Transcript David Nieva Gómez

GEOTHERMAL ENERGY:
A reliable, renewable energy source
IANAS Workshop:
Toward a sustainable energy future
GEOTHERMAL ENERGY:
A reliable, renewable energy source
OUTLINE

Origin of geothermal energy

Classification of geothermal resources

Utilization of geothermal resources

Geothermal power generation around the world

Virtues of geothermal technology

Barriers to further development
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Depth
km
The heat flows toward the external layers. The crust is a
very good thermal insulator. The mantle is partially
melted and supports convective heat transport. The
external nucleus is postulated to be in a liquid state and
the internal nucleus is in a solid state.
In addition to the heat flowing to the crust from the inner
layers of the Earth, the concentration of radioactive
isotopes in the crust and upper mantle, mainly 40K, 232Th,
235U and 238U, generate an estimated 4.7x1020 cal/year.
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Volcanos and island arcs align on the plate
boundaries.
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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New crust is formed from rising magma in
divergent plate boudaries. One plate slides
under another in convergent plate boundaries.
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Thermal gradient along the Earth’s
radius

As a result of tectonic processes, the thermal
gradient in the crust varies enormously from
one site to another.

A “normal” thermal gradient is considered to
be about 30oC/km(depth). However, in some
sites it could be as high as 800 oC/km.
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Geothermal resources classified on the
basis of temperatures found at
“reasonable” depths:

High temperature (220 oC – 320 oC)

Mid temperature (120 oC – 220 oC)

Low temperature (50 oC – 120 oC)
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Geothermal resources classified on the
basis of geological and hidrological
factors:
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Hidrothermal

Hot, dry rock

Geopressurized

Marine

Magmatic
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A hydrothermal reservoir contains all the elements:
hot rock, source of water, permeability.
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Use of Geothermal Energy
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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High Temperature Hydrothermal
Systems




Electric power generation by direct separation
of steam
Electric power generation through organic
Rankine cycles, utilizing "spent" fluids
Large-area thermal conditioning of living and
commercial quarters
Direct uses of heat in "spent" fluids in
industrial or agricultural processes
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Medium temperature hydrothermal
sources

Electric power generation through
organic Rankine cycles

Large-area thermal conditioning of
living and commercial quarters

Direct uses of heat in industrial or
agricultural processes
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Geothermal resources classified on the
basis of geological and hidrological
factors:
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008

Hidrothermal

Hot, dry rock

Geopressurized

Marine

Magmatic
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Incipient: Engineered hot-dry rock
resources
Electric power generation
from heat delivered to the
surface by circulating
exogenous water through
the hot rock
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Power generation with geothermal energy
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Virtues of Geothermal Energy

Reliable and continuous

Flexible; could be used as base
generation or load-following mode

Low CO2 emissions

Competitive costs
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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AVERAGE PLANT FACTORS
PLANT FACTORS
Technology
Plant factor
Ref.
Coal
0.75
1
Other fossil fuels
0.55
1
Geothermal
0.85
1
Hydro
0.40
1
Nuclear
0.90
1
0.18 - 0.45
2
Wind
References:
1.- Calculated from installed capacities and power generated (Jan-Sep, 2008). Data from CFE webpage.
2.- NEA&IEA (2005) “Projected costs of Generating Electricity: Update 2005”
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Virtues of Geothermal Energy

Reliable and continuous

Flexible; could be used as base
generation or load-following mode

Low CO2 emissions

Competitive costs
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Virtues of Geothermal Energy

Reliable and continuous

Flexible; could be used as base
generation or load-following mode

Low CO2 emissions

Competitive costs
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Levelised Costs
LEVELISED GENERATION COSTS
Technology
Cost (cUSD/KWh)
Ref.
Coal
(2.5) 3.5 - 6.0 (6.8)
1
Gas
4.0 - 5.5 (6.4)
1
5.0 - 5.3
2
4.2
1
4.5 - 4.8
2
Geothermal (New Zealand)
3.7 - 5.2 (8.1)
3
Hydro
6.5 - 10 (24)
1
Nuclear
3.0 - 5.0 (6.8)
1
Fuel oil
6.3 - 10
2
Solar
20 - 75 (190)
1
Wind
4.5 - 10 (14)
1
Gas, combined cycle
Geothermal (USA)
Geothermal (Mexico)
References:
1.- NEA&IEA (2005) “Projected costs of Generating Electricity: Update 2005”
2.- CFE (2005) “Costos y parámetros de referencia para la formulación de proyectos de inversión”
3.- Barnett, P. (2007) “Cost of Geothermal Power in New Zealand: 2007 Update”, New Zealand Geothermal Workshop,
November 2007
IANAS Workshop, Buenos Aires, República Argentina, 30-31 October 2008
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Disadvantages of Geothermal
Energy

A measure of uncertainty

Capital-intensive initially
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www.iie.org.mx
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