produce green hydrogen due to the higher power
densities, higher capacities and quicker start-up times
supported by PEM electrolysis compared to other
electrolysis methods. PEM’s share of technology is
increasing.
Fig.1 Diagram showing the basic principles of PEM
electrolysis: Water molecules are split into hydrogen and
oxygen using electrical energy
1 How much iridium does PEM electrolysis
use today?
At present, every GW of PEM electrolysis
capacity installed reportedly uses about 1.5 tonnes of
iridium, according to Heraeus, a leading provider of
precious metals services and products[1]. At these
loadings, we estimate PEM electrolysis accounts for
several hundred kg of iridium demand per year today.
This demand can easily be met from existing
production. At present, around seven tonnes of iridium
is mined each year, the vast majority of which comes
from South Africa (see Fig.2).
Fig.2 Mined output of iridium from South Africa
(Source: SA Govt statistics)
2 How much could iridium demand from
this sector grow over the next decade?
Future iridium demand from this sector will
depend on two factors; the demand for PEM
electrolysers and the loading of iridium that they need.
There is growing interest from governments in
hydrogen and fuel cell technologies. The uptake of
hydrogen technology is primarily being driven by
government policies, many of which are predicated on
the availability of carbon-neutral hydrogen. The drivers
for promoting hydrogen and fuel cells in energy policy
relate to improving the reliability, efficiency and
security of energy systems, reducing environmental
impacts, and developing new low-carbon industries,
with their associated employment opportunities and
skills.
There are a variety of government targets for new
PEM electrolysis capacity. A cumulative installation of
35 GW of PEM electrolysis capacity worldwide by
2030 would be a reasonable estimate relative to
government targets, and is in line with the IEEFA’s
estimates[2], published in August 2020.
There is a heavy focus on thrifting iridium
loadings on PEM electrolysers to a small fraction of
today’s levels. There is widespread consensus that this
will occur, and we are confident loadings in the future
will be far lower than they are today. How far could
they fall? Heraeus suggests loadings could fall up to 90%
from current amounts i.e. as low as 100 kg/GW.
Another estimate by E4tech, a consultancy, suggests
low-case iridium loadings could be as little as 50
kg/GW.
On the basis that PGM loadings will fall heavily
from today’s level, we think it would be reasonable to
expect annual iridium demand from PEM electrolysis
to be somewhere up to 1 tonne per year in 2030. Again,
this could easily be met from mined iridium production
of around 7 tonnes per year.
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