Critical minerals are those that are required for important applications and are at risk for supply disruption . Example applications are high technology devices, defense applications and energy technologies. Low-carbon technologies require a wide range of critical minerals. For example, batteries require cobalt, lithium, nickel, manganese, and graphite, whereas wind turbines and electric vehicles require rare earth elements .
Abundant access to critical minerals is crucial for the popular low-carbon energy technologies. Why? Because these technologies require several-fold larger amounts of critical minerals compared to conventional technologies .
Currently, adequate access to critical minerals is not an issue because the deployment levels of low-carbon technologies are very small. For example, wind and solar combined provide less than 5% of the total global energy and electric cars represent 1% of the total global car stock [4,5].
But a low-carbon energy transition will cause a drastic change. The deployment of solar, wind, battery energy storage and electric cars will need to increase enormously over the next few decades. An extraordinary increase in the production of critical minerals will be required to support such a deployment [3,6].
Mining and processing of minerals is extremely resource intensive. Examples of resources are energy, land, water, chemicals, and labor. History has shown that resource intensive processes when carried out at very large scales have serious unintended consequences.
Also, resource intensive processes have high associated costs and can lead to supply concerns. Such concerns are expected to increase with an increasing demand for these materials.
The key concerns about critical minerals are summarized below [2,3,6]:
Concern about energy security: The production and processing of critical minerals is concentrated in fewer geographical locations than fossil fuels . For example, just three countries control the global output for lithium, cobalt, and rare earth metals. Moreover, certain countries such as China have an alarmingly large share. Chinese companies have also made large investments in countries–such as Australia, Chile, Democratic Republic of Congo, and Indonesia–that have large capabilities for producing critical minerals. In other words, the few countries who currently control the supply of critical minerals could control the global energy supply. This is an energy security risk for the rest of the world.
Concern about environmental impact: Examples of environmental impact related to the production and processing of critical minerals are soil erosion, soil contamination, biodiversity loss, contamination of water bodies by chemicals, reduced surface water storage capacity, hazardous waste, and air pollution from fine particles. A large increase in the production and processing of mineral resources could markedly increase the risk of severe environmental impacts.
Concern about costs and supply: Several factors contribute to the cost and supply risk of minerals. Key factors are highlighted. A decrease in the quality of resources in the future is a significant concern. The extraction of metals from inferior quality ores requires more energy and creates more waste. Thus, deteriorating quality of resources impacts both cost and the environment. Mining projects typically require many years to move from discovery to production–which has significant supply related implications. Also, the massive and long-term need for critical minerals can cause periodic disruptions in energy supply, which can lead to large cost fluctuations.
What about recycling? Will that easily solve the problem?
Recycling involves the collecting and processing of materials that would otherwise be discarded as trash and turning them into new products. Recycling has several benefits such as reducing waste, conserving resources, and avoiding pollution.
But recycling has some major challenges. Several requirements must be satisfied simultaneously for successful recycling. The requirements include a) an efficient process for collecting and separating materials at the end-of-life, b) a recycling process that can provide the desired material quality with low processing losses, and c) a stable long-term supply of the recycled material.
It is very difficult to satisfy such requirements because of the logistical, technical, and cost challenges. The degree of the challenge depends on the type of material that is being recycled and nature of the application.
The difficulty in achieving high recycle rates is evident from historical data. For reference, we will consider plastic waste and electronic and electrical waste (e-waste) recycling.
According to recent OECD reports, less than 10% of global plastic waste is recycled [8,9]. For reference, the recycling rate for plastics in 2018 was only about 9% in the United States .
Recycling of e-waste has also been low. The world produces about 50 tons of e-waste annually. Although e-waste contains expensive materials, only 20% of the e-waste is formally recycled according to the United Nations Environment Programme .
What is the current state of recycling for the low-carbon technologies?
In case of solar power, the solar panels require the largest amounts of raw materials. Historically, recycling of solar panels has been very small. For example, only about 10% of the solar panels in the U.S. are recycled . In case of wind power, about 85% of the wind turbine blades can be supposedly recycled . But current recycle rates are very low because of the challenges [14,15].
Moreover, recycling cannot satisfy the massive critical minerals needs of the low-carbon technologies. There are two reasons.
First, the current recycling of critical minerals is far from adequate. For example, less than 1% of lithium is recycled .
Second, even if high rates of recycling were miraculously achieved for all critical minerals, only a small fraction of the critical minerals demand can be met by recycling. Why? Because addressing the goals of the Paris Agreement requires a rapid increase in low-carbon technologies and thereby rapid access to large amounts of critical minerals.
Considering the challenges and the historical data from other technologies, the hope that recycling will be an easy solution is not realistic.
Summary: The main concerns related to the critical minerals required for a low-carbon transition are energy security, environmental impact, supply risk and cost escalation. Any of these can cause serious problems. For example, a few countries control the production and processing of some of the critical minerals. This poses an energy security risk for the rest of the world. What about recycling? Several requirements must be satisfied simultaneously for successful recycling. The requirements include a) an efficient process for collecting and separating materials at the end-of-life, b) a recycling process that can provide the desired material quality with low processing losses, and c) a stable long-term supply of the recycled material. Examples from history–such as plastics and e-waste–inform that it is extremely difficult to satisfy such requirements because of logistical, technological, and cost challenges.