National Grid: Calculating our greenhouse gas emissions baseline

The following table is our best endeavour to set a robust baseline for the Company and our UK and US operations. We have only used data from years where it has been both published and verified, either in a National Grid or predecessor company's Annual Report and Accounts, coporate responsibility / environmental reports, or as part of regulatory reporting.

Data is shown as either Scope 1 or Scope 2 in line with the World Resources Institute Greenhouse Gas Protocol Initiative.

Approximately 95% of our baseline emissions for 2008/09 are based on data traceable back to1990/01.

Restating our baseline

Where our business changes, such as the sale of National Grid Wireless and Advantica in 2007 or the acquisition of KeySpan the same year, we adjust the baseline accordingly to ensure a fair comparison with our current emissions can be made.

Baseline update: 2008/09 and 2007/08

Country	Operations	gas	Source	Baseline year	Verification source	Scope 1 Baseline (tonnes CO₂ e)	Scope 2 Baseline (tonnes CO₂ e
UK	Gas transmission	CO₂	Gas-powered compressors	1990/01	Lattice environmental report 2001	304,546
UK	Gas transmission	CO₂e	Electric-powered compressors	2003/04	National Grid Transco annual report and accounts 2003/04		1115¹
UK	Gas transmission	Natural gas	Venting and other losses	2000/01	Lattice environmental report 2000	204,981
UK	Gas transmission	CO₂e	Electricity use at NTS sites	2000/01	Lattice environmental report 2000		11,132
UK	Electricity transmission	SF₆	Losses from switchgear, etc.	2000/01	National Grid environmental report 2000/01	432,542
UK	Gas distribution	Natural gas	Leakage and venting	1990/01	Lattice environmental report 2000	3,970,182
UK	National Grid offices	CO₂e	Electricity used	1997/98	National Grid environmental report 97/98		71,264
UK	Lattice offices	CO₂e	Electricity use	2000/01	Lattice environmental report 2000		47,316²
UK	Lattice offices	CO₂e	Gas use	2000/01	Lattice environmental report 2000	19,502²
UK	LNG storage	CO₂e	Venting and other losses	2001/02	Lattice environmental report 2001	51,660
UK	LNG storage	CO₂e	Energy used	2001/02	Lattice environmental report 2001	14,230	55,718
UK	National Grid operational sites	CO₂e	Gas and oil used	2001/02	National Grid environmental report 2000/01	1,014
UK	Lattice	CO₂e	Fleet and company vehicles	2000/02	Lattice environmental report 2000	39,437²
UK	National Grid	CO₂e	Fleet and company vehicles	1995/96	National Grid environmental report 2000/01	6,344
US	Generation	CO₂e	Emissions from generating facilities	1990/01	Regulatory reporting	11,413,896
US	Gas distribution	Natural gas	Mains leakage and venting	1990/01	Regulatory reporting	2,025,743
US	Gas distribution	Natural gas	Other leakage and venting	2007/08	Regulatory reporting	321,698
US	Electricity transmission and distribution	SF₆	Losses from switchgear, etc.	2000/01	Regulatory reporting	213,191
US	All operations	CO₂e	Energy used	2008/09	2008/09 Inventory	242,400	66,340
US	All operations	CO₂e	Transport	2001/02	2008/09 Inventory	109,024
US	All operations	CO₂e	Diesel / heavy fuel oil	2001/02	National Grid annual report and accounts 2001/02	3,189

Total						19,373,579	252,885

Grand total							19,626,464

^1.The Annual report and accounts sets out Company greenhouse gas emissions for the relevant year but does not include a breakdown by business or emission source. In these cases, the baseline is derived from the detailed data collection and consolidation used to calculate the Company emissions.

^2.The baseline figure is 62% of the data reported, reflecting the sale in 2005 of four of the eight gas distribution networks represented by the original data.

Calculating our greenhouse gas emissions baseline

2008/09 baseline