provide Renewable Energy Technologies engineering and project development
services. We incorporate many energy-saving technologies, products and
services into our renewable energy power and energy projects that may
include the use of; Absorption Chillers,
Adsorption Chillers, Automated
Demand Response, BioMethane, Cogeneration,
Concentrating Solar Power, Demand
Response Programs, Demand Side
Management, Energy Master Planning,
Energy Performance Contracting,
Performance Contracting, Engine
Driven Chillers, Geothermal Power
Plants, Landfill gas to Energy,
Ocean Thermal Energy
Conversion, Quadgeneration, Solar
CHP, Solar Cogeneration, Solar
Trigeneration, Trigeneration and Energy
company provides turn-key project solutions that include all or part of the
and Economic Feasibility Studies
Design, Engineering & Permitting
Funding & Financing Options
Savings program with no capital requirements.
and "Renewable Energy Credit" Applications/Processing
more information: call us at: 832-758-0027
Unlike most companies,
we are equipment
supplier/vendor neutral. This means we help our clients select the
best equipment for their specific application. This approach provides our
customers with superior performance, decreased operating expenses and
increased return on investment.
* Geothermal Energy... Power from the Depths
The Earth's crust is a bountiful source of energy—and fossil fuels
are only part of the story. Heat or thermal energy is by far the more
abundant resource. To put it in perspective, the thermal energy in the
uppermost six miles of the Earth's crust amounts to 50,000 times the
energy of all oil and gas resources in the world!
The word "geothermal" literally means "Earth" plus
"heat." The geothermal resource is the world's largest energy
resource and has been used by people for centuries. In addition, it is
environmentally friendly. It is a renewable resource and can be used in
ways that respect rather than upset our planet's delicate environmental
Geothermal power plants operating around the world are proof that the
Earth's thermal energy is readily converted to electricity in geologically
active areas. Many communities, commercial enterprises, universities, and
public facilities in the western United States are heated directly with
the water from underground reservoirs. For the homeowner or building owner
anywhere in the United States, the emergence of geothermal heat pumps
brings the benefits of geothermal energy to everyone's doorstep.
There's a relatively simple concept underlying all the ways geothermal
energy is used: The flow of thermal energy is available from beneath the
surface of the Earth and especially from subterranean reservoirs of hot
water. Over the years, technologies have evolved that allow us to take
advantage of this heat.
In fact, electric power plants driven by geothermal energy provide over
44 billion kilowatt hours of electricity worldwide per year, and world
capacity is growing at approximately 9% per year. To produce electric
power from geothermal resources, underground reservoirs of steam or hot
water are tapped by wells and the steam rotates turbines that generate
electricity. Typically, water is then returned to the ground to recharge
the reservoir and complete the renewable energy cycle.
Underground reservoirs are also tapped for "direct-use"
applications. In these instances, hot water is channeled to greenhouses,
spas, fish farms, and homes to fill space heating and hot water needs.
Geothermal energy use extends beyond underground reservoirs. The soil
and near-surface rocks, from 5 to 50 feet deep, have a nearly constant
temperature from geothermal heating. As a homeowner or business owner, you
can use the Earth as a heat source or heat sink with geothermal heat
pumps. According to the U.S. Environmental Protection Agency (EPA),
geothermal heat pumps are one of the nation's most efficient—and
therefore least polluting—heating, cooling, and water-heating systems
available. In winter, these systems draw on "earth heat" to warm
the house, and in summer they transfer heat from the house to the earth,
which ranges in temperature from 50° to 70°F (10° to 21°C) depending
A Clear Advantage
Geothermal energy delivers some powerful environmental and economic
benefits. If you live in an area that uses geothermal resources for
electricity production, you're quite fortunate. Consider Lake County,
California, which is home to many of the geothermal power plants at our
nation's best-developed geothermal resource, The Geysers. It's no
coincidence that the Lake County air basin is the first and only one in
compliance with all of California's stringent air quality regulations.
Perhaps you own a greenhouse and need to cut exorbitant energy bills in
order to stay in business. If you are located near a geothermal resource,
you should know that most greenhouse growers estimate that direct use of
geothermal resources instead of traditional energy sources reduces heating
costs by up to 80%. This can save about 5% to 8% in total operating cost.
Assume you're a home or business owner who has installed a geothermal
heat pump. You're not only doing your part to help make the world a
cleaner place to live and breathe, you're rewarded with low operating and
maintenance costs, and, usually, lowest life-cycle costs. (Life-cycle cost
is the total cost of the equipment spread over the useful life of the
equipment.) In practical terms, your heat pump investment may cost you $15
per month more in mortgage payments, but it may save you $30 per month on
your electric bill.
In all three of these cases, domestic, not foreign, resources are being
used—a practice that has merits all its own. Nearly half of our nation's
annual trade deficit would be obliterated if we could displace imported
oil with domestic energy resources. A nation's trade deficit represents a
permanent loss of wealth for the citizens of that nation. Keeping the
wealth at home translates to more jobs and a robust economy. And not only
does our national economic and employment picture improve, but a vital
measure of national security is gained when we control our own energy
Types of Geothermal Resources
The center of the Earth is 4000 miles (6400 kilometers) deep. How hot
is this region? Our best guess is 7200°F (4000°C) or higher. Partially
molten rock, at temperatures between 1200° and 2200°F (650° to 1200°C),
is believed to exist at depths of 50 to 60 miles (80 to 100 kilometers).
Heat is constantly flowing from the Earth's interior to the surface.
Most types of geothermal resources—hydrothermal, geopressured, hot dry
rock, and magma—result from concentration of Earth's thermal energy
within certain discrete regions of the subsurface.
Hydrothermal resources are reservoirs of steam or hot water,
which are formed by water seeping into the earth and collecting in, and
being heated by fractured or porous hot rock. These reservoirs are tapped
by drilling wells to deliver hot water to the surface for generation of
electricity or direct use. Hot water resources exist in abundance around
the world. In the United States, the hottest (and currently most valuable)
resources are located in the western states, and Alaska and Hawaii.
Technologies to tap hydrothermal resources are proven commercial
Geopressured resources are deeply buried waters at moderate
temperature that contain dissolved methane. While technologies are
available to tap geopressured resources, they are not currently
economically competitive. In the United States, this resource base is
located in the Gulf coast regions of Texas and Louisiana.
Hot dry rock resources occur at depths of 5 to 10 miles (8 to 16
kilometers) everywhere beneath the Earth's surface, and at shallower
depths in certain areas. Access to these resources involves injecting cold
water down one well, circulating it through hot fractured rock, and
drawing off the now hot water from another well. This promising technology
has been proven feasible, but no commercial applications are in use at
Magma (or molten rock) resources offer extremely
high-temperature geothermal opportunities, but existing technology does
not allow recovery of heat from these resources.
Earth energy is the heat contained in soil and rocks at shallow
depths. This resource is tapped by geothermal heat pumps.
Geothermal Power Plants—from Water to Light
Flip a switch and light up a room—what could be easier? Push a button
on the TV remote control and be entertained. It all seems so simple that
we are often unaware of the true environmental and social cost of these
conveniences—and who would want to give them up even if we had to
account for every penny?
But rather than thinking in terms of giving things up, let's think
positively: in the United States, right now, the installed generating
capacity for geothermal stands at about 2700 megawatts. That's the
equivalent of about 58 million barrels of oil, and provides enough
electricity for 3.7 million people. The cost of producing this power
ranges from 4˘ to 8˘ per kilowatt hour. The geothermal industry is
working to achieve a geothermal life-cycle energy cost of 3˘ per kilowatt
hour. And remember, this is clean energy produced from domestic resources.
How clean? In terms of air emissions, geothermal power plants have an
inherent advantage over fossil fuel plants because no combustion takes
place. Geothermal plants emit no nitrogen oxides and very low amounts of
sulfur dioxide—allowing them to easily meet the most stringent clean air
standards. The steam at some steam plants contains hydrogen sulfide, but
treatment processes remove more than 99.9% of those emissions. Typical
emissions of hydrogen sulfide from geothermal plants are less than 1 part
per billion—well below what people can smell. The low levels of air
emissions produced are mostly carbon dioxide, which many people believe
acts as a greenhouse gas to trap heat within Earth's atmosphere. Even so,
geothermal plants emit minimal amounts of carbon dioxide—1/1000 to
1/2000 of the amount produced by fossil-fuel plants.
Geothermal water sometimes contains salts and dissolved minerals. In
the United States, the geothermal water is usually injected back into the
reservoir from where it came, at a depth well below groundwater aquifers,
after its heat energy has been extracted. This recycles the geothermal
water and replenishes the reservoir. However, some geothermal plants also
produce some solid materials, or sludges, that require disposal in
All U.S. geothermal power plants are located in the states of
California, Nevada, Utah, and Hawaii—home to some of the most majestic
scenery on Earth. It's fortunate, then, that these plants consume only a
small amount of land, and can coexist with numerous other land uses,
including agriculture, with minimal impact on the surrounding beauty.
They're reliable and efficient, too. Taken as a group, geothermal power
plants are available to generate power 95% or more of the time; they are
seldom off-line for maintenance or repair. And, they have the highest
capacity factors of all types of power plants. Capacity factor is the
ratio of the amount of electricity a plant produces to how much
electricity it is capable of producing.
Dry Steam Power Plants were the first type of geothermal power
plant (in Italy in 1904). The Geysers in northern California, which is the
world's largest single source of geothermal power, is also home to this
type of plant. These plants use the steam as it comes from wells in the
ground, and direct it into the turbine/generator unit to produce power.
Flash Steam Power Plants, which are the most common, use water
with temperatures greater than 360°F (182°C). This very hot water is
pumped under high pressure to equipment on the surface, where the pressure
is suddenly dropped, allowing some of the hot water to "flash"
into steam. The steam is then used to power the turbine/generator. The
remaining hot water and condensed steam are injected back into the
Binary Cycle Power Plants operate on the lower-temperature
waters, 225° to 360°F (107° to 182°C). These plants use the heat of
the hot water to boil a "working fluid," usually an organic
compound with a low boiling point. This working fluid is then vaporized in
a heat exchanger and used to turn a turbine. The geothermal water and the
working fluid are confined to separate closed loops, so there are no
emissions into the air.
Because these lower-temperature waters are much more plentiful than
high-temperature waters, binary cycle systems will be the dominant
geothermal power plants of the future.
Developing and commercializing geothermal power technologies
contributes not only to a cleaner environment, but to a healthy U.S.
industrial base, as well. Around the developing countries of the world,
demand for electric power is burgeoning—and nearly half of these
countries have geothermal resources. These markets have proven
particularly receptive to clean energy produced with indigenous resources,
creating attractive export options for geothermal technologies and
expertise. In fact, U.S. geothermal companies have signed contracts worth
more than $6 billion in the past few years to build geothermal power
plants in some of these developing countries.
Direct Use of Geothermal Energy
If you've ever soaked in water from a natural hot spring, you're one of
the millions of people around the world who has enjoyed the direct use of
geothermal energy. And while this naturally occurring hot water may be the
perfect tonic for frayed nerves and sore muscles, it's capable of much
more. In the United States alone, direct geothermal applications (not
including geothermal heat pumps) have an installed capacity of 500 thermal
megawatts, which is roughly equivalent to saving half a million barrels of
oil per year. This includes approximately 40 greenhouses, 30 fish farms,
190 resorts and spas, 125 space and district heating projects, and 10
The resource required for these applications is widespread across the
western third of the United States. This is water in an underground
reservoir, at low-to-moderate temperatures usually ranging from 68° to
302°F (20° to 150°C). The consumer of direct-use geothermal energy can
count on savings in energy costs—as much as an 80% reduction from
traditional fuel costs, depending on the application and the industry.
Direct-use systems typically require a larger initial investment, but have
lower operating costs and no need for ongoing fuel purchases, therefore
reducing life-cycle costs.
In a typical application, a well brings heated water to the surface; a
mechanical system—piping, heat exchanger, controls—delivers the heat
to the space or process; and a disposal system either injects the cooled
geothermal fluid underground or disposes of it on the surface.
The direct use of geothermal energy offers some heartening
possibilities. Imagine an entire community of people having their homes
heated geothermally. Sound like something way off in the future? Not at
all. In 1893, the citizens of Boise, Idaho, put their pioneering spirit to
work and built the world's first geothermal district heating system by
piping water from a nearby hot spring. Within a few years, the system was
providing heat to 200 homes and 40 downtown businesses—and the system
continues to flourish today.
There are now 18 district heating systems in the United States
(including one in Klamath Falls, Oregon, that melts snow from the city's
downtown sidewalks), and the potential for more is tremendous. A recently
updated resource inventory of 10 western states identified 271 communities
located within 5 miles (8 kilometers) of a geothermal resource.
Greenhouse operators are taking advantage of geothermal direct use in
growing numbers, with nearly 40 greenhouses (many of which are several
acres in size) producing vegetables, flowers, houseplants, and tree
seedlings in eight western states. Operators of fish farms are profiting
from the lower energy costs and improved fish growth rates that geothermal
energy delivers. Other industrial and commercial applications that match
well with geothermal direct use include food dehydration, laundries, gold
processing, milk pasteurizing, and swimming pools and spas.
The Heat Pump Solution
The geothermal heat pump doesn't create electricity—but it greatly
reduces consumption of it. If you would like to reduce the cost of heating
and cooling your home, you might want to consider installing a geothermal
heat pump, an economical and energy-efficient technology for space heating
and cooling and water heating. Nationwide, more than 350,000 of these
systems are in operation in homes, schools, and businesses. And the
geothermal heat pump industry expects to be installing 40,000 systems per
year by 2000.
In winter, heat pump systems draw thermal energy from the ambient
temperature of the shallow ground, which ranges between 50° and 70°F (10°
to 21°C ) depending on latitude. In summer, the process is reversed to a
cooling mode, using the ground as a sink for the heat contained within the
building. The system does not convert electricity to heat; rather, it uses
electricity to move thermal energy between the building and the ground and
condition it to a higher or lower temperature according to the heating or
cooling requirements. Consumption of electricity is reduced 30% to 60%
compared to traditional heating and cooling systems, allowing a payback of
system installation in 2 to 10 years. And these low-maintenance systems
have long lives of 30 years or more. Some systems are also capable of
producing domestic hot water at no cost in summer and at small cost in
An analysis by the EPA found these systems to be among the most
efficient space-conditioning technologies available—with the lowest
environmental cost of all that were analyzed. But this might be the most
compelling statistic: Surveys show that the number of satisfied geothermal
heat pump customers stands at 95% or higher.
Geothermal Heating And Cooling
Geothermal Power Plant
Geothermal Power Plants
* From the Department of Energy
website with permission