1. Electricity is generated at power stations around the country. These power stations use a variety of fuels - principally coal, gas, oil, nuclear and wind - to generate electricity, and the stations are generally sited to be close to fuel and cooling water rather than to be near centres of demand. Electricity is then transmitted from the power stations through a national network of electricity lines which operate at high voltage. National Grid owns the electricity transmission network in England and Wales and operates the electricity transmission system throughout Great Britain. Local distribution companies then supply electricity at progressively lower voltages to homes and businesses.
2. This transmission system which operates at 400,000 and 275,000 volts (400kV and 275kV) is known as the “national grid” and covers some 4,500 route miles of overhead line, 420 route miles of underground cable and more than 335 substations. The system, which connects the electricity generators’ power stations with the networks of the local distribution companies, also connects with some large industrial customers who, by reason of their size and technical characteristics or location, are directly connected to the transmission system.
3. Under the Electricity Act 1989 National Grid is the holder of a transmission licence. It is required in this capacity to develop and maintain an efficient, coordinated and economical system of electricity transmission and to facilitate competition in the supply and generation of electricity.
4. Unlike virtually all other commodities, electricity cannot be stored in bulk until it is needed; it has to be generated in the right quantities, at the time it is needed. The vast majority of generating capacity in England and Wales is connected by National Grid’s transmission system. This enables the operation of power stations to be coordinated, offering potential benefits of reducing the amount of spare generating capacity and generating reserve needed, and the ability to select power generation to supply the needs of the moment.
The energy industry is currently going through a period of significant change resulting in a multi-billion pound investment programme. This will encompass small and largescale electricity generation and substantial investment in energy networks to replace and upgrade ageing assets, construct new infrastructure to connect and efficiently deliver new energy sources, as well as maintaining the levels of safety and reliability to which everyone has become accustomed.