Paul Warde

On 30th September 2024, Britain used coal to generate electricity for the very last time. The age of coal as a source of power – both economic and political – is over. The speaker of the House of Lords traditionally sits on a sack of wool, an ancient representation of England’s trading wealth. In the 1860s, when Britons embarked on a brief but heated debate over whether they were running out of fossil fuels, it was commented that he should really sit on a bag of coal.  

Everyone knows that the Industrial Revolution was based on coal. Everyone now knows the environmental consequences we have reaped from making a world from fossil fuels. Yet why have fossil fuels been so important? To understand this, we need to go back to the world that came before – the world that the historian Tony Wrigley called ‘the organic economy’. 

Energy

Every activity we do requires energy. The origin of all of this energy is the sun. Sunlight warms the air and is trapped around the planet by our atmosphere. It warms the seas and allows plants to grow through photosynthesis. For land-dwelling creatures like us, nearly all of our food, and hence our energy intake, derives from plants, even when we consume it indirectly by eating herbivores.  

If the amount of energy we have available for work is limited by the food we consume, this means that the energy available to us is limited by the amount of the sun’s heat reaching the surface of the Earth, the amount of that energy converted into plant matter by photosynthesis, and the efficiency with which we are able to turn plants into useful energy in our bodies. This is what is called ‘the photosynthetic constraint’. 

Of course, the energy we use in our economies is not limited to that required to keep our brains ticking over and work our arms and legs. We can make tools which extend our power and reach. We can ride on horses or harness animals to carts. In exceptional circumstances, we can employ the power of gravity or wind. Put a log in a river and it will take it downstream – this is the power of gravity, combined with the fact that because there is so little friction as the log is carried along, no more energy input is required. Put the same log at the top of a slope and give it a push, and it will eventually come to a stop through friction. This is the basic reason why transport by water has always been cheaper than transport over land. 

But harnessing the wind and water is difficult. You need equipment, such as sails (on a ship or a windmill). It can only be done in specific places. And then, for most of human history, the equipment itself is made from plants: wood, canvas, papyrus. It is the product of photosynthesis. The fuel to keep us warm (wood), the fabric that keeps us warm and also shapes our societies and culture (fibres such as cotton, wool and flax), the material out of which much housing and tools and everyday objects are made (again wood) – all products of photosynthesis. For nearly all of human history, we could only live from what grows.  

As organic material does not last very long, it must regularly be replaced. And the demand for plants was overwhelmingly to directly generate heat or as food. In Europe before the Industrial Revolution, roughly half of energy consumed was in the form of firewood, and most of the other half roughly divided between food consumed by humans and fodder consumed by livestock that provided power (like horses and oxen). 

The ‘photosynthetic constraint’ 

Why was this a problem? An awful lot of energy reaches us from the sun; over 50,000 GJ per hectare. As a well-fed adult might consume about 4 GJ per year (a little under a million calories), this might sound like a lot to go round. But only 0.1 percent of the sun’s radiation is converted into plant matter. In turn, most plant matter is indigestible to us, and often grows only at particular times of the year and then rapidly decomposes. Suddenly, an animal seems not just a convenient converter of plants into useful qualities, like wool, hides for leather, or tasty meat and dairy products. A sheep or a cow or a pig is a kind of battery that hoovers up plant matter and stores it for times when we can make use of it. 

In the organic economy, energy from the sun might be plentiful, but energy we can use economically is not. It is scarce, and is limited by both the areas of land available, and the efficiency with which plants convert it into useful matter (which is very low). This means that human populations must also be limited in any given area of land. It is difficult and even dangerous to gather too many people in one place. Cities are mostly very small. People feared armies, including their ‘own’ army, not just because of violence or the diseases they carried, but because of their tendency to strip the country bare.  

Most economic activity must be devoted to simply getting by, and hence even when many people worked in manufacturing such as making textiles, they did so in the countryside, often also working on the land part-time. People were no less ingenious than later in devising ways to make energy go further – in domestic life, think of bedpans, box-beds and four-posters with curtains to keep the heat in, heavy felted clothes and hats – but there was simply a lot less energy to go round. And so people were materially much poorer than us. 

Limits to power

Yet very little of what we consume today comes from our immediate surroundings. Why couldn’t people do that in the past? Why couldn’t they bring it from elsewhere?

The problem is that in the organic economy, the same challenges to concentrating activity applied everywhere. To transport something overland, one needed horses or oxen, and they needed to be fed hay or grain. They could not be concentrated in sufficient volumes to shift large amounts of goods. So most ‘cities’ were in fact no bigger than a market town today, a few tens of thousands of people at best. There were a tiny number of places where hundreds of thousands gathered: in European capitals like Paris, or Istanbul, but these were absolute exceptions and permitted by the actions of powerful states that redistributed resources from all over their realms. 

People were also limited by power in a physical sense. One horse delivers, for a short period, one “horsepower”. There is a reason this unit was invented – it compared the new technology of the Industrial Revolution with the norm of the past. Yet harnessing many horses together will never allow you to multiply their power to reach the speed and endurance of a motor car. Very quickly, additional horses just reduce the burden on each horse. Your average family car today will have a horsepower of at least 100, and a lorry many 100s. In the past, moving something any distance, whether vertical or horizontal, was difficult and expensive. 

The organic economy did not lack invention or change. Over the centuries, many new agricultural techniques were developed. Global trade and colonization spread higher yielding foodstuffs like potatoes and rice around the world. Foresters came to systematically replace slower growing with faster growing varieties of trees. Yet unavoidably it was also a world of scattered populations, relatively little movement of goods, and where a large amount of economic life – probably at least half – was devoted to simply securing enough energy from the land to survive and reproduce.  

Fossil fuels

This helps us see the revolutionary impact of fossil fuels, first of all coal. The energy in coal of course also comes, originally, from the sun. It has been converted into plant matter by photosynthesis. Yet while in the organic economy, the plant matter – if we can use it – is mostly limited to that which grows in a single year, coal is the fossilized remnants of ancient forests that accumulated over many millions of years. Digging into a coal mine allows us to access all the energy at once – or as quickly as we can get it out of the ground. We move from being able to use the limited annual ‘flow’ of solar radiation captured by plants to the ‘stock’ built up over aeons of time. 

The link between land and energy is broken. We must still produce food to eat. But most ‘work’ in the economy is done by machines powered by engines or electricity. This allows us to produce many more things than could be done by human hands alone. Farming itself is mechanized, and during the 20th century became much more productive through the use of artificial fertilizers that require huge amounts of energy to produce. Even though there are eight times more people in the world today than in 1800, on average those people are much better fed and have a far greater amount of possessions. The total size of most developed world economies is dozens of times larger than two hundred years ago, however measured.  

This has been permitted by the greater availability of energy. No longer constricted by photosynthesis, populations can urbanize to a far greater extent, in much larger cities, concentrating and multiplying every kind of relationship.  

The use of coal

The very first steam engines, powered by coal, were developed in the 18th century and their major use was in coalmines themselves, to pump out water and lift loads as they got larger and deeper. The famous steam engine of James Watt had the power of around 40 horses. After 1780, coal-fired engines were attached to machines and could produce rotary motion in wheels; from there it was a short step to the modern factory, and then the locomotive running on smooth rails to reduce friction. Despite the expense of building railway networks, they operated at a fraction of the cost of going by wagon, and were far faster than canal. Later, the internal combustion engine would ensure virtually nowhere was beyond the reach of the fossil–fuelled transport network.    

However, these changes could not happen in an instant. Britain was the first country whose energy economy became dominated by coal. This was a slow process that lasted around two centuries, starting from Tudor times. At first, coal was largely a direct substitute for wood because in many places it lay near to the surface, was easily mined, and (compared to continental countries) near to population centres.  

Already by the time of English Civil War in the 1640s, coal probably provided more fuel than alternatives like wood and peat. This was not because Britain had run out of trees, some kind of ‘timber famine’, but simply because as the country became more commercial and as demand for fuel grew, coal was cheaper. A coalminer could provide more energy than a woodcutter. Having a higher energy content by weight (largely because of less moisture), coal was cheaper to transport – especially in an organic economy where transport was expensive!  

However, this did mean economic activity was always cheaper the closer you were to coalmines. Even before the factory age, the centre of gravity of the British economy began to shift towards the coal fields. 

An organic future?

Now we stand at the other end of this process. Coal is nearly gone in Britain, although fossil fuel use still prevails in the form of oil and natural gas. Due to climate change and environmental impact these must be phased out. Should we, or can we, go back? To supply today’s energy consumption in Europe from the land (and not counting imported goods), that land would need to be around 30 times more productive than it was before the age of coal. Even with modern technology, this is unlikely. The whole world faces these challenges, so we cannot simply draw our biomass from elsewhere.  

We cannot return to a ‘biomass’ energy economy. While it may play some part in the future, the answer is to circumvent the ‘photosynthetic constraint’ that we still face, and tap into abundant solar energy in different forms – wind and wave power, solar power, and heat pumps. If we worry about the impact this new energy infrastructure has on our towns and countryside, it is worth remembering that the landscapes of the past – green and pleasant fields, woodlands and hedgerows – were in fact also landscapes of energy production, that evolved to extract energy most efficiently from the land in the conditions of ‘the organic economy’. 

Tags: coal, energy, fossil fuels, industrial revolution, organic economy

| This entry was posted on Thursday, October 24th, 2024 at 12:30 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.