As reported in 2008, we have adopted a long-term target of reducing our Scope 1 and 2 greenhouse gas emissions by 80% against our baseline by 2050 as part of our climate change strategy. We have now set an intermediate objective of a 45% reduction in our emissions by 2020.

This year, we have focused our efforts on educating our employees on the targets and how we aim to achieve them. We have conducted an inventory of our greenhouse gas emissions to ensure that we have up-to-date information on the size of the reductions necessary and the parts of the business where reductions can take place.

We have also established internal working teams tasked with developing opportunities to achieve our 80% target. During 2009/10, we will implement carbon budgets. Each financial year, each line of business in National Grid will be set a maximum level of greenhouse gas emissions which can be emitted. Subsequent years will see a reduction in these budgets that is needed to achieve our 2020 and 2050 targets.

Our greenhouse gas emissions

We report our greenhouse gas emissions in line with our corporate responsibility reporting principles, which includes our interpretation of the World Resources Institute Greenhouse Gas Protocol. The Protocol provides a breakdown of direct emissions (Scope 1), indirect emissions resulting from purchased electricity (Scope 2) and other indirect emissions (Scope 3). We believe our breakdown provides greater transparency and focuses attention on those emissions over which we have the greatest control.

Restatement of 2007/08 Scope 1 and 2 emissions

In 2008/09, we completed a detailed review of our greenhouse gas emission inventory for the year ended 31 March 2008 and included the operations acquired as part of the KeySpan transaction as if we had owned them for the entire year.

On this basis, our total Scope 1 and 2 emissions for 2007/08 would have been approximately 12.1 million tonnes carbon dioxide equivalent compared with the approximate 4.1 million tonnes previously reported for that year.

2008/09 Scope 1 and 2 emissions

Our Scope 1 and 2 emissions for 2008/09 amounted to approximately 11.3 million tonnes carbon dioxide equivalent, an approximate 7% reduction compared with the previous year.

While there have been lower emissions across a number of our operations, the primary reason for the year-on-year change is lower emissions from our generating facilities in the US. Emissions from these depends on, inter alia, the mix of primary fuel used and the running hours of individual units in a given year.

We also measure our carbon intensity. For 2008/09, this was 726 tonnes (carbon dioxide equivalent) per £ million of revenue compared with 982 tonnes in 2007/08 (stated as if KeySpan had been owned for the entire year).

Carbon intensity trend data

Restatement of baseline

When our business changes, such as following the sale of National Grid Wireless or the acquisition of KeySpan in 2007, we adjust our Scope 1 and 2 greenhouse gas emissions reporting baseline accordingly to ensure a fair comparison with our current emissions can be made.

In our Annual Report and Accounts 2008/09, we restated the percentage emission reduction against our baseline for 2007/08 as if we had owned KeySpan for the entire year. This restatement equated to an appoximate 30% reduction against baseline compared with the 38% reported in our Annual Report and Accounts 2007/08, which did not include KeySpan emissions.

Since the completion the 2008/09 Report , we have been able to verify historic data for the ex-KeySpan gas distribution network, taking the baseline for this emission source back to 1990. Approximately 95% of our baseline emissions can now be tracked back to 1990/01.

As a result, the 11.3 million tonnes carbon dioxide equivalent emissions for 2008/09 equate to a 42% reduction against this revised baseline.

The 12.1 million tonnes emissions for 2007/08 equate to a 38% reduction against this revised baseline.

Scope 3 emissions

We report emissions associated with losses on our electricity transmission and distribution networks as Scope 3, reflecting the limited control we have over these emissions (see our corporate responsibility reporting principles for a detailed explanation).

Emissions associated with our electricity transmission and distribution networks in 2008/09 equated to some 5.1 million tonnes carbon dioxide equivalent.

As yet, we do not measure other Scope 3 emissions.

Scope 3 emissions trend data