The transition to 100% renewable energy is going to take pretty large quantities of stuff, that is, metals, minerals, oil (sadly) , natural gas, concrete and so on to build the solar panels, wind turbines, batteries and other equipment we will need. There is some debate about whether or not there will be enough of the stuff to make it happen. Given this uncertainty we will take a look at the question do we have enough of the key resources, in particular metals and minerals, to make the 100% renewable energy transition in this article.
In a previous article I mentioned that time is another precious commodity in this renewable energy transition and that we might only have 20-30 years of it left to complete the transition (if we are lucky). Given this fact, even with reasonably abundant resources, a key factor will be the rate of extraction of all the resources we need. This rate of extraction can be altered by a whole host of factors including, price spikes, economic turmoil, political unrest, climate change, extreme weather etc etc it is beyond the scope of this article to forecast rates of extraction over 30 years and it might in fact be impossible to do so with any accuracy, never-the-less it is something that needs to be kept in mind.
Liebigs law of the minimum
Liebigs law of the minimum (actually conceived by Carl Sprengle but popularised by Justus Von Leibig) states that the growth of a plant is dictated by the scarcest critical resource, that is, if (for example) nitrogen is in the shortest supply it doesn’t matter how many other resources a plant has available (water, potassium, CO2 etc) the growth rate of the plant will be dictated by the supply of nitrogen.
This law equally applies in industrial processes including those that produce solar panels, wind turbines, batteries etc. Given Liebigs law we will attempt to determine the scarcest resource for all of the key equipment needed for the transition.
The table below shows the reserves of key metals needed for the energy transition at 2017 rates of production and during a boom (or 10% growth in demand for 10 years)
As an example the global production of rare earth metals as at 2020 was 140,000 tonnes/yr but if demand grew at 10% for 10 years by the end of 2030 a rare earth extraction rate of 330,000 tonnes/year would be required.
Key equipment for the transition and its limiting resource
The transition to 100% renewable energy is a massive and complex task requiring an enormous number of specialised equipment, it would be impossible to mention all of the equipment individually but you can get around that by focusing on things that need to be scaled up the fastest. The following is an attempt to list of the key components of our energy transition and their limiting input.
Solar PV
We essentially have three generations of solar panels.
generation 1: crystalline silicon.
generation 2: thin film
generation 3: cadmium telluride (CdTe) panels.
The vast bulk of solar panels are generation 1 crystalline silcon cells.
Realistically crystalline silicon cells are the only technology that will scale up to the multi TW scale, but even they have limiting constituents so lets take a look at what they contain. A generation 1 (Sunpower Maxeon 3) panel contains:
- Glass (panel surface) 76% -14.4 kg
- Polymer (encapsulant and back sheet) 10% 1.9 kg
- Aluminium (frame): 8% – 1.52 kg
- Silicon (solar cells) 5% – 0.95 kg
- Copper (inter connectors) 1% – 0.19 kg (190g)
- Silver (contact lines) <0.1% 0.019 kg (19g)
In a previous article I calculated that we are going to need approximately 30 billion (400W) solar panels to provide solar’s part of the energy transition, that is assuming we can cut our energy consumption by 70% which is like Australia reducing its per capita energy use to a country like Cyprus.
Of the constituents of a solar panel, the only two that are relatively scarce are copper and silver. Given we need about 30 billion (400 W) panels to complete the transition we will need 5.72 billion kg (5.72 million T) of copper and 572 million kg (0.572 million T) of silver so the question is do we have it handy?
Short answer yes and no, we have about 870 million T of copper in total global reserves, more than enough. But unfortunately we only have 0.5 million T of silver left (out of 1.7 million T found), this is a serious constraint and unless we find new reserves (or a substitute for silver can be found) the growing scarcity of silver could drive up panel prices significantly.
Wind Turbines
We will look at the 2 MW Vestas V90 – 2 in this analysis. The V90 turbine has over 50 GW of installs currently and is considered proven technology. An average wind turbine is comprised of:
- 79% Steel
- 12% Plastic, fiberglass and resin
- 5% Iron and cast Iron
- 1% Copper
- 2% Aluminium
- 1% other including rare earth magnets
20% of wind turbines (those using direct dives i.e the best performing and highest efficiency kind) use rare earth magnets (containing neodymium and dysprosium) and it may be possible to make high performance wind turbines easily without them however it is not a commercialized technology yet.
From my previous article I calculated we are going to need about 6.3 million 2 MW wind turbines and each 2 MW turbine that uses rare earth magnets uses about 360 kg of neodymium and 60 kg dysprosium which means 2.2 million T of neodymium and 0.378 million T of dysprosium, so do we have enough?
We have about 8 million T of neodymium globally however current production rates are only 7000 T/yr which would need to significantly increased to meet demand. Actual global reserves of dysprosium are hard to come by but if we assume there are 111 million tonnes of rare earths in global reserves and given that dysprosium is about 1.1% of rare earth production we can assume 1.22 million T of dysprosium or enough to meet demand even if we can’t find an alternative to rare earth magnets.
Batteries and Electric Vehicles
Electric cars have two components in them (apart from circuit boards and microchips) that require resources that are potentially limited (for our purposes), namely batteries and motors.
Batteries contain constraining materials such as: nickle, manganese, cobalt and lithium, EV motors (like wind turbines) contain neodymium and dysprosium.
Taking the Tesla battery as an example, the cathode (the terminal positive ions depart from during discharge) for the (453 kg) 70 kWh battery pack contains: 80% nickel, 15% cobalt and 5% aluminium. The only potential ‘rare’ element in the anode and electrolyte is lithium (63 kg used per battery pack) but given there are an estimated 80 million T of economic lithium resources worldwide, lithium is not an immediate concern.
Getting at other componets in the battery are a little tricky but, given the cathode of a Li-ion battery typically takes up 25% of the weight and the 70 kWh of (80650 cell type) Li-ion batteries (46g per cell x 5850 cells) weigh 269 kg, we can assume 54 kg of nickel and 10 kg of cobalt for each electric car.
As for the motor in a Tesla it contains 2 kg of ‘neomagnets’ which are 24% neodymium and 7.5% dysprosium, so we will assume 480 g of neodymium and 150 g of dysprosium. There are about 1 billion cars in the world and 400 million trucks (which are far more important to our civilisation).
Let’s assume we don’t give everyone on earth a car and only replace the cars we have but we add 100 million trucks. So we need to replace 1 billion cars and 500 million trucks. Trucks have 200 kWh battery packs and twice the number of motors of current (dual moter) EVs so pro rata numbers of rare Earths work out to be:
EV motors: 960,000 T of neodymium and 300,000 T of dysprosium
EV batteries: 131,142 T of nickel and 24,000 T cobalt
With 93 million T of nickel reserves globally and 7 million T of cobalt we, in theory, have enough constrained metals to make the transition but of course this assumes we don’t use these metals for any other purpose which is a bit unrealistic.
However it is worth knowing that if required we could divert enough materials to build out the EV motors and batteries to make the switch to battery electric transport. And as for Lithium, it is actually of much less concern that rare earth metals like dysprosium and neodymium and as such is not the limiting factor in the transition (at least as far we are currently aware).
Microchips, circuit boards and other electronics
The renewable energy transition will require billions of microchips, circuit boards and other electronics to be the brains for a whole host of devices including: inverters, optimisers, smart meters, battery management systems, power control equipment, EV microprocessors, monitors, measurement devices, SCADA systems, grid management systems etc. As such microchips, circuit boards and the materials that they require also need to be considered, however a detailed analysis is beyond the scope of this article.
Initially just 12 minerals and metals were used to fabricate microchips now it is 60 including:
- Silicon
- Phosphorous
- Neodymium
- Hafnium
- Tantalum
- Palladium
- Copper
- Boron
- Cobalt
- Tungsten
- Potassium
- Tin
- Gold
- Lead
- Beryllium
- Indium
- Aluminium
- Yttrium
- Lanthanum
- Terbium
- Europium
- Gadolinium
- Arsenic
- Amtimony
Circuit boards contain:
- Gold
- Silver
- Copper
- Tin
- Zinc
- Palladium
- Bismuth
- Indium
- Antimony
Consider a smartphone contains:
- 0.034g of gold
- 0.34 g of silver
- 0.015 g of palladium
Also consider that 1.5 billion smartphone alone are sold each year and that smartphone are often required to optimally use many devices including EVs and PV systems.
It is beyond the scope of this article to calculate the amount of limiting rare earths used in electronics critical to the transition but it should be abundantly clear that there are many points of failure in the electronics industry when it comes to elements required in their manufacture, that is, a shortage of any one of the 60 elements required to produce microchips for whatever reason (political instability, shortages, natural disasters) may pose problems for manufacturing key electronic components required for the renewable energy transition.
Metals recycling
Another concern in the transition to ‘renewable energy’ is that it won’t be renewable at all unless we get serious about recycling the PV panels, wind turbines, batteries and motors (not to mention electronics) and all of the materials they contain at end of life. If we fail to recycle transition equipment well enough, within a few generations we will deplete our store of resources and be unable to manufacture anymore critical equipment sending us right back to before the industrial revolution (only this time without large reserves of fossil fuels).
And recycling complex devices (especially electronics with so many different elements in the one device) will not be easy. At present only 1% of rare earths are recycled world wide, this is no where near good enough, if this is not significantly increased all the ‘transition to renewable energy’ will be is a transition out of the fossil fuel frying pan and into the failing and non-renewable generation equipment fire.
Other sources of rare metals and minerals
Given the precarious supply situation with some key minerals and metals needed by the transition it is worth asking the question if there are any other potential sources of these elements. The answer to that question is yes there are but with some serious caveats. Here is a list of potential but novel sources of rare earths.
Mining Waste
Over the many years we have mined the earth for its resources an enormous quantity of mining waste (aka tailings) has built up, much of which is simply stored in large ponds. Within these wastes are rare earths that were either not considered valuable at the time (i.e. the were created pre mass electronics) or there was no easy process to extract them. With the cost of rare earths rising over time, this waste is being seen by some as a resource, with new processes to extract rare earths from it, such as the process described in this video.
Landfill
In the millions of cubic meters of landfill dumps on earth there is a substantial quantity of e-waste that contains rare earth metals and other useful elements. With a growing awareness of the totally unsustainable nature of landfill, new processes and devices (such as the one in the video below) are being implemented to try and extract valuable materials from landfill, which has concentrations of such materials many times higher than is found in natural ores.
Asteroid mining
While a bit of a ‘hail Mary’ option at the moment asteroid mining may not seem so ridiculous if ambitious space exploration plans of some of the worlds wealthiest people pan out. It is not a serious consideration for the renewable energy transition but who knows what will happen in the decades after (assuming we make it), perhaps recycling rare earth recycling will turn out to be extremely hard in and uneconomic (currently it involves a lot of nasty chemicals) in which case trying to nab an asteroid with highly concentrated rare earth resources might seem like the more feasible option. Here is a video discussing the possibility of asteroid mining in the future.
Conclusion
The future availability of the metals and minerals we will need for the transition is not entirely clear, yes many of the key elements are available in sufficient quantities (in theory) but their rate of extraction (which is equally key given we have limited time) is unknown (and potentially unknowable). We do not yet know how feasible recycling of key resources is, only that we must do it to have any chance of having a truly sustainable energy system.
Given all of these uncertainties it is absolutely crucial that we put the majority of our efforts into doing more with less, that is delivering all of the services that we require with the absolute minimum energy expenditure. We need to lighten the task of transitioning to 100% renewable energy as much as possible to have a chance of success, I will examine some of the ways we might do that in the next article.
Suburban Earthship 