H2Tech - Q3 2022 - 16

SPECIAL FOCUS PATHWAYS FOR SUSTAINABLE H2
ever, other battery technologies-particularly those built with
low-cost and abundant materials like iron, zinc and sodium-
are coming into the market.
In early 2022, Massachusetts-based startup Form Energy
announced that it would collaborate with Georgia Power to
deploy an energy storage project of up to 15 MW/1,500 MWh,
using an iron-air battery that the company says can offer up to
100 hr of electricity storage. This is 15 times larger than the
first pilot project announced in 2020 by Minnesota utility
Great River Energy, which promised 1 MW/100 MWh.
This latest project marks a tremendous leap forward from
current storage projects and would provide backup power to
cover more than 99% of all localized grid outages. However,
100 hr is only about 1 wk, and this is still not nearly enough to
enable monthly or seasonal energy shifting.
These iron-air batteries promise to store multiple days'
worth of energy. They will not degrade or catch on fire and are
more attractive against the rising raw-material cost of lithiumion
battery cells (there is even a battery chemistry based on
antimony, another low-cost element).
A surge in funding for research and development has helped
overcome many challenges around iron and zinc batteries, with
promising advancements. For example, ZAF Energy Systems
is exploring nickel zinc batteries to support data centers (one
of the fastest-growing markets for energy storage), pushing beyond
what was traditionally driven by lead-acid and lithiumion
energy storage.
Iron-air batteries derive their power from the interaction
of iron and oxygen, which causes oxidation. AZO Materials
reports that iron-air batteries save more energy than lithiumion
batteries-1,200 Wh/kg vs. 600 Wh/kg. In addition, they
are extremely durable, capable of withstanding more than
10,000 full cycles from fully charged to completely discharged
and back again (the charge life of lithium-ion batteries is only
3,000 cycles-5,000 cycles).
Zinc batteries rely on a water-based electrolyte to charge
and discharge, making them safer than potentially flammable
lithium-ion batteries. Additionally, according to a 2020 scientific
paper, zinc batteries offer an energy density of up to
1,350 Wh/kg, and the production costs are much lower than
lithium-ion batteries. Canadian-based startup Zinc8 reports
that the capital cost of its 8-hr storage product is about $250/
kWh, declining to $100/kWh for a 32-hr system and $60/kWh
for 100 hr. By contrast, lithium-ion projects cost about $300/
kWh for any duration over 8 hr.
However, the downside is that these iron and zinc batteries
still do not achieve very long-duration energy storage. While
100 hr is a huge improvement over lithium-ion's 8 hr, it is still
not enough to enable that critical seasonal shifting. In addition,
the amount of storage capacity is directly tied to the size of the
unit. Increasing storage capacity would require increasing the
size of the unit, making it more site constrained.
Traditional battery energy storage is extremely mineral intensive.
According to an article from Canary Media, batteries
require the mining of 11 different mineral ores, from which
everything from aluminum to zinc are refined. The article
states, " Of all the clean-energy technologies set to boom in
coming decades, none will put a strain on minerals supply like
batteries. They account for about half of the projected growth
16 Q3 2022 | H2-Tech.com
in minerals demand over the next two decades in a rapid decarbonization
scenario. "
H2: A step toward long-duration energy storage. Advanced
energy storage technology is where H2
Bringing batteries and H2
comes in.
age issue in a fast, potentially economical manner. H2
in the future. Also, green H2
together can solve the energy stor,
as a
form of chemical energy storage, can both complement and
serve as a reliable alternative to batteries, particularly when
considering that H2
prices will become more competitive
-which is produced through
electrolysis of water, powered by renewable energy-takes
it one step further by offering a carbon-free solution. To be
economical, batteries must be charged and discharged daily,
discharging for a few hours. Conversely, H2
can be produced
continuously and stored, providing storage systems of very
long durations-such as seasonal storage that can be used for
backup power, limited only by storage volume capacity.
In tandem with batteries, H2
can be deployed when it is
needed, much like the natural gas or diesel backups in use today.
This flexibility and its features as a carbon-free, mineralfree
electricity generator provide premium benefits that offset
the conversion losses as H2
is extracted from water, stored, and
then used in backup turbines or engines that are the conventional
power equipment sources that produce electricity.
Small amounts of H2
(up to a few MWh) can be compressed
and stored in pressure vessels or, with new technology,
adsorbed by solid metal hydrides or even advanced nanotubes.
Very large amounts of H2
salt caverns of up to 500,000 m3
can be stored in underground
at 2,900 psi, which would
mean about 100 GWh of stored electricity, according to the
U.S. Energy Storage Association.
H2
can also be converted into green ammonia, a liquid
chemical consisting of nitrogen and hydrogen that can be
produced using 100% carbon-free renewable energy. Being
a liquid makes green ammonia easier to transport and store,
especially when using existing liquefied natural gas (LNG) infrastructure.
This ammonia can then serve as an energy storage
medium, and it can even be burned directly as a carbonfree/emissions-free
energy source-or, since it is composed
of one nitrogen and three hydrogen atoms, it can be cracked
to convert it back into H2
The H2
, then used as described previously.
can then produce the electricity used in engines,
directly with the oxygen in air to produce
energy storcombined-cycle
gas power plants and even in fuel cells that
would use the H2
electricity and heat, emitting only water vapor.
After touching on the mineral intensity of traditional battery
energy storage, it must be said that while H2
age would still require minerals to build the electrolyzers that
split water into H2
trolyzer is built, it can process huge amounts of H2
, that capital is a sunk cost. Once the elecfor
long periods
of time (decades), unlike lithium, iron and zinc batteries,
which would require an ongoing feed of minerals, considering
their shorter lifetimes.
Cost does remain an issue for H2
. Although H2
costs down.
offers several
benefits vs. traditional battery energy storage, iron and
zinc do win out when it comes to capital cost requirements.
H2
has not yet reached the economies of scale that will bring
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