POWER May 2021 - 28

HYDROGEN
Carbon-Neutral Blue Hydrogen
Can Be More Than a Bridge in a
Transformed Hydrogen Economy
Many advocates for a hydrogen economy believe " green " hydrogen, which is produced
through electrolysis using renewable energy, will eliminate the need to curtail wind
and solar generation. However, there are many reasons why " blue " hydrogen, which
is produced from natural gas while using carbon capture technology to reduce
or eliminate greenhouse gas emissions, could be a better long-term option for
hydrogen production.
Clinton Noack, PhD
and Briggs White, PhD
N
ow is not the first hydrogen (H2
)
revolution. The promise of hydrogen's
energy density and carbonfree
combustion has attracted the attention
of innovators for years, with the
earliest concepts on the hydrogen fuel
cell published in 1801. As large-scale efforts
to decarbonize the global economy
ramp up in earnest, hydrogen is once
more being positioned as a critical solution
for numerous sectors.
Hydrogen produced from fossil energy
resources is commonly viewed as a
bridge in this energy transition, enabling
the build-out of midstream infrastructure
and downstream demand while the cost
of renewably driven electrolysis of water
to produce " green " hydrogen continues
to fall. However, a 100% green hydrogen
economy may fail to deliver on the
potential for hydrogen or unnecessarily
delay progress. To avoid another missed
opportunity, " blue " hydrogen (derived
from fossil fuels with carbon capture,
utilization, and storage [CCUS]) must
comprise a considerable market share
of the hydrogen economy.
Hydrogen's Cost Conundrum
Failures of the hydrogen economy to materialize
have centered on the chicken-orthe-egg
challenge of a paradigm shift in
tightly integrated, capital-intensive industries.
Analyses have shown that hydrogen
becomes the low-cost, low-carbon
solution in a majority of potential end-use
markets at $2/kilogram (kg) H2
.
Currently, fossil-based hydrogen without
carbon capture, known as " gray "
hydrogen, can deliver less than $1.50/kg
H2
28
costs while carbon capture can add
$0.10/kg to $0.30/kg. Green hydrogen
currently delivers approximately $5/kg
unit costs, although these estimates are
dropping sharply with advances in electrolyzer
manufacturing and oversupply
of renewable power expected to achieve
$2.60/kg prices by 2030 and less than
$1.50/kg by 2050.
High cost and a lack of carbon pricing
limit demand across the end-use sectors
where H2
can be most impactful. Without
this demand pull, investment into new
production capacity and new or retrofitted
transmission, distribution, and storage
infrastructure has been unjustifiable.
Commercial consortia, such as the
Hydrogen Council; industry first movers,
like Air Products in Saudi Arabia; and
intergovernmental strategies, including
the European Union Hydrogen Backbone
project, have initiated the investment
needed for the transformation of the hydrogen
economy. However, in each case,
blue hydrogen is at most a steppingstone
to a green hydrogen market: a gray-toblue-to-green
transition. This
strategy
has three primary limitations that may be
resolved through continued utilization of
blue hydrogen. They are:
■ Geographic variability of resource availability.
■
Energy inefficiencies of electrolysis.
■ Intermittent supply limiting build-out of
constant demand end-uses.
Water and Energy Availability Are Key
Hydrogen production requires abundant,
low-cost water or simple hydrocarbons
(primarily
methane).
Green
while gray and blue H2
hydrogen
consumes at least 9 kg of water per kg
of H2
requires
half as much (when produced via steam
methane reforming with a subsequent
water-gas shift). Water is increasingly a
www.powermag.com
1. Capacity factors of potential electrolyzers
running on curtailed renewable power in
the California Independent System Operator
(CAISO) market. Analysis of the data from 2020
found that only 451 tons (t) of hydrogen could
be produced from CAISO's curtailed renewable
energy. Source: National Energy Technology
Laboratory (NETL)
POWER | May 2021
limited resource, with complex and interdependent
uses for energy, agriculture,
and sanitation. In many regions across
the world, often those with abundant renewable
energy, water stress may not allow
for production at the scale required to
meet local demands.
Conversely, utilization of shale gas reservoirs
has dramatically expanded the
geographic footprint of natural gas extraction.
Suitable geologic carbon dioxide
(CO2
) storage capacity is also available
and plentiful. Infrastructure availability is
also vastly different between blue and
green hydrogen. The natural gas value
chain is globally mature, and both financial
and regulatory stakeholders understand
its operation in detail; these " soft "
infrastructures require development in an
all-green hydrogen scenario.
In addition to higher water consumption,
green hydrogen requires approximately
11 times as much energy per unit
H2
produced compared to fossil-based
routes (before carbon capture) and it
needs to be cheap. Greening the current
global gray hydrogen supply would require
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POWER May 2021

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