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Geothermal energy and HDR |
| Category: Fundamental, Products / Services |
Published: 14-12-2007 |
By: perdant |
| [click to enlarge] |
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| HR Geothermal Compared with other energy sources |
The purpose of posting this work is to share my research with Top$tock members
regarding the processes and models of geothermal energy and to highlight the
enormous potential this has to both the energy sector and for investors
alike.
I would like to preface this piece of work by stating that I have
no professional background in the energy sector or in financial advising. This
post has been compiled purely for the information of the forum. The information
presented here has been compiled by an amateur and is designed to offer you a
starting point and encourage further research on your part. All of the
information in this post is publicly accessible and I hope that I have
acknowledged all material presented here in my
references.
Warning: The ASX companies
referred to here are not meant to be investing tips, neither are they mentioned
to ‘ramp up’ interest. I currently hold some of the companies
mentioned.
I hope you find this post both informative and helpful. I’m
sorry it’s so long.
Perdy.
Geothermal energy
Geothermal
energy is a renewable resource originating deep within the Earth where
temperatures can reach up to 6000 degrees Celsius. Geothermal energy is
harnessed by mining the Earth’s heat resources at depths of up to five
kilometres from the Earth’s surface, where average temperatures are in excess of
200 degrees Celsius.
Geothermal energy is responsible for volcanoes and
earthquakes. High geothermal activity occurs where the Earth’s crust is thin and
molten rock and steam at high pressure is able to force its way to the surface.
Geysers, hot springs and mud-pots are also created by geothermal
energy.
Geothermal power is generated in over 20 countries around the
world including: Iceland which produces 17% of its electricity from geothermal
sources; the United States; Italy; France; New Zealand; Mexico; Nicaragua;,
Costa Rica; Russia; the Philippines which has a production output of 1931MW or
27% of electricity – second to US; Indonesia; the People's Republic of China;
Australia; Canadia and Japan.
Geothermal activity is sometimes associated
with The Pacific Ring of Fire which is a zone of frequent earthquakes and
volcanic eruptions encircling the basin of the Pacific Ocean. In a 40,000 km
horseshoe shape, it is associated with a nearly continuous series of oceanic
trenches, island arcs, and volcanic mountain ranges and/or plate
movements.
img
src="http://upload.wikimedia.org/wikipedia/commons/thumb/0/09/Pacific_Ring_of_Fire.png/300px-Pacific_Ring_of_Fire.png">
Geothermal
resources
There are four main types of geothermal energy –
Hydrothermal, Geo-pressured, Hot Dry Rock [HDR] and Magma. These are
briefly explained here but both Hydrothermal and Hot Dry Rock [HDR] methods are
explored in detail further on.
Until recently, Hydrothermal resources and
models were the only source used to generate commercially viable energy. Whilst
geo-pressured and magma resources are undergoing further research and
development, hot dry rock resources could be an emerging industry and offer
enormous potential.
Hydrothermal [hot water]
Hydrothermal
resources are derived from hot water and steam formed in porous or fractured
rock at relatively moderate depths from 100 metres to five kilometres. The hot
water and steam are formed from the intrusion of molten magma into the Earth's
crust or the deep circulation and heating of groundwater through faults and
fractures. High-grade hydrothermal resources are used to generate electricity
and lower grade resources can be used in direct heating applications.
To
generate electricity, hot water at temperatures ranging from 180°C to 350°C is
brought from the underground reservoir to the surface through production wells,
and is flashed to steam in special vessels by release of pressure. The steam is
separated from the liquid and fed to a turbine engine, which turns a generator.
Spent geothermal fluid is injected back into peripheral parts of the reservoir
to help maintain reservoir pressure. In direct heating, the geothermal water is
usually fed to a heat exchanger before being injected back into the
Earth.
Heated domestic water from the output side of the heat exchanger
is used for a variety of purposes including home heating, greenhouse heating and
vegetable drying. http://geothermal.marin.org/pwrheat.html#Q2 provides further
reading and examples of non electricity generation uses of geothermal
energy.
Geo-pressured
Geo-pressured energy is derived from hot,
pressurised waters containing dissolved methane, trapped at depths of three to
six kilometres in sedimentary formations. The water temperature ranges from 90°C
to 200°C.
Three forms of energy can be captured from geo-pressured
sources – thermal energy from the hot water, hydraulic energy from the high
pressure, and chemical energy from burning the dissolved methane.
Hot
Dry Rock [HDR]
Hot dry rock is a heated geological formation consisting
of dry, impermeable rock. Unlike hydrothermal resources, the fractures and
faults required to conduct water to the surface are not present, therefore water
must be pumped into the rock at high pressure to create an artificial
underground reservoir of steam or hot water. The Eromanga Basin in south-west
Queensland has more than 80 percent (18,949 petajoules) of Australia’s HDR
resources.
Magma
Magma is the molten or partially molten rock
that is found at depths between three and 10 kilometres below the Earth's crust
and reaches temperatures up to 1200°C. While some magma resources are at
accessible depths, a practical means of extracting magma energy has yet to be
developed.
Information relating to Hydrothermal
resources
Formation of Geothermal reservoirs
In some
regions with high temperature gradients, there are deep subterranean faults and
cracks that allow rainwater and snowmelt to seep underground, sometimes for
miles. There the water is heated by the hot rock and circulates back up to the
surface, to appear as hot springs, mud pots, geysers etc.
If the
ascending hot water meets an impermeable rock layer, however, the water is
trapped underground where it fills the pores and cracks comprising 2 to 5% of
the volume of the surrounding rock, forming a geothermal reservoir. Much hotter
than surface hot springs, geothermal reservoirs can reach temperatures of more
than 350 degrees celsius and are powerful sources of energy.
Accessing
Geothermal energy
If geothermal reservoirs are close enough to the
surface, we can reach them by drilling wells, sometimes over two miles deep.
Scientists and engineers use geological, electrical, magnetic, geochemical and
seismic surveys to help locate the reservoirs.
Renewability and
sustainability
The Earth’s heat is continuously radiated from within, and
each year rainfall and snowmelt supply new water to geothermal reservoirs.
Production from individual geothermal fields can be sustained for decades and
perhaps centuries.
Conservation of resources
When we use
renewable geothermal energy for direct use or for producing electricity, we
conserve exhaustible and more polluting resources like fossil fuels and nuclear
energy. Installed geothermal electricity generation capacity around the world is
equivalent to the output of about 10 nuclear plants.
Worldwide, direct
uses of geothermal water avoids the combustion of fossil fuels equivalent to
burning of 830 million gallons of oil or 4.4 million tons of coal per year.
Worldwide electrical production from geothermal reservoirs avoids the combustion
of 5.4 billion gallons of oil or 28.3 million tons of coal.
Protection
of the environment
As with all sources of energy, developers and
consumers must work to protect the environment. The challenges differ with the
type of energy resource, and the differences give geothermal energy certain
advantages. Geothermal direct use facilities have minimal or no negative impacts
on the environment. Geothermal power plants are relatively easy on the
environment.
How is electricity generated using hydrothermal
energy?
In geothermal power plants steam, heat or hot water from
geothermal reservoirs provides the force that spins turbine generators and
produces electricity. The used geothermal water is then returned down an
injection well into the reservoir to be reheated, to maintain pressure, and to
sustain the reservoir.
There are three main types of geothermal power
plants. The type built depends on the temperatures and pressures of a
reservoir.
A dry steam reservoir produces steam but very little
water. The steam is piped directly into a dry steam power plant to
provide the force to spin the turbine generator. The largest dry steam field in
the world is The Geysers, near San Francisco which has been producing
electricity since 1960.
A geothermal reservoir that produces mostly hot
water is called a hot water reservoir and is used in a flash power
plant. Water ranging in temperature from 150 – 370 degrees Celsius is
brought up to the surface through the production well where, upon being released
from the pressure of the deep reservoir, some of the water flashes [explosively
boils] into steam in a separator. The steam then powers the turbines. To
conserve the water and maintain reservoir pressure, the geothermal water and
condensed steam are directed down an injection well back into the periphery of
the reservoir, to be reheated and recycled.
A reservoir with temperatures
between 120 - 180 degrees Celsius is not hot enough to flash enough steam but
can still be used to produce electricity in a binary power plant. In a
binary system the geothermal water is passed through a heat exchanger,
where its heat is transferred into a second [binary] liquid, such as isopentane,
that boils at a lower temperature than water. When heated, the binary liquid
flashes to vapor, which, like steam, expands across and spins the turbine
blades. The vapor is then re-condensed to a liquid and is reused
repeatedly.
In this closed loop cycle, there are no emissions to the air.
The geothermal water passes only through the heat exchanger and is immediately
recycled back into the reservoir.
Although binary power plants are
generally more expensive to build than steam-driven plants, they have several
advantages:
1) The working fluid (usually isobutane or isopentane) boils
and flashes to a vapor at a lower temperature than does water, so electricity
can be generated from reservoirs with lower temperatures. This increases the
number of geothermal reservoirs in the world with electricity-generating
potential.
2) The binary system uses the reservoir water more
efficiently. Since the hot water travels through an entirely closed system it
results in less heat loss and almost no water loss.
3) Binary power
plants have virtually no emissions.
In some power plants, flash and
binary processes are combined. These are known as Hybrid Power Plants. An
example of such a system exists on the island of Hawaii, where the hybrid plant
provides about 25% of the electricity used on the island.
Advantages
of Geothermal energy
• Clean. Geothermal power plants, like
wind and solar power plants, do not have to burn fuels to manufacture steam to
turn the turbines. Generating electricity with geothermal energy helps to
conserve nonrenewable fossil fuels, and by decreasing the use of these fuels, we
reduce emissions that harm our atmosphere.
• Small environmental
footprint. The land area required for geothermal power plants is smaller per
megawatt than for almost every other type of power plant. Geothermal
installations don't require damming of rivers or harvesting of forests -- and
there are no mine shafts, tunnels, open pits, waste heaps or oil spills.
• Reliable. Geothermal power plants are designed to run 24
hours a day, all year. A geothermal power plant sits right on top of its fuel
source. It is resistant to interruptions of power generation due to weather,
natural disasters or political rifts that can interrupt transportation of fuels.
• Flexible. Geothermal power plants can have modular designs,
with additional units installed in increments when needed to fit growing demand
for electricity.
• Keeps Dollars at Home. Money does not have to
be spent to import fuel for geothermal power plants. Geothermal fuel - like the
sun and the wind - is always where the power plant is; economic benefits remain
in the region and there are no fuel price shocks.
• Helps Developing
Countries Grow. Geothermal projects can offer all of the above benefits to
help developing countries grow without pollution. Installations in remote
locations can raise the standard of living and quality of life by bringing
electricity to people far from electrified population centers.
Geothermal
energy delivers base load electricity. This means electricity can be generated
continuously, 24 hours a day, 365 days a year. Electricity supplies generated by
geothermal energy are not dependent on sunshine, wind or waves, which are
variable and interruptible sources, and also subject to climate change and
seasonal fluctuations.
Base load electricity generated from geothermal
energy is clean, renewable and has minimal impact on the environment. The closed
loop circulation of fluids is environmentally benign. Unlike burning fossil
fuels, the process emits no greenhouse gases, pollution or hazardous wastes.
Geothermal power plants have small footprints compared to coal, nuclear power
plants and windfarms. Geothermal injection and production wells are lined with
metal casing and cement so that the circulating fluids are isolated from
groundwater and the environment. Customers can access safe, environmentally
friendly, renewable, and long life domestic base load energy resources. It also
reduces the need for imported fuels.
A comparison of other energy sources
for the generation of electricity has been added at the end of this post [keep
scrolling!]
Direct Use Developments Worldwide
Geothermal
direct use applications provide about 10,000 thermal megawatts (MW-th) of energy
in about 35 countries. (In an additional 40 countries there are hot springs used
for bathing, but facilities for commercial use have not been developed.) In the
U.S. alone, there are some 18 district heating systems, 38 greenhouse complexes,
28 fish farms,
12 industrial plants, and 218 spas that use geothermal waters to provide
heat.
Geothermal Power Production Worldwide
As of 1999
8,217 megawatts of electricity were being produced from some 250 geothermal
power plants running day and night in 22 countries around the world. These
plants provide reliable base-load power for well over 60 million people, mostly
in developing countries.
About 2850 megawatts of geothermal generation
capacity is available from power plants in the western United States. Geothermal
energy generates about 2% of the electricity in Utah, 6% of the electricity in
California and almost 10% of the electricity in northern Nevada. The electrical
energy generated in the U.S. from geothermal resources is more than twice that
from solar and wind combined.
Improving Geothermal
technology
Since the 1970's the geothermal industry, with the
assistance of government research funding, has overcome many technical drilling
and power plant problems. Improvements in treatment of geothermal water have
overcome early problems of corrosion and scaling of pipes. Methods have been
developed to remove silica from high-silica reservoirs. In some plants silica is
being put to use making concrete, and H2S is converted to sulphur and sold. At
power plants n the Imperial Valley of California, a facility is being
constructed to extract zinc from the geothermal water for commercial
sale.
As a result of government-assisted research and industry
experience, the cost of generating geothermal power has decreased by 25% over
the past two decades. Research is currently underway to further improve
exploration, drilling, reservoir, power plant and environmental technologies.
Enhancing the recoverability of Earth’s heat is an important area of ongoing
research.
Enhancing Hydrothermal systems
Geothermal energy
is accessible if there is sufficient heat, permeability, and water in a system,
and if the system is not too deep. The available heat cannot be increased, but
the permeability and water content can be enhanced.
Enhancing
Reservoir Water. One unique example of enhancing reservoir water is at The
Geysers steam field in California, where treated wastewater from nearby
communities is being piped to the steamfield and injected into the reservoir to
be heated. This increases the amount of steam available to produce electricity.
With this enhancement, reservoir life is increased while providing nearby cities
with an environmentally safe method of wastewater disposal.
Enhancing
Reservoir Permeability. Permeability can be created in hot rocks by
hydraulic fracturing, a process of injecting large volumes of water into a well
at a pressure high enough to break the rocks. The artificial fracture system is
mapped by seismic methods as it forms, and a second or more wells are drilled to
intersect the fracture system. Cold water can then be pumped down one well and
hot water taken from the other well[s] for use in a geothermal plant. This is
known as hot dry rock technology and is being tested in Japan, Germany,
France, England, Australia and the U.S.
Hot Dry Rock HDR
Technology
GDY offers an animated explanation of how HDR Energy
extraction works. It’s worth the time to watch it. You can view it here:
http://www.geodynamics.com.au/IRM/content/howtoanim.htm
The
Concept
Hot Rock Energy is a vast, environmentally friendly, economically
attractive energy source. As this diagram shows, the concept is very simple.
Water is injected into a borehole and circulated through a "heat exchanger" of
hot cracked rock several kilometres below the surface. The water is heated
through contact with the rock and is then returned to the surface through
another borehole where it is used to generate electricity. The water is then
re-injected into the first borehole to be reheated and used again.
The Hot Rock
Energy system works with 2 closed circulation loops:
The subsurface
loop
This loop circulates water down an injection borehole where it
passes through the underground "heat exchanger" and is heated. The superheated
water is then recovered by one or more production boreholes which return it
under pressure to the surface. By keeping the water under pressure and
preventing it turning to steam, any materials dissolved from the underground
rock mass [such as silica or carbonates] are kept in solution and can be
returned to the ground.
At the surface, the superheated water is passed
through a metal heat exchanger where most of the heat is removed. The now cooled
water is then returned to the injection borehole where it is sent down
again to recover more heat.
The power station loop
At the
surface a second closed loop fluid system is used to transfer the heat into the
power station and generate the electricity in a turbine.
The fluid used
in the power station loop can be water, but more usually a lower boiling point
fluid is used. Organic fluids such as refrigerants and iso-pentane are often
used.
The energy
The median global heat flow through Earth's
surface is around 60 mWm-2. While this figure is small in comparison to mean
global insolation [solar energy], which is around 1400 Wm-2, the temperature in
Earth's crust nevertheless increases worldwide at an average rate of around 17 -
30oC/km. This means that temperatures high enough to produce energy are quite
accessible in many places worldwide.
As is discussed in the Economics
section though, the cost of drilling is the biggest single cost involved in
using Hot Rock Energy. It is therefore necessary at present to identify areas
that are suitable for energy extraction at only moderate depths. Future
developments using new technologies such as largely automated drilling and
advanced drilling bit designs, may well be able to economically tap Hot Rock
Energy almost anywhere on Earth.
Building a Hot Rock Energy
System
Heat is extracted by pumping water through an engineered heat
exchanger connecting two or more wells. This heat exchanger is a volume of hot
dry rock with enhanced permeability. It is fabricated by hydraulic stimulation.
This involves pumping high pressure water into the pre-existing fracture system
that is present in all rocks to varying degrees. The high pressure water opens
the stressed natural fractures and facilitates micro-slippage along them. When
the water pressure is released, the fractures close once more but the slippage
that occurred prevents them from mating perfectly again. The result is a
million-fold permanent increase in permeability along the fracture systems and a
heat exchanger that can be used to extract energy.
In a typical system,
an initial borehole is sunk into the hot rock mass and a hydraulic stimulation
is performed. A three dimensional microseismic network deployed on the surface
and in nearby wells is used to record "acoustic emissions" (i.e. small noises)
caused by the slipping fractures. The network records the locations of the
acoustic emissions while pumping continues over several weeks. In this way, the
progress of the stimulation is monitored and the size and shape of the growing
heat exchanger is mapped.
A second well is then drilled into the margin
of the heat exchanger 500 metre or more from the first well. Now water can be
pumped through the underground heat exchanger and in superheated form it can be
returned to the surface. There it can have its energy extracted before being
reinjected to go around the loop again.
The Resource
Studies at
ANU and previously at Geoscience Australia have looked at the prospects for Hot
Rock Energy in Australia. These studies have established that a very significant
resource exists.
A database of sub-surface temperature measurements for
the continent has been built. This database contains around 3,500 temperature
measurements made in boreholes at depths between ~100 metres and 4 - 5
kilometres. With the database a picture has been built of the way that
temperature at depth across the Australian continent. An example is shown here.
This image shows the estimated temperature at a depth of 5km across Australia.
Blue hues indicate relatively low temperatures at this depth while reds
represent areas where the temperature is estimated to be particularly high.
Notice that the old crust of the Yilgarn Block and the Pilbara region in
Western Australia is relatively cool whereas parts of Central Australia are
predicted to be >300oC at 5km depth.
The prime cause of
all this heat is the slow decay of isotopes of potassium, thorium and uranium
that exist throughout most of the Earth in low concentrations. If it wasn't for
this slow decay, which has been going on ever since the Earth was formed, our
planet would be a frozen, lifeless ball in space.
The local variations in
crustal temperature that occur in Australia, and everywhere else across the
globe for that matter, exist for a number of reasons:
Variations in
heat flow into the lower crust from the Earth's mantle.
Dynamic processes
going on in the Earth's interior such as the convection currents responsible for
continental drift and Plate Tectonics, cause big differences in the heat flow
coming into the lower crust. On a global scale this produces very large
differences in crustal temperature.
However in Australia, this is
probably a minor effect because the whole continent is within the Australian
Plate and away from regions of active volcanism and deformation.
Local
generation of heat in the Earth's crust
The Earth's crust is made up of
many different types of rocks and these rocks contain different amounts of
potassium, thorium and uranium. Some rocks contain more of these elements and
tend to be self-heating, while others contain little or no radiogenic elements.
Granites and some volcanic rocks can sometimes contain appreciable amounts of
potassium, thorium and uranium. Rocks like clean sandstones and limestones
contain almost none.
A particular class of granites called High Heat
Production (HHP) granites can generate significant heat over geological time. A
typical HHP granite might contain ~4% potassium, 50 parts per million thorium
and 20 parts per million uranium. With this composition, the HHP granite would
generate around 10 microWatts of heat per cubic metre of rock. On the face of
it, this doesn't sound like a lot of heat, but granite bodies are usually quite
large and often contain billions of cubic metres of HHP rock. The total amount
of heat generated can be significant over geological time
scales.
Local heat retention in the Earth's crust
If the heat
generated in the crust and that heat flowing into the crust from below is
prevented from easily escaping through the Earth's surface, then temperatures
will build up.
The presence of low conductivity rocks such as shales,
siltstones and coals can provide just such a thermal blanket. These rocks have
relatively low thermal conductivity which means that heat can't pass through
them easily. It is therefore no coincidence that the presence of sedimentary
basins full of such low conductivity sediments often goes hand-in-hand with
high crustal temperatures.
In the Australian crustal temperature map at
the top of this page for instance, the region of high temperatures in Central
Australia lies under the Great Artesian Basin (GAB). The GAB has appreciable
thicknesses of low conductivity sediments.
In the Australian context, the
best prospects for Hot Rock Energy are those locations where HHP granites are
buried under thermal blankets of insulating sediments. The Central Australian
region highlighted in the map above meets both these criteria. Another location
where this correspondence of heat production and heat retention occurs is a
small region known as the "Muswellbrook Geothermal Anomaly" which is south of
the town of Muswellbrook in the Hunter Valley of New South
Wales.
Calculations of Australia's Resource
Based on
temperature data from more than 3,500 boreholes, mostly oil and gas exploration
wells, the Australian resource of hot dry rock has been quantified to the five
kilometre level. The resulting image map of temperature at a depth of five
kilometres is shown above.
Conservative assumptions were also made in
calculating the size of the resource, in the following terms:
• the
resource was defined by a minimum temperature of 225ºC at a depth of 5km
• the resource was assumed to be only 1.5 km thick with temperature
ranging from 225ºC at the bottom to 165ºC at the top (ie average temperature
195ºC)
• higher temperatures, known to exist at some locations, were
ignored in the calculation
• 165ºC was the assumed average temperature
when the resource would be exhausted
The resulting estimate of energy
available for electricity generation was 23 million petajoules (1 petajoule
=1015 joules) or 7,500 years of Australian energy consumption at the current
level. Over 80% of this resource is located in the Eromanga Basin, an area
covering the NE corner of South Australia and the SW corner of Queensland. The
distribution of the resource is given in Somerville et al (1994) [ERDC Report
243]: [apologies but this table will probably not display correctly – it may be
found here: http://hotrock.anu.edu.au/resource.htm]
TABLE 1 - Hot Dry
Rock energy resources in Australia (from ERDC Report 243, 1994)
Locality
Sub-Locality Estimated Heat Energy Available
(thousand petajoules)
Eromanga Basin Cooper Basin
Galilee Basin
Cacoory
Mulkarra West
Denbight Downs
Brookwood
Ayrshire
Banmirra
Yanbee
Chandos
7,821
6,237
2,079
1,089
990
297
178
119
69
70
18,949
McArthur
Basin
Otway Basin
Murray Basin
Perth Basin
Sydney Basin
East
Queensland
Hunter Valley 2,871
495
119
49
15
8
3,557
TOTAL 22,506
Hot granite
bodies
About 11% of these energy resources [2.5 million petajoules],
or more than 800 times the current annual demand for electricity in Australia,
are thought to be in granite rock which is the most favoured host rock for heat
extraction. Granite bodies are typically large in size, uniform in properties,
and suitably cracked or jointed for the formation of heat mining reservoirs. As
granite has a relatively low density, the presence of subterranean granite
bodies can be inferred from geophysical surveys using microgravity measurements.
This applies particularly to high heat producing granites, so in Australia, the
occurrence of a gravity low together with high temperature in the Earth’s upper
crust is generally indicative of a buroed granite hot-rock resource.
The
1994 ERDC Report mapped the occurrences in the Eromanga Basin geothermal area
where granite had already been found or was indicated by gravity lows. The
estimated energy resources in these hot granite bodies are given in Table 2.
[Again apologies if the table does not load correctly. It may be viewed here:
http://hotrock.anu.edu.au/resource.htm. This table also includes figures for the
Hunter Valley geothermal anomaly.
Table 2 - Estimated energy resources in
granite bodies (from ERDC Report 243, 1994)
Gravity Low Estimated area of
granite in square kilometres Estimated temperature at 5 km depth (°C) Average
depth to basement in kilometres Thickness, in kilometres of granite above 5 km
and above 165ºC Estimated average temperature of resource (°C) Petajoules per
cubic kilometre (2.2 *(average temp-165)) Estimated volume of resource in
granite and above 5 km (cubic kilometres) Resource in petajoules (1015 joules)
(cut off temp. of 165ºC) Multiple of Australia's annual energy
usage
Nockatunga 3000 250 2 2 200 77 6000 462000 154.0
Longreach 1500 275
1 2.25 220 121 3375 408375 136.1
Kyabra 2200 250 2 2 200 77 4400 338800
112.9
Innamincka 900 300 3.5 1.5 260 209 1350 282150 94.1
Betoota 750 300
1.5 2.5 230 143 1875 268125 89.4
Mungeranie 1400 250 1.5 2 200 77 2800
215600 71.9
Windorah 1500 225 2 1.75 185 44 2625 115500 38.5
Quilpie 500
250 2 2 200 77 1000 77000 25.7
Orientos 850 225 2.5 1.75 185 44 1487.5 65450
21.8
Ambathella 400 225 2 1.75 185 44 700 30800 10.3
Adavale 1100 200 2.5
1.25 175 22 1375 30250 10.1
Kahduwarry 1000 200 3 1.25 175 22 1250 27500 9.2
Cowarie 850 200 2 1.25 175 22 1062.5 23375 7.8
Simpson Desert 850 200
2.5 1.25 175 22 1062.5 23375 7.8
Charleville north 800 200 2 1.25 175 22
1000 22000 7.3
Charleville south 750 200 2 1.25 175 22 937.5 20625 6.9
Callabonna 750 200 1 1.25 175 22 937.5 20625 6.9
Wanaaring 700 200 1
1.25 175 22 875 19250 6.4
Charleville west 600 200 2 1.25 175 22 750 16500
5.5
Hungerford 500 200 1 1.25 175 22 625 13750 4.6
Lake Eyre 350 225 1.5
1.75 185 44 612.5 26950 9.0
Cooladdi 200 200 2 1.25 175 22 250 5500
1.8
Muswellbrook 50 275 3.5 1.5 250 187 75 14025 4.5
TOTAL 21500 36425
2527525 842.3
Geothermal energy to desalinate
water?
Desalination refers to any of several processes [e.g.
reverse osmosis] that remove the excess salt and other minerals from water in
order to obtain fresh water suitable for animal consumption or irrigation, and
if almost all of the salt is removed, for human consumption, sometimes producing
table salt as a by-product. Desalination of ocean water is common in the Middle
East because of water scarcity.
As of July 2004, the two leading methods
were Reverse Osmosis (47.2% of installed capacity world-wide) and Multi Stage
Flash (36.5%).
The traditional process used in these operations is vacuum
distillation — essentially the boiling of water at less than atmospheric
pressure, and thus a much lower temperature than normal. Due to the reduced
temperature, energy is saved.
In the last decade, membrane processes have
grown very fast, and Reverse Osmosis [R.O.] has taken nearly half the world's
installed capacity. Membrane processes use semi-permeable membranes to filter
out dissolved material or fine solids. The systems are usually driven by
high-pressure pumps, but the growth of more efficient energy-recovery devices
has reduced the power consumption of these plants and made them much more
viable; however, they remain energy intensive and, as energy costs rise, so will
the cost of R.O. water.
Forward Osmosis [F.O.] employs a passive membrane
filter that is hydrophylic [attracts water], slowly permeable to water, and
blocks a portion of the solutes. Water is driven across the membrane by osmotic
pressure created by food grade concentrate on the clean side of the membrane.
Forward osmosis systems are passive in that they require no energy inputs. They
are used for emergency desalination purposes in seawater and floodwater
settings.
The problem associated with Reverse and Forward osmosis is that
is always a highly concentrated waste product consisting of everything that was
removed from the created "fresh water". These concentrates are classified by the
U.S. Environmental Protection Agency as industrial wastes. With coastal
facilities, it may be possible to return it to the sea without harm if this
concentrate does not exceed the normal ocean salinity gradients to which
osmoregulators are accustomed. Reverse osmosis, for instance, may remove 50% or
more of the water, doubling the salinity of ocean waste.
The hypersaline
brine has the potential to harm ecosystems, especially marine environments in
regions with low turbidity and high evaporation that already have elevated
salinity. Because the brine is more dense than the surrounding sea water due to
the higher solute concentration, discharge into water bodies means that the
ecosystems on the bed of the water body are most at risk because the brine sinks
and remains there long enough to damage the ecosystems. Careful re-introduction
attempts to minimize this problem.
Geothermal desalination is an
experimental process under development for the production of fresh water using
heat energy extracted from underground rocks. Claimed benefits of this method of
desalination are that it requires less maintenance than reverse osmosis
membranes and that the primary energy input is from geothermal heat, which is a
low-environmental-impact source of energy.
Around 1995, several
entrepreneurs came together with an idea to use geothermal water directly as a
source for desalination. The experiment was moved to northern Nevada. It was
moderately successful, and was a proof of concept. The developers, Douglas
Firestone and Adjunct Professor Ronald A. Newcomb, have designed a series of
prototypes.
A total of five prototypes and three modifications
demostrated that, with process water approaching 210 Fahrenheit (99 Celsius)and
a chill source about 35 F (2 C), a full-size device would produce about one-half
acre foot (about 160,000 gallons or 600 cubic metres) of water per day. Salt
concentration in the wastewater would only be about 10% above the level of the
original water, thus, from, say, 35,000 to about 38,000 parts per million, well
within the ability of osmoregulators to adjust.
Douglas Firestone began
working with evaporation/condensation air loop desalination about 1998 and
proved that geothermal waters could be used as process water to produce potable
water in 2001. In 2003 Professor Ronald A. Newcomb, now at San Diego State
University Center for Advanced Water Technologies began to work with Firestone
to enhance the process of using geothermal energy for the purpose of
desalination. Geothermal Energy is a primary energy source.
In 2005 some
testing was done in the fifth prototype of a device called the “Delta T” a
closed air loop, atmospheric pressure, evaporation condensation loop
geothermally powered desalination device. The device used filtered sea water
from Scripps Institute of Oceanography and reduced the salt concentration from
35,000 ppm to 51 ppm w/w.
ASX listed companies
– a watchlist
Certainly worthy of mention is South Australia’s world
class HDR geothermal energy resources. The Cooper Basin is one of the world’s
hottest locations for HFR energy and is the site for the Geodynamics
(ASX:GDY)
demonstration plant.
The operation consists of drilling two wells
approximately 5 kilometres into the ground. A heat exchanger is then formed by
hydraulic stimulation where the temperature of the granites is approximately
270°C. The technology and concept is not new. France has the Soultz HDR project
which is considered the most advanced HDR geothermal project in the world. HDR
geothermal energy uses proven binary power plants and proven drilling techniques
used everyday in the mining industry. HDR geothermal exploration in Australia
was kick started by SA and NSW’s recognition of HDR by granting Geothermal
Exploration Licences (GELs) and the Government’s Renewable Energy (Electricity)
Act 2000.
Geodynamic’s economic modeling suggests it can produce power
from a 13MWe demonstration plant at around $63MW/h. This is cheaper than wind,
and has simular infrastructure costs. A scaled up plant of 275MW is suggested to
produce power at a cost of $40MW/h which is the first base load zero emissions
renewable energy source to rival the cost of conventional fossil fuels. This
data is produced in collaboration with MIT and has been independently reviewed
by Sinclair Knight Merz.
Geodynamics has successfully obtained a
technological transfer agreement and sub licence for the use of Kalina Cycle
technology. Kalina Cycle is the world’s highest efficiency heat to power
conversion technology which when used in the proposed binary geothermal power
plant can increase the efficiency by as much as 25%. Such increases has been
demonstrated in a plant in Iceland. Traditional plants have used an Organic
Rankine Cycle (ORC) based on organic fluids where the Kalina Cycle uses a water
ammonia mixture.
One of the problems with producing power of this
quantity in the Cooper Basin is the cost of connecting it to the High Voltage
Transmission Network. As Geodynamics has another GEL for the Hunter Valley
(close to Sydney) some wonder why this site was not chosen for the demonstration
plant. However Geodynamics points out the temperature of the granites may be
tens of degrees lower at the Hunter Valley site which can cause power output to
be cut substantially.
The 275MWe scaled up plant could be connected to
the High Voltage Distribution Grid with a line to Olympic Dam. This proposal is
suggested to cost approximately $5 to $10MW/h still making the project very
viable. The 275MWe plant harnesses an area of HDR 2.5 x 2.5 kilometres.
Geodynamics GEL97 & GEL98 HDR geothermal exploration tenements in South
Australia alone cover an area of 991 square kilometres and with mention of
future capacities in the thousands of MWe, We can only wait and see what
eventuates of this exciting technology. The 1000 square kilometre HDR resource
is the equivalent of 50 billion barrels of oil or 10.3 billion tonnes of coal.
This is 20 times larger than all the known Australian oil reserves and
equivalent to 40 years current black coal production.
Habanero 1 & 2,
Geodynamic’s first two geothermal wells (named after a hot chilli pepper) has
produced very exciting results. Hydraulic stimulation of the underground heat
exchanger, the most riskiest part of the project, has been successfully
completed. It was reported to have exceeded all expectations with a heat
exchanger seven times larger than expected. A initial water circulation test in
mid April 2005 lasting 40 hours reached temperatures of 198.5°C. A five week
diagnostic flow test programme is now expected to start the week beginning 2nd
May 2005 and after completion, a 3MW geothermal power plant will be built to
demonstrate HFR geothermal energy. Literally it’s full steam ahead for
Geodynamics.
Petratherm Limited (ASX:PTR) has a
different strategy to that of its peers. Instead of focusing on obtaining the
highest temperatures, they are aiming to find hot dry rock in excess of 220°C
but at a depth less than 3.5 kilometres and positioned close to infrastructure.
They believe finding hot dry rock close to established infrastructure but at
lower temperatures out weighs the cost of drilling deeper and running
transmission lines across the state.
Unfortunately we will have to wait a
couple of years to see if this strategy proves correct. Petratherm has announced
it will drill its first exploration well in the forth quarter of 2004, kick
starting a two-year exploration program. Petratherm have identified three areas
of interest and have obtained geothermal exploration licences GEL156 Paralana
and GEL157 Callabona, both northeast of Leigh Creek and GEL158 Ferguson Hill,
approximately 70 kilometres north of Olympic Dam.
This taken from the
Petratherm prospectus:
Exploration Models
High
Temperature Rocks
There are two main components required for a rock
within the earth’s crust to achieve the high temperatures needed to be a
potential hot rock geothermal energy resource.
Intrinsic heat
production
The amount of heat produced by a rock is due largely to the
concentration of naturally occurring radiogenic minerals. As the concentrations
of the radiogenic minerals are very low (commonly less than 50 parts per million
or 0.005%) a large volume of the rock needs to be present to generate
significantly elevated temperatures. Granites are an example which commonly
occur as large masses which have volumes of greater than 100 cubic kilometres,
and are thus an ideal geothermal resource
target.
Insulation
Without an insulating cover of material, all
the heat generated by the heat-producing rocks would be rapidly dissipated. To
trap the heat effectively, the blanketing cover must be a good thermal insulator
and must also have a minimum thickness of at least three kilometres to maintain
suitable temperatures.
South Australia’s Hot Rocks
The geology
of South Australia is dominated by Proterozoic rocks, which were formed between
570 and 2,500 million years ago. While these rocks are not uncommon worldwide,
those in South Australia generate significantly more heat than most Proterozoic
rock systems elsewhere in the world. Temperature readings, and measurements of
heat flow from deep bores define an area of South Australia’s crust which is
twice as hot as most Proterozoic crust elsewhere in the world. This area of
elevated heat flow is known as the South Australian Heat Flow Anomaly or SAHFA.
It is likely that the SAHFA exists because the upper part of the South
Australia’s Proterozoic crust is extremely rich in a type of granite that
produces far more heat than other rock types. In areas where these granites
outcrop, for example in the northern Eyre Peninsula, the heat they produce
dissipates immediately producing no thermal anomaly. However where younger
sediments bury them, they can reach temperatures in excess of 250°C at depths of
less than 5 kilometres. For this reason, the SAHFA is an exceptional exploration
target area for hot rock geothermal energy. Although temperatures within the
SAHFA are elevated compared to typical Proterozoic crust, the temperatures
within this area are not uniform. At a smaller scale, temperatures will vary
according to the localized geology – some areas may be relatively cool, whilst
others are much hotter. Location of target sources is based on the use of two
specific geological models known as the thermally anomalous granite (TAG) model
and the radiogenic iron oxide (RIO) model. Each has clearly defined geological
parameters.
Thermally Anomalous Granite (TAG) Model
Analysis of
Petratherm’s geological and geophysical database has highlighted the location of
a number of thermally anomalous granites within the SAHFA. Measurements on
outcrops of these exceptional granites in the Mount Painter region in the
northern Flinders Ranges indicate that they produce an average of eight and up
to twenty five times the heat of most granites, and 50% more heat than typical
rocks within the SAHFA. This makes them amongst the most thermally active
granites in the world. Thermal modelling indicates that under favourable
conditions, rocks meeting the TAG criteria can generate temperatures of around
250 degrees Celsius at depths of 3.5 kilometres.
Radiogenic Iron Oxide
(RIO) Model
This model focuses on areas where ancient volcanic and
granitic rocks released hot sub-surface fluids that permeated through the
surrounding rocks and altered their composition. Olympic Dam is an example of
this. Natural, low-level radiogenic decay results in extremely high heat
production rates (Figure 13). Measured heat production rates in RIO bodies may
be as much as 50 times greater than those from average granite, and thermal
modelling shows that under favourable conditions temperatures in excess of 200°C
may be generated at depths of around three kilometres. Petratherm has a number
of techniques, developed by MNGI Pty Ltd, to identify RIO bodies by using
detailed gravity (measuring density changes) and magnetic data to detect the
iron oxide associated with these systems.
Enhanced Natural Thermal
System
In some instances, the heat transfer from a TAG or RIO body may be
enhanced by favourable geological conditions. Specifically, pre-existing faults
may already focus natural superheated groundwater. These fault-controlled heat
reservoirs telescope potential resources much closer to the surface, allowing
cheaper development costs. Development of a heat exchanger is also much simpler,
as there is already a natural flow system, which can be enhanced to maximize
heat extraction.
Eden Energy (ASX: EDE), a
subsidiary
of Tasman Resources (ASX:TAS) has applied
for seven geothermal licences in South Australia. It intends to harness Hot Dry
Rock energy not only for electricity generation, but also for the production of
hydrogen fuels.
Eden Energy has a significant stake of Brehon Energy,
which holds world leading technology and patents for the cryogenic storage of
hydrogen and the production and use of Hythane, a mixture of compressed natural
gas (CNG) and hydrogen. This technology has initially been developed over the
past 15 to 20 years as part of the NASA space program, been trialed in a wide
range of applications and is now ready for full-scale
commercialisation.
Eden has just announced details of a joint project to
replace Beijing’s 10,000 diesel buses with low emission Hythane alternatives.
This technology will be ready and on show to the world at the up coming 2008
Beijing Olympics.
Green Rock Energy Limited (ASX:GRK), formally
Mokuti Mining Limited has acquired Perilya Geothermal Energy Pty Ltd & Green
Rock Energy Pty Ltd which each own a 50% share of five geothermal exploration
licences around the Olympic Dam area covering 2200 square kilometres. Green Rock
Energy will start drilling investigation wells in the 2nd quarter of 2005 and
subject to good results will drill it’s first geothermal exploration well in
2006.
Green Rock says 1 km3 of hot rocks initially at 200ºC has the
potential to produce about 10 MW electricity annually if the rock temperature
falls to 180 ºC over 20 years.
Green Rock is currently undergoing a
rights
issue and trading at 6 cents. The issue price is 5 cents per share
with a free attaching option for each 2 shares subscribed for. If you like this
one, it might be worth waiting a week or so as there may be some immediate
profit taking.
Geothermal-Resources (ASX:GHT), a spin off
from Havilah Resources (ASX:HAV) has
recently announced an IPO. Geothermal Resources currently owns GEL181, 208, 209
and 210 in South Australia’s Lake Frome area and have applied for GELA214, 215,
216 and 217.
Renewable energy company, Pacific Hydro is also hot on hot
rocks. Pacific Hydro has a record eighteen geothermal exploration licences in
South Australia covering a total of 8,894 square kilometres. A quick search of
this company at delisted.com.au shows “shares to be suspended
from quotation at close of trading on 20 July 2005 following receipt of a
compulsory acquisition notice from IFM Renewable Energy Pty Limited. IFM paid
$5.00 per share
While South Australia and New South Wales were the first
to recognise Hot Rock Geothermal exploration, it would appear the NT, Victorian,
Queensland and more recently Western Australia are busy passing legislation
allowing the exploration of Hot Rocks.
The future for Geothermal
energy
The outlook for geothermal energy use depends on at least
three factors: the demand for energy in general; the inventory of available
geothermal resources; and the competitive position of geothermal among other
energy sources.
The Demand for energy will continue to grow.
Economies are expanding, populations are increasing (over 2 billion people still
do not have electricity), and energy-intensive technologies are spreading. All
these mean greater demand for energy. At the same time, there is growing global
recognition of the environmental impacts of energy production and use from
fossil fuel and nuclear resources. Public polls repeatedly show that most people
prefer a policy of support for renewable energy.
The Inventory of
accessible geothermal energy is sizable. Using current technology geothermal
energy from already-identified reservoirs can contribute as much as 10% of the
United States energy supply. With more exploration, the inventory can become
larger. The entire world resource base of geothermal energy has been calculated
in government surveys to be larger than the resource bases of coal, oil, gas and
uranium combined. The geothermal resource base becomes more available as methods
and technologies for accessing it are improved through research and
experience.
The Competitive Position depends primarily on
cost:
Costs: Shorter and Longer Term.
Production of fossil
fuels (oil, natural gas and coal) are a relative bargain in the short term. Like
many renewable resources, geothermal resources need relatively high initial
investments to access the heat, hot water and steam. However, geothermal fuel
cost is predictable and stable. Fossil fuel supplies will increase in cost as
reserves are exhausted. Fossil fuel supplies can be interrupted for any number
of reasons. Renewable geothermal energy may offer a better long term
investment.
Costs: Direct and Indirect.
The monetary price we
pay to our natural gas and electricity suppliers, and at the service station, is
our direct cost for the energy we use. However, the use of energy also has
indirect or externalcosts that are imposed on society. Examples are the
huge costs of global climate change; the health effects from ground level
pollution of the air; future effects of pollution of water and land; military
expenditures to protect petroleum sources and supply routes; and costs of safely
storing radioactive waste for generations. Geothermal energy can already compete
with the direct costs of conventional fuels in some locations and is a clean,
indigenous, renewable resource without hidden external costs. Public polls
reveal that customers are willing to pay a little more for energy from renewable
resources such as geothermal energy.
Costs: Domestic and
Importing.
Investment in the use of domestic, indigenous, renewable
energy resources like geothermal energy provides jobs, expands the regional and
national economies, and avoids the export of money to import
fuels.
Energy demand is increasing rapidly worldwide. Some energy and
environmental experts predict that the growth of electricity production and
direct uses of geothermal energy will be revitalized by international
commitments to reduce carbon dioxide emissions to avert global climate change
and by the opening of markets to competition.
The push to alternative
energy sources
The Commonwealth Government has
• committed to
maintain the target for greenhouse gas (“GHG’’) emissions from fossil fuel at no
more than 108% of 1990 levels during the period 2008-2012
• decided to
encourage additional energy generation from ecologically sustainable renewable
sources;
• recently instigated a review of the Mandatory Renewable Energy
Target (“MRET’’), which required an extra 9,500 GWh by 2010, the review
recommending the target be increased to 20,000 GWh by 2020;
• previously
created a system of renewable energy certificates (“RECs’’) to encourage the
meeting of targets, which would, if the new recommendations are implemented, for
projects commencing after 2005, have a 15 year life; and
• in the
current review indicated renewable energy industry sales are about $1.8 billion,
with a target of $4 billion by 2010 (MRET review).
Policy Responses to
Global Warming
Increasing scientific and political concerns saw global
warming introduced to the United Nations agenda. During the 1990s there was a
succession of resolutions aimed at marshalling eff orts to counter global
warming. The focus of these is the reduction of emissions of greenhouse gases
(GHG). The 1992 Framework Convention on Climate Change was the first formal
international statement of concern and agreement to take action to stabilise
atmospheric carbon dioxide concentrations. In this context the 1997 Kyoto
Protocol was negotiated. The Kyoto Protocol specified commitments by individual
developed countries to reduce emissions by on average 5.2% below 1990 levels in
the “commitment period” from 2008 to 2012.
As a result of negotiations at
Kyoto, Australia was given a target of emissions to be no more than 108% of 1990
levels for the period 2008 to 2012. Although not formally ratifying the Kyoto
Protocol, the Australian Government appears committed to its Kyoto target of
limiting emissions.
Australia’s Greenhouse Gas
Emissions
Greenhouse Australia, a government office devoted to greenhouse
issues, has recently released an inventory of Australia’s GHG emissions for
2001, suggesting Australia released 543 million tonnes net of CO2e (using Kyoto
Accounting Protocols) into the atmosphere in 2001. The so-called stationary
energy sector, which includes the generation of electricity as well as the
direct consumption of solid, liquid, gaseous, biomass and other fuels for
purposes other than electricity generation, was responsible for nearly 48% of
these emissions. Seventy percent of the emissions in the stationary energy
sector are from electricity generation.
The contribution to GHG emissions
by electricity generation has been increasing, rising by about 35% between 1990
and 2000. Electricity generation now represents about one third of the total of
Australian GHG emissions.
Government Response To encourage the use
of renewable energy, the Commonwealth Government introduced the Renewable Energy
(Electricity) Act 2000 (“the Act”). One of the initiatives introduced by the Act
is known as the Mandatory Renewable Energy Target (“MRET”). The Act aims to
achieve an additional 2% of Australia’s electricity from renewable sources. The
objectives of the Act are:
• to encourage the additional generation of
electricity from renewable sources;
• to reduce emissions of greenhouse
gases, and
• to ensure that renewable energy sources are ecologically
sustainable.
The additional generation targets are specified for ten
years and are national targets. They are not apportioned to States but to
electricity retailers on the basis of how much electricity they sell. The Act
specifies acceptable renewable sources.
The task, as mandated by the Act,
is to generate an additional 9,500 gigawatt hours (GWh) of electricity per annum
by renewable means by 2010. The Electricity Supply Association of Australia
estimates that an additional 3000 megawatts (MWe) of renewable capacity will
need to be brought on line to generate the required amount of renewable
electricity. Renewable energy sources are shown in the diagram at the bottom of
the post [way, way down the bottom].
Renewable Energy Certificates
Generators of electricity from renewable sources may register with the Office of
the Renewable Energy Regulator, and receive Renewable Energy Certificates
(“RECs”) for the renewable energy that they generate. These certificates can be
traded with liable entities (eg electricity retailers), which are required to
obtain and surrender a certain number of certificates per year.
The
Renewable Energy (Electricity) (Charge) Act 2000 sets a non tax-deductible
penalty of $40 per megawatt-hour (MWh) for retailers who fail to surrender the
correct number of certificates. This price is anticipated to encourage new
renewable generation projects.
In September 2003, the MRET Review Panel
was established and their report recommends that after 2010 the $40 penalty
should be indexed and that the RECs should have a 15 year period applicable to
all projects commenced after 2005. The Panel also recommended that the target
increase in renewable energy should be increased to 20,000 GWh by
2020.
National Electricity Market In late 1998, the National
Electricity Market (NEM) commenced operating. The aim of the NEM is to promote
competition throughout the electricity supply chain. The NEM provides power to
7.7 million customers through an interconnected grid that takes in Queensland,
New South Wales, the Australian Capital Territory, South Australia and Victoria.
Tasmania is set to join in 2005 with the completion of BASSLINK. Approximately
$8 billion worth of electricity is traded annually through the NEM.
The
National Electricity Market Management Company Limited (NEMMCO) operates a
wholesale market for trading electricity between generators and electricity
retailers in the NEM. All electricity output is pooled and then scheduled to
meet electricity demand. Pool price varies according to electricity demand and
available generating capacity. To minimise the risk of volatile pool prices,
market participants buy and sell electricity hedge contracts, which provide
price certainty for fixed quantities of electricity. Contracts can be sold
between generators and retailers. There are also some intermediaries, such as
brokers and banks, who trade with the market participants.
Advantages
Power generation, based on HR energy, has key advantages over the other sources
of power generation (Figure 7). In particular, it is capable of providing
large-scale base-load electricity. For instance, our model suggests that a block
of granite one kilometre thick and with a surface area of 25 square kilometres,
and having an average initial temperature of 270°C, will support the generation
of 1000 MWe of emission-free electricity over a 25 year period. As the granites
are constantly generating heat, the resource is renewable. Th ermal studies have
shown that it takes approximately one and half times longer than the operating
life of the underground heat exchanger to reheat. By the careful rotating of
operating wells within the well fi eld, an electricity plant can potentially use
this source of energy over many centuries. Unlike wind and solar electricity
production, HR geothermal electricity is driven by an essentially unchanging
energy resource, allowing continual base-load supply. Its other great
environmental strength, apart from being CO2 emission-free is its relatively
small visual and land use impact. HR Geothermal Compared with Other Energy
Sources Figure 7 unchanging energy resource, allowing continual base-load
supply. Its other great environmental strength, apart from being CO2
emission-free is its relatively small visual and land use impact. base-load
supply. Its other great environmental emission-free is its relatively small
visual and land use impact.
Economic models
The Australian
National University [ANU] has undertaken extensive research into various
economic models for Geothermal energy. Whilst the research is based on 1994
costs, it is none the less worth a read. It includes exploration costs,
powerplant, drilling costs, acoustic monitoring, pilot development etc. For
those who are so inclined [and if you got this far what’s another 40 pages,
hehe!] you can find it here: http://hotrock.anu.edu.au/economics.htm The site
also has information on various projects.
Well that’s it! I hope you got
something out of that and it helps you make some money. Other posts in the 06
summer series by perdy include: Uranium, Zinc, Copper, Nickel, and Coal Bed
Methane CBM. See you all next summer.
Phewwwww.
Futher reading
and references
http://today.reuters.co.uk/news/articlenews.aspx?storyid=2007-01-04T105032Z_01_NOA439018_RTRUKOC_0_GEOTHERMAL-POWER.xml
http://geothermal.marin.org/pwrheat.html#Q2
They have a glossary there
too
http://www.greenrock.com.au/additional/glossary.htm
http://www.epa.qld.gov.au/register/p00395aa.pdf
http://hotrock.anu.edu.au/
http://en.wikipedia.org/wiki/Hot-Dry-Rock#column-one#column-one
http://www.greenrock.com.au/index.php
http://www.petratherm.com.au/exploration/index.htm
http://www.geodynamics.com.au/IRM/content/
http://www.geodynamics.com.au/IRM/content/howtoanim.htm
http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire
http://hotrock.anu.edu.au/aus_links.htm
http://www.beyondlogic.org/southaustraliapower/#HDR
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; "HR Geothermal Compared with other energy sources")