Geothermal Potential of Jamaica

Geothermal Potential
of
Jamaica
- Status of Development
Suresh Bhalai
MINES AND GEOLOGY DIVISION
Ministry of Energy and Mining
Hope Gardens, Kingston 6

OUTLINE
GEOTHERMAL ENERGY?
Geothermal Resource vs Conventional Power Resources
Current Production Methods
JAMAICA - GEOTHERMAL ENVIRONMENT
Geology
Status of geothermal development
Exploration guides
Further exploration
Known areas
Exploitation technique
Some considerations – benefits and barriers

GEOTHERMAL
ENERGY?
Geothermal: „geo‟ = earth; „thermal‟ = heat
“heat from the earth”
Earth abounds in thermal energy.
Heat generated from breakdown of naturally occurring
radioactive materials.
Heat is present everywhere beneath the surface.
Heat rises to the surface and escapes to the
atmosphere.
„Renewable‟ OR Sustainable?

? ? ? ?
Geothermal environments:
High- and moderate-temperature rocks with considerable
available water and (or) steam are the only geothermal
environments that can currently be developed to generate
electricity.

Geothermal Energy
as a
Resource

Geothermal Energy as a Mineral Resource
SIMILARITIES
Occur everywhere,
Anomalous concentrations are favourable,
Have measurable GRADE and SIZE
Economic deposits – those at depths accessible by
current extraction technology while remaining cost
efficient.
80°C 180°C
LOW GRADE MEDIUM GRADE HIGH GRADE

Geothermal Energy as a Mineral Resource
CHARACTERISTICS MINERAL RESOURCES GEOTHERMAL ENERGY
Extractive process
digging, crushing and
processing of large quantities
of earth material
Liquid
(brought to surface by hot
springs or wells)
Extractive method
Economic characteristics
mine shafts, tunnels, pits and
spoil heaps
Size and/or grade determines
profitability and efficiency of
operation
Drilled wells
Usable over a very wide
spectrum of temperature and
volume

Geothermal Energy vs Conventional Power Resources
Environmentally benign – low emission
• Hot water and steam plant:

Geothermal Energy vs Conventional Power Resources
CO 2 EMISSIONS
Similar contrasts for the emission of sulphurous gases

Geothermal Energy vs Conventional Power Resources
RELIABILITY
Once online geothermal power plants are very reliable
Off-line ~5% (avg.) of the time.
CLIMATE CHANGE
Geothermal energy is an environmentally-friendly option.

Current Production Methods
Hot Water
Hydrothermal System
Vapour-dominated
Hydrothermal System
Moderate Temperature
Hydrothermal System

STATUS OF GEOTHERMAL
DEVELOPMENT IN JAMAICA
HISTORY/ STATUS OF DEVELOPMENT
Late 1600s: Bath, St. Thomas,
Mid-1700s: Milk River Bath
1950s – Geological Survey Department
1980s:
• Preliminary examinations
• OLADE – Latin American Energy Organization, 1982
• Ittracon – 22 Springs in tourist areas
• Occidental Geothermal Inc. – Blue Mountain area
• Geological Survey Division
OLADE Summary report available.

Jamaican Geology

JAMAICAN GEOLOGY
JAMAICA - >65 million years ago

JAMAICA - TODAY

JAMAICA - STRUCTURE

Exploration Guides

EXPLORATION GUIDES

EXPLORATION GUIDES
Position on the
Caribbean Plate
= low –
moderate
resources

EXPLORATION GUIDES
Hot/ warm
springs
Potentially
water-bearing
rocks and
structures
GEOTHERMAL
RESOURCES
Subsurface
temperature
anomalies
Seismic zones

POTENTIAL AREAS:
EXPLORATION
GUIDES
Faulted rocks older than the White Limestone,
Boundary between different older rocks,
especially intrusive igneous rocks.
Shale
White
Limestone
Yellow
Limestone
Sandstone
Dacite
Conglomerate
Granodiorite
Andesite
Marble
Serpentinite

# NAME TEMP
°C
FLOW
litres/sec
EXPLORATION
GUIDES
1 Guava River Spring 53 0.3
2 Bath Spring 54 0.3
3 Mt. Felix Spring 31 0.3
4 Garbrand Hall Spring 29 1.5
5 Rockfort Spring 30 50
7 Salt River Spring 33 100 – 200
8 Milk River Springs 38 40 – 50
9 Black River Spring 29 45 – 50
10 Windsor Spring 36 0.5
10
11 Yankee River Spring 26 0.5
12
12 Buxton Spring 29 1.2
11
2
9
4
8
7
3
6
5
1
4
1
3
2

EXPLORATION GUIDES
LIMITATION:
Low possibility of abnormally high
heat flow,
Little information on geothermal
gradients,
Low flow rates,
Contamination by seawater
# NAME TEMP
°C
1 Guava River Spring 53 0.3
2 Bath Spring 54 0.3
3 Mt. Felix Spring 31 0.3
4 Garbrand Hall Spring 29 1.5
5 Rockfort Spring 30 50
FLOW
litres/sec
7 Salt River Spring 33 100 – 200
8 Milk River Springs 38 40 – 50
9 Black River Spring 29 45 – 50
10 Windsor Spring 36 0.5
11 Yankee River Spring 26 0.5
12 Buxton Spring 29 1.2

EXPLORATION
TECHNIQUE
Binary systems would be
most suitable
Waterbearing
rocks and
structures

Some Considerations

SOME
CONSIDERATIONS
EXPLORATION PROGRAM:
Joint Government-Private coupled program,
Successful in the USA,
Local knowledge combined with experience,
Reduces financial and discovery risks associated with
exploration,
Research direction: develop techniques and strategies to
identify hidden systems at greater depths.

SOME
CONSIDERATIONS
CHALLENGES:
Are our resources within economically drillable depths?
What is the state of the subsurface energy system?

REFERENCES
Duffield, W. A. and Sass, J. H., 2003, Geothermal Energy –
Clean Power from the Earth‟s Heat. U. S. Geological Survey,
Virginia, Circular 1249, 36pp.
Hylton, H. A., 1987, Mineral Springs of Jamaica. Geological
Survey Division, Kingston Bulletin No. II, 69pp.
Jamaica Public Service, 2007, JPS – An Overview. JPS,
Kingston, unpublished report, 14pp.
Latin American Energy Organization, 1982, Geothermal
Resource Exploration, Reconnaissance, Review and
Utilisation Report. Geological Survey Division, Kingston,
unpublished report, 169pp.