The Material Limits of Energy Transition: Thanatia

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021

A. Valero et al.The Material Limits of Energy Transition: Thanatiahttps://doi.org/10.1007/978-3-030-78533-8_1

1. What Is This Book About?

Alicia Valero¹  , Antonio Valero² and Guiomar Calvo³

(1)

Instituto CIRCE, University of Zaragoza, Zaragoza, Spain

(2)

Instituto CIRCE, University of Zaragoza, Zaragoza, Spain

(3)

Instituto CIRCE, University of Zaragoza, Zaragoza, Spain

Alicia Valero

Email: [email protected]

Abstract

Humankind has relied on the extraction of different raw materials for centuries, starting with iron, copper or gold to a large number of metals and fossil fuels currently used in multiple sectors, thanks to technological development. Still, this change has also led to other issues, such as increasing CO2 at a global level and climate change. One way to mitigate these problems is to rely on renewable energy sources that use the Sun or wind to generate electricity instead of burning fossil fuels. However, these technologies need certain elements that are scarce on the planet or very complicated to extract. To assess our planet’s mineral loss, in this book, we will use thermodynamics, specifically its second law, that will allow us to explain this degradation process physically. Using Thanatia as a baseline, a hypothetical land where all concentrated materials have been extracted and dispersed, and all the fossil fuels have been consumed, we can assess the cost of replacing minerals through a grave-to-cradle approach and combine it with the more traditional cradle-to-grave approach.

Everything around us is made up of minerals. Dozens of chemical elements are used in smartphones, household appliances, vehicles, concrete, paints, detergents, etc., that come from the extraction and processing of these minerals. We start from the advantage that the natural processes that have been taking place over millions of years on our planet have been concentrating these elements in the form of mineral deposits. Mining becomes then our primary source, from where we extract the minerals that we then use. Since these mines are not infinite, it is legitimate to ask what limitations may exist in the short, medium and long term.

The increase in population, globalisation and the change in consumption trends are causing the use of resources to increase dramatically every year. In fact, the primary extraction of quarry products, metallic minerals, fossil fuels and biomass increase year on year. On a limited planet, are we going to be able to maintain this pace forever? What consequences will this have on future generations and on the planet?

Historically, the extraction and use of raw materials have been closely linked to human development. We have gone from consuming about 3 kg of natural resources per inhabitant per day in prehistory to 44 kg in our current industrialised society (Friends of the Earth, 2009). Our prehistoric ancestors obtained mineral resources through surface collection, selecting those materials most suitable to serve as cutting tools, such as quartzite or flint. Other readily available materials have historically been used as cosmetics and for decorative purposes. The Egyptians used mixtures of oils with dust from the crushing of lead minerals, such as galena, and copper, such as malachite, among others, to make kohl, a thick black substance that they later applied to outline their eyes (Hallmann, 2009).

With the emergence of more complex societies, mining became much more relevant, using materials for own consumption and exchange. Different metals gradually gained more weight, including copper, bronze (an alloy of copper and tin), and gold, highly desired both for ornamentation and jewellery and for its economic value.

A well-known example globally is the ancient gold mine of Las Médulas, located in the province of León (Spain), considered the largest open-pit metal mine in the Roman Empire (Fig. 1.1). The exploitation was carried out by the force of water, with the method known as ruina montium. Water was channelled and accumulated at the top of the mountain and, as this water was released through steep galleries, and by the force of gravity, the mountain would erode, dragging the gold to the washing sites located at the bottom (Pérez García et al., 1998). It is estimated that the Romans were able to extract between five and seven tons of gold from this location, which has left as an inheritance the characteristic landscape that this area presents. Such is the value of this natural space that UNESCO included it as a World Heritage Site in 1997.

Fig. 1.1

Ancient gold open-cast exploitation of the Roman Empire of Las Médulas (Castilla y León, Spain). Author Rafael Ibáñez Fernández. GNU FDL. Wikimedia Commons

Historically, gold that appears in its native state has also been mined manually using pans. This technique, widespread in past centuries, consisted of using a pan filled with sand and immersed in water; through a series of circular movements, and due to the difference in density of the materials, the gold deposited at the bottom while the gravel was washed off (Fig. 1.2). This same technique was also used during the gold rush in the United States in the middle of the nineteenth century, along with the sluice boxes, where the material was washed. During this time, dry gold washing also became popular, driven by the lack of water in many regions. In this case, the mineral was deposited inside a conical wooden pan. Throwing the material into the air, lighter materials dispersed leaving the heavier ones at the container’s bottom. However, as can be assumed, this was not a very effective method since only large gold nuggets could be recovered (Taylor Hansen, 2007). The use of pans and decantation in artisanal gold mining continues to this day.

Fig. 1.2

Engraving from the work of Georgius Agricola, De re Metallica, published in 1577, representing gold extraction techniques in Germany in the sixteenth century. The sluice boxes ensured that gold, a denser material, accumulated in the channels. There is also a person panning, a traditional method still used in some places

The technological development that has taken place over the centuries has progressively increased the number of metals and other elements that are used, from just a few in the seventeenth century to practically all of those contained in the periodic table today. This is even more evident in the case of elements used in the energy sector (Zepf et al., 2014). Initially, the materials necessary to manufacture mills that harnessed the energy of the wind were few: chiefly iron, wood and stone; the same occurred with candles or oil lamps used for lighting. With the industrial revolution and the steam engine’s invention, other elements were introduced in the energy sector: copper, tin, lead, manganese, etc., but they were still few in number. The appearance of motor vehicles changed the situation drastically again, increasing not only the consumption of fossil fuels but also that of other metals that until now had not been very useful.

Today, we use many elements in different applications that increase our convenience and comfort. For instance, in a smartphone, we can find several dozen elements of the periodic table, which include tin and indium oxide in the touchscreen and rare earth elements that produce the colours we see and, of course, lithium in batteries (Merchant, 2017).

Electricity generation is no exception either, since it requires large amounts of elements, some of them very valuable and scarce, to produce wind turbines, photovoltaic panels, etc. For example, to produce one gigawatt (GW) of electrical power equivalent to that which a natural gas-fired power plant could supply would require a total of 200 5-megawatt (MW) wind turbines or 1,000 1-megawatt (MW) wind turbines. This would imply the use of approximately 160,000 tons of steel, 2,000 of copper, 780 of aluminium, 110 of nickel, 85 of neodymium and 7 of dysprosium for its construction. These are not negligible amounts if it is estimated that in the future the energy produced by wind turbines in 2050 could be around 2,200 GW (International Energy Agency, 2019).

Worse still, as can be seen in Fig. 1.3, wind turbines are one of the renewable technologies that require the least variety of elements for their production, but others such as the electric car employ over 40 different elements, and that’s before considering the rest of the necessary materials such as plastics, glass, polymers, etc. (Valero, 2018).

Fig. 1.3

Some of the elements that are used to manufacture clean technologies (Valero et al., 2018)

Considering the intense use of materials from clean technologies, will the deployment of renewable energy required to achieve the Paris Agreement goal (preventing Earth’s temperature rise of over 2 °C before the end of the century) be possible? We want to move from a society based on non-renewable energy sources to one based on renewable sources. However, what has been rarely considered is that these technologies require a greater diversity of materials than conventional energy sources and that, in addition, they are highly voracious in many different elements.

As we currently know, society is completely dependent on many elements, almost all of which come from the primary extraction of certain minerals. In our society, no product exists that does not contain minerals or whose production does not directly involve minerals. Consequently, the global extraction of natural resources has increased exponentially, as can be seen in Fig. 1.4, and the same situation can be observed for other materials.

Fig. 1.4

Global material extraction from 1900 to 2017 in billions of tons (International Resource Panel, 2019)

The amount of biomass that has been extracted, comparing 1900 and 2017 data, has increased fivefold, in the case of fossil fuels 15-fold, and by a factor of 43 and 65 in the case of metallic and construction minerals, respectively (International Resource Panel, 2019). In fact, so far in the twenty-first century (in the last 20 years) we have extracted almost the same amount of copper that was extracted in the entire twentieth century, and this same situation can be extrapolated to many other elements (USGS, 2018).

However, this extraction of raw materials is not equally distributed across the globe. In the case of mineral resources, it is geology that conditions the places where the elements have been concentrating over time. In Australia, for example, there are economically profitable deposits of practically all the elements, while in Spain, despite having a considerable amount of mineral deposits of different elements, only a few basic metals such as copper, lead or zinc can be economically extracted.

If we take as an example some of the elements that are most crucial to our economy, such as lithium, which is essential for electric car batteries, approximately 55% of the total global extraction originated in Australia in 2019. Another representative example of that same year are rare earth elements, used in many technological applications; in this case, China dominated the market with a global extraction quota of over 60% (USGS, 2020).

Furthermore, this unequal extraction of resources is associated with consumption that is also unevenly distributed. For example, in Europe, three times more resources are consumed than in Asia, and four times more than in Africa, and someone born in the United States consumes even more than an average European. For example, a child born in the USA in 2019 will, throughout their life (78.6 years), require a total of 9,129 kg of iron, 937 kg of primary aluminium, 444 kg of copper, 432 kg of lead, 211 kg of zinc, 13,693 kg of salt and 6,503 kg of phosphate rock, among many other elements, in addition to some 1,800 barrels of oil, 150 tons of coal and 7.7 million cubic meters of natural gas (Minerals Education Coalition, 2019). This implies that if all the inhabitants of the planet tried to live today as an average US citizen, we would need to multiply the current copper extraction by two to cover the demand of a single year and something similar would happen with the rest of the raw materials.

The exponential extraction of materials also entails an increase in the required energy dedicated to mining, which in turn can significantly impact the environment. According to studies by the International Energy Agency, the mining industry consumes between 8 and 10% of global energy. As an example of how intensive mining is in terms of energy use, each year, the Australian mining industry consumes as much electricity as Portugal, and if the cost of transport is also factored in, it is equal to the energy consumed in Spain. It is clear that there can be no materials without energy, but neither can there be energy without materials.

So, what does the future hold? Knowing the consumption of mineral resources in the past or the present is relatively simple: we resort to the mining statistics of the different countries to obtain approximate figures. However, of equal or greater importance is trying to predict what future behaviour will be to anticipate eventual shortage problems. To this end, different models have been created based on statistical calculations and trend analysis, among others. Some striking insights can be gleaned from these studies. In the case of silver, gold, copper or nickel, their demand is estimated to increase fivefold by 2050. Taken alone, this figure doesn’t provide much value but compared to the known amount of these elements in mines today, it exceeds by far the amount that would be possible and profitable to extract at current prices (Halada et al., 2008). This implies that we will end up needing much more than the Earth can provide and that the true costs of the depletion of non-renewable natural resources, and the consequent degradation of ecosystems, will be much greater and will steadily increase if this trend continues.

In short, the planet Earth has become an enormous mine. Not only are many elements extracted, but millions of tons of sterile rock are generated that accumulate around the mines. In 2000, mineral processing and refining were responsible for around 12% of sulfur dioxide emissions, a gas that is the main cause of acid rain (Smith et al., 2004). To this figure, we must add the landscaping impact of the mines, the impact on land use and the possibility of accidents such as the one that occurred in Brazil in early 2019 where an iron ore containment dam collapsed causing serious damage, both in loss of human lives as in material and environmental terms.

Indeed, nature is no longer as abundant as before; if it were, perhaps the contribution of mining would not be as devastating. However, the intense technological development of the twenty-first century is forcing society to react, each of us becoming increasingly aware of the detrimental effects our actions are having on the planet.

Another reaction to exponential extraction is increased global awareness of the fact that we are experiencing a loss of natural capital that will never be regenerated. In other words, there are limits to growth. In fact, many decades ago this was evidenced by the report to the Club of Rome of the book The Limits to Growth (Meadows, 1972), based on a report carried out at the Massachusetts Institute of Technology, a book that was updated in 2004 (Meadows et al., 2004). It predicted that population growth, coupled with the exponential use of fossil fuels and minerals, would bring the world to the brink of collapse in just a few generations. This prediction became increasingly real, especially with the subsequent oil crisis in the 1970s and 1980s, only to be forgotten during the bubble boom of the late 1990s and early 2000s. At that time, global growth was driven by the idea that the planet could absorb all the environmental impacts caused by social development, that mineral and energy resources were sufficient to maintain unlimited growth, and that innovation and technological development would be able to solve existing or future problems.

Looking back, the lack of accurate data generated by those early predictions of future scarcity does not weaken the Club of Rome message. Environmental problems worldwide have been worsening and the environmental footprint generated by the planet’s population is already exceeding the limits of what the Earth can support.

Earth Overshoot Day is the day in which all the resources that the Earth can regenerate in a year have been consumed (Fig. 1.5). That is, if we maintained a sustainable rate of consumption and generation of waste that our planet was capable of absorbing, this day would occur on 31 December. Already in 1970, this overcapacity limit was reached on 23 December, not too far from the ideal date; however, in 2019 the limit of the planet was reached on 1 August. In 2020, this day was pushed back three weeks, until 22 August, mainly due to the global COVID-19 pandemic, which slowed down the consumption of materials, reaching levels similar to 15 years ago (Earth Overshoot Day, 2020). What does this mean? Essentially it means that each year we need around 1.75 planets to maintain our growth rate, but as we all know, we only have one (WWF, 2018). In addition, due to the unequal distribution of consumption, if all the inhabitants of the planet wanted to live at the level of an average Spaniard, it would take two-and-a-half planets, a figure that would increase to five planets if we all wanted to live at the same level as an American.

Fig. 1.5

Evolution of Earth Overshoot Day from 1970 to 2019 (Global Footprint Network: www.​footprintnetwork​.​org)

The environmental footprint of each one of us continues to increase, and it does so even more considerably in developing countries, which seek to raise their quality of life to the level of developed countries. The expected large deployment of renewable energy will also affect the type of materials that are extracted, producing a shift from dependence on fossil fuels to dependence on scarce materials, as we will see later. Although many continue to deny the existence of materials shortages and the need to address them from an economic point of view, the fact is that physical exhaustion is related to the limited amount of natural resources that the Earth has to offer. If this threat is to be taken seriously, we must begin to rigorously account for what raw materials are produced, from their primary extraction to the manufacture of the final product, and then from their disposal to full dispersal.

Such monitoring could be carried out through life cycle assessment (LCA), a widely established methodology to evaluate the environmental footprint and the associated environmental impacts from the start of a good or service, the so-called cradle, until the end of its life, the grave. This cradle-to-grave analysis, and in the opposite direction, can be extended to cover the entire planet, and when applied to the extraction of mineral resources the loss of mineral wealth caused by human actions can be analysed.

With this idea in mind, thermodynamics, specifically its second law, allows us to explain any degradation process in a physical way. The ultimate goal is to be able to carry out a thermodynamic analysis of the depletion of raw materials on Earth through the entire life cycle, that is, from cradle-to-grave, and then from grave-to-cradle. This cyclical process occurs naturally in ecosystems if sufficient time elapses, thanks to the action of the Sun. However, the Sun has little influence on the cycle of minerals, and once they enter the technosphere (the system formed for all the elements created by human beings), they end up dispersing, rarely being available for reuse.

The mineral cycle is much more complex, and humans are shortening it at will. The minerals, concentrated in deposits, can be considered nature’s great repository. This warehouse, once it is subjected to extraction and processing, becomes part of the industry. After the products are manufactured, the minerals already belong to the inventories (or stock) that are in use, and when they reach the end of the useful life of these products, that is, when society no longer needs them, they usually end up in landfills or, at best, recycled. In landfills, the elements end up dispersing, making their recovery practically impossible and, even in the case of recycling, full recovery cannot be achieved. Therefore, instead of a cycle as such, the life of these materials can be represented through a spiral that never closes, since even applying the best recycling techniques, it is not possible to recover all the material used for its manufacturing due to thermodynamic limitations.

Today, large amounts of minerals are mined without considering this dispersion process, something that could be avoided if studies on recovery costs were carried out both now and in the future. Knowing, or at least having an order of magnitude of, what the costs of trying to close these cycles are, that is, estimating the cost of reconcentrating those minerals dispersed by humans in a deposit, can be crucial. It could help to clarify the size of the problem. Only in this way will we understand the need to adequately manage the scarce resources that nature provides us without asking for anything in return.

In a planetary cradle-to-grave study, and then from grave-to-cradle, it is necessary to clearly identify what we mean by cradle and what we mean by the grave. The cradle is simple to determine in this case: it refers to the repository where the minerals are initially, which have been concentrated over time through natural processes, that is to say, the mineral deposits and the mines. Extrapolating this idea to all the mineral resources that humans use, the cradle is then the Earth as we know it today. The grave, however, is somewhat more complex to define. When analysing the life cycle of a material, the grave is normally the dump where they end up; by establishing a simile, on a planetary level, the grave could be the final dump where all resources have been irreversibly dispersed, that is, a planet commercially dead in resources. In order to develop this hypothesis of a planetary grave, it is necessary to create a model capable of adequately representing the commercial purpose of the planet, hence the Thanatia model (Valero & Valero, 2014).

The word Thanatia comes from the Greek Thanatos, meaning death, and represents a hypothetical land where all concentrated materials have been extracted and dispersed throughout the crust and in addition, where also all the fossil fuels have been consumed (Fig. 1.6).

Fig. 1.6

Conceptual hourglass of the passage from Gaia (our planet today) to Thanatia (planet with dispersed and/or totally consumed natural resources)

This crepuscular planet would have an atmosphere, hydrosphere and continental crust with a determined composition different from the current one. For example, since there are no concentrated mineral deposits in it and all the fossil fuels have been burned, the atmosphere would have higher CO2 concentrations than current ones. Similarly, almost all the water available in the hydrosphere would have a different composition as the fresh water (representing only 3% of the planet’s total water) would be mixed with salt water. This model does not mean that Thanatia is the end of life for our planet; it only implies that resources would no longer be available in their current form, concentrated and ready for extraction.

Starting from Thanatia, it is possible to assess the cost of replacing minerals through a grave-to-cradle approach, since this cost would be that corresponding to the useful energy needed to re-concentrate those minerals to the concentration that appears in their respective deposits, that is, moving from a dispersed environment like Thanatia’s to the concentration of current mines. To have a unified vision and make comparisons between different resources and countries, exergy is used as a unit of measurement, which also helps us take into account not only the quantity but also the quality of these resources.

It is essential to keep in mind that the quality of mineral resources is not always the same, that is, it makes no sense to add a ton of iron to a ton of gold. It would be like comparing apples to pears since the processes involved in extraction and processing are not comparable at all. Because of this exergy, and specifically, exergy replacement costs, consider the terms not only of quantity but also of quality, which allows us to compare apples to apples. Accordingly, the mineral loss caused by the past extraction and the one to come can be evaluated using exergy and the Thanatia model.

All the concepts involved in this process, the materials cycle, the life cycle assessment of mineral resources, exergy, replacement costs, etc., will be explained in detail throughout the book using applications and practical cases, focused on the thermodynamic evaluation of mineral resources, the energy transition and technologies.

Given the current trends in the extraction of materials, the depletion of mineral resources does not seem to be a priority, but to prevent our planet from becoming Thanatia, we need to act now.

References

Earth Overshoot Day. (2020) Earth overshoot day. https://​www.​overshootday.​org.

Halada, K., Shimada, M., & Ijima, K. (2008). Forecasting of the consumption of metals up to 2050. Materials Transaction,49(3), 402–410.Crossref

Hallmann, A. (2009) Was ancient Egyptian kohl a poison? In: J. Popielska-Grzybowska, O. Białostocka, & J. Iwasczuk (Eds.) Proceedings of the third central European conference of young Egyptologists (pp. 69–72).