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Map of USA Geothermal Power Hotspots

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Geothermal Energy Resources Map of USA

Sunday, October 19, 2008

Speculative Microcap Geothermal Energy Companies

For those who are looking for the closest thing to a blue chip stock in the green energy investing sector, well, you could do a lot worse than Ormat Technologies, the leading USA geothermal power company, and a global pioneer.

For those hoping to discover the next Ormat, here are a few smaller geothermal energy stocks for you to begin researching:

Company  Stock Symbol Price Mkt Cap

Raser Technologies RZ 3.60 212.08M





Wednesday, October 8, 2008

Bargain Green Energy Stocks; Investments for the Obama Rally

Yes global stock markets have taken a pounding and continue to suffer from high levels of fear and capitulation, and these are both signs of an impending bottom. When the markets turn, and they will, green power companies will be among equity market leaders.

Here are some alternative energy stocks that are off at least 50% from their highs, yet would appear to have years of high growth potential ahead of them.



Flywheel Technology energy storage company has proven that 25 flywheels can store and deliver a megawatt of energy, and in recent tests has shown how ten of its new flywheels operating as one system can store and flow one megawatt. Down to $1.14 from a high of just 2.49, this little known green stock may in future years play a crucial role in steadying energy flows. 


First Solar (FSLR)

The undisputed global market leader in the solar photovoltaics industry, FSLR designs and manufactures solar panels utilizing thin film semiconductor technology; cadmium telluride used to convert sunlight into electricity. The one medium term concern is tellurium supply, but with the shares at 127.43 (down from a high of 317), one may be staring at an opportunity to own the next Google.



Comverge Inc. is a clean energy company with substantial revenues, from providing peaking and base load capacity to electric utilities, grid operators and associated electricity markets. At 4.15 the stock is off 85% from its high. I don't know much about this company but am fascinated by the steepness of the drop, as the firm has revenue and cash in the bank. Worth looking into.


Ormat Technologies (ORA)

A true American success story, at 27.42, ORA shares are down over half from a high of 57.93. ORA develops, owns and operates geothermal power and recovered energy-based electricity power plants in the United States and renewable geothermal power plants in other countries around the world, and sells the electricity generated by these plants. Much of the equipment utilized is designed and maunfactured by Ormat.


AMSC supplies electrical systems used in wind turbines; sells power electronic products that regulate wind farm voltage to enable their interconnection to the power grid; licenses wind energy system designs to manufacturers of such systems, and provides consulting services to the wind industry, At 14.20 (down from 47.53), the shares present an interesting entry point for access to a wind-related stock with explosive revenue growth.


Leading USA company is a major provider of wind power, solar energy, water desalination / purification and other emerging technology systems and services. At 20.65, the stock is down by half, trades at a P/E of 9.7 and yields 6%!

Applied Materials (AMAT) Inc. 

High quality USA clean energy technology company offering the SunFab thin film solar line of photovoltaic electricity systems. Based in Santa Clara, California, AMAT yields 1.92% at today's close of 12.47 and trades at a reasonable P/E of just 15.



Sunday, October 5, 2008

Alphabetical List of Top Renewable Power Websites and Blogs

Green Energy Investing links, find blogs on clean energy technology, global wind power industry, thin film solar photovoltaic power companies, green mutual funds, links to alternative energy companies and other publicly-traded renewable power investments.


Best of the Best Green Power Investing Websites:

Saturday, September 20, 2008

Bargains emerging in geothermal power stocks? 4 geothermal energy companies to research

Look for renewable energy mutual funds and clean green power investment funds holding stocks like these and consider dollar-cost averaging into some of them.


Ormat Technologies

Global geothermal power industry leader, the close of Friday, September 19th, 2008 of 43.62, equals a market capitalization of $2 billion, and represents a discount off the year's high of 57.93.


Calpine Corporation

Geothermal power producer is also America's largets producer of CHP Combine Heat and Power electricity generation, with 8,000 of its 24,000 megawatts being CHP installations. Major USA clean power producer seems undervalued relative to other renewable energy stocks. At 14.31 versus a year high of 23.36, a lot of air is out of it now, but the market capitalization of $6 billion plus a P/E of 2 indicates debt concerns are still out there.


More speculative:

Nevada Geothermal Power

At friday's close of 0.76, the stock now represents a market cap of 72mil is down by half from its high of 1.55.

Western Geopower

Developing a 35 megawatt geothermal power plant in northern California, Western Geo may be fine for risk takers looking at exciting penny stocks. The close of 0.225 (down from 0.50) gives the firm a market cap of just over 42 million, and with over 1,000 acres in The Geysers project plus the South Meager (potential 100 megawatts in British Columbia) in development, it may be time for the brave to take a look at this one.

Complete list of geothermal power stocks, publicly-traded geothermal companies

Full List of wind power stocks, publicly-listed wind energy companies



Friday, September 5, 2008

5 Top Geothermal Power Stocks - Long-term Clean Energy Investments

Here are some geothermal power companies to consider investing in for the long term:

1. Ormat Technologies (ORA) top geothermal company

2. Raser Technologies (RZ) geothermal power / electric motors

3. Sierra Geothermal (SRA.V) diversified geothermal power developer

4. Nevada Geothermal (NGLPF) USA geothermal energy company

5. US Geothermal Power (UGTH) American geothermal energy developer


Many alternative energy stocks will offer buying opportunities in coming months, as the oil price continues to skid ... so those looking to acquire good renewable power companies to hold for the next 5 to 10 years could do worse than adding some of these names in a judicious manner.

This is not a buy signal, but rather an invitation for your serious research to begin. Clean energy will transform the world, and you can be a part of making it happen.

Peace from Toronto,

Joe T


More names to look at:

Western Geo (WGP)

WFI Industries (WFI)



Sunday, August 31, 2008

Geothermal Power stocks, Alternative Energy News; August 2008 Roundup

Clean Energy, Geothermal Power and green investing links for August 2008


Geothermal project in Ramallah, Palestine



Google America's Biggest Investor In Geothermal Research




USA, Australia and Iceland form Interational Partnership for Geothermal Technology




August 2008 Geothermal Industry News



What is Geothermal? Globe-net geothermal power tutorial



Geothermal energy stock quotes



Google.org invests in EGS - Enhanced Geothermal Systems



Google goes geothermal; Australia finds massive geothermal potential



Nevada Geothermal reports Blue Mountain Faulkner 1 project proceeding




Raser Tech Adds 33,000 Acres to Its Geothermal Holdings



Leading Geothermal Power publicly-traded stocks



Recovery of Minerals and Metals from Geothermal Energy Plants



Geothermal power investing, water purification technology, desalination company



Solar Power, wind energy and Renewable Power News - August 2008


Twenty leading Alternative Energy Stocks August 2008



GreenChipStocks.com article, Global Wind Energy Potential



Wind Energy Company websites, windpower stocks



News on The Pickens Plan for American Energy Independence



The Pickens Plan - Reviews and Online Analysis



Global Clean Energy Stocks: Ten Top Renewable Power Investments



Green Party of Canada has first Member in Canadian Parliament



McCain VP choice Palin; Mrs. Cleaver and/or the anti-Hilary?



Barack Obama speech in Denver: USA Energy Independence in a decade



Joe Biden speech; "Obama's energy plan will bring 5 milion new jobs



Joe Biden Interview on USA Energy Policy



Joe Biden is strong on energy, environment, women's issues and foreign policy



SolarWall shines at 2008 Olympics in Beijing



Microturbines and Fuel Cells; Capstone and Fuel Cell Energy



Full List of Solar Energy and Renewable Power Companies

Sunday, August 24, 2008

What is Geothermal? Globe-net.com article, abundant pollution-free energy

There are many ways to utilize the heat beneath the earth's surface, and even the cool rocks just below our feet are used in geothermal air conditioning systems. Now the emerging focus of investors is utility-scale geothermal power plants, and many people are wondering how exactly is the heat turned into electricity, and is it really as clean as proponents claim? My belief is that geothermal and conservation will be the two biggest contributors to Canadian efforts to combat global warming, complemented by wind energy systems, thin-film solar for buildings and vehicles, clean fuels such as ethanol in the south, biodiesel in the north, plus natural gas powered, hydrogen, fuel cell and electric cars.

The following article from Globe-net.com is one of the best explanations of geothermal exploration, development and production I have ever read. As more mining companies enter the geothermal exploration and development field, the idea of utilizing geothermal plants as a source of valuable minerals and metals (such as lithium-ion, used in laptop and electric car batteries) filtered from the water flow will become more predominant. Even the waste water from oil wells is hot enough to produce some power, so there are many ways geothermal can improve the efficiency of our economy.

Enjoying the summer,

Joe T


January 23, 2008 (GLOBE-Net) - Geothermal energy is clean, quiet, virtually inexhaustible and able meet the world’s annual electricity and heating needs many times over with little impact on the climate or the environment. In many jurisdictions, geothermal energy is emerging as a reliable and affordable alternative to fossil fuels. This fourth article in the GLOBE-Net series on renewable energy discusses the dark horse of renewables.

What is Geothermal?

Geothermal technology harnesses the energy created by the massive amount of heat at the earth’s core. This vast and renewable energy source can be utilized for either direct heating or cooling of a building or to generate electricity.

Geothermal heating uses heat pumps for efficient water and space heating in buildings and uses the earth as the heat exchanger. Typically hot water stored below the earth’s surface is moved through pipes which transfer heat through the walls and flooring of buildings. In hot months, geothermal heating systems are capable of pumping hot air back into the ground which cools buildings. The technology can be applied to water heating and cooling.

Geothermal technology is more efficient than combustion furnaces for heating or cooling because it only transfers heat from one location to another - as opposed to converting one kind of energy to another. Installation costs are about 50 to 100 per cent higher than that of conventional fossil-fuel-fired furnaces. However it saves homeowners up to 70% heating costs, 75% in maintenance costs and can pay itself back in four years. Solar technology can also be used to power a low energy geothermal heat pump for a completely renewable heating/cooling source.

Geothermal power plants use steam to drive turbines. The steam is naturally generated from water heated deep below the Earth’s surface which is collected then reinserted into the Earth continuously to generate power.

At current global capacity geothermal power plants supply electricity to about 60 million people, roughly the population of the United Kingdom. These power plants are built where there is access to a geothermal reservoir, which typically occurs along continental plate margins with tectonic activity.

Most geothermal plants in the world gather the steam from underground pockets of water. The water ranges from 100 to 400 degrees Celsius and remains in a liquid state due to the high pressure environment in which it exists. By drilling into these pockets, the high pressure on the water is relieved and it vaporizes, rising to the surface for geothermal energy use.

Future "hot dry rock" plants may inject water into hot underground areas that lack moisture, producing steam. The equipment used for this form of geothermal drilling is similar to that used for oil wells, but must go much deeper and be wider to accommodate the water cycle.

The Pacific "Ring of Fire", a zone of active volcanoes around the Pacific, provides some of the hottest spots on the planet for geothermal power. More efficient technologies for channeling underground heat are helping extend geothermal power’s reach beyond the "ring of fire".

"When power plant technology in the 1980s was developed to take advantage of lower temperature geothermal resources, the geothermal industry was revolutionized," notes Alyssa Kagel, author of the US Geothermal Energy Association report The State of Geothermal Technology Part II: Surface Technology (part one can be found here). The report discusses new and underused technologies - a few that could revolutionize the industry such as recovery technologies for sought-after minerals in geothermal water and new power plant materials that could resist the wear and tear of time.

New turbines can draw power from underground water that is not hot enough to create high-pressure steam. In July, a 200-kilowatt generator in Alaska started making electricity from water at 74 degrees Celsius, the lowest temperature on record.

"Geothermal is going into a renaissance age," said Doug Heffernan, chief executive of Mighty River Power, one of New Zealand’s largest power retailers. "It’s the only reliable renewable."

Investment Potential

Geothermal energy recently began to draw serious investor attention when the Massachusetts Institute of Technology (MIT) released The Future of Geothermal, a comprehensive study on geothermal resources in North America. The study said if 40% of the heat under the US could be tapped, it would meet demand 56,000 times over. It said an investment of $800 million to $1 billion could produce more than 100 gigawatts of electricity by 2050, equaling the combined output of all nuclear power plants in the US.

Investors can support geothermal power by supporting technology development; investing in existing plants; or by underwriting resource exploration and development. Harnessing geothermal energy involves higher initial investments, sometimes requiring years of drilling to map underground heat sources. Geothermal exploration and development is also risky and timeframes to come on line does not make it an investor friendly sector.

Government risk-sharing, tax exemptions or subsidies could greatly increase the value proposition of geothermal prospects to outside investors. The growing success of geothermal energy in the United States has mostly been attributed to tax credits handed out to the industry

"New federal and state initiatives to promote geothermal energy are paying off," said Karl Gawell, executive director of the US Geothermal Energy Association. "State renewable standards coupled with the federal production tax credit are creating a renaissance in U.S. geothermal power production."

In the later life of a geothermal plant, operations produce excellent income streams. While the plants often require refurbishment, with careful management geothermal reservoirs need not degrade over time, and net margins often exceed 60%. The fuel for geothermal energy is essentially free which not only allows for lower energy bills for consumers, but allows for a quick turnaround on capital investments.

Current projects typically develop over a three year period, which is actually quite quick when compared to typical 5 year lead times for coal plants.

Geothermal Around the World

  • The United States has 86 geothermal projects in development that will provide over 3,300 MW of electric power capacity making the U.S. total over 6,300 MW, enough to meet the energy needs of six million homes.

  • The town of Unterhaching, Germany, 22,000 will be warmed by hot water piped from geothermal sources beginning in May, 2008.
  • In Unterhaching, geothermal energy will be produced from a 3.4-megawatt generator being installed by German electronics giant Siemens.

  • Germany may have more than 200 megawatts of geothermal power-generating capacity by 2016, according to government forecasts.

  • In New Zealand, a 90-megawatt plant now under construction will cost $194 million and will boost the country’s geothermal capacity by 25 percent, producing more power than all the country’s wind farms combined.

  • In Iceland, there are five major geothermal power plants which produce about 26% (2006) of the country’s electricity. In addition, geothermal heating meets the heating and hot water requirements for around 87% of the nation’s housing.

Geothermal Potential in Canada

Canada has been slow to get into the geothermal game and remains the only Pacific Rim country to not make any serious investments in the energy technology. Many industry experts believe Canada is missing a golden opportunity to tap into its vast thermal resources for electricity production, particularly in the west, and virtually all Canadian homes can utilize geothermal heating using new technology for low heat sources.

In Canada, where one quarter of all energy is used for space and water heating and cooling, there are only 30,000 geothermal heating installations that are used for residential, commercial, institutional and industrial applications, but many believe this is not enough.

"We’re so far out of the game," says Alison Thompson, vice-president of the Canadian Geothermal Energy Association (CanGEA), based out of Calgary, who was quoted in an article in the Toronto Star.

Thompson is quoted as noting that existing data suggests that conventional geothermal projects in British Columbia could amount to 3,000 megawatts, but figures the number is likely closer to 6,000 megawatts. Alberta and the Yukon also have tremendous potential, but a lack of data makes it hard to pin down. Vancouver-based Geothermal Power has leases on 15 properties covering roughly 70,000 acres of land it believes could generate 250 MW of power.


Full report explaining: How Geothermal Energy is harnessed to produce electricity


More renewable energy links:

Wind Energy Stocks, Renewable Power Company Info



Solar Power Investing, leading solar energy companies

Geothermal energy companies including stock symbols for publicly-listed stocks



Major companies in the global geothermal power industry, plus junior exploration and development companies:



Map Illustrating Geothermal Energy Potential in Canada


Click for Larger View Map of Canadian Geothermal Energy Potential



More geothermal energy news:

Google launches Enhanced Geothermal Systems, invests in geothermal power companies



For wind energy and solar power stocks, check:

WindIntell.com Windpower Investing, Renewable Energy Stocks



For Solar Power investing, incl. companies websites:

SolarIntell.com Solar Power Company Website Links

Saturday, August 23, 2008

Google.org invests in Enhanced Geothermal Systems (EGS)

Google has taken another step forward in offseeting its own carbon emissions and has shown corporate leadership in advocating American self-sufficiency in energy. Northern California already gets about 3,000 megawatts of geothermally generated electricity, and this number is likely to rise fivefold over the next decade.

Check out the map that shows the geothermal power potential of all the USA, plus the geothermal energy resources of each individual State! Great work, Googlites!!!




USA Geothermal Energy Resources Map shown above is from www.nextbigfuture.com



A Googol of Heat Beneath Our Feet

The energy from the heat beneath the earth's surface is essentially an unlimited resource. What if it could be developed to help solve our energy challenges and fight global warming? Enhanced Geothermal Systems, or EGS, attempts to do just that. EGS produces heat and electricity by harnessing the energy from hot rock deep below the earth's surface, expanding the potential of traditional geothermal energy by orders of magnitude. EGS is a big challenge, but with the potential to power the world many times over, it demands our immediate attention. At Google we've launched an effort to advance EGS through R&D, investment, policy and information.


Google announces Enhanced Geothermal Systems, investments in geothermal power R&D



More Clean Energy links:

SolarPower Stocks, Renewable Energy Investing Information


Wind Energy Investing, Renewable Power Stocks

Friday, August 22, 2008

Google goes geothermal; Australia touts massive potential of hot rocks

The excellent website GreenChipStocks.com hosts The Green Chip Review, and yesterday they had an interesting article about Google's push into geothermal power, plus the vast untapped potential of geothermal energy in Australia.

Peace 2 All,

Joe



26,000 Reasons Google's Pushing Geothermal Down Under

By Sam Hopkins Thursday, August 21st, 2008

The Aussies have a head, and a continent, full of steam.

This week, geothermal energy enthusiasts in the Australian government are throwing out some astounding projections of how much potential underground steam-based power the continent-country possesses.

Enter Google, the world's # 1 search engine... and why founders Sergey Brin and Larry Page should head down under.

Anthony Budd, an official at national agency Geoscience Australia, told Reuters on Wednesday that "One percent of [Australia's] reserves would produce 26,000 years of energy supplies."
You read that right. 1%=26,000 years.

That's a massive number that puts into digits what Australia's leaders are already putting into words and policy action.

Australia's Geothermal Energy Push

Australia Resource Minister Martin Ferguson vigorously stands behind geothermal as bearing "huge potential... both as a solution to climate change and in terms of national energy security." And Prime Minister Kevin Rudd made his first move as head of state to sign his country onto the Kyoto Protocol to mitigate global warming.Up here in the Northern Hemisphere, Google.org, the charitable wing of the search engine company that has already changed the way the world works, annonced this week that it is pursuing "hot rock" geothermal energy research with a planned investment of $11 million.

Of course, it's not just about philanthropy for Google and its non-profit arm. While the company's motto is "Don't be evil," Google's data centers host ever-proliferating racks of servers that whir at dizzying speeds, 24/7/365, and make the company one of the top energy consumers in the world.

Geothermal could help Google buffer a lot of that energy impact.

In Google's neck of the woods in western U.S., geothermal resources already provide some 3,000 megawatts of power to residences and businesses.Yet underground energy is woefully underutilized... And that's something Google hopes to change.Scientific American quotes geothermal drilling entrepreneur Lou Capuano as saying that out of "roughly 1,900 drilling rigs in the U.S., seven, maybe up to 11 now, are geothermal."Now consider that by using 5,722 existing holes across Australia's vast landscape, Geoscience Australia's Anthony Budd and his colleagues have appraised the national natural resource that could and should take the country away from dependency on coal-fired electricity.

Those holes were all there because of previous mineral and fossil fuel exploration, and that's the Transitional Energy Economy we at Green Chip International have seen develop around the world. Old offshore oil rigs, drill holes, and other engineering feats of the hydrocarbon industry are providing a bridge to clean, renewable power.

Putting Money into the GroundThe Australian Geothermal Energy Association's research says that up to 40% of the government's 20% by 2020 renewable energy capacity goal could be reached with steam generated by injecting water deep into the earth. And appropriators in the capital of Canberra are digging deep into the national coffers, putting $43 million into advanced geothermal power plant creation.Washington, for its part, is now officially outpledged by Google.org in its geothermal energy exploration funding. That may change with a new presidency here, but it's clear that the combination of efforts by Google.org and Australia could put American geothermal far ahead of where it is now.

Google.org is putting its first dollars down in California's AltaRock Energy ($6.25 million) and deep drilling specialist Potter Drilling ($4 million).

Paul Thomsen of Green Chip Stocks holding and global geothermal heavyweight Ormat Technologies (NYSE:ORA) says drilling is key to advancing geothermal on a national scale. "The deeper you drill, the more expensive it is," Thomsen says. "Geology brings magma and heat closer to the surface in the western U.S. If we could drill deeper, then we could move east."

Moving east in the U.S. with geothermal projects entails first looking south to Australia, north to Iceland (where most of that tiny country's electricity already comes from geothermal sources), and wherever else it takes to get the best cooperative technology. Then we'll see the emergence of a strong worldwide geothermal industry, spawning more technologies and companies to invest in.

Regards,

Sam Hopkins
GreenChipStocks.com



More Green Energy Links:

Wind Energy Stocks, Renewable Power Investing

Solar Energy Investing, Solar Power Stocks

A Green Realtor Blog

Wednesday, August 13, 2008

Recovery of Minerals and Metals from Geothermal Effluent Brine

To me it is extremely exciting that geothermal power plants may also be able to supply valuable rare metals and minerals, such as lithium-ion, used for batteries in laptop computers and electric cars.

The following excerpt from a research paper on extracting metals from geothermal energy effluent is also linked in entirety to the html here: Recovering Metals from Geothermal Power Plant Effluent

Peace 2 All,

Yuya Joseph






DOE Report on Recovering Minerals / Metals from Geothermal Effluent

This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.
March 9, 2005

Recovery of Minerals and Metals from Geothermal Fluids

William Bourcier, Lawrence Livermore National Laboratory
Mow Lin, Brookhaven National Laboratory
Gerald Nix, National Renewable Energy Laboratory


ABSTRACT

Geothermal fluids are potentially significant sources of valuable minerals and metals.
These fluids are water that is heated by the natural heat flow from the depths of the earth.
Hotter fluids, typically with temperatures greater than 120°C, are used to generate
electricity. Lower temperature fluids are directly used to supply thermal energy to
applications such as agriculture, aquaculture and space heating. The geothermal waters
have had intimate and lengthy contact with the layers of the earth’s crust that they flow
through, resulting in dissolution of minerals and metals from the rocks, and solution into
the hot water. These aqueous solutions can be processed to recover minerals and metals.
Potential products include silica, zinc, lithium, and other materials. Recovery of minerals
and metals from geothermal fluids can be viewed as “solution mining by nature”,
followed by application of established or new hydrometallurgical techniques for isolation
and purification. This paper discusses the opportunities, the processes, the challenges,
the current status, the economics and the potential for recovery of minerals and metals
from geothermal fluids.


INTRODUCTION

Geothermal fluids contain significant concentrations of potentially valuable mineral
resources. Although their mineral content was often considered more a nuisance than an
asset, there is now increasing interest in improving the economics of geothermal energy
by co-producing and marketing some of the dissolved constituents. Simple cost-effective
methods are needed to extract mineral byproducts from geothermal fluids. Useful
methods may have already been developed in the hydrometallurgical industry that could
be modified for use with geothermal fluids. Although the enrichment of target elements
in geothermal fluids is not as high as the enrichment in fluids commonly treated with
hydrometallurgical methods, the costs associated with resource extraction from
geothermal fluids are potentially low for several reasons:

Plant costs are split between power and mineral production. Geothermal power
plants already pump and process the fluids. Mineral extraction would consist of
an additional treatment step added to existing plant facilities;

There are no costs associated with mining and physical processing of the ore, and
no negative environmental impacts;

There are no costs associated with dissolution of ore minerals into an aqueous
phase because they are already in solution;

Geothermal systems process large volumes of water, commonly tens of millions
of gallons per day, so that the mass of mineral resource is large in spite of
relatively low concentrations.

This paper reports on previous and current research aimed at developing technologies for
resource extraction from geothermal fluids, and provides a summary of the targeted
mineral by-products, their potential value, and extraction methods being considered. It
also summarizes zinc and silica extraction work at CalEnergy’s Salton Sea, California
field, silica extraction work in New Zealand geothermal plants, and current work to
develop silica and other metals extraction at Dixie Valley, Nevada, and Mammoth Lakes,
California.

CHEMISTRY OF GEOTHERMAL SYSTEMS

Geothermal fluids are waters that percolate through and are heated by hot rocks. Most
geothermal systems are therefore located in active volcanic areas such as the Pacific Rim
and Iceland. Some are located in fractured areas that allow water circulation to great
depths where the fluids are heated by the earth’s natural heat, such as some Basin and
Range fields in Nevada and Utah in the U.S. The source of the water may be meteoric,
connate (filling the pores of the rocks), or a mixture, and in some cases a magmatic
component is present from de-volatilization of hot magma. Fluid compositions are
therefore variable. Acidities range from pH 5 to 9, and salinities from 1000 to over
300,000 ppm TDS. Most fluids have low oxidation states and may contain ferrous iron
and reduced sulfur.

The chemical components of geothermal fluids are determined by their source (e.g.
meteoric, seawater, magmatic), the rock types with which they have reacted along their
flowpath, the temperature of those interactions, and the chemistry of the fluid. Reservoir
processes such as mixing and boiling also impact fluid chemistry. The chemistry of fluids
sampled at the surface therefore reflect their chemical and physical history. Certain
elements may be especially indicative of their source. For example, lithium, cesium and
rubidium are often enriched in fluids hosted by silica-rich volcanic rocks. Silica
concentrations are generally controlled by strongly temperature dependent equilibration
with silica polymorphs. Systems with more saline chloride-rich fluids are enriched in
metals such as iron, zinc, and other base metals that form strong chloride complexes.
Such fluids can be derived from reactions with evaporite-rich sedimentary rocks, as in the
geothermal fluids from near the Salton Sea, or from seawater-basalt interactions.

Geothermal fluids are produced from subsurface reservoirs at depths commonly between
500 and 3000 meters. Their heat is extracted and used to generate power. The fluids are
then reinjected into the subsurface to replenish the fluid reservoir. Resource removal
optimally takes place after or near the end of the energy extraction process, but prior to
reinjection. The temperatures of reinjected fluids are commonly between 50 and 150 degrees C
and pressures at or slightly above steam saturation. In some cases, mineral extraction may
allow further energy extraction that, without treatment, would be uneconomic due to
scale formation. For example, the geothermal plants at Wairakei, New Zealand terminate
energy extraction as the fluids cool to below 130 degrees C because silica scaling becomes too
difficult to control (Brown, 2000). Silica extraction would allow additional energy

1. Fossil basalt-seawater geothermal systems are the hosts of “massive sulfide” base metal ore deposits that are major sources of the world’s lead, zinc, copper, silver, and barium.


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