The beginning of the 19th century saw rapid advances in electrical science with inventions like the electric motor by Michael Faraday, the invention of the battery by Alessandro Volta and analysis of electrical circuits by Georg Ohm. These inventions marked the beginning of the second industrial revolution and prompted a whole new branch of engineering: electrical engineering. Electricity had quickly become far more than just a curious play thing for quirky scientists; it had become a driving force in the industry as well as everyday life.
The need to transport electricity across the country quickly emerged as electricity established itself as an integral part of everyday life in Britain. During these early days, electricity was largely being generated in direct current (DC), which posed a significant problem to the electrical engineers of the day for several reasons.
Firstly, transporting a high current along power lines incurs high losses. As current and voltage are inversely proportional, one needs to raise the voltage to minimise these losses. Unfortunately, it is very difficult to raise the voltage of a DC current and so transporting it long distances is very inefficient.
Moreover, different electrical loads require different voltages. The voltage required to light a home, for example, is very different to the voltage required to power an industrial motor. As the voltage in DC current is difficult to alter, this meant different generators and different circuits were required for different loads.
The invention of an alternating current (AC) distribution system changed all this and shaped the way the UK electricity industry looks today. The most important invention that came as part of the AC system was the transformer; used to step up (and subsequently step down) voltages for both transmission and to supply different circuits.
Suddenly, electricity could be generated by common plants and transmitted across the country for us by every type of load. The economies of scale and increased transmission efficiencies drove down electricity prices and revolutionized the way power was generated and transmitted across the world. A secondary, but still very important, consequence of allowing multiple interconnected generator plants was the ability to meet variable demand throughout the day. This increase reliability further drove down costs and led us, in part, to where the UK power transmission industry is today.
The current National Grid has its roots as far back as 1925, when the British government appointed industrialist Lord Weird to fix the problem of the country’s fragmented electricity supply. Working alongside Charles Merz, an electrical engineer who had already established an integrated power supply system in the North East, Weir proposed the very first plans for a national grid. The following year, the Central Electricity Board was set up and began to create the UK’s very own AC grid.
By the late 1930s, the grid was operation nationally. It proved its worth during the Second World War as power stations in South Wales were able to meet the demands of central London, which had lost the supply of electricity from power stations in Battersea and Fulham due to the blitz.
Since the second world war, the UK power system has been upgraded several times to its current standard. There are several thousand miles of transmission lines, almost 200 power stations and almost 100,000 pylons across the entire country. Its total capacity is around 80GW, provided by a combination of nuclear, coal, gas and some renewable sources.
The system itself is made up of four main parts. The generators are the power plants that produce electricity from nuclear, coal, gas and renewable sources. They are not owned by the national grid, instead selling the electricity to suppliers across the country.
The suppliers, the second major part, are the middleman between the generators and consumers of electricity. They use the national grid’s transmission network along with their own transmission networks to supply homes and businesses with electricity from the generators.
The national transmission network is owned by the National Grid. It consists of thousands of miles of transmissions lines, thousands of transformers and almost one hundred thousand pylons and transmission towers.
Finally, distributors are responsible for transmitting electricity from the National Grid and into homes and businesses across the country. They do not sell the electricity to consumers, but are responsible for the upkeep of their own distribution networks. These are the smaller electricity masts and pylons, which are made of either wood or steel. Transmission cables are attached with metal power line fittings, like those manufactured by Brooks Forgings. The distributors also maintain smaller transformers to ensure the correct voltage enters the consumer’s properties ready for use in their electrical appliances and machines.