste to landfill for all other sites. Potentially, this may overstate the total waste to landfill figure.

Purchased electricity for base building power in leased buildings where the agency is not the sole tenant

Scope 3

This figure has been extrapolated from the data available for the largest of the ministry's sites. Information on base building power is not readily available from building owners and could not be obtained within the time frame available for the 2006/07 inventory. Significant work with landlords will be required to obtain it in for future reporting. The calculation methodology is likely to have overstated the total base building power figure.