We are currently living in what future historians will almost certainly call the 'coal age'. Coal first gained economic significance when supplies of wood became scarce in the fifteenth century and continued to grow in importance up to the 1950's. Coal has always been the single most important commodity carried by the railways, many of the early lines were built specifically to carry coal and the Midland Railway was built by a consortium of coal mine owners. The curious British system of using privately owned coal and coke wagons added much to the colour and character of the railway scene up to the 1950's.
The contribution of coal to the evolution of western civilisation from the seventeenth century up to the present day is hard to overstate. Coal fires heated homes, coal fuelled the steam railway engines and coal fired boilers supplied the steam for industry. Up to the early 1990's coal was used to generate over seventy percent of Britain's electricity, although this figure has fallen since the government eased restrictions on the use of North Sea Gas in power stations.
Coal consists of carbon mixed with a range of impurities, different seams of coal produce different mixtures and these all have specialised uses. For example power stations would prefer coal which leaves as little ash as possible as they have to pay to have the ash taken away (ash is made up of rock and other materials which do not burn).
If coal is heated in a sealed chamber interesting things begin to happen. Above about three hundred and fifty degrees Celsius the impurities are driven off as thick oily smoke, keep heating to above five hundred and fifty degrees Celsius and the carbon residue turns to solid coke but this coke is still rather soft and is only used as a fuel. As the impurities have been removed coke burns without producing smoke and Britain, with its abundant coal reserves and a densely crowded population, has done more work than anyone on making smokeless fuels (for details see Lineside Industries - Gas Works, Coking and Smokeless Fuel Plants).
If you keep on heating the oven the coke begins to change, once you reach nine hundred degrees there is no more gas given off and the coke that comes out of the oven is strong and hard. This hard coke is the kind used by iron and steel works (for details see Lineside Industries - Iron and Steel).
The gases driven off consist mainly of hydrogen which was piped to homes and factories as 'town gas' (discussed as a fuel below). Also driven off from the coal are a range of oily liquids, these were condensed as 'coal tar'. Coal tar proved crucial to the development of the worlds chemical industries, only with the advent of large oil refineries in the 1950's and 60's did the importance of coal tar diminish. For further details on modelling associated industrial plant see Lineside Industries - Tar Distillers and Gas Works. The coke made from coal was crucial to industry for a wide range of purposes. As a fuel it was burned in place of coal and being 'smokeless' could be used where the impurities in the coal would cause problems (such as in sintering metal ores ready for loading into blast furnaces). Up to the 1940's a lot of coke was also used to make 'producer gas' and 'water gas' for use in factories (see below).
Coke for fuel was readily available from the local town gas works and most was sold for hauling away by road with little shipped by rail. Coke for iron and steel works was prepared at specialist plants and was regularly hauled by rail however, fleets of coke wagons were built for the job.
From the eighteenth century up to the mid 1980s the coal mining industry was one of the largest in the country employing many thousands of men and women and supporting a wide range of other industries supplying tools, equipment and other services to the mines. The larger mines were nationalised and operated by the National Coal Board after 1947, although small mines continued to operate in the private sector, notably in Wales and the Forest of Dean. During the 1970s, following the 'oil crisis' (discussed below), there were many strikes as the increased cost of fuels caused disruptions. The coal mines, being a single organisation in which the personnel were represented mainly by a single large union, wielded considerable power and caused the government a great deal of trouble. In the early 1980s more trouble loomed and the government decided that the coal miners unions should not be allowed to cause such problems, given that coal could be imported at lower cost than home production the decision was made to effectively wind the industry up. The first stage was privatisation, to break the industry up, then they offered north sea gas at knock down prices so the power stations would switch from coal. By the end of the century there were only a few hundred people working in all types of mining and quarrying in Britain and the government had demonstrated it was in power (although what it was in power over was by this time no longer a major industrial power).
Gas from coal comes in various forms, most common before the 1970's was plain coal gas or 'town gas'. Coal had been heated to produce gas since the seventeenth century but a prolific Scottish inventor called William Murdock improved the process and used it to light his cottage and office in Cornwall in 1792. Murdock was the local agent for Boulton & Watt steam engines and when he moved the firm's head office in Birmingham in 1802 he was allowed to install lighting throughout the Soho works. Over the following decade Boulton & Watt, as well as supplying the steam engines for which they were famous, installed a number of gas lighting systems in mills and factories. Murdock is one of the unsung heroes of his age, he built a working model of a steam road carriage which inspired Trevithick to build his full size machines and he also solved the problem of getting the dead yeast out of beer by using dried fish skins (the same basic process used today for fining 'real ales').
Some early gas works selling gas to the public supplied the gas in containers delivered by horse and cart but in 1812 the Gas Light and Coke Company was formed in London, supplying customers with gas through buried pipes from a central gas works. This pioneering enterprise was a great success and by the 1840's many towns had their own local gas works.
Early public and industrial gas works were generally small affairs, supplying only enough gas for street and domestic lights or for lighting workshops. The first gas works to be operated by a town corporation was opened in Manchester in 1817. This was paid for from the 'rates' and this lead to considerable debate regarding profits made from selling the gas. In the mid nineteenth century local town corporations began buying up private gas works, usually as part of the general 'town improvement' schemes pressed for by the new 'health boards'.
The Manchester Police Commissioners bought the town's private gas works (built in 1817) in the 1830's. Note that the Police Commissioners in the 1830's were something very new and not at all the same thing as the modern police force. The change to being a municipal undertaking made public finance available and there was a shift towards larger works to take advantage of the economies of scale.
Gas was used almost exclusively for lighting, both domestic and public (i.e. street lights), until the 1880's. The gas was burnt in simple jets at first, giving a similar light to a candle but cheaper if rather more smelly. In the early 1830's a fan-tail burner was developed which gave more light and in the 1840's air was admitted to the gas stream at the burner to give a brighter flame (the same principle as the Bunsen burner used by chemists).
Gas lighting might not have survived competition from the electric light which arrived in the 1880's had it not been for the incandescent 'gas mantle' invented by an Austrian by the name of Welsbach in 1885.
By this time the gas works were already looking for alternative markets, gas water heaters (usually called geysers) were introduced in 1865, gas cooking rings appeared in 1867 and gas fires with radiant ceramic elements were on sale by 1880. Gas cooking caught on in the 1870's but it was a few years before gas heating became popular, mainly after the production process improved and more of the smelly impurities were removed.
After processing and cleaning coal gas consisted of about 50% hydrogen, 30% methane, 10% carbon monoxide (poisonous), 5% ethylene and other volatiles (which gave colour to the flame) and traces of air. For further details on gas works buildings and associated plant see under Gas Works.
Coke from the coal fired town gas works was in turn used to make 'producer gas', 'water gas' and 'carburrated water gas' for burning in various processes. Producer gas is made by passing air over hot coke, the gas that comes off contains carbon monoxide, which is flammable, and carbon dioxide which is not. Producer gas is therefore not a very good fuel, but it is cheap and easy to make with no complicated by-products to deal with. Water gas is made by blowing superheated steam through a bed of red hot coke, the gas produced is composed of roughly equal parts carbon monoxide and hydrogen but retains a measure of carbon dioxide. Although water gas gives a lot more heat than producer gas this is still only about half that of coal gas, it was used by industry as it is was cheaper than buying gas from the gas works. When the steam is blowing over the coke it cools the coke so every few minutes the steam is turned off and air is blown through to get the coke hot again. This of course generates 'producer gas' but as water gas is a better fuel this is often allowed to escape. Water gas has been used in making hydrogen and synthetic fuels as well as being a general purpose industrial fuel. Most water gas plants also produced carburrated water gas, this has oil sprayed into the hot gas flow, which breaks the oil down and adds calorific value to the gas.
Fig ___ Producer gas plant
Liquid Petroleum Gas (LPG - Butane and Propane)
Liquid Petroleum Gas (LPG) was produced in Britain by the Riverside Oil Co around the turn of the century although there was little interest in it at the time. In America however things moved rather more quickly and by the time of the First World War the Americans were using butane for domestic heating and cooking. The idea was taken up by the French and in about 1935 the Modern Gas and Equipment Company was set up in Britain to sell imported French 'Calor Gas'. Customs officers felt that butane was a rather dangerous material to be shipped across the channel so supplies were purchased from Shell Mex and BP (both of whom viewed it as a waste product at the time). As no British firm had ever made gas cylinders the Home Office and ICI (who were making petrol from coal at Billingham with butane as a by-product) devised a British specification. In 1936 dealerships were established to sell cylinders of calor gas, each dealer was given an eight horsepower Fordson van, and supplies were delivered in cylinders by rail. LPG is not piped into homes or industries it is shipped in pressurised containers, some is used by industry and quite a lot is used for domestic heating systems (mainly in the form of small cylinders which are paced in a free-standing heater). In outlying areas and isolated farms and the like a larger tank for LPG can be set up outside the building to supply gas for heating (and very occasionally for lighting).
North Sea Gas and LNG
Natural gas had been in use in America for many years before the British changed over to using supplies from the North Sea oil fields in the 1970's. Natural gas is usually stored refrigerated to minus 160 degrees Celsius or pressurised to its liquid form and is usually called LNG, short for Liquefied Natural Gas. From the 1960's to the 1980's coal was used to generate synthetic natural gas (SNG), for further information and a description of the plant see under Lineside Industries - Gas Works.
After the Second World War the gas supply industry was nationalised and a co-ordinating Gas Council was set up. Natural gas is usually found in oil wells, it is mainly methane with a little hydrogen, large quantities were found in the oil wells of the North Sea. In 1966 the Gas Council decided the country should switch from coal gas to natural gas and a complete new pipeline system was laid across the country to build a gas-grid similar in principal to the national electricity grid (discussed below). The pipelines were buried and they were marked with six foot tall posts topped with an orange 'Frisbee'. The change over took until 1977 to complete as every single gas appliance had to be modified to take the new gas. This change saw the end of the last of the old gas street lights as it was not worth while to convert these to natural gas.
In the 1980s there was a government sponsored shift to using North Sea supplies of natural gas as widely as possible (mainly it would seem to reduce the countries dependence on coal and thereby reduce the power of the coal miners unions), unfortunately no real though was given to the longer term and when the gas began to run out in the early 21st century the only option was to use gas imported from Russia (with a smaller quantity imported by ship from further afield). In the interim the old gas works had all been pulled down and the land sold off, and the British coal mining industry had been wound down, so the government found themselves with no viable alternatives open to them.
One odd point that came up when talking with a banker was that current banking practice will only tolerate a lag of three years before gaining a return on their investment. The early gas industry, competing with existing systems and requiring investment by consumers, seldom saw a return in less than five years (the first customer was often the local corporation street lighting and the gas was often supplied at cost as the advertising value and development of the mains supply was worth having). Hence, if the gas supply were being proposed today it would not receive the required funding and we would have to do without it, continue to candles for lighting and there would be no Bunsen burners for chemists. This three years limit has undoubtedly impacted British industry, whilst German and French engineering firms are booming supplying high tech equipment to the world British manufacturing is still contracting at a steady three percent per year (and the bankers seem to think this is a 'Good Thing'). Perhaps more importantly it begs the question what options today, perhaps relating to matters such as clean drinking water, are not being pursued because of this arbitrary limitation.
There are three types of oil; vegetable, animal and mineral. Vegetable oils are mainly recovered by crushing seeds (see Lineside Industries - Industries associated with docks and harbours - Seed Crushing) and are not generally used as a fuel (rape seed oil was used in oil lamps in the eighteenth and nineteenth centuries).
Oils recovered from animals fall into two main groups, tallow and whale oil. There are other animal oils, for example lanolin is recovered from wool, but these are not used as fuels. Tallow is a white nearly tasteless fatty solid produced by melting down the fat of cattle and sheep. Tallow was used to make candles and as a lubricant (it was also used to make soap, see (see Lineside Industries - Industries associated with docks and harbours - Soap & Margarine). Tallow is still used today. The word grease originally meant animal fat or tallow but it is now used as a general term for any paste-like carbon based (organic) lubricant and is usually associated with those produced from petroleum oils.
Whale oil is often called train oil but there is no connection with the railways. Whale oil is actually made from the thick layer of fat under the skin called `blubber', it was used as a lubricant and for making candles (later soap and later still margarine) and was also used as a liquid fuel in lanterns. Sperm oil is taken from the head of the sperm whale, it is not actually an oil as such but a wax like substance which was widely used in the leather industry and as a lubricant. In 1980 a synthetic substitute based on tallow and coconut oil was developed. Ambergris is a waxy substance from the intestines of the sperm whale which was mainly used in making perfumes. Whaling had been in progress for many hundred of years before the coming of the railways. Demand was considerable and whaling ships began operating in the Pacific in 1789. In the Atlantic the Greenland Bowhead whales had been hunted to extinction by the nineteenth century. In the mid nineteenth century Arctic bowhead whales were discovered and quickly exploited. They had been virtually wiped out by 1914, mainly due to the deployment of the harpoon gun, invented by a Norwegian called Foyn in 1870. In 1890 the Californian grey whale was believed to be extinct after forty years of hunting, however some survived and they are now protected. Early in the twentieth century the whaling ships moved into the waters around Antarctica and in 1925 the first factory ships were deployed. These ships served as bases for the whale hunters and processed the whales at sea, this meant the hunters did not have to return to their island whaling stations and this accelerated the rate of kill. By 1946 it was realised that the whales were being killed far too fast and the International Whaling Commission (IWC) was established. This organisation had little effect and the all-time high was reached in the early 1960's when over sixty four thousand whales were killed in a single twelve month period. In the mid 1980's the IWC introduced a ban on whaling but this was not total and the stocks of whales in the oceans continued to fall. By the end of the 1980s nearly all of the blue, fin, humpback, and sperm whales had been wiped out. Their low reproduction rates mean that populations are slow to recover and some may become extinct. The IWC's decision May 1994 to create a vast Southern Ocean whale sanctuary was supported by 23 member states; Japan voted against it, and Norway abstained.
Mineral oils are recovered from coal and petroleum, both provide a complex mixture of chemicals, mainly composed of various combinations of hydrogen and carbon (the so called hydrocarbons). The oily products from coal processing are discussed in detail under Gas Works and Coking Plants. Petroleum has been known and used for centuries, it is sometimes called 'rock oil' to distinguish it from other mineral oils, indeed the word petroleum is derived from the Latin 'Petros' (rock) and 'Oleum' (oil). Because of the way the various constituents are separated at the oil refinery they are usually called 'fractions'. The mix is different in different parts of the world, the American oils tend to be heavy and thick whilst those in the Middle East and the North Sea are light and runny. Generally speaking the lighter oils are of more interest for use as fuels, the heavier oils make better lubricants.
Oil seeping to the surface had been used in various countries, mainly as a medicine or liniment. The problem with this method of collection is that the lighter fractions of the oil tend to evaporate, leaving only the thick pitch. The Sumerians used naturally seeping oil in 3800 BC. and the first recorded oil well was dug in southern Iran about 500 BC. Oil wells were dug in Burma in the 13th century AD to provide oil to burn in lamps.
The modern (petroleum) oil industry really began with the discovery of oil in western Ontario in 1857. In 1859 a chap called Edwin Drake used a steam driven pile driver to punch a well down about seventy feet in Pennsylvania and struck oil. The value of the oil was already known, supplies of tallow and whale oil simply could not meet the existing demand for lubricants and fuels and more wells were soon operating in America, Canada and Mexico. The first oil pipe line was built (again in Pennsylvania) in 1865, although six miles long it was only a couple of inches in diameter. Commercial oil production began in Romania in 1860 and in Venezuela in 1878. Oil was found in Iran in 1908, Iraq in 1923, Bahrain in 1932, and Saudi Arabia and Kuwait in 1938. Each oil field produced different types of oil, each suited to a particular application, in the early years little was done to refine the oils produced.
In 1888 the American company Standard Oil established a British subsidiary called the Anglo American Oil Company known these days as Esso (Eastern Section Standard Oil). British companies were soon set up and by 1914 there were a number of large companies trading in Britain including Shell, Russian Petroleum, Burmah, Anglo Mexican, British Petroleum and Anglo Persian Oil Co.
After the 1890's there was a growing interest in oil fuelled engines and many thousand were built. Most were small engines for powering light industrial machines and agricultural equipment. Coal was plentiful and cheap, many firms had their old steam engines already and these were long-lived beasts but oil fueled internal combustion engines were better suited to powering road vehicles. The world's navies switched to oil firing for their war ships in the period before the First World War, at the time up to half the crew of a war ship were 'stokers' employed in shoveling coal into the boilers, oil reduced the crew size, allowing the same issue of food and water to last a lot longer and hence enabling longer patrols. The first deployment of British troops in the First World War was to Basra in modern day Iraq to secure the area from German interests. It was the 1920's before oil began to challenge coal as the prime industrial fuel, mainly because the growth of the motor vehicle produced a demand for the lighter fractions and oil companies began selling the heavier fuel oils at cut prices for use in the furnaces of steam power plants already in place. Interest in the industrial use of fuel oils developed in the 1930's. After the second world war refineries were built in Britain so that the cheap crude oil could be bought and the expensive products produced domestically.
Up to the 1960's the Americans produced most of the world's oil but as the oil fields of the Middle East developed the Arab nations became the worlds largest suppliers. In 1961 the Organisation of the Petroleum Exporting Countries (OPEC) was established to avoid exploitation of member countries (America was not a member but most countries in the Middle East and South America joined up). This organisation began pushing up the price of oil, which prompted the development of hitherto untapped areas such as the North Sea. By the 1970s the two main areas of production were the Middle East and South America (mainly Venezuela).
OPEC raised the oil price dramatically in 1973 and precipitated a world-wide 'energy crisis' although this only really affected the industrialised countries where much of the economy relied on cheap oil fuels. The International Energy Agency (IEA) was established 1974 to protect the interests of oil-consuming countries. In 1983 the North Sea replaced the Middle East as the worlds largest exporting area for oil.
The British government had reacted to the crisis in the 1970's by offering incentives for industry to switch from oil to coal as a fuel for its heating boilers and other uses. This policy was abandoned in the mid 1980's and instead the price of 'North Sea Gas', which had been maintained artificially high, was allowed to fall, As a result both industry and the power generators switched to gas as a fuel. In the early 21st century the north sea oil and gas reserves began to run out and Britain again became a net importer of both fuels. Sadly the government appeared to have squandered those revenues it had secured (it is generally felt the oil and gas were sold off to the oil companies much too cheaply) and the country was left with little to show for the bounty, other than having no domestic coal industry and being dependent on Russian gas.
For power station modelling details see Lineside Industries - Electricity Generating Stations.
Electricity is not a fuel, it is produced either from a chemical reaction or by mechanical means using magnets. Once created the electricity is difficult to store, Alessandro Volta (1745-1827) invented the basic battery in 1799 but this was a use-once throw-away design (called a 'primary cell'). In 1802 an Englishman called William Cruickshank developed the first battery that could be produced commercially and in 1839 John Daniell (1790-1845) devised the first really reliable primary cell in 1836. In 1866 the French engineer Leclanche (1839-1882) invented the zinc-carbon primary cell, technically called a Leclanche cell. This cell was adopted by the Belgian telegraph system and soon became the standard cell for hand held equipment such as electric torches. It was the most common type of battery in use right up to the 1990s.
The lead-acid re-chargeable electric storage battery (called a 'secondary cell') was invented in 1859 by a French physicist called Gaston Plante (1834-1889). Although heavy and full of corrosive liquid it remains one of the most practical portable storage system for electricity. For use in aircraft (which have a tendency to turn upside down) a variant was developed that uses a 'gell' in place of the liquid, these lead acid gell cells have since found employment on various portable devices (notably high power industrial torches).
Smaller scale applications such as portable radios have, since the mid 1980s, made increasing use of rechargable batteries with a solid or gell electrolyte. These have been developed into a number of different technologies with mercury based cells largely replacing the zinc-carbon types and rechargable batteries of increasing efficiency developed (not least for use in portable computers).
Electricity produced from chemical reactions is comparatively expensive and for domestic and industrial use electricity is produced in large power stations which use coal or other fuels to generate steam which drives mechanical generators. Electricity was first generated using mechanical means in 1832 by a chap called Hippolyte Pixil, also in 1832 Michael Faraday (1791-1867) produced a crude but workable dynamo and a year later he developed the idea of the transformer which could alter the voltage of alternating current electricity supplies. An improved armature was developed in 1856 by Werner Von Siemens (1816-1892) and the 'ring armature' invented by Zenobe Gramme (1826-1901) produced the first practical dynamo in 1870.
Early power stations used steam reciprocating engines to drive the generators, the development of Parsons steam turbine in the 1880's allowed much higher rotational speeds for the generating plant and greater efficiency.
The first railway station with electric lighting was Glasgow in 1878 and a year or two later the first hotel electric lighting was installed in the same city. The first mine to be equipped with electric lights was at Hamilton in Scotland where the lights were installed in 1881.
The first public electricity supply in the UK was for lighting in Godalming in 1881, however the cables (actually two D shaped copper rods mounted on insulators and housed in an iron pipe which was then filled with bitumen) had to be laid in the gutters of the road as no one had powers to grant licences for these to be run underground. The Electric Lighting Act of 1882 was intended to lay down the ground rules for public electricity supplies but as provision was only made for short term licences there was little incentive for private companies or local authorities to invest in large installations.
The first publicly owned electricity generating station, from which people could purchase electricity, was built by the City of Worcester in 1883 at a place called Powick close by the river Teme. Private firms set up in most towns over the following couple of decades, most being fairly small establishments and in most cases the power produced was Direct Current (DC) following the American model of Thomas Edison. The result was a proliferation of small establishments, reaching a total of some 482, each supplying only a limited area and with no real standardisation on the nature of power supplied. Rodney Street (the Liverpool equivalent of Harley Street) had DC supplies on one side of the road and AC on the other and some power stations supplied both types of power to consumers. Voltages and the frequency of AC supplies varied from station to station, anything from one hundred to two hundred and fifty volts and from twenty five to one hundred cycles per second. In Manchester the electricity supply was DC and the distribution system used five wires, power being tapped from these at four different voltages of 100, 200, 300 and 400 volts as required.
Edison believed there should be small local stations supplying a small area however a British electrical engineer called Dr. Sebastian Zani de Ferranti challenged this 'neighbourhood station' approach. He believed that the energy efficiency of larger power stations would be a telling advantage. The power supplied by electricity is a function of both the voltage and current but the losses in transmission are almost entirely related to the current. Hence high voltage and low current supplies are preferable for transmission, but at the consumer lower voltages, and a higher current, are what is required. Ferranti believed that Alternating Current (AC) supplies, capable of being transformed to very high voltages for passing through transmission lines and then dropped down in 'sub stations' to more useable voltages for the end user, were the best option. It was Ferranti's approach that won the day and laid the foundations for the modern National Grid system.
Ferranti made and sold his first alternator in 1881 and went into partnership with the Irish physicist William Thompson (Lord Kelvin) in 1882. As Chief Engineer of the London Electric Supply Company from 1887-1892 he built the first really big generating station at Deptford in 1890. To carry the high tension (high voltage) supply at 10,000 volts Ferranti developed an improved form of cable for use underground, with an inner conductor of copper tube (about an inch across) wrapped in brown paper soaked in ozokerite (a mineral wax) inside an outer copper tube (also wrapped in impregnated paper) all enclosed in an iron tube. This could only be made in 20 foot lengths (giving over 300 joints per mile) but when the last of it was removed in 1931 it was still functioning perfectly. Paper wrapped cables were still used into the 1940s although they were by then wrapped in lead to provide the watertight covering.
As voltages were increased to maximise the benifits of the stepped down supply method problems appeared with the cables, at voltages above 33,000 volts a single cable with three cores (for the three phase supplies) proved very troublesome. Adding more insulation did not help and the problem was traced to a number of causes, including tiny breakdowns in the isulation that allowed a small current to pass, heating and destroying the insulation and small 'voids' in the insulation that allows a breakdown to occur. Adding paper coated with metal as a 'screen' helped and oil-filled cable was adopted with reservoirs at intervals to maintain the oil level in the cable. Some cables use nitrogen gas under pressure in place of the oil. By the 1930s they were able to make a single three core cable to carry the 132,000 volt national grid supplies and single core cables were made to carry up to 250,000 volts.
For runs of any length it is perferable to suspend the cables from tall pylons but these high tension cables are used to cross rivers (where overhead cables would not be practical) and in places where the very high voltages must be run underground. The length of the cable produced in limited only by the maximum size of the rum on to which it can be rolled. In the 1930s this type of cable was laid up from cores of multi-strand wire wrapped in impregnated paper and a metalised paper 'screen' along with any additional cables (telephone lines for the engineers are sometimes included), there are also additional materials added to fill in the spaces between the cores and other cables. Ths lot is rolled onto a drum and put into a big tank where it is heated under vacuum to drive off any moisture, the tank is then filled with impregnating liquid under pressure. The coated cable is then fed into a machine where molten lead is applied under pressure to form an outer waterproof wrapper and the whole is then wrapped in jute. Where the cable must be armoured or where it is to be pressurised with nitrogen, additional wrappings of steel tape or wire are added, with a final out coating of jute. Since the Second World War new materials (notaboy PVC) and technologies for adding metal tubing to the cable have been developed and the outer wrapper of the cable is these days usually some form of plastic.
Originally the supply was a three-phase 220v system, with 110v between phases tapped off for domestic supplies to houses and the full 220v supplied to industry. Fairly soon it was realised that more power was required by industrial machines and things began to change to a 440v three phase supply with 220v tapped off for domestic customers.
As with the gas works the licensing arrangements for the electricity generators included a provision for them to be bought-out by the local corporation but this option was not as widely applied as with the gas works. In my local town the Altrincham Electricity Supply Ltd generating station opened in 1894 and by the following year several electric street lights were in use. Located on a plot of land between the Bridgwater Canal and the LNWR line to Warrington this firm soon laid cables for a distance of some 42 miles. Although the possibility of a corporation purchase was discussed many times this had not happened by the time the National Grid made it redundant in the late 1930's. The National Grid and the Super Grid are discussed below.
Domestic use of electricity was initially only for lighting, an electric water heater had been exhibited by a man called Fox at the 1851 Great Exhibition but he had to admit that it was unlikely to be of much use until houses were connected to the electricity supply. Practical use of electricity in homes and offices probably dates from the electric fan invented by S. S. Wheeler in 1882, this was followed by the electric iron in 1882, the electric stove in 1896, the Singer sewing machine in 1889 and the washing machine in 1907. The manual Bissell carpet sweeper of 1876 and the horse-drawn vacuum cleaning machines built by Hubert Booth in 1901 were soon challenged by the electric vacuum cleaner, the first practical version of which appeared in 1905. An American inventor in search of finance demonstrated a vacuum cleaner to a Mr. William Hoover, a maker of leather equipment for horse drawn vehicles. Mr. Hoover pinched the idea and founded one of the modern industrial giants. Perhaps the most significant development of all for the domestic application of electricity was the separate attachable plug and socket invented by H. Hubbell in 1904.
The buried cables used for electricity supplies took time to develop and it was the early twentieth century before the technology was properly mastered. Prior to this time most services used conduits under the pavements containing solid copper conductors of anything up to four square inches (26 square cm) in cross section. These were coated in vulcanised India rubber and then wrapped in cloth impregnated with bitumen. When the rubber perished the electricity began to leak to earth, generating a lot of heat in the process. This 'cooked' the bitumen, releasing explosive gasses which built up inside the conduit forming a highly dangerous gas-air mixture. When something finally ignited the gas (for example when the leak to earth burned itself out) several yards of pavement were liable to explode with the force of a land mine. Quite a few people were killed and injured by these explosions and in Manchester the Electricity Board conducted some expensive research to solve the problem. They developed a new asphalt coating for the cables which offered better insulation and did not release nearly as much gas when a fault developed. Finding the faults in a buried cable is no easy task, it was the 1930s before equipment was developed which could reliably locate such a fault. In the early part of this century the Manchester police were instructed to look for dry patches on pavements after rain and were advised that horses might be skittish or that children might experience 'tingling sensations' in their feet near a faulty line.
By the time of the First World War Britain was lagging behind most other industrial countries in its use of electricity, mainly as a result of the proliferation of supply standards. In 1919 the government set up an Electricity Commission to look at the problem. By this time there were over five hundred companies selling electricity of which about four hundred owned power generating stations but there was no standardisation of supplies. In the industrial North West forty two companies had agreed to standardise on a 220v AC service so that power could be exchanged as required and this had proved a success. The commission decided that there should be a national system with all stations connected to it such that if one were to fail the others could maintain supplies. This was part of a Defence Plan, for it was pointed out that a single bomb from a single Zeppelin could destroy the power station supplying Woolwich Arsenal and it would take three years to build a replacement plant. The plan was to concentrate electricity supply in over a hundred of the larger, more efficient, power stations and close the smaller ones down.
In 1926 the Electricity (Supply) Act laid the foundations for the a national system, in 1927 the Government appointed a Board of eight business men (the Central Electricity Board). They were charged with organising and implementing a national scheme co-ordinating the electricity supply and arranging for its interconnection in what has become known as the National Grid. By this time there were about 400 power stations, many of them small, there were 43 different voltages on offer and 642 separate suppliers of which 282 supplied AC only, 77 supplied DC only and 283 supplied both AC and DC. About 23% of homes and factories were supplied with electricity as against 88% with gas. In London there were seven different railways and tramways all producing electricity but all to incompatible standards and on the domestic and industrial supplies there were twenty four different voltages, most were alternating current by this time but these were produced with ten different frequencies. In Altrincham, my local town, there was a rather odd system which featured highly dangerous unprotected step-down transformers for local distribution. These were mounted in manholes and the engineer had to reach underneath the thing to make connections, surprisingly they were finally replaced wholesale only in the 1950s.
In 1926 the Central Electricity Board (later renamed the Central Electricity Authority, that may have been on nationalisation) was established to buy all the power supplied (it did not own any generating stations and only supplied power to larger installations and (more commonly) to third party distributors. The interconnection into a national system (the National Grid) with a transmission line voltage of 132kV (132 thousand volts, dropped to 66,000 volts for underground cables in cities) was started in 1928 and virtually completed by 1933. In 1949 the electricity generating stations were nationalised, and in 1956 the CEA was split into the Central Electricity Generating Board, dealing with power stations, the National Grid arranging the country wide distribution of power and the Electricity Council, dealing with local distribution via the local Electricity Boards.
After much heated debate it had finally been agreed that the main lines of the grid were to be carried aloft on pylons. People objected to the pylons but to bury the cables would have required massive amounts of insulation which at the time was liable to fail so the maintenance cost would have been prohibitive. This period saw extensive cable running to outlying districts, farms were singled out and offered a free connection however far they were from the nearest sub-station. Hence one load into a country yard might be open wagons carrying the wooden poles (twelve to twenty feet in length and typically eight inches in diameter). The poles were a dark grey/brown colour but the lower ten foot or so was painted with heavy black pitch. The insulators were supplied in light wooden boxes, packed in straw and shipped in sheeted open wagons or vans. Farms were supplied with three phase electricity requiring lines consisting of 3 wires, typically there would be a single cross bar with an insulator on each side and a third on the top of the pole. Pylons had been used for several of the earlier supplies, the sketches below show the two-masted main pylons sketched from photographs taken before World War One (the size of the insulators suggest these were not carrying very high voltages), the smaller mast in the centre is a single three-phase supply for a farm or small village.
Fig___ Timber pylons (1900-1940s)
In practice although the grid had been built the plan to concentrate power generation in a smaller number of stations had made little progress by the Second World War. This was fortunate as it made the task of the German bombers much more difficult. There was some movement in this direction however, by the later 1930's there were only 122 stations on the grid and as larger stations are much more efficient the cost of electricity was falling. In the later 1930's each unit of electricity, as a national average, required the burning of about one pound (0.5 Kg) of coal as against about four and a half pounds (2 Kg) only twenty years earlier.
The local authorities, in the form of Electricity Boards and the dwindling number of private supply companies, remained largely independent. The A56 close by where I now live was the boundary between two separate boroughs and when electricity replaced gas street lighting in 1926 each borough settled on different designs of street light (Blaizolite and Rodalux), one on each side of the road, this situation remained until 1936 when the road was rewired as a single entity.
By the mid 1950s the average Briton was consuming 37 megawatt hours (MWH) of power a year, as against 62 MWH in the USA and 2.7 MWH in India. At this time it was decided to upgrade the National Grid to carry power at 400kV (four hundred thousand volts). It was not possible to shut down the existing system so a second set of pylons and cables was superimposed on the original. The Supergrid as it was called came into operation in the later 1960's.
British power stations were mainly coal fired (prior to the introduction of nuclear power, discussed below) with a few hydro-electric stations in mountainous areas (mainly in Scotland). During the 1970s there were many strikes in the coal industry and this lead to power cuts. Things changed from the later 1980s when the government decided to sell supplies of North Sea Gas at knock down prices as they felt that the coal miners held too much political power. Many power stations changed from using coal and many new gas-fired stations were built. The coal British industry was effectively wound up and by the turn of the century had effectively ceased to exist. When the north sea gas reserves started to run out in the early 21st century the country was faced with paying for Russian gas to keep the system working. I am told that this was considered a necessary price to pay for establishing that the power ultimately lay with the politicians (although what they then had power over was rather less valuable than it had been).
XXX Privatisation in early 1990's
The first nuclear reaction was engineered by Enrico Fermi at a lab in Chicago in 1942. There is currently no way of extracting power directly from a nuclear reaction but it does generate a lot of heat which can be used to make steam. In 1956 Britain opened the world's first commercial nuclear powered electricity power station at Calder Hall and went on to build several more stations. The driving force behind the nuclear power industry was the need to develop weapons, considerations such as commercial viability and safety were not major concerns. There have been some serious accidents at these stations, including a very serious incident in Scotland that contaminated a large area with highly radio active material, however for 'reasons of national security' the government feels these should not be openly discussed.
Faced with their own failure to prepare for the end of north sea energy supplies, and a pressing need to reduce carbon dioxide emissions, the current plan in Westminster is to build more nuclear stations. I gather these will be simple copies of the existing designs that have 'had problems' in the past and no money is to be spent of developing better systems. I am also told that there is some doubt regarding the figures for nuclear power, although the actual energy generation produces no CO2 the processing of the materials, and indeed building the plant, produces a considerable quantity of the gas (and uses up a lot of the energy produced). Also the long term prospect of safeguarding the waste for a thousand years or so does not (I believe) figure in the calculations.