Human influence on Earth is strongly intertwined with energy consumption. Restructuring the energy sector (electricity, heat, and transport) is therefore essential for tackling climate change. The energy sector is responsible for almost three-quarters of the world's greenhouse gas emissions (see figure below). The agriculture, forestry, and land-use sector account for the second-largest share of greenhouse gas emissions, about one-fifth of the emissions. This section examines, on a long-term global scale, the major turning points in energy production in human history. This section first examines, on a long-term global scale, the most important turning points in energy production in human history and the energy transformations that have shaped the current fossil fuel-based system. Secondly, we look at a few key points about the current energy transition.

Definitions of energy transition vary, but most often the change refers to the following:

1. a change in the energy source, such as the transition from conventional renewable energy sources to coal or from coal to oil;
2. energy technological change, such as the transition from steam engines to internal combustion engines
3. more broadly, the transformation of energy systems, in which human actors play a key role in energy production, distribution, and end-use;

The figure shows global greenhouse gas emissions by sector in 2016 when global greenhouse gas emissions were 49.4 billion tonnes of carbon dioxide equivalent. 73.2% of total emissions came from the energy sector. Of these, energy use in the industry was the largest emitter. Within this sector, iron and steel production (7.2% of total emissions) and the chemical and petrochemical industry (3.6%) account for the largest emissions. Energy use in buildings accounts for 17.5% of emissions, with a larger share coming from residential buildings than from commercial buildings. Transport is the third major emitter in the energy sector. Emissions from road transport are clearly higher than from aviation and shipping.

From a physics perspective, one textbook definition of energy is the ability to do work. In human history, the energy required for work has, to a large extent, meant the muscle strength of either animals or humans. Muscle power, like almost all energy used by humans, derives directly or indirectly from the Sun. All available energy on Earth is derived from the following sources:

1. From the Sun, from which all biological material (biomass) is derived, including fossil energy sources; solar power and heat; hydro, wind, and wave power; and heat from Earth’s surface. With the exception of fossil fuels, these are renewable energy sources.
2. Nuclear power, ie the fission of heavy atomic nuclei or the fusion of light nuclei
3. Tidal power due to the gravity of the Moon (in addition to the Sun). This is a renewable energy source.
4. Geothermal energy from heat generated during the original formation of the planet and the radioactive decay of materials. This is also renewable energy.

In addition, renewable energy sources can be classified as traditional and modern renewable energy sources, although these do not have precise well-established definitions. Traditional renewable energy is the burning of at least some biomass – such as wood, animal waste, and traditional charcoal. New renewable energy sources include at least solar, wind, and wave power, tidal energy, geothermal and geothermal energy, and modern biofuels. Hydropower may be classified in either category.

Humankind has gone through several energy transitions throughout its history. The main energy sources have changed, for example, from muscle and hydropower to coal and from coal to oil. We are currently in the midst of the latest energy transition, a shift towards more sustainable, renewable energy such as wind and solar power. In general, energy transitions have evolved over several decades or centuries.

The graph presents the global primary energy consumption by source. The use of coal began to grow strongly from the 1840s. Oil displaces coal as the largest source of energy in the 1960s. The transmission and distribution of natural gas were considered difficult until the mid-20th century, after which the technology for exploiting gas and the gas market developed. Since then, the use of gas has also increased for environmental reasons, as the use of natural gas causes significantly fewer emissions per unit of energy than coal or oil. The share of renewable energy is still quite small, but the use of modern renewable energy is growing rapidly.

Thus, as can be seen from the previous graph, energy transitions are not about a complete replacement of one energy technology and source by another, but energy transitions often mean that new energy sources have emerged alongside old forms of energy. Previous energy sources have also continued to grow, albeit at a possibly more moderate pace. This is one possible future of the current energy transition that should be avoided. The concern, then, is that the growth in total energy consumption will undercut the growth in renewable energy. Greenhouse gas emissions will only decrease when the use of fossil fuels decreases as they are replaced by, for example, renewable energy or energy efficiency.

A brief history of energy transitions – the birth of fossil economy

The first great energy transition was the domestication of fire. It enabled humans to cook, which increased the variety of food supply and thus offered more fuel for muscles and the brain.  The fire also made it possible to settle in those areas where living required heating of the dwellings. 

Another energy transition was the domestication of plants and animals. It allowed for a steady intake of calories and the utilization of animals in heavy work. 

For millennia energy from the Sun was tapped through the burning of biomass that was recently alive, such as wood. The revolutionary turn was the transition to the systematic burning of fossilized biomass – first coal and later oil and natural gas. Fossil fuels enabled the industrial revolution and continue to power the economies still today. 

Coal was the first widely used fossil fuel in human history. It was first introduced in China, during the reign of the Song Dynasty, from the mid-900s to the late 13th century. Coal was also used early in England. As early as the 13th century, it was used to heat homes, especially in London. However, China and England were exceptions, with wood and charcoal being the main sources of energy in most of the world. Prior to 1780, agriculture was the world’s largest sector of economic production, with the main sources of energy being mostly renewable energy sources. As long as coal was only used to heat residential buildings, its role as a form of energy grew moderately. It was not until the use of coal for industrial purposes that coal became an important source of energy in its time.

After 1780, coal began to be mined extensively, and Britain became the world’s largest coal producer (see figure below). It had the largest coal reserves throughout the 19th century and dominated the science, technology, and industry associated with coal. It has been calculated that by the middle of the 19th century, the land area of the UK would not have been nearly enough to produce the amount of wood energy equivalent to coal use at that time. Coal-fuelled advances in industrial manufacturing and transport launched the Industrial Revolution and Britain's rise to global dominance. Its coal-powered navy dominated the seas and ensured the free movement of goods and people both within its empire and around the world.

The figure illustrates the rise of coal as the main fuel for industrialization in the 19th century. The figure shows coal production and coal imports from abroad in 1700-2019 in the UK. Coal production at the start point in 1700 is roughly the same as at the endpoint in 2019, about 2 million tons. Coal production increased throughout the 19th century and peaked in 1913, at about 292 million tons. Since 2001, imports have been higher than production, but are now strongly declining, reflecting the current energy transition. 

Carbon-powered advances in industrial manufacturing and transportation paved the way for the Industrial Revolution and Britain’s rise to global dominance. Its carbon-powered fleet ruled the seas and ensured the free movement of goods and people both within its empire and around the world.

Controlling the most important source of energy at any given time does not automatically mean global hegemony. However, since the transition to fossil fuels, the country with global dominance has been the largest or one of the largest producers of the dominant energy source and also the leading producer of technologies for that energy source - such as Britain as a coal producer from 1815 to 1873 and the United States as oil producer from 1945 to the present.

Steam engine powers the world to the age of the fossil economy

At the turn of the 19th century, a fairly small number of British industrialists decided to start using coal as a source of power in their textile factories to produce steam instead of using muscle power and hydropower. So why did the British cotton industry move the world into the fossil economy from the middle of the 19th century at the latest? Why the fossil economy did not emerge already in China centuries earlier, even though the Chinese knew how to exploit their vast coal reserves? One of the most significant innovations that enabled the Industrial Revolution was the development of the steam engine, most notably an improved version patented in 1769 by James Watt. The steam engine allowed the combustion of coal to be combined into mechanical energy, rotating motion, which in turn allowed all kinds of products to be produced, and also transport to grow.

However, it has been pointed out that the steam engine principle has been known almost since the beginning of our Common Era (although at first, it had no practical purpose) but British cotton producers continued to use the water wheel for decades after the patenting of the Watt steam engine and the Industrial Revolution did not accelerate until the early 19th century, and especially since the 1840s. The first major profits in the British cotton mills were thus still made by the water wheel, even though Watt and the partners marketed their own steam engine heavily. This suggests that there were reasons for the breakthrough of the steam engine other than those directly related to the physical properties of the coal and the steam engine.

One relatively recent perspective in the study of the transition to a 19th-century British fossil economy has been the consideration of the suitability of a new energy source and technology for the prevailing capitalist logic of economic organization. From this perspective, better labor-management was the main motivation for the shift from hydropower to coal. This perspective holds that the use of hydropower required coordination and centralized planning, which was destructive to the competitive spirit of capitalism. Similarly, labor was scarcer in areas where hydropower was available and workers tended to organize and go on strike. Fossil fuels, unlike hydropower, were not tied to a place but allowed factories to be set up in exponentially growing cities with plenty of cheap, easy-to-control labor. From this perspective, fossil fuels were not so much better in price or efficiency than water but were superior in their compatibility with the logic of competitive capitalism and private property.

The coal supply chain from coal mines through railways and ports to end-use has also been considered to include the potential for an increase in working-class power. Instead of the owner of the coal mine, the workers had the technical know-how, which provided the workers with considerable tacit knowledge, which in turn made it more difficult to replace the workers from the employer's point of view. Similarly, the flow of coal from coal mines to factories, offices, and homes by means of transport, which were also based on steam power, made the strikes very effective. The workforce, which was particularly concentrated at important nodes in the coal chain, was well placed to organize and share ideas, but also simply to threaten the flow of coal, which had become a necessity for society. This gave the working class a new kind of political power.

From coal to oil

World Wars spurred the transition from coal to oil. The potential importance of oil as a fuel for warships was understood in British and US navies as early as the 1860s; almost a century before it became arguably the most important source of energy in the world (after World War II, and especially beginning in the 1960s).

Oil was the bedrock in enabling the “golden age” of the global economy. During this period, from the early 1950s until the outbreak of the first oil crisis in 1973, the European and American economies, in particular, grew at an unprecedented rate and similar growth rates have not been reached in the West since. Mass consumption-based growth in human material well-being – a period known as the “Great Acceleration” that began in the 1950s – has had enormous consequences for the environment.

Oil began to rise alongside coal as the most important source of energy in the late 19th century, above all in the fleets of the then great powers, Britain, Germany, and the United States. The power struggle between dominant Britain and the emerging rival superpower Germany intensified and the rivalry of the navy accelerated. 

Oil had clear physical advantages as a fuel for warships compared to coal: it had a higher energy content, which allowed oil-powered fleets to travel longer distances and thus, for example, to choose the best battlefields against coal-fired ships. In addition, the oil required less storage space than coal and was easier to move along the pipelines. The oil also burned cleaner, making it less noticeable to the enemy, and feeding the liquid into the combustion did not require heavy and dirty shoveling work like coal.

During World Wars, in wartime exceptional conditions, the use of oil became necessary in many sectors of societies, such as transportation and agriculture. The energy, transport and food systems overlapped more firmly, and all of them were increasingly driven by oil. Rapid developments in technology, infrastructure, science, and institutional conditions during the wartime underpinned oil-intense societies in the post-war economic “golden age”.

As with the transition to coal, there were also many other reasons for the transition from coal to oil than the physical properties of the oil. Where the chain of coal from production to consumption enabled the growth of political power of the working class and was vulnerable to strikes, from the employer’s point of view, the oil that flowed in the pipes did not cause similar problems. It has also been argued that the United States sought to influence the European political order after the Second World War, inter alia, by seeking to make the energy system oil-based and thus reduce the political power of coal workers.

Oil is also associated with the development of an energy-intensive lifestyle. From the point of view of maximizing the profits of oil companies, the profit from oil will, of course, depend on a sufficiently high world market price. It can be influenced by oil producers not only by reducing total production but also by increasing consumption and demand. New political arrangements in the Middle East, along with the development of a middle-class American lifestyle (exemplified by the popularity of fuel-intensive vehicles, for example) allowed oil to remain a scarce enough resource to ensure oil companies' economic success on the road among the largest companies in the world.

The oil era was also reflected in new environmental disasters due to oil accidents. At the same time, the development of the environmental movement gained new momentum. But most of all, oil contributed to the period of unprecedented growth with its unprecedented environmental problems. Indeed, humanity faces a great challenge to break free from oil dependence over the next few decades. 

The importance of understanding past energy transitions

So why is it important to study and understand the energy transitions that have already taken place? Energy history shows that inferior energy options for humans and the planet may well achieve dominance. Many researchers have pointed out that a massive increase in wind farms and solar panels alone is not enough for a truly sustainable energy revolution, but the logic of maximizing the profit of economic growth as a basis for well-being must be questioned. Citizens' movements, in particular, have been concerned that future renewable energy systems may also only renew asymmetric power relations and strengthen the power of those responsible for the current problems in the first place.

Current Energy Transition

Earlier in this section, a few important turning points have been described in which the fossil fuel-based energy system has evolved. Fossil economy has enabled unprecedented, albeit unevenly distributed, material wealth. However, the current global fossil fuel-based economy is not sustainable by any criteria of sustainable development, not socially, economically, or ecologically.

Fossil energy sources are very unevenly distributed on the planet, resulting in a wide range of geopolitical tensions, especially around oil. It must also be remembered that today, hundreds of millions of people on earth do not even enjoy the fruits of previous energy transitions, but in 2019, more than 750 million people still lived without electricity. In addition, the small particles generated by the combustion of fossil fuels cause the premature death of millions of people every year. This is also a problem in rich countries, in addition to which indoor air pollution due to the use of traditional biofuels is a huge health problem in developing countries (see figure below).

Energy prices are also on the rise, although there is a lot of fluctuation in oil prices, for example. In particular, if the external costs of energy production, such as those related to environmental pollution and human health, are included in energy prices, the system does not appear to be economically sustainable either. There are therefore other reasons for energy transition than just the threat of climate change.

The figure shows the number of premature deaths due to indoor air pollution per 100,000 individuals in 2017. Indoor air pollution is one of the leading causes of premature deaths in the world - an estimated 1.6 million people die each year from indoor air pollution (in total around 57 million people died in 2017). Indoor air pollution is caused by the burning of solid fuels (such as grain waste, manure, wood, and charcoal) in poorly ventilated fireplaces for cooking and heating. Small particles from incineration are a risk factor for a large number of diseases, such as heart and respiratory diseases. The vast majority of deaths occur in low-income countries in sub-Saharan Africa and Asia. With the use of cleaner fuels and electricity, deaths due to indoor air pollution are declining almost everywhere in the world.

Because of these problems, the entire world energy system needs to be reformed, and even within a few decades. The global energy transition is a necessary part of climate change mitigation, and simultaneously, more evenly distributed renewable energy resources are most likely to reduce energy security problems. But at best the change in energy systems is only at the beginning. As seen in the figure below, fossil fuels, namely oil, coal, and natural gas, are powering the economies, while renewables, especially the modern renewables, such as wind and solar power – still have a share of a few percent on global terms.

The figure shows global energy consumption by energy source in 2019. Fossil fuels produce 84.3% of world energy consumption (oil 33.1%, coal 27%, and natural gas 24.3%). In 2000, the share was 86.1%. Renewable energy sources cover 11.4% of consumption (hydropower 6.4%, wind power 2.2%, solar energy 1.1%, biofuels 0.7%) Nuclear power accounted for 4.3%.

However, the growth of renewable energy sources will inevitably continue and accelerate in the future. This is because, in much of the world, solar and wind power have become the cheapest way to generate electricity when building new electricity generation capacity. 

We will look at the current energy transition in more detail in the last part of the course.

For reflection: which do you think would be the first priority in reducing the environmental impact of the energy sector: reducing energy use or increasing non-fossil energy production? You can share your reflections and discuss with other course participants on the page linked below.

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