H2Tech - Q3 2021 - 23

SPECIAL FOCUS: HYDROGEN INFRASTRUCTURE DEVELOPMENT
H2 value chain analysis comparing different
transport vectors-Part 1
N. CHODOROWSKA and M. FARHADI, Wood, Reading, UK
Meeting the anticipated 10-fold increase in hydrogen requirements
by 2050 has led to many studies evaluating the most
techno-economic means to achieve this target. While fully
green, large-scale value chains are still some way off, there is adequate
hydrocarbon infrastructure in place where blue H2
could
be produced.
This article assesses the options to convert a portion of the
LNG supply chain already in place between Qatar and the UK
into blue H2
H2. Transporting the H2
(NH3
) or other liquid organic H2
and the different transport vectors to convey the
as liquid or in the form of ammonia
carriers (LOHC), such as
methylcyclohexane (MCH), are common comparisons; however,
retaining liquified natural gas (LNG) as the energy carrier
is also considered. It is shown with available technology that
LNG as the transport vector is economic compared to ammonia
and LOHC, with liquid H2
(LH2
) still somewhat more expensive
but anticipated to decrease in cost.
Introduction to project study. As a result of global demand
for natural gas and the general fact that the resource-rich areas
of the world are at significant distances from their markets, wellestablished
production and transportation methods have been
developed. Full value chains, from gas wells to regasification
terminals, have been put in place with economy of scale, equipment
efficiency and optimization of every aspect being developed
over the years.
Replacing these value chains with low-carbon and green
forms of energy will require significant development of new
and large-scale technologies not yet developed or proven. The
largest electrolyzer project in development is 24 MW, with an
expected carbon dioxide (CO2
MMtpy,1
) emissions reduction of 0.04
approximately 3% of the scale of this study. The reuse
of existing infrastructure should be considered as an interim
measure while new technologies are developed if the lower CO2
emissions targets of 2030 and 2050 are to be achieved.
This article examines a well-established LNG value chain
and the options to change a portion of it, limited by downstream
infrastructure specifications, to blue H2
to market, as there is significant cost involved in storagainst
either liquid NH3
or
. A number of
studies and papers compare different transport vectors for delivering
H2
age and transportation. However, these studies generally compare
only the transportation of LH2
an LOHC, such as methanol or MCH.
The results of the studies vary depending on the export location,
the import location and the distance between the two.
Concept basis. This study considers four transportation vectors
to convert natural gas from Ras Laffan Industrial City in
northeast Qatar into an H2
product at South Hook LNG terminal
in Milford Haven, West Wales, UK.
The product is transported 6,140 nautical mi (approximately
11,371 km) by ship from Qatar to South Hook LNG terminal in
the UK.3
via the Suez Canal,4
As shown in FIG. 1, the sea route is an established route
through which a large Q-Max LNG tanker
of 266,000 m3 can pass.5
the same quantity of H2
In all scenarios considered in this study,
delivery to the injection point on the
UK gas grid is targeted.
The LNG regasification terminal in South Hook has a design
capacity of 15.6 MMtpy.6
An H2 blend with natural gas is conH2Tech
| Q3 2021 23
Therefore, it can be concluded that one solution probably will
not fit all situations in the future, and concept feasibility studies
will be required for defined configurations. This is not dissimilar
to LNG value chains, where the specific project characteristics
determine the final detailed configurations.
One aspect to be considered in the production of blue H2
the disposal of the CO2
is
captured in the process. It is generally
assumed to be reinjected and stored permanently at the export
location; however, two additional options exist:
1. The CO2
2. The CO2
at the import location
location for reinjection.
can be reinjected into permanent storage
can be transported back to the export
In this article, the second option is considered so that the
four transportation vectors can be compared on a reasonably
equal basis.
The Qatargas 2 (QG2) project is a fully integrated value
chain linking all of the components from wells to market in a
single project. Offshore wells in Qatar deliver gas to Ras Laffan,
where two LNG mega-trains (Trains 4 and 5) are installed.
The LNG is transported in dedicated Q-Max LNG carriers to
the South Hook LNG terminal in Wales, UK.
There is consensus that up to 20 mol% H2
can be mixed
with natural gas into the UK gas grid without many complications
with respect to pipeline materials and end users receiving
the gas.2
Siting a blue H2
Qatar by ship for reinjection. All three comparison options
have the blue H2
plant sited at Qatar, where the captured CO2
is also compressed and reinjected.
plant consisting of steam methane
is liquefied and returned to
reformers (SMRs) with carbon capture at this location is the
reference for this study. The CO2
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