Town Gas on the Canals

Gas is very topical at the moment, with world supply issues increasing the prices we are all having to pay. These problems show how natural gas has become an internationally traded commodity, and how much things have changed since each town had its own local gasworks, making and distributing gas to light and heat homes, as well as powering industry.

Until the late 1960s most of our gas was manufactured by heating bituminous coal in an oxygen-free retort – the coal often being supplied from local collieries. In the absence of a national supply grid for the finished gas, the raw coal was transported to the local gasworks, generally by boat or train, and the gas was then delivered to consumers via a network of iron pipes.

The discovery of natural gas in the North Sea changed all that but, before then, much of the coal was delivered by canal, and narrowboats were used to move many of the by-products created during the gas-manufacturing process. As such, the town gas industry represented one of the last mainstays of commercial canal traffic.

Before we take a look at the canal trade associated with the gas industry, we probably need to examine the history of town gas, more accurately referred to as ‘coal gas’.

History of town gas

If we wind the clocks back to the early 1800s, the main sources of illumination were candles (made from animal fat called ‘tallow’) and oil lamps (powered initially by whale oil and later by kerosene extracted from shale oil). These sources of illumination were both weak and expensive, setting the stage for the development of a better alternative.

In the first decade of the 19th century, several innovators experimented with the creation of gas from wood, coal, peat and biomass. William Murdoch can be singled out as one of the pioneers of gas created from coal distillation, initially using coal gas to light his home in Cornwall and later to illuminate Boulton & Watt’s Soho factory in Birmingham. From these humble beginnings in 1804, the use of manufactured gas spread fast. By 1821 every town of 50,000 or more had its own piped supply, and by 1826 this had spread to every town of 10,000 or more.

At first the gas was piped directly into jets that delivered fan-shaped naked flames. But these provided relatively low levels of illumination for the amount of gas consumed. Increased efficiency was obtained by using the gas to create light indirectly via incandescent mantles for bright white light, or limelight systems which were more controllable and used extensively in theatres. The emergence of gaslight was a key element in the Industrial Revolution as it allowed manufacturing processes to be continued into the hours of darkness.

Initially there was little central control over the expansion of the manufactured gas industry, with each town having its own gasworks and associated pipe network, and being free to set its own prices. While town gas lighting was generally 70% cheaper than its oil predecessor, the hundreds of local gas companies were often accused of profiteering and exploiting their monopolistic positions.

For all its advantages, town gas as a source of light and heat was far from perfect. Firstly, the manufactured gas was poisonous, resulting in many deliberate and accidental deaths. Secondly, while green issues were not very high on the agenda at the time, the production of coal gas and its associated industries were highly polluting, and widespread use had a massively negative impact on the environment in the form of emissions into the atmosphere and toxic residues seeping into the ground.

Coal carrying

The carriage of coal was at the root of most successful canals, initially to power industry and heat homes, and latterly to feed the gas and electricity industries. Wherever possible, towns near rivers or canals had a waterside gas plant, and archive photos often show loaded canal boats waiting to offload their cargoes of coal.

This sight of loaded boats moored next to gasworks was in fact a pragmatic solution to two very real problems. Gas companies liked to hold several weeks’ worth of coal in store as a precautionary measure against supply issues caused by canal closures or industrial action at the collieries. However, this desire to stockpile came with its own problem as large mounds of coal have a tendency to self-combust, particularly when wet. The answer to this was to store the coal in small quantities, or even in underwater bunkers. How better to achieve this for small gasworks than in 20-ton loads in the holds of canal boats, which can be sunk in the event of a fire, thus putting out the blaze and limiting the risk of an inferno spreading?

The industrial Midlands was largely powered by Staffordshire coal measures and the transport distances from colliery to production site were generally short – often less than a day’s journey. However, for communities that were more distant from the nearest coalfield, the waterborne loads could take several days to reach their destination – the carrying trade between the Warwickshire coalfields and London is a good example.

Tar distillers

Unlike natural gas, which is mainly pure methane, the production of coalbased town gas produced numerous – sometimes useful and often toxic – by-products including coke, coal tar and ammonia, each of which found a place as a raw material in other industrial processes. The problem was that most of these commodities emerged locked into a thick black substance known as coal tar, which had to be put through a distillation process to separate them out.

Fractional distillation involved reheating the coal tar and collecting the various elements which were released progressively as the temperature increased and included: tar for use in road construction; benzole used as motor fuel; creosote for wood preservative; phenols to be used in plastics; and cresols for use in disinfectants. Further elements of the gas-making process also delivered sulphur for sulphuric acid, synthetic resins, paints, varnishes, medicinal drugs, saccharin, explosives and ammonia (which was used in fertilisers).

Open gas lights.

A gas mantle light.

To give some scale of this lost tar distilling industry, each of the millions of tons of coal used in gas production created between 10 and 15 gallons of coal tar. When you think of the volumes of coal being used by the town gas industry, that is a lot of coal tar by-product.

The coal tar distillation was a messy business and, while most of the input was processed and converted into other useable materials, there was inevitably some spillage, which resulted in various toxins leeching into the soil. These pollutants are heavier than water and sank deep into the ground, making restoration nearly impossible. To this day many of the tar distillery sites remain heavily contaminated, and the underground pollutants created by the distilling operations continue to seep into the adjacent canal beds. You only have to stand next to the bottom lock of the Crow flight in Oldbury and breathe in to capture that peculiar tang associated with coal tar soap.

This brings us to the movement of the waste by-products created by the gas-making processes. These immense volumes of coal tar contained many valuable commodities but the substance had to be moved to a distillery. To minimise transport, some tar distilleries were located close to the larger gasworks, with the hot coal tar being piped between the two sites. But for the many smaller gasworks, the coal tar was often transported by canal boat to centralised distilleries. Initially this was in barrels loaded into the boat holds but, as the trade grew, specialist tanker narrowboats were constructed with the hot coal tar being piped into waterproof tanks built into the boats and sucked out again at the other end. This tanker approach ensured larger loads were carried but, as the coal tar solidified as it cooled, it was sometimes necessary to reheat it in the hold with steam before it could be pumped out again for processing. The repeated heating and cooling of the tanker boats’ wooden sides played havoc with their structures and often resulted in a condition known as hogging, where the stern sags down over time.

The by-products of the tar distilleries were also heavy and, therefore, well suited to further canal transport to other industries around the country.

Brownhills gasworks from above.

Loading coke at Swan village gasworks.

Nechells tar distillery and gasworks, Birmingham, in 1922.

Nechells tar distillery in 1946.

Thomas Clayton (Oldbury) Ltd

It would be difficult to tell the story of town gas without mentioning Thomas Clayton (Oldbury) Ltd. This business specialised in the transport of waste material from the many gasworks in the Black Country and beyond. The company could trace its roots back to 1842 when William Clayton set up a general canalcarrying business, initially trading from an Aston base. This location was close to several Birmingham gasworks which gave the company a way into the gas trade contracts.

In 1889 most of Claytons’ business merged with Fellows, Morton & Co, creating the now-famous Fellows, Morton & Clayton fleet, a transaction which included its Saltley wharf but not the 30 specialist tanker boats serving the gas industry. The coal tar business was hived off and relocated to Oldbury at the foot of Oldbury Locks on the Titford Branch of the BCN, next to what became the main Midland Tar Distillers Ltd site. Business prospered as the production of town gas grew, and the fleet expanded to about 80 boats in the 1920s carrying coal tar, gas water and creosote.

Claytons’ boats at Oldbury.

Online Transport Archive

In 1951, when the gas traffic was at its peak, Claytons of Oldbury was carrying 150,000 tons of tar and tarrelated products each year for Midland Tar Distillers, which had itself become the region’s market leader following a number of acquisitions and mergers. As a result, Claytons’ beautifully maintained boats could often be seen heading out in all directions each morning to any of the 150 local coalgas plants and then returning loaded to Oldbury in the afternoons.

Decline

The end, when it came, was abrupt to say the least. The 1950s saw the nation’s coal extraction peak at just over 200m tons per year, and coal-based town gas production reached an all-time high of 2.4m therms. This tailed off in the mid1960s as it was temporarily replaced by oil-derived town gas, which was itself displaced by natural gas piped from the North Sea from 1968.

As a child I lived near Bacton in north Norfolk, one of the main receiving stations for the first North Sea Gas. These days natural gas is all moved via a national network of pipelines, and you can often see the marker poles on either side of the canals indicating the presence of highpressure pipes. But, back in the 1960s, the first gas ashore was transported in a cooled and liquified state, which is 600 times denser than gas. Initially this movement was by lorry to the local rail heads and then on to the local networks, and later via a rapidly expanding National Grid.

Natural gas was a better option in almost every way as it was innately cleaner, contained a higher calorific value when consumed and proved safer, as it produced fewer toxic fumes when burned. The convenience and abundant supply fuelled the massive expansion of gas-fired central heating and gas-powered electricity generation, replacing inefficient coal-fed open hearths, driving another nail in the canal-transported coal trade’s coffin.

It was during this period in the late 1960s that demand for coal to feed local gasworks came to an end and the nation’s fuel of choice switched to its natural alternative, with every local coal-gas site being decommissioned. This resulted in many redundant canalside sites which were often heavily polluted and unsuitable for alternative uses, without significant remediation. It also saw the end of many of the iconic gas storage tanks, often referred to as gasometers, which were huge cylindrical structures that dominated most urban skylines. With little need to store gas in tanks, the few gasometers that have survived are mostly used to regulate gas pressure levels.

Conclusion

For a century, town gas (or coal gas) and its associated industries was central to the prosperity of our nation and then, almost at the flick of a switch, it was gone. This industry represented one of the last big cargoes for the canal-carrying trade. For more background on the Thomas Clayton story see NB Spring 2006 and NB Winter 2019.

Umea entering the MTD canal arm at Four Ashes in 1966.

Neil Clayton

Nechells Gasworks.

Swan village gasometer.

Claytons’ Oldbury boatyard

Neil Clayton