National Grid 2008 Annual Report Download - page 555

BOWNE INTEGRATED TYPESETTING SYSTEM
CRC: 44463
Name: NATIONAL GRID
Date: 17-JUN-2008 03:10:51.35Operator: BNY99999TPhone: [phone]Site: BOWNE OF NEW YORK
Y59930.SUB, DocName: EX-15.1, Doc: 16, Page: 37
Description: EXHIBIT 15.1
0/11233.00.00.00Y59930BNY
[E/O] EDGAR 2 *Y59930/233/11*
BOWNE INTEGRATED TYPESETTING SYSTEM
CRC: 44463
Name: NATIONAL GRID
Date: 17-JUN-2008 03:10:51.35Operator: BNY99999TPhone: [phone]Site: BOWNE OF NEW YORK
Y59930.SUB, DocName: EX-15.1, Doc: 16, Page: 37 Description: EXHIBIT 15.1
0/11233.00.00.00Y59930BNY
[E/O] EDGAR 2 *Y59930/233/11*
Table of Contents
Annual Report and Accounts 2007/08
45
838 and 26 99.9999% 100% 98.6%
Electricity substations
and gas compressor
stations
UK electrical system
reliability
UK gas system
reliability
US electrical system
availability
About Transmission
Our Transmission business operates in both the UK and the
US. As a consequence of the differences in economic and
regulatory environments, we report the results of
Transmission as two segments: Transmission UK and
Transmission US.
This section should be read in conjunction with the rest of
this Operating and Financial Review, in particular our vision,
strategy and objectives, business drivers and risks and
external and regulatory environments, set out on pages 15 to
19.
Principal operations
Transmission UK
Our transmission operations in the UK encompass both
electricity and gas transmission, comprising the following
principal activities:
Electricity
transmission
owner
We own the electricity transmission system in
England and Wales.
Our electricity assets comprise approximately
7,200 kilometres of overhead line, about 675
kilometres of underground cable and 337
substations at 244 sites.
Gas
transmission
owner
We own the gas national transmission system in
Great Britain. This comprises approximately 7,400
kilometres of high pressure pipe and 26
compressor stations, connecting to 8 distribution
networks and to third party independent systems
for onward transportation of gas to end
consumers.
Electricity
system
o
p
erator
We are the Great Britain System Operator,
responsible for managing the operations of both
the England and Wales transmission system that
we own and also the two high-voltage electricity
transmission networks in Scotland.
Day-to-day operation of the Great Britain electricity
transmission system involves the continuous real-
time matching of demand and generation output,
ensuring the stability and security of the power
system and the maintenance of satisfactory
volta
g
e and fre
q
uenc
y
.
Gas
system
o
p
erator
We operate the gas national transmission system.
Day-to-day operation includes balancing supply
and demand, maintaining satisfactory system
pressures and ensuring gas quality standards are
met.
French
interconnector
We own and operate the UK assets, and a portion
of the subsea cables, that comprise the electricity
interconnector between England and France as
part of a joint arrangement with the French
transmission o
p
erator.
LNG storage
We own and operate four liquefied natural gas
(LNG) storage facilities in Great Britain.