Amid present concerns over a potential scarcity of critical elements and raw materials that are essential for modern technology, including those for low-carbon energy production, a survey of the present situation, and how it may unfold, both in the immediate and the longer term, appears warranted. For elements such as indium, current recycling rates are woefully low, and although a far more effective recycling programme is necessary for most materials, it is likely that a full scale inauguration of a global renewable energy system will require substitution of many scarcer elements by more Earth-abundant material (EAM) alternatives. Currently, however, it is fossil fuels that are needed to process them, and many putative EAM technologies are insufficiently close to the level of commercial viability required to begin to supplant their fossil fuel equivalents, necessarily rapidly and at scale. As part of a significant expansion of renewable energy production, it will be necessary to recycle elements from wind turbines, and solar panels (especially thin-film cells). The interconnected nature of particular materials, e.g. cadmium, gallium, germanium, indium, tellurium, all mainly being recovered from the production of zinc, aluminium and copper, and helium from natural gas, means that the availability of such “hitchhiker” elements, is a function of the reserve size and production rate of the primary (or “attractor”) material. Even for those elements that are relatively abundant on Earth, limitations in their production rates/supply may well be experienced on a timescale of decades, and so a more efficient (reduced) use of them, coupled with effective collection and recycling strategies should be embarked upon urgently.
Of all essential commodities, the fossil fuels may well run into production limits during the next few decades, and indeed, the underpinning determinant of how we extract resources, inducing those of energy, is the availability of energy itself, and those resources that provide it. As we, inevitably, use up high grade ores, and move on to poorer quality deposits, in which the desired element is increasingly diluted by other materials, the energy input to the whole extractive and processing mechanism increases: in terms of the production of energy resources, this is expressed as declining Energy Return on Investment (EROI). As the quality of mineral deposits declines, the volume of material that needs to be exhumed from the Earth, and processed, enlarges relentlessly, leading overall to increasing amounts of waste for each mass unit of metal, or other element, recovered, and much more additional energy is needed. A coupling between the declining quality both of ores and energy sources can only compound the situation.
It has been indicated that there are insufficient, proven, reserves (and resources too, in certain cases) of several metals required to build a fully renewable energy system, to meet the global demand for energy that is expected by 2050. For scarce elements, recycling is indicated to be of limited value. It is possible that incorporating potentially less efficient technologies (but based on elements that are more widely available) might prove a viable strategy for reducing the risks of supply constraints . The future development of renewables may also rely on the recovery of materials from conflict zones and other politically unstable regions, which could pose problems for its large scale expansion. Moreover, how such a fully renewable energy system might be maintained, beyond 2050, remains a serious open question. Meanwhile, major changes in our global demand for energy are necessary, and it may be wise to spend the fossil fuel equivalent of our remaining carbon budget on the extraction of metals required for low-carbon energy technologies.
Current consumption of resources means that the global materials base is unsustainable, and it is necessary to optimize our use of energy, to close material cycles, and to curb irreversible material losses, of all kinds. Mining of sand and gravel, used to furnish concrete, glass, asphalt and electronic devices, has risen to the point that their supply too is a matter of concern; levels of freshwater use are also now approaching newly defined planetary boundary limits. Natural resources are being consumed on an unprecedented scale, and currently, an annual 92 billion tonnes of raw materials are being extracted, which corresponds to around 12 tonnes for every person on the planet. The timescale of our intentions regarding the use of resources is critical, and the question of whether technology can solve our current problems, and meet future needs “sustainably”, has yet to be answered fully. Perhaps such considerations of what is sustainable only properly make sense, if societal viability over the duration of a civilization (say, 500 years) is planned for; yet we have only the next few decades, at most, to undertake the appropriate actions to establish this. In regard to the sustainable use and regeneration of essential natural resources, it seems likely that the Earth Stewardship scenario, with the design system of permaculture as a creative response pathway toward achieving it, may be the most effective option.
Endangered elements, critical raw materials, conflict minerals, conflict resources, indium, Energy Return on Investment, EROI, planetary boundary, low-carbon energy, civilization, permaculture, circular economy, renewables, renewable energy, fossil fuels, Earth stewardship, Earth-abundant materials, periodic table, wind energy, solar energy, phosphorus, indium, fracking, sand, gravel, sand mining, freshwater.