Hydrogen
storage
is
essential
for
the
development
of
secure
and
flexible
renewable
energy
systems
to
meet
our
2050
carbon-neutral
goal.
We
compile
information
on
underground
gas
(UGS)
sites
in
Europe,
assess
their
capacities,
when
repurposed
hydrogen,
estimate
corresponding
costs.
The
maximum
working
(WGE)
hydrogen
existing
UGS
Europe
349
TWh,
which
25%
WGE
natural
gas.
Site-specific
capital
costs
retrofitting
range
between
$10
million
$0.5
billion,
with
86%
requiring
less
than
$100
million.
Storage
depleted
fields
or
saline
aquifers
0.5
TWh
have
a
levelized
cost
$1
per
kg
H2.
In
contrast,
salt
caverns
lower
H2
due
higher
cycling
frequency.
Increasing
experience
capacity
expected
decrease
these
We,
therefore,
use
Wright's
law
that
future
can
be
as
low
$0.2
after
three
cycles.
Based
such
techno-economic
aspects,
we
identify
are
most
suitable
deployments.
Fuel,
Journal Year:
2024,
Volume and Issue:
364, P. 131038 - 131038
Published: Jan. 28, 2024
With
the
long-standing
efforts
of
green
transition
in
our
society,
underground
hydrogen
storage
(UHS)
has
emerged
as
a
viable
solution
to
buffering
seasonal
fluctuations
renewable
energy
supplies
and
demands.
Like
operations
hydrocarbon
production
geological
CO2
storage,
successful
UHS
project
requires
good
understanding
subsurface
formations,
while
having
different
operational
objectives
practical
challenges.
Similar
situations
problems,
information
formations
at
field
level
cannot
be
obtained
through
direct
measurements
due
resulting
high
costs.
As
such,
there
is
need
for
characterization
monitoring
scale,
which
uses
certain
history
matching
algorithm
calibrate
numerical
model
based
on
available
data.
Whereas
have
been
widely
used
activities
better
reservoirs,
best
knowledge,
present
it
appears
relatively
less
touched
area
problems.
This
work
aims
narrow
this
noticed
gap,
investigates
use
an
ensemble-based
workflow
3D
case
study.
Numerical
results
study
indicate
that
works
reasonably
well,
also
identifying
some
particular
challenges
would
relevant
real-world
iScience,
Journal Year:
2023,
Volume and Issue:
27(1), P. 108771 - 108771
Published: Dec. 20, 2023
Hydrogen
storage
is
crucial
to
developing
secure
renewable
energy
systems
meet
the
European
Union's
2050
carbon
neutrality
objectives.
However,
a
knowledge
gap
exists
concerning
site-specific
performance
and
economic
viability
of
utilizing
underground
gas
(UGS)
sites
for
hydrogen
in
Europe.
We
compile
information
on
UGS
assess
potential
capacity
evaluate
associated
current
future
costs.
The
total
Europe
349
TWh
working
(WGE),
with
capital
costs
ranging
from
$10
million
$1
billion.
Porous
media
salt
caverns,
boasting
minimum
0.5
WGE,
exhibit
levelized
$1.5
$0.8
per
kilogram
hydrogen,
respectively.
It
estimated
that
can
potentially
decrease
as
low
$0.4
after
three
experience
cycles.
Leveraging
these
techno-economic
considerations,
we
identify
suitable
sites.
Fuel,
Journal Year:
2024,
Volume and Issue:
371, P. 131893 - 131893
Published: May 18, 2024
This
paper
comprehensively
reviews
mechanical
weakening
and
crack
development
in
the
caprock
during
underground
hydrogen
storage
depleted
gas
reservoirs.
Hydrogen
loss
due
to
geochemical
interactions
of
minerals
critically
impacts
integrity.
As
shown
review,
it
is
conspicuous
that
properties
also
change
with
injection,
affecting
its
brittle-ductile
behaviour.
Furthermore,
stress–strain
behaviour
changed,
undergoes
irreversible
deformations
under
influence
confining
pressure,
cyclic
loading,
changes
mineral
composition.
The
fracturing
another
critical
impact
on
integrity,
which
may
create
new
routes
for
permeation
through
caprock.
Cracks
form
multiple
ways,
mainly
03
ways;
1)
Highly
pressurized
injection
creates
cracks
when
pore
pressure
exceeds
fracture
toughness,
called
cracks,
2)
injected
accumulates
gravity
segregation
and,
eventually,
diffuses
into
caprock,
displacing
fluid
(brine).
Consequently,
capillary
stress
pores
increase
developing
shrinkage
3)
Geomechanical
interaction
between
hydron-pore
fluid-rock
biotic
environment
(micro-organisms)
available
at
sites
can
cause
degradation
forming
low
conditions,
sub-critical
cracks.
Although
or
tensile
formation
process
has
been
widely
studied
existing
studies,
minor
attention
given
other
possible
processes
including
hydrogen-induced
cracking
geomechanical
reactions
causing
cracking.
In
addition,
this
overall
structure
flow
characteristics
hasn't
properly
understood,
adding
extra
uncertainty
caprock's
integrity
process.
Scientific Reports,
Journal Year:
2025,
Volume and Issue:
15(1)
Published: Jan. 2, 2025
Abstract
Salt
caverns
are
widely
regarded
as
a
suitable
option
for
the
underground
storage
of
hydrogen.
However,
an
accurate
assessment
hydrogen
leakage
through
walls
salt
into
surrounding
formations
remains
crucial.
In
this
work,
flow
formation
is
evaluated
by
assuming
that
rock
consists
bundles
tortuous
nano-capillary
tubes.
A
formulation
was
then
proposed
to
model
in
linear
and
radial
domains.
The
formulations
based
on
newly
unified
gas
valid
entire
range
Knudsen
numbers
accounts
slippage,
bulk
diffusion,
diffusion.
finite-difference
approximation
with
iterative
procedure
used
treat
nonlinearity
solve
presented
formulations.
were
validated
against
experimental
data
reported
literature.
results
obtained
indicated
over
wide
pore
radii
operating
pressures
temperatures,
slippage
regime
must
be
considered.
cavern
relevant
dimensions
conditions,
cumulative
after
30
years
cyclic
only
0.36%
maximum
capacity.
It
also
noticed
most
leaked
would
back
at
times
when
pressure
lower
than
pressure,
e.g.
during
production
subsequent
idle
times.
At
low
very
tight
rock,
diffusion
important
mechanism
transport.
high
though,
viscous
became
predominant
mechanism.
presence
thin
interlayer
such
mudstone,
carbonate,
anhydrite
body
can
have
significant
impact
amount
leakage.
appeared
although
increasing
from
120
135
bar
led
11.9%
increase
capacity,
loss
increased
significantly
0.007%
bar.
Furthermore,
absolute
rate
natural
higher
storage,
relative
relation
capacity
much
lower.
compared
storage.
study
help
better
understanding
it
comes
large-scale
