A new paper in
Joule does statistical analysis of needed materials for electricity generation
in different climate scenarios for the energy transition and concludes that those
materials like steel, concrete, fiberglass, critical minerals, and rare earth
elements are in sufficient supply in all scenarios in terms of manufacturing capacity or geological reserves. The paper
calculates material demand and material-associated emissions for new generation
infrastructure. This analysis does not include battery materials or CO2 removal
and sequestration technologies. It focuses mostly on wind and solar but also
nuclear and hydro. It seems to address technically recoverable reserves rather
than economically recoverable reserves and does not address things like public
opposition to mining projects, regulatory delays, and the time it takes to
bring new mines and new discoveries to market, which can be on the order of
decades. It concludes that future demand for these materials for electricity generation
can be supplied. I don’t disagree and this is not generally in dispute, but the
question remains whether they can be supplied economically. They also conclude
that the carbon emissions of obtaining these materials are “non-negligible,
but limited in magnitude.”
The paper is
written by several former veterans of the Breakthrough Institute, which has
championed a pragmatic approach to energy and climate, which I have found to be
sensible. I have read much sane analysis from these authors. This is not an
activist-scientist analysis like those of Stanford’s Mark Jacobson or Saul
Griffith of ‘Rewiring America,’ advocating for a war-like effort of massive
spending to decarbonize 100% in a short time. However, these kinds of meta-statistical
analyses can be tricky and debatable.
We know there
are plenty of mineral reserves, but questions remain whether they can be
recovered economically. For instance, it has been noted that remaining copper
ores are getting less concentrated and will require more ore, more processing, more
water, more energy, and more emissions to produce the same amount of copper
than in ores with higher concentrations. Most rare earth elements are not
really rare, but they can be expensive to recover from less concentrated
sources. The same is true of lithium and other materials. China enjoys a
monopoly on many rare earth elements as well as their processing due both to
their geologic endowment of concentrated supply as well as significant
government subsidization which allows them to sell them on the global market at
a great discount to other supplies.
The paper
concludes, rather obviously, that the faster decarbonization of electricity
generation takes place, the more will be the strain on materials supply. Faster
decarbonization also means greater likelihoods of demand and price spikes of
materials. They did analysis for 75 different integrated assessment models
(IAMs) in order to keep global temperatures under 2 deg C or lower. They note
that scenarios where solar and wind will make of 40% or more of electricity
generation by 2050 show considerably higher demand for structural material like
cement, steel, copper, and aluminum and for raw materials like neodymium (Nd), tellurium
(Te), and silver (Ag). The authors note: “In 1.5°C scenarios, most
material-related emissions are associated with solar-grade polysilicon … and
cement.” As in other analyses it is acknowledged that mining and production
of materials will need to increase:
‘Rare earths for wind turbines alone might require
tripling global rare earth metal production, while buildout of CdTe thin-film
solar could necessitate an even larger increase in global Te production.
Estimated future solar-grade polysilicon demand will also outstrip current
production, potentially by more than a factor of two. These results are similar
to the findings of a recent report by the International Energy Agency (IEA),
which projects a 3- to 7-fold increase in demand for the rare earth metals (the
IEA scenario also includes rare earth demand from electric vehicles) and a
2-fold increase in polysilicon demand between 2020 and 2040.”
In the following
statement they do acknowledge that economic uncertainties can affect the
ability to supply the materials for these scenarios cost-effectively:
“Ultimately, growth rates in mineral production and
changing estimates of economically recoverable mineral reserves depend on not
just geology, but also commodity prices, demand, and extraction techniques. For
byproduct commodities, production and reserves depend on demand for the primary
mineral and other co-products in addition to the byproduct in question.”
They also note
that the materials-associated carbon intensities of wind and solar depend also
on our ability to decarbonize the cement and steel sectors. Although there has
been some progress in these areas in recent years it could easily be 2040 or
later when such decarbonized steel and cement begin to be widely implemented.
That means that near-term emissions will stay high for such materials. The high
carbon footprint of solar-grade polysilicon is due to its dominant manufacture
in coal-intensive China. I don’t believe that is likely to change much before
2040.
For electricity
transmission and distribution infrastructure, which is included in the study, the
main materials concerns are bulk materials: cement, steel, copper, and aluminum
and these needs are smaller than for electricity generation – they estimate
less than half. They do, however, acknowledge that their methodology here may underestimate
transmission and distribution needs in high wind and solar scenarios due to the
geographic distribution of those resources which may require more transmission and
distribution.
In a section
of the paper, they note key limitations of their study and these certainly can
affect the feasibility of meeting especially the more aggressive
decarbonization scenarios. The study does not include “material requirements
and emissions associated with fuel production, parts manufacturing,
construction, fuel combustion, operations, and decommissioning and end-of-life
processes. Similarly, the embodied emissions per ton of material reflect a
cradle-to-factory-gate scope that incorporates emissions associated with
mining, ore processing, and refining, but not the manufacturing of finished
parts or the end-of-life phase.”
“Our study’s results may consequently underestimate
true raw material requirements, while our selected materials of interest is
also not comprehensive. Our simplistic separate estimate of material
requirements associated with off-site transmission and distribution, which may
require sizable quantities of Cu, steel, cement, and Al, omits much of the
transmission grid’s real-world complexity.”
I think it is
important to point out these issues since they could easily make something seemingly
feasible and realistic into something not feasible and realistic. They
acknowledge that estimates for raw materials needed for clean energy technologies
in different scenarios may vary widely. They also acknowledge potential ‘wildcards’
that could make materials needs less, including technological improvements,
material substitution, recycling, and alternative technological choices.
Overall, I
think the paper is a great effort to understand and quantify materials needs. The
conclusions, however, do not, for me at least, decrease my uncertainty about the
technological feasibility and especially the economic feasibility of
decarbonization, especially vastly accelerated decarbonization. The conclusions
seem to be that there are enough materials there and the emissions of producing
those materials are manageable. However, the economics of producing those
materials at sufficient quantities to meet demand that could spike at any time,
were not adequately addressed. It would be very difficult to do so, in fact.
References:
Future demand for
electricity generation materials under different climate mitigation scenarios. Seaver
Wang, Zeke Hausfather, Steven Davis, Lauren
Liebermann, Guido D. Núñez-Mujica, Jameson McBride. Joule. January 27, 2023. https://doi.org/10.1016/j.joule.2023.01.001
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