Gas Supplies in the UK
The earliest use of gas in daily life was as a light source. It was the British inventor William Murdock who first discovered that if coal was heated, it gave off a gas which could be ignited – and Murdock realised the blue flame could be used for illumination purposes.
The only artificial lighting before that had been oil lamps and candles. Incandescent gas light was far, far superior, and it radically altered people’s lives. The streets became safer, dark evenings could be spent reading and writing – and factories and mills were able to work nightshifts.
Gas – Lighting Up the 19th CenturyFrom early experiments with gas lighting at the beginning of the 19th century, widespread adoption was very rapid. In 1805 King George IV, then Prince of Wales, had gas lighting installed. In 1807 Pall Mall became the first street in the UK to be lit by gas, and within a decade most of the UK’s towns had gas lighting.
By the end of the century, electric street lights were becoming popular; but by that time gas was well established as a form of domestic and industrial energy. Just about every town had its gasworks, many homes in the UK had piped gas supplies for cooking and heating as well as lighting, and British manufacturing was thriving thanks to gas. Gas and electricity have continued to co-exist with a certain amount of rivalry as domestic and industrial fuels, ever since.
What’s in the Pipeline?Prior to 1967, the UK used ‘town gas’ – manufactured in gas plants, usually from coal. Natural gas reserves were discovered in the North Sea in the 1950s. Around that time gas was being overtaken by electricity in popularity, for several reasons. One was that electricity was supplied via the National Grid and could easily be connected to new housing developments; another reason was that a greater range of electrical appliances was available, including new central heating systems such as storage heaters and underfloor heating; and a third was a growing customer perception of electricity as clean, and gas as dirty and smelly.
The gas industry saw that it had to compete. It invested in its supply network; it improved the design and efficiency of gas fires and developed new gas central heating systems; and in 1967 it switched over to North Sea gas, offering a cleaner and more environmentally-friendly fuel.
Natural gas is the cleanest burning of all the main fossil fuels. It is composed chiefly of methane (CH4), which produces only carbon dioxide and water when burnt. Unlike coal gas, it is not in itself poisonous, although incomplete combustion and leaking flues can cause carbon monoxide poisoning. Since natural gas is odourless, a substance called mercaptan is added to give it an unpleasant smell so that leaks can be detected more easily.
Calorific ValueThe amount of heat produced by natural gas depends on its precise composition. Natural gas is not a pure gas; it is a mixture of hydrocarbons, and it may contain a few impurities such as carbon dioxide which is not combustible. Its heating capacity – or Calorific Value (CV) – is therefore not quite constant. However, the customer must be charged in accordance with the amount of heat provided, not simply the quantity of gas. Therefore, the CV must be measured in the pipeline. Chromatographs are used to analyse the composition of the gas. The CV of each different gas is known, because this is invariable; so once the gas has been separated into its constituent hydrocarbons and the proportions ascertained, its overall CV can be calculated.
Bottled GasJust as electric batteries provide an alternative where there is no mains connection, so bottled gas can be used to power appliances where no piped gas supply is available. Bottled gas is compressed and stored in liquid form, and is either butane (usually in a blue gas bottle) or propane (usually in an orange bottle). Of the two, propane is more suitable for outdoor use, such as camping and motorhome applications, during the winter months, as it vaporises at lower temperatures where butane does not. Propane and butane are found in natural gas fields and alongside crude oil in oilfields, and are separated off at the gas processing plant or oil refinery.
Another application of propane is in LPG, or Autogas, used as a vehicle fuel. In the UK, LPG is normally 100% propane but in other countries it is generally a mixture of propane and butane