POWER April 2023 - 31

GEOTHERMAL
cooling, and power; a storage resource;
and a mineral resource, " she said. " The
Earth itself has the potential to address
a variety of hurdles in the transition to a
clean energy future. "
Geothermal hydrogen production has
2. Pilot installation of an SLB REDA Thermal power-efficient geothermal electric submersible
pump (ESP) at Zorlu Enerji's high-enthalpy well field resulted in a net increase of 1.7 MW in
geothermal power supplied to the Turkish grid. Zorlu Enerji has requested 14 additional ESP
units for wells at its Kizildere Field, along with digital services for ESP monitoring and surveillance.
Courtesy: SLB
More novel technologies on the horizon
that could allow for geothermal energy
production from deeper geothermal
resources include enhanced geothermal
systems (EGS), advanced geothermal
systems (AGS), and supercritical geothermal
systems. Geothermal startup
Fervo Energy, a company participating
in the U.S. government's EGS laboratory
in Utah, plans to build, own, and operate
power plants that will source energy
from hot rock reservoirs using existing
innovations, such as horizontal drilling
and distributed fiberoptic sensing.
Canadian
firm
Eavor Technologies,
meanwhile, is demonstrating an Eavor-lite
facility-a full-scale prototype
closed-loop built in 2019 to demonstrate
its innovative Eavor-Loop technology. The
system connects two vertical wells with
many horizontal multilateral wellbores
creating a closed sealed radiator-like system.
Eavor, notably, is building its first
8.2-MWe commercial implementation of
an Eavor-Loop in Bavaria south of Munich
near Geretsried, Germany.
In March, another startup, Californiabased
GreenFire Energy, announced it
would provide its AGS closed-loop technology
to run a closed-loop geothermal
test using a test well at Baker Hughes'
Energy Innovation Center in Oklahoma
City, Oklahoma. " The project will create
the first of its kind closed-loop geothermal
laboratory in the world. GreenFire
Energy and strategic partner, Vallourec,
will provide in-kind materials and labor
for construction, testing, and piloting, "
the company said.
Leveraging Oil and Gas Expertise
Many startups entering the geothermal
space are notably bolstered by O&G
investments or have leadership teams
comprising lifelong O&G industry veterans.
That's because geothermal relies
on some of the same technologies
April 2023 | POWER
used in the O&G industry, including
drilling and well completion technologies,
and underground resource assessment
technologies. EGS, for example,
was developed using technologies that
expanded U.S. shale oil and natural gas
production, including directional drilling,
hydraulic fracturing (fracking), and reservoir
stimulation and management tools.
Among startups leveraging O&G expertise
to advance geothermal is Quaise. The
Boston-headquartered firm is developing
" millimeter wave " drilling systems that
have the potential to drill down to temperatures
of 500C and depths of 20 kilometers
(km) " to greatly increase the performance
and geographical reach of geothermal energy, "
it said. The company plans to develop a
first-of-its-kind " 100 MW+ geothermal field
by 2026 and to repower a full coal-fired thermal
power plant by 2028, " it said.
Another company, Houston-based
Sage, is working to optimize power generated
from geothermal systems using
GeoTwin, a tool based on " decades of
experience modeling subsurface fluids
and processes in the drilling of oil and
gas wells. " The company targets lower
temperatures of 100C to 250C at depths
of 3 km to 6 km worldwide.
New Applications on the Horizon
Meanwhile, several startups are exploring
new geothermal energy applications,
such as recovering minerals from geothermal
brines, increasing synergies with
hydrogen production, improving the efficiency
of electricity production from medium-temperature
geothermal resources,
hybrid configurations, and carbon capture.
These prospects extend geothermal's
usability and could potentially give it
more market clout, noted Amanda Kolker,
geothermal laboratory program manager
at the National Renewable Energy Laboratory
(NREL). " Geothermal is a triple
resource: an energy source for heating,
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so far been pioneered in Taupo, New
Zealand, by Halcyon Power, a 50/50
joint venture between New Zealand's
Tuaropaki Trust and the Japanese firm
Obayashi Corp. Halcyon's project began
production in December 2021 and uses
geothermal power to produce about 180
tonnes of hydrogen annually. Meanwhile,
in 2021, startup Geo40 commissioned
the world's first sustainable large-scale
commercial silica recovery plant from
geothermal brine at the 110-MWe Ohaaki
electric power station also located in
the Taupo Volcanic Zone of New Zealand.
That project can produce 5,000 tons per
year of colloidal silica. The achievement
is notable because " Colloidal silica has
traditionally been manufactured in a very
carbon-intensive fashion, which required
quartz-rich sand to be melted in a blast
furnace at very high temperatures, " the
company said. " Geo40 extracts its silica
directly from solution downstream of
the power station, without the need to
disturb the surface with mining. The depleted
solution is then re-injected back
into the hydrothermal aquifer, helping to
maintain its water balance. "
Meanwhile, several companies are
also developing lithium extraction facilities.
Vulcan Energy Resources, developer
of the Zero Carbon Lithium project, says
it intends to produce a " battery-quality "
lithium hydroxide chemical product from
its combined geothermal energy and
lithium resource in Germany-Europe's
largest lithium resource. In January, Vulcan
signed a binding term sheet for a
multiphase project with Dutch automaker
Stellantis to develop new geothermal
projects aimed at decarbonizing the energy
mix of Stellantis' Rüsselsheim industrial
site in Germany.
Finally, geothermal developers venturing
into carbon capture include Fervo
Energy. In February, the company announced
that it would design and engineer
a fully integrated geothermal and
direct air capture (DAC) facility with support
from the Chan Zuckerberg Initiative
(CZI). " Geothermal can deliver the
carbon-free power and heat needed to
make DAC a viable means for removing
carbon dioxide from the atmosphere, "
noted Tim Latimer, CEO of Fervo. ■
-Sonal Patel is a POWER senior
associate editor.
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POWER April 2023

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