TABLE OF CONTENTS The UK's electricity supply system works in much the same way as the supply of any other commodity. Electricity is 'manufactured' at power stations, and bulk supplies are transported across the high-voltage transmission network. Retailers ('suppliers') buy the bulk power and sell it on to domestic and commercial customers, to whom it is supplied via a low-voltage local network operated by a distribution network operator (DNO).
The generators, high-voltage network operator (National Grid), DNOs and retailers are very different companies.
The generators and retailers operate in a competitive market, making contracts directly with one another to buy and sell power. The amount of electricity that is required can vary markedly. Generally the highest demand is in the winter, when people tend to be inside and it is dark for longer, so they are using more appliances. Although there are heavy industries that require large amounts of power continuously, it is usually domestic use that governs the peak load. So the highest peak is on winter evenings between 6 p.m. and 9 p.m., when most people are arriving home, making dinner and using domestic appliances, and there is a smaller peak in the early morning.
The overall load in summer is lower than in winter but the increase in hot summers and the growing use of air conditioning have meant that the summer peak is increasing. This has important implications for the way the UK electricity system is managed. In...
