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INCREASING CARBON-FREE ENERGYWITH INTELLIGENT DIGITAL SOLUTIONS
Geothermal resources tosupport electric power
generation are available
worldwide. New andexisting plants can be
more productive using thelatest digital technologies.

Domo de San Pedro Geothermal Power Station in Nayarit,
Mexico © Image courtesy of Geotérmica para el Desarrollo

GEOTHERMAL:A SOURCE FORDISPATCHABLE
RENEWABLE ENERGY
The world is hungry for more energy, while climate change
requires lower emissions from power plants. Powergeneration companies must supply more energy and lower
emissions at the same time. One type of power plant thathas an edge when it comes to supplying carbon-free energy
is geothermal. Geothermal power generation involves nofossil fuel combustion because it uses magma heat energy
inside the earth. Therefore, it emits little carbon dioxide to theatmosphere during operation and is very effective against
global warming.

Geothermal power plants can run all the time, given that
their fuel source is constant. Thus increasing energy
generation with geothermal offers decarbonization withfully dispatchable renewable and carbon-free energy.
It is a valuable baseload source of renewable power thatis not susceptible to external factors like the availability ofwind and sun, neither of which can be considered to bereliably dispatchable.
Geothermal plants even have some advantages overexisting hydro plants in times when there is low rainfall
or drought threatens, and perhaps longer term if climatechange continues to redistribute rainfall. Geothermal is
the only renewable energy resource that truly is reliably
available 24/7/365.
Thus anything that can sustain the long-term power output,
reliability or availability of a geothermal power plant isvery valuable.

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USA

TurkeyPhilippines

Iceland

GLOBAL OPPORTUNITIESFOR NEW AND EXISTING
GEOTHERMAL POWER
There are hundreds of geothermal power plants in operationin 30 countries around the world that are already capable ofgenerating nearly 16 GW (Source: Proceedings of the World
Geothermal Congress 2021+1), and there is opportunity tobuild additional plants in many areas.

LIFE CYCLE CO2 EMISSIONS (g-CO2/kWh) FROM POWER-GENERATIONTECHNOLOGIES

A significant challenge for operators of geothermal power
plants is that sources of geothermal energy graduallychange their characteristics over time, so regular optimizationof O&M practices and thermal cycle equipment are needed
to maximize the productivity of geothermal plants.
Another challenge is that the steam generated fromgeothermal sources can contain impurities that require
special attention to sustain the maximum potential
electrical output from the geothermal heat source.
The growing opportunities for application of new digitaltechnologies based on extensive geothermal plant
construction, operation and maintenance experience,
combined with experience developing advanced technology
for gas and steam turbine applications, provide a firm
foundation for tailoring intelligent solutions that help
geothermal plant operators manage the unique conditionsof their plants for improved efficiency and reliability.
The latest monitoring, plant process simulation and advanced
analytics provide the data for early identification of anomalies,

performance degradation trends and optimization
opportunities. Once identified and classified by root cause,
corrective actions to offset the changes can restore the plant
to optimum performance in the most cost-effective manner.

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TECHNOLOGYADVANCEMENTS FORGEOTHERMAL POWER
PLANTSKEY PLANT AND WELL PARAMETERS

In recent years, there have been many advancements in
geothermal power plant technology that improve theirefficiency, reliability and profitability. A real-world
example of advancements in technology that increases
reliability and efficiency is at the Domo de San Pedro
Geothermal Power Station in Nayarit, Mexico.
The Domo de San Pedro Geothermal Power Station is
the first geothermal power plant in the world to add
Mitsubishi Power’s TOMONI® intelligent digital solutions
to improve efficiency and reliability. TOMONI solutions
were applied to the Domo de San Pedro Power Station
to sustain its long-term competitiveness through asset
optimization, analytics for operator and maintenancesupport, and artificial intelligence.
Mitsubishi Power built the 25-MW Domo de San Pedro
plant under a turnkey engineering, procurement andconstruction contract completed in 2016. Because
geothermal production wells change over time andsteam conditions diverge from optimal design, geothermal
plants should be optimized periodically to compensate
for these changes.

AUTOMATED TRACKING AND REPORTING

The intelligent digital solutions applied at Domo de San Pedro
include remote monitoring and real-time data analysis of
the total power plant systems. Mitsubishi Power combines
its experience in plant design and operation with actual
operating data to develop real-time models that identify
opportunities to optimize plant operation and maintenance.
For example, equipment is monitored online for degradationof thermodynamic performance, an indicator of scale
accumulation caused by naturally occurring minerals inthe steam and hot water, so optimal outage plans can be
developed based on the plant’s actual condition rather thanon standardized remedial schedules. Remote monitoringand support services can also shorten or even prevent
unplanned outages by detecting anomalies and providing
early countermeasure planning and operational guidance.
Domo de San Pedro now has the tools to diagnose andpredict changing operating conditions and to develop optimal
solutions that allow the plant to continuously adapt tomaximize plant performance and reliability. Those tools
have been supporting detailed simulation and analysis ofcurrent geothermal resource conditions and have identified
plant modifications that will increase net plant output of

the existing generating unit by nearly 10%. They have also
identified several opportunities for the existing equipment tooperate more efficiently and reliably, thereby increasing thelong-term cumulative generation from the plant (results onother plants may vary based on plant configuaration andwell condition).

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Nagasaki, Japan TOMONI HUB
that supports geothermal power plants

REAL-TIME
INTERACTIVE SUPPORTOF GEOTHERMAL PLANTSTOMONI HUB provides connected software and services thatmonitor and provide early warning of impending issues orneeded corrective action to avoid unit trips or load reductions
while reducing energy-efficiency losses and avoiding
unnecessary maintenance.
FLEXIBLE
O&M
OPTIMIZATIONOPERATIONSSOLUTIONSThe TOMONI HUB Analytics and Performance Center in the
Mitsubishi Power Nagasaki Shipyard and Machinery Worksin Nagasaki, Japan, remotely supports operations andmaintenance (O&M) for various types of power-generating
equipment, including geothermal power systems, with thefull expertise of plant and equipment designers.
For geothermal power plants, O&M support includes a
focus on scale precipitation within the steam processing
equipment and steam turbines of geothermal generators,
as these are routinely placed in harsh environments that arehighly susceptible to corrosion. It tracks and trends changes
in geothermal well characteristics such as pressure, flow
and impurity composition to compare to the equipment
design basis and allows identification of the most effective
and economic cycle optimization over time. It also applies
analytics proven on fired boiler and other steam turbine–
based thermal cycles, electric generator and BOP systems
to maximize the performance of the total plant.

DATA FOUNDATION& ENABLERS

For over 20 years, Mitsubishi Power has been steadily
expanding the capabilities of its TOMONI HUB network andhas been successfully providing remote monitoring andincreasing the use of advanced analytics to make power
plants more reliable and profitable.

PERFORMANCEIMPROVEMENTIMPROVEMENTSOLUTIONSFLEXIBLE
OPERATIONSOPERATIONSSOLUTIONSDATAFOUNDATIONFOUNDATION& ENABLERS& ENABLERSTOMONI HUBs are centralized resources that can support all
types of energy systems, long-term and short-term energystorage systems. Proven benefits show plants connected
to TOMONI HUB have on average two to four fewer days of
unplanned downtime per year and three to four fewer days ofplanned downtime per year than similar unconnected plants,
providing millions of dollars of annual value for their owners.
Increasing the energy generated by geothermal plants
significantly contributes to decarbonization goals to cut
emissions and supply carbon-free energy. Combined withnew technology advancements such as artificial intelligence,
analytics and remote monitoring, geothermal power plants will
improve their efficiency, reliability and profitability to create
more energy from existing and future geothermal power plants.
O&M
OPTIMIZATIONPERFORMANCEPERFORMANCEIMPROVEMENTIMPROVEMENTSOLUTIONSFLEXIBLE
FLEXIBLE
OPERATIONSOPERATIONSSOLUTIONS TOMONI intelligent digital solutions for geothermal
power plants monitor, analyze and model data to:• Simulate expected performance versus actual
performance• Optimize the thermodynamic cycle• Mitigate scale accumulation effects• Reduce maintenance intervals and costs• Identify opportunities to optimize and improve
performance

TOMONI® is a suite of intelligent solutions that accelerates decarbonization with power plant design, O&M and system knowledge, together withstrong customer and partner collaborations. TOMONI leverages advanced controls, artificial intelligence and machine learning with multi-layered
cybersecurity to make energy systems smarter, more profitable and ultimately more autonomous on the road to a sustainable future.

O&M
OPTIMIZATION© Mitsubishi Heavy Industries, Ltd. All rights reserved. TOMONI® is a registered trademark of Mitsubishi Heavy Industries, Ltd.
Mitsubishi Power is a power solutions brand of Mitsubishi Heavy Industries.

Data Foundation & Enablers
O&M Optimization
Performance Improvement
Flexible Operations
METP-11DS41E2-A