Dr. Pri Utami Geothermal Research Centre

Faculty of Engineering Gadjah Mada University

Jalan Grafika 2, Yogyakarta 55281, Indonesia

Geothermal Energy in Indonesia & Western Pacific Region: Scientific and Technological Challenges for Development

TALK OUTLINE

Introduction to Geothermal Energy High-temperature Geothermal Systems in Western Pacific Region

Tectonic settings Natural characteristics Changes in time and space

Challenges for Exploration and Development Update on R&D and Capacity Building UGM Milestones

What is geothermal ? Heat energy from the Earth Geothermal System A general term that describes natural heat transfer within a confined volume of the Earth's crust where heat is transported from a “heat source” to a “heat sink,” usually the free surface.

Worldwide Installed Geothermal Capacity in 2010 (Bertani, 2010)

Map of geothermal sites of Indonesia. Total potential of > 20,000 MW (40% of world total potential), scattered in 250 locations

The type of geothermal system that is economically most feasible for development in Indonesia is where magmatic intrusions are emplaced high enough in the crust that they induce the convective circulation of groundwater There are other types of geothermal system (a-magmatic) such as those occurring due to heat sweep through deep-reaching fractures, or deep basin brines, but these are too cool, too deep, or too saline to allow the economic generation of electricity at this time in Indonesia

Classification of geothermal systems (adapted from Hochstein & Browne 2000 )

(Adapted from Corbett & Leach, 1994)

Hydrothermal system A type of geothermal system where heat transfers from a heat source (often a cooling pluton) to the surface by “free convection,” involving meteoric fluids with or without traces of magmatic fluids. Liquids discharged at or near the surface are replenished by meteoric water derived from the outside (“recharge”) that is drawn in by the rising fluids.

1. ENVIRONMENT-FRIENDLY Geothermal power generations discharge very significantly much lower pollutant compared to that of fossil fuels.

ADVANTAGES OF GEOTHERMAL ENERGY (cyclic, high-temperature, magmatic related systems)

CO2 emission (Fridleifsson, 2000)

H2S emission (Hunt, 2001)

Geothermal fluid whose heat has been extracted is re-injected into the deep reservoir, such that no thermal fluid is let to contaminate the surface/near surface environment.

2. RENEWABLE Its heat source and recharge fluids are both naturally renewed. 3. SUSTAINABLE

Geothermal systems are long-lived (Western Pacific: ~300 - 500 ka) and the produced thermal fluids is naturally recharged.

There is engineering strategy to ensure their sustainability, i.e., re-injection of the extracted fluids for maintaining the heat and mass balance of the geothermal reservoir.

4. INDIGENEOUS

5. RELIABLE Being renewable, sustainable and indigenous therefore, geothermal energy is reliable, because its supply is INDEPENDENT from season and energy market situation outside the country.

Geothermal is an indigeneous energy, meaning that it can only be directly utilized in place, and can not be transported elsewhere before being converted into electricity. Being indigenous energy resource, its development must be prioritized in order to elevate the prosperity to their surrounding community.

(Illustration by W. Dimwani, 2001)

With the increasing demand of energy in one hand and the shortage of fossil energy resources in another, we are now facing a challenge to the increase utilization of renewable energy, including geothermal, to ensure our energy security. Geothermal energy development requires a continuous effort for ensuring sustainable cultivation of the resource. Consequently, we have to accelerate our human resource capacity building as well as activities in Research and Development (R&D) in geothermal.

EXPERTISE MATTERS !

GENERAL MODEL – High Temperature Geothermal System in Western Pacific Historically inactive volcano, spatially associated with active volcano(es) High-relief terrain; long lateral outflows Upflow often associated with magmatic fluid conduits Complex fluid flow patterns

(Utami, 2011)

(Utami, 2011)

Natural Changes of Geothermal System in Time and Space (adapted from Browne, 1995)

System Notable change(s) – Indicator(s) Related event – Timing

LAHENDONG 1. Shift of the focus of activity – Shift of the focus of the shallowest occurrence of the mineral geothermometers Eruption centered at Lake Linau – (?)

(Utami et al, 2007) 2. Cooling – ∆(T mineral – T measured) Incursion of groundwater – since LGM (?)

TIWI

1. Discharge and recharge cycle: a. Deep fluid discharge – silica sinter b. Upwelling and boiling – (Quartz ± adularia ± epidote ± pyrite ± base metal sulfide) c. Heating of recharge fluids – (calcite and anhydrite)

Tectonic and subvolcanic intrusion – (?)

(Moore et al, 2000) 2. Renewed heating – thermal modeling Igneous intrusion – 10 to 50 ka

3. Incursion of sea water – sea water component in fluid inclusions Regional subsidence along Bicol Arc – (?)

KAMOJANG Change from liquid to vapor-dominated –

a. Altering fluid VS present-day fluid phases b. Reduced permeability due to mineral deposition

Unknown

(Utami, 2000)

KARAHA – T. BODAS

Change from liquid to vapor-dominated – a. Field-wide deposition of chalcedony b. Fluid inclusions microthermometry

Rapid depressurisation due to flank collapse of Mt. Galunggung – 4.2 ka

(Moore et al, 2004)

ULUMBU 1. Local heating and cooling – ∆(Th fluid incl – T measured)

Unknown

(Utami et al, 1996) 2. Reopening of fluid channels – changes in optical properties of minerals

Deformation – (?)

Examples of Natural Changes in Some Geothermal Systems in Western Pacific (exctracted from Utami, 2011)

EXPLORATION STAGE

Challenges: resource confidence (high-T & permeability, benign fluid chemistry), reduction of exploration risk and cost !

Exploration design Execution Data interpretation Exploration drilling Field delineation

(Photograph by W. Warmada, 2012)

EXPLORATION STAGE Facing the challenges – The power of 3G! Geological Surveys To map geologic features and thermal manifestations Geochemistry Surveys To sample and characterize the surface fluid and to interpret the subsurface temperatures, process and flow paths Geophysical Exploration To identify heat sources and permeability structure

Resource assessment

Well targeting Reservoir characterization

Environmental baseline Pre-commissioning micro-seismicity, groundwater quality, ground deformation, surface manifestations

DEVELOPMENT STAGE

Challenges: Correct understanding on thermal, chemical and hydrological structures and behavior of reservoir Correct design and construction of surface facilities

(Courtesy of GNS Sciene, 2011)

(Courtesy PT PGE, 2012)

DEVELOPMENT STAGE

Facing the challenges:

Rig geology petrology & mineralogy of cores and drill cuttings, assessment of

reservoir temperature, permeability, reservoir fluid chemistry Borehole Imaging

interpretation & integration of borehole image with wireline data, lithology and drilling data 3-D Geological Modelling

comprehensive modelling of field geology Reservoir Simulation

reservoir dynamic under fluid withdrawal and re-injection Experimental Geochemistry

laboratory and computer-based simulation studies of mineral saturation & scaling Surface Facility Design & Construction

well, pipelines, power station, condensers, etc

PRODUCTION STAGE Challenges:

Ensure the sustainability of energy production Improved effectiveness Mitigation of environmental impact

Facing the challenges: Resource management

Photograph: courtesy of PT. Geo Dipa Energy (2010)

RESEARCH & DEVELOPMENT

Multidisciplinary scientific research programs to support environmentally sustainable growth of geothermal resource Exploration and utilization of deep (>> 3 km) high temperature resources Development of new ideas and innovative tools Exploration & extraction of valuable geothermal by-products minerals Biodiversty and ecology research to assist management of geothermal ecosystems

Development of field management protocols Development of community partnership Building economic and policy framework that support geothermal development Development of of international partnership for Research & Development and capacity buliding

HUMAN RESOURCE CAPACITY BUILDING

Formal training in geothermal geoscience & technology at universities Specialized training for geothermal industry staff Geothermal induction for Government staff & policy makers Geothermal “training the trainers” Geothermal education for everyone !

Bring geothermal closer to everyone’s heart …

UGM Milestones in Geothermal Education, Research, Community Services & International Partnership

Universitas Gadjah Mada • Yogyakarta • Indonesia • www.ugm.ac.id

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