The starting point for this post was some old family accounts which extended, with gaps from the 1920s to the 1940s. This was augmented by some figures found in the online version of Hansard. Some local history material provided a human dimension to the numbers.
The graphs should be treated with caution as they are random in both time and location. House coal can be priced in several ways, my family always discussed it in terms of cost per hundredweight (112 pounds or very roughly 50 kg). In 1835 it became compulsory to sell coal by weight rather than volume, before that there are references to "chaldrons", this was a volumetric measure which might account for 0.5 - to 1.5 tons.
The economics of coal consumption are complex, at £10/cwt, the energy cost is around 2p/kwh which is lower than for gas or electricity. However, the "benefit" derived from a kg of coal depends on the efficiency of the device in which it is burnt. When used in a cooking range, a lot of energy is used just warming up a large lump of iron before the thing is warm enough to boil a kettle for tea. Early ranges were not insulated, which made them inefficient cooking devices, but a desirable source of warmth in the kitchen, modern solid fuel range cookers are well insulated which minimizes heat loss. In England, houses were heated with open fires which have a very low efficiency (10 - 20%?) with most of the heat going up the chimney. From limited research, it seems that the French prefer stoves which use coal more efficiently.
During the 20th century, the overall trend in the "real" price of coal was upwards. At the end of the 1960s coal began to compete with "North Sea Gas" in the domestic fuel market. Gas was both cheaper and more convenient than coal and coal's share of the market started to decline. By the end of the century, coal had become a "niche" product and costs rose as the economies of scale that had been possible faded away.
The retail price of coal has always been subject to wide variations and fluctuations. In 1795 it was feared that France would invade England and for a time the price of coal was around 55 shillings per chaldron, this would be more than £50/cwt in today's money. Households purchase coal for the heat it produces when burnt, premium grade Welsh Steam Coal might have a calorific value of more than 30 MJ/kg whilst that of lower grade fuel might be half that. Some of the variation in the price shown on the graphs is due to variation in the grade of coal.
Apart from events in the wider economy, the price of coal was determined by who you were and where you were. A well-off, well managed household would buy several tons for delivery in large loads during the summer when they would benefit from lower prices. At the other end of the scale, those on low incomes might have had to buy coal by the stone (14 lb) or lesser quantity and paid a high unit price (there is an analogy here with today's pre-payment meters). Some coal merchants operated "coal clubs" which allowed fuel costs to be evenly spread over the year.
Transport was a significant part of the cost of distributing coal from the mines to the consumer, by the late 19th century coal merchants were often clustered around railway goods yards. The coal merchant was responsible for unloading the trucks, if this was not done within an agreed period, say, three days, the buyer was charged demurrage until the wagon was empty. In the early part of the century it was not unknown for captains of collier brigs from the Tyne to run their vessels on to the beaches of seaside towns if they thought they could get a better price for their cargo than they would get at a port a few miles down the coast. If the cargo was discharged at a port, then the buyer would have the cost of transport to the point of use. There was always a risk that they could be stranded for several days until favourable weather and tide allowed them to re-float.
A wide variety of enterprises were active in the local coal markets, some companies operated across regions, some were local businesses, maybe just a father and son working together with a horse and cart and below them were the barrow boys. Our family favoured the Co-Op, probably to get the "divi".
A coalman's job was hard and dirty, often it was delivered to the consumer in sacks containing one and a quarter hundredweight (roughly 60 kg). Large houses would have purpose built coal stores and some town houses had coal cellars which extended under the pavement which could be filled through a hole normally covered by an iron cover. The difficult ones were small terraces where the coal had to be carried through the house to the scullery, a task which had to completed without upsetting the housewife.
