Bigger cities, more wealth and increasingly complex products demand more metallic ores. This is also true for the transition towards sustainable energy. Metals will become scarcer, while mining them will take more energy. The problem bites in its own tail.
In the forty years to come, the urban population is expected to double, and we will have to build all the cities we know now again. Not only cities like Paris, New York and Tokyo, but also Chongqing, Guangzhou and Chengdu. We shall be needing vast amounts of construction materials for the buildings, the roads and railways and underground transportation systems of these big cities. In that same period incomes of average citizens is estimated to treble. This means that considerably more cars, refrigerators, TVs, computers and luxury goods will be produced. All this contributes to a strong increase in the demand for materials.
At the same time the products we use are getting increasingly complex in terms of assemblage. According to the periodic system, known from physics classes, we dispose of some 90 elements occurring in nature. We use them to make all the items we manufacture. If in the 1990s we could do with 16 elements from the periodic system to build a computer chip, currently we’re using more than 60. If some decades ago the technology of a car was primarily mechanical in nature, based on steel, rubber and plastics, nowadays even the simplest vehicle has dozens of computers and electro-engines on board. A similar trend is visible in white goods such as refrigerators and washing machines, which are increasingly linked to the internet. The development of increasingly complex products leads to a strong increase in the demand for specific metals with specific properties.
Sun and Wind
In addition to rising demand as a result of urbanisation, the growth of wealth and the increase in the complexity of products, there is yet another trend which leads to a further future growth in the demand for metallic ores. That is the transition towards a sustainable energy system.
First of all, we’re left with no alternative: if we want to seriously do something against climate change, we shall have to convert to a CO2-low energy supply in the four decades ahead. It can be based on fossil fuels, storing produced volumes of CO2 underground, with the help of extra materials such as carbon capture plants, pipelines and soil injection. (In generating electricity from natural gas some 30% more steel is needed to store CO2; in generating electricity from coal some 60%.) Taking into consideration the discussions on the safety of underground CO2 storage, the additional advantages of sources such as sun and wind and the rapid decrease in energy prices from these sources, it isn’t very likely that underground storage is a realistic storage system for the large-scale supply of energy.
Sun and wind, however, start off with a significant disadvantage in regard to fossil fuels: they draw on a source with a much lower intensity (exergy). In order to obtain a substantial amount of energy from sun and wind a relatively large area of land is required. To replace a large 1,000 MegaWatt coal-fired power station around 500 large wind turbines are needed. (Modern turbines on land with a peak capacity of five MW supply two MW on average.) In the Netherlands, ideally placed solar cells supply some 120 kilowatt-hour per square kilometre a year. It is easy to calculate that we need 66 square kilometres of solar cells in order to produce the same amount of electricity of a 1,000 MW coal-fired power station, running at a capacity of 90% of its volume on average. This is not counting the systems needed to compensate the variation in production as a result of variable wind velocity and sun intensity. Even if solar cells can be manufactured with the utmost efficiency and a density of a few millimetres, still a great deal of material is needed for the cells and, in the case of land-based cells, not to mention the frames needed to place the cells in the appropriate position.
Rare Earth Metals
A switchover to a sustainable energy system means that we will have to have electricity-fuelled or maybe even hydrogen-fuelled cars. This requires means of transport with a different transmission and a battery or a hydrogen tank instead of a petrol tank. Batteries are known for their use of scarce metals. In addition to nickel, metal hybrid batteries contain lanthanum. Lithium batteries, found in virtually all laptops, tablets and smart phones, contain a relatively large amount of cobalt, in addition to lithium. A car like the Tesla model S (the new Schiphol Airport taxi) has a large number of lithium batteries on board, approximately the equivalent of 1,000 modern laptops. Then there are the electro engines, some types of which (not those of Tesla) contain permanent magnets manufactured on the basis of neodymium and a smaller amount of dysprosium. Both of these are rare earth metals, the production of which occurs virtually solely in China.
Therefore, it is very important in the choice of sustainable energy technology to aim at the most efficient technology, but also take the availability of materials into consideration. Ultimately we are looking for technologies contributing substantially to a universally sustainable energy system. This means that both cost price and upscaling are two of the most important criteria for the eventual choice.
Even if we succeed in limiting the amount of scarce metals, we will need a great deal of material to build all those wind turbines and solar cells. These could be bulk materials such as steel, concrete and aluminium, rather common metals like nickle, copper and tin, but still with a number of scarce metals such as silver, rare earth metals and indium. At the same time, climate researchers teach us that the switchover to a sustainable energy system will have to take place in the short-run in order to keep climate change within reasonable limits. In other words, within the same period in which all those new cities are going to be built.
The question which then arises is: can we, in that relatively short period of several decades, produce the metals needed to keep up with the increase in demand?
Currently a great deal is written about scarce and/or critical materials, whereby the exhaustion of geological reserves is often used as a criterion for the level of scarcity of a metal. If one divides the reserves in the earth’s crust by the annual production, the resulting figure is an indication of the number of years these reserves will last, the so-called R/P ratio. In real terms this measure doesn’t actually say very much, at any rate not about the scarcity of a mineral. Generally, the calculation used says something about economically extractable reserves. However, it depends strongly on technological progress and the extent to which specific raw materials are explored. When the R/P ratio exceeds a period of 20 or 30 years, there is little reason for mining corporations to explore any further.
In addition, in contrast to fossil fuels, the available supply of a metal doesn’t diminish due to mining. When we build a ship made of iron, manufactured from iron ore, the iron doesn’t get exhausted. What is more, after the ship is discarded, the iron left is available in a fashion which is even more easily converted into a new product. There are losses, especially in the form of corrosion or the loss of parts. But generally, if we look beyond the economical supply available to mine, the geological reserves are seldom so small that scarcity is manifest.
Actually, we have to go back to the basis of the economy: scarcity occurs when demand exceeds supply. Therefore, scarcity is much more related to the flows (supply and demand) than to stocks (the geologically available material). The question is not so much if there is sufficient metallic ore in the earth’s crust, but whether we can upscale the supply of those ores sufficiently in order to keep up with strong increases in demand.
The supply of metals partly comes from the available stocks in the economy (recycling) and partly from newly mined output. Recycling is well-intended and the circular economy is a promise which can lead to a much more efficient use of available materials. There are many successful initiatives in this field. But the amount of materials available coming from recycling will greatly lag behind the rise in demand in a growing economy with sustainable products. Many more mines will therefore be needed in order to meet the demand. Mining corporations are likely to respond to that, but only if they can be sure that demand will indeed rise. Urbanisation is a rather constant factor, but the trebling of average incomes of the world population is relatively insecure, given the current developments in the world economy. The pace, or rather the lack of pace, of the transition to a sustainable energy supply will not be a reason for mining corporations to increase production. Climate policies are much too tame. More is needed to convince shareholders and investors of the need to invest in new mines.
Even if mining corporations succeed in getting support for the construction of new mines, they will only be operational in ten years’ time. Added to the fact that the quality of ores deteriorates, partly because the richer ores were mined in the past and partly because, with the current large-scale strip mining, the extraction of large supplies of lower-quality ores is often cheaper than mining smaller high-quality reserves. The use of low quality ores leads to more mine wastage and an increased use in water and energy per kilogram of produced metal. At present more than seven per cent of the total amount of energy which we consume worldwide is used for the production of primary materials. If the quality of ores decreases, this volume will rise in absolute terms. One could argue that the problem bites its own tail here: more metals are needed for the energy transition and more energy is required for the mining of those metals.
We live in interesting times, with all the ambivalence that comes with it. There is much hope that we can draw on the fast growth in sustainable energy sources. At the same time, we shall have to make available those materials needed for a genuine energy transition. A smart choice of technologies can help us, combined with the prevention of wastage as well as working towards a circular economy. Eventually any economy, no matter how advanced or virtual, is based on the foundation of the physical world, which consists of materials and energy.
This article was originally published in Bureau de Helling.