Quick guide to geothermal energy extraction

Geothermal energy is abundant renewable energy resource that is yet to fulfill its immense potential because geothermal energy is currently being harnessed in only 24 countries of the world, with U.S. still being the world’s largest geothermal producer. Harnessing geothermal energy refers to extracting heat below the Earth's surface for electricity generation and for heating/cooling purposes.

Geothermal energy is basically a heat within the Earth's core. This heat remains at a relatively constant temperature throughout the entire year, meaning that geothermal energy does not suffer from intermittency issue like this is the case with solar and wind energy, and is available 24-7 without the need for some backup energy storage solution. This naturally available energy is extracted by a series of pipes filled with water buried below the Earths surface. This hot water is then used in our homes for heating purposes or to generate electricity.

Geothermal Power Plant - Hot water is pumped from deep underground, turned to steam to power turbines and generate electricity, cooled back to water and then pumped back into the Earth.

What is the main working principle of geothermal energy? Within the Earth's core, somewhere around 4000 miles below the surface, temperatures can reach over 9000 degrees Fahrenheit. This enormous amount of heat originated four billion years ago in a fiery combustion of dust and gas in time when our planet was created. It is the radioactive decay of the inner core that keeps the heat generating and flowing outward from this inner core to the mantle of harder rock which surrounds the core. Once the temperature and pressure reach high enough levels, some of this mantle rock melts. Then, because the melted rock or magma has lesser density when compared to surrounding rock, it rises and moves slowly up to the Earth's crust.

In rare occasions the hot magma moves all the way to the Earth's surface in a form of a volcanic eruption, but in most cases the magma remains underground and heats the adjoining rock as well as any water that has seeped down through holes and cracks. Some of this water, whose temperatures can reach as high as 700 degrees, travels back up through cracks to the Earth's surface and emerges in forms of hot springs and geysers. In most cases, however, the water and magma are trapped within the rock, forming a natural underground geothermal reservoir. It is these underground geothermal reservoirs that are the enabling us the extraction of geothermal energy for the purposes of heating and generating electricity.

Geothermal Heat Pump - In winter cold air or water is pumped trough underground pipes to heat, and in the summer hot air or water is pumped trough underground pipes to cool. 

In order to use geothermal energy for heating/cooling purposes one needs to install geothermal heat pumps. Geothermal heat pumps are significantly more efficient compared to conventional heating and cooling systems and their main advantage is the fact that they can move heat in two ways: during the hotter summer months, the geothermal heat pump operates by removing the heat from the building and dissipating it back into the ground, while in the cold winter months heat gets withdrawn from the ground (the heat source) and is used to heat building.

The process of using geothermal energy for electricity generation is as follows: extremely hot water from the underground is pumped to surface and once it reaches surface it turns to steam where it is used to power turbines that generate electricity.

Geothermal energy – Quick homeowners guide

Geothermal energy is a very interesting alternative to traditional fossil fuels in many parts of the world, not just for the electricity generation but also for heating and cooling purposes. By using more geothermal energy instead of solely relying on coal, oil and natural gas we could help lower global carbon footprint, and thus help our planet tackle the threats of climate change and global warming.

According to a U.S. Department of Energy and Environmental Protection Agency geothermal energy is one of the most efficient and environmentally-friendly options to heat and cool your home. The number of households that employ this source of energy for lowering their electric bill and helping the environment is constantly growing, not just in United States but the rest of the globe too.

The working principle of geothermal energy is not that complicated - geothermal energy uses the natural heat flow inside the earth (from the radioactive decay of elements) for heating and cooling purposes. Geothermal heat pumps, once installed, take heat from underground, and send the energy to the surface to use for heating purposes. For cooling purposes, the opposite is done and the heat is taken away.

The costs of installing geothermal system are significantly higher compared to those of a traditional heating/cooling system, but the total investment will usually be paid off in only a few years’ time – this is since the monthly savings can be pretty substantial because geothermal heating systems are, in average, 50-70% more efficient traditional heating and cooling systems; it has been calculated that some systems can save the homeowners up to 50% on the water heating bill just by preheating the tank water.

Geothermal systems are also connected with easy maintenance and with very little upkeep. In many states there are different manufacturing companies, utilities, and lending institutions that offer rebates and incentives to install geothermal heating and cooling systems.

More geothermal energy instead of staying with fossil fuels does not only mean less greenhouse gas emissions, but also helps lower the threat of ozone layer destruction - by using factory-sealed refrigeration systems.

Geothermal heat pumps are about the size of traditional heating/cooling units. After you install geothermal heat pumps the only costs connected with them will be the electricity that needed to operate the pump, compressor and fan, otherwise they are completely "free" energy. Their electricity needs are fairly low as they do not need large amounts of electricity to function properly.

There are many reasons to give geothermal energy a chance, both economical as well as environmental. The popularity of geothermal energy will no doubt continue to grow in years to come, not just because world is looking for new clean energy solutions, but also because further technological advancement will lead to better cost-competiveness of geothermal systems.

How practical is geothermal energy?

Geothermal energy attracts plenty of interest on global energy market, despite the fact that this energy source is still far off from turning its abundant potential into a more significant role in generating clean electricity. Geothermal energy has abundant resources that are estimated to be larger than those of fossil fuels and uranium combined. There has been a variety of different studies aimed to determine how much usable geothermal energy is available, and the consensus seems to indicate there is enough resources to last somewhere between 500,000 and 1,000,000 years. From our perspective this certainly looks like limitless form of renewable energy

Geothermal power is mostly used to generate electricity in geothermal power plants. The deciding factor for most companies when building any new power plant are the construction and maintenance costs. If we compare geothermal power plant with the one fired by fossil fuels we can see that the cost of operating the geothermal plant is pretty much competitive to that of the plant that uses fossil fuel to power the turbines. The obvious distinction between the two is that the emissions that fossil fuels give off are full of pollutants, which is not only one of our major health concerns but also contributes to climate change, while geothermal energy is connected with minimum amount of harmful emissions.
The best example on how to really benefit from geothermal energy comes from Iceland. There should be no surprise here because harnessing geothermal energy seems logical and natural with so many geothermal springs on the island. In fact, with all the volcanic activity they have one might say that Iceland is one big geothermal spring. Currently about 75% of Iceland's power comes from geothermal energy and they are striving to be the first county to be 100% renewable by primarily focusing on geothermal energy and to the lesser extent on other renewables such as hydro and wind.

In order for practically and commercially harness geothermal energy developers must first find an adequate site known as a geothermal spring. Once a promising site is found, drilling is needed to determine if there are sufficient geothermal resources below. How deep you have to drill is not the same in all case, the basic rule is that for every 100 meters you go deeper into the earth’s crust, the temperature of the rocks increases by 3 degrees Celsius (5.4 degrees Fahrenheit). Once an appropriate geothermal spring has been located, geothermal power plant is constructed and the generation of clean electricity can start.

The vast majority of currently harnessed geothermal springs are found along the major tectonic boundaries, which represents the area where the majority of volcanic activities and earthquakes are concentrated. The most active volcanic areas have been located along the so called "Ring of Fire"

There are still certain drawbacks that prevent geothermal power from being widely used source of energy. For instance, geothermal springs are found only in limited number of areas and the technology to harness geothermal energy is yet to become commercial though EGS (enhanced geothermal systems) provide a certain level of optimism that the feasibility of building new geothermal power plants could be spread to many new areas all over the world.

Energy history facts

From ancient times people use various energy sources. Geothermal energy were used for springs and heating, hydro and wind energy were used for mills, sailing, water pumps and other mechanical devices, solar energy was used for heating, biomass and coal were used for heating, illumination, cooking, and so on.  For example, nearly 2000 years ago the Greeks used water wheels to grind wheat into flour.

Steam engines were first serious “modern” power source in the world. Steam engines were mostly powered by biomass and coal. The first commercial steam-powered engine device was a water pump, developed in 1698 by Thomas Savery. It used a vacuum to raise water from below, then used steam pressure to raise it higher.

Edwin Drake's 1859 well near Titusville, Pennsylvania, is popularly considered the first modern crude oil well. In the 1840s, the process to distill kerosene from crude oil was invented by James Young in Scotland and the first refinery was built by Ignacy Łukasiewicz, providing a cheaper alternative to whale oil.

The world's first power plant consisted of 24 dynamo electric generators which were driven by a steam engine. It was built by Sigmund Schuckert in the Bavarian town of Ettal (Germany) and went into operation in 1878. Power plant is industrial facility for the generation of electric power.

The first commercial power plant in the United States using three-phase alternating current was at the Mill Creek No. 1 Hydroelectric Plant near Redlands, California, in 1893 designed by Almirian Decker.

In 1878 the world's first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power a single arc lamp in his art gallery.

The first major hydro-electric power plants were built by Nikola Tesla and George Westinghouse in 1895 on Niagara Falls (USA). These Power Plants practically started the electrification of the world.

In 1911 the world's first commercial geothermal power plant was built in Larderello, Italy. Experimental generators were built in Beppu, Japan and the Geysers, California, in the 1920s, but Italy was the world's only industrial producer of geothermal electricity until 1958.

Photoelectric effect was first observed 1839 by Edmond Becquerel, a physicist from France. In year 1876 Adams and Day observed the photovoltaic effect in solid selenium.  Modern solar cell was discovered in 1954. The first 1 MWP solar park was built by Arco Solar at Lugo near Hesperia, California at the end of 1982, followed in 1984 by a 5.6 MWP installation in Carrizo Plain.

On June 27, 1954, the USSR's Obninsk Nuclear Power Plant became the world's first nuclear power plant to generate electricity for a power grid, and produced around 5 megawatts of electric power. Obninsk is in today’s Russia.

About 500 B.C. the Chinese discovered the potential of natural gas. Finding places where gas was seeping to the surface, the Chinese formed crude pipelines out of bamboo shoots to transport the gas, where it was used to boil sea water, separating the salt and making it drinkable. Britain was the first country to commercialize the use of natural gas. Around 1785, natural gas produced from coal was used to light houses, as well as streetlights.

Opened on the 26th November 1966, the Rance Tidal Power Station is the world's first tidal power station and also the world's second biggest tidal power station. The facility is located on the estuary of the Rance River, in Brittany, France.

An early application of wave power was a device constructed around 1910 by Bochaux-Praceique to light and power his house at Royan, near Bordeaux in France. In 2008, the first experimental wave farm was opened in Portugal, at the Aguçadoura Wave Park.

Italy - One of renewable energy leaders

Current situation with renewable energy in EU is looking exceptionally good, and Italy is no exception, in fact the Apennine peninsula country has in the last couple of years become one of the European clean energy leaders. According to the official government figures Italy is well on the track to meet its EU target of generating 26 percent of energy from renewable energy sources by 2020 since currently renewable energy satisfies more than 20% of Italy's energy demand.

The country's renewable energy capacity increased significantly in 2011 to the total amount of 41,352MW at the end of the year. Hydroelectricity is still the most important renewable energy source though the wind power is looking better than ever, and wind power is currently the second largest renewable energy source in the country (in 2009 alone Italy's wind energy capacity has increased by nearly 40 percent). At the end of 2009 Italy's total wind power capacity was around 4,850 MW. Most new wind farms were installed in Sicily, Puglia and Calabria.

According to the Italian Wind Energy Association (ANEV) around 6TWh of electricity were produced by wind energy in 2009. At the end of 2011, the country passed 6000 MW mark in installed wind power capacity, and is currently sixth largest wind energy producer in the world. Though wind power development is looking exceptionally good there are still some things that need to be improved, for instance Italy still suffers from inadequate grid infrastructure because the current capacity of grid is too low, and Italy's old-fashioned 150kV lines are incapable to dispatch all the power produced by the wind farms which has lead to some wind farms operating at 30% less than their normal capacity.

Solar power is also looking good, and this is mostly the result of generous incentives for solar power that have attracted many solar companies in Italy. Thanks to these favorable incentives Italy has now become a world's second largest photovoltaic market, behind the Germany. At current pace Italy is adding around 150 MW of solar capacity per month, around three times more than US, and Italy has even managed to surpass the US in total installed solar capacity in the first quarter of this year. California, the leading US state in installed solar power capacity, is currently adding around 20 MW of solar capacity per month, and for comparison Italy is three-fourths the size of California. By the end of 2010 Italy's total solar power capacity accounted for more than 2500 MW while at the end of 2011, total installed solar power capacity in Italy was 12,750 MW, which is quite an accomplishment, and Italy has certainly become one of the global solar energy leaders and of the largest photovoltaic markets in the world.

Italy also has volcanically active areas, like Larderello in Tuscany in central Italy. Those places are perfect for geothermal power production. Geothermal power accounts for about 1.7% of the total electric energy production in Italy and is about 7% of the total renewable energy produced in 2010. The total energy from geothermal sources was 5,376 GWh in 2010. Italy is the fifth country by geothermal installed capacity.

As said before, renewable energy is not only looking really good in Italy but also in entire EU, and vast majority of EU states are on track to meet their renewable energy targets, which should in the end result in 20 percent of European energy coming from renewable energy by 2020.

Renewable electricity accounted for the 24.5% of all electric energy produced in Italy in 2011. Italy is today one of the most significant renewable energy markets in the world, even despite the recession that is still taking heavy toll in the country.

General energy facts – Part 01

China is the world's largest manufacturer of not only solar panels but also wind turbines.

Standard commercial solar panels have a lifespan of 20+years.

Coal is still the mostly used fuel to generate electricity on worldwide scale.

Approximately 40% of the world electricity production comes from coal.   

According to the study by the Michigan State University it is 36 percent more efficient to grow grain for food than for fuel.

Geothermal heat pumps are always more efficient at heating compared to being used as pure electric heaters, even when extracting heat from cold winter air.

According to the study from Brazil's National Institute hydroelectric dams hurt climate more than oil by releasing significant amounts of methane into the environment, because of the rotting vegetation submerged when the reservoir floods.

Colorado was the first U.S. state to create a renewable portfolio standard (RPS), back in 2004.

World fastest growing energy technology is photovoltaic production that is increasing by an average of 48 percent each year since 2002.

Wind power provides about 20% of electricity production in Denmark which is significantly higher proportion than in any other country in the world.

Unlike wind and solar resources, which are more dependent upon weather fluctuations, geothermal resources are available 24 hours a day, 7 days a week.

The New Hope Power Partnership, located in South Bay, Florida, is the largest biomass power plant in North America.

Currently around 90 % of all buildings in Iceland are heated with geothermal power.

Biomass is the second most common renewable energy source in United States that satisfies around 4% of nation's electricity demand.

The world's largest wind farm is located in Texas, The Roscoe Wind Farm with the capacity of 781 MW.

California has more photovoltaics installed than all other U.S. states together.

Solar panels perform optimally when placed in direct sunlight so it is always wise to position your photovoltaic array directly under the noontime sun in order to achieve maximum efficiency.

Global geothermal heat pump capacity is growing by 10% annually.

Biofuels provided 1.8% of the world's transport fuel in 2008.

Coal is mostly used energy source to generate electricity (approximately 49% of the United States electricity comes from coal) despite being the "dirtiest" energy source of them all.

In the 2010 there were more than 85,000 people employed in the US wind industry.

Chinese plan to have 5 million electric cars on the nation’s road by 2020.

Biodiesel has 10 to 12 percent lower energy density compared to standard diesel fuel meaning you get a lower mileage for biodiesel compared to ordinary diesel fuel.

In 2009 U.S. accounted for only five percent of the world’s solar cells production.

US has very long history in harnessing geothermal energy because the first U.S. geothermal power plant was opened at The Geysers in California, more than 50 years ago, in 1960.

Geothermal heating and cooling systems can reduce energy bills

Geothermal energy is renewable source of energy with the abundant potential in many parts of the world. Geothermal energy refers to the heat stored within the earth's core. This heat can not only be used to generate electricity but also for heating and cooling purposes via geothermal heating and cooling systems.

In the coldest days of winter and the hottest days of summer, energy costs related to heating and cooling can rise significantly due to the increased use. Add to this the additional costs of the fuels needed for heating systems, such as gas or oil and one can get really high bills that can present real burden to home budget.

Many people are trying different methods to cut down energy bills by doing everything from wearing lot more clothes and keeping the thermostat way down in the winter, to keeping all of the windows open and running several fans in the summer.

There is however one more method that doesn't require to sacrifice comfort in order to reduce energy bills, namely the installation of geothermal heating and cooling systems. Geothermal heating and cooling systems are able to use thermal energy stored beneath the earth's surface for both heating and cooling purposes. 

The geothermal system at Argonne's Visitor Center saves $4,000 in heating costs per year and 53 tons of greenhouse gas emissions.

A geothermal heat pump gets installed in the ground outside home and gets stored down into the earth to a level where the temperatures consistently remain between 50 and 60 degrees Celsius. During cold winter period, geothermal heat pump transfers the warmer air from beneath the earth up into the home, heating home in the process.

Switching the direction of heat flow, the same system can be used to circulate the cooled water through the house for cooling in the summer months. The heat is exhausted to the relatively cooler ground (or groundwater) rather than delivering it to the hot outside air as an air conditioner does. As a result, the heat is pumped across a larger temperature difference and this leads to higher efficiency and lower energy use.

What this basically means is that the geothermal heat pumps rely primarily on an energy exchange between the air within house (or other building) that is being heated/cooled and the ground.

Geothermal heating and cooling systems are becoming increasingly popular renewable energy option but they are yet far off from fulfilling their potential as currently there is less than 30 GW of geothermal heating capacity installed worldwide, accounting for approximately  0.07% of global primary energy consumption.

The economics of geothermal heating and cooling systems is constantly improving with the U.S. Environmental Protection Agency (EPA) claiming that these systems save homeowners 30–70 percent in heating costs, and 20–50 percent in cooling costs, when compared with conventional heating and cooling systems. The EPA has even called these systems as „the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available.“

The additional advantage of these systems is that they are extremely reliable, do not require much maintenance, and once built can last for decades. They are also less polluting as compared to the traditional ones.

Geothermal energy – Quick facts

Introduction to geothermal energy

Geothermal energy is a very rich source of energy, as it lies directly beneath us, just a few kilometers below the surface of the earth. Geothermal energy is not connected with massive carbon emissions like this is the case with fossil fuels. Underground water near geologically active areas gets heated and even boiled at high temperatures and produce steam. The water is collected by drilling wells. The steam and hot water is separated. Steam is purified and used in power plants to generate energy. Water is used in reservoirs to produce more steam. This is a simplified example that explains the generation of geothermal energy. No fuel is consumed in the process of creating geothermal electricity and so it's emission free.

Geothermal power plants include: binary cycle power plants, hot dry rock geothermal energy, dry steam plants, flash steam plants, direct heat, and geothermal heat pump. The most common are binary cycle geothermal power plants, mostly because they have the large capacity for generation since the energy source (hot water) is constantly supplied. Geothermal power plants do not require large areas in fact they take up very small space compared to other power plants due to the fact that main components are underground pumping the water. One of the downsides connected with geothermal energy is the fact that fluids that are being used have low boiling points and are corrosive meaning that extra maintenance and care is required.

This brings us to the pros and cons of using geothermal energy.

Pros of Geothermal Power are as follows:
* The long tradition of direct geothermal energy use. Even in ancient times people have used geothermal power directly for purposes of taking baths, preparing meals, and heating their homes. Today, heating homes buildings is the most common direct use of the energy, and it's accomplished through use of district heating systems (geothermal heating is best developed in Iceland, especially in Iceland's capital Reykjavik). These systems pipe hot water into buildings from the surface of the earth, and are available for immediate use.
* None or very low greenhouse gas emissions. Fossil fuels when burns create massive carbon emissions that have not only resulted in climate change but also in acid rain and other harmful pollutants. With extra care geothermal energy can even be energy source 100% free of harmful greenhouse gas emissions.
* Geothermal energy is renewable energy source which means it will always be at our disposal because the earth continually replenishes our water supply through rain, and the earth's interior is in a constant state of producing heat.

Cons of Geothermal Power are as follows:
* Geothermal energy is still only scarcely used renewable energy source and most countries still do not make use of geothermal energy, and as a result, if you opt to install geothermal system in your home or office, it could become a very difficult to find qualified personnel for the job.
* Also when it comes to installation, wide spaces and long pipes are needed. As a result, areas of dense population will have a tougher time getting the energy into homes.
* Relatively high installation costs mostly due to the high drilling costs.
* Not a viable solution for all countries given current technological level, and still cost-effective only in areas near tectonic plates.

Geothermal power plant principle

Unlike other power plants that rely on coal or other fossil fuels to generate electricity for homes and businesses, geothermal power plants use superheated fluids from the earth’s geothermal resources to generate electricity. The natural heat of the earth creates geothermal resources. This heat comes from molten rock, called magma, located at the earth’s core deep below the geothermal resource. Over thousands of years, rainwater seeps through cracks in the earth’s surface and collects in underground reservoirs. The magma heats the water until it becomes a superheated fluid.

Geothermal power plant.

To reach the superheated fluid, wells are drilled 5,000 to 10,000 feet (1.5 km to 3.0 km) below the surface of the earth (1.5 km to 3.0 km). These wells, called production wells, bring the superheated fluid to the earth’s surface where it can be used to generate electricity for homes and businesses. Geothermal power plant from the video bellow uses crystallizer-reactor clarifier technology, a process that turns the geothermal superheated fluid into steam while removing solids from it. The steam is used to drive a turbine and generate electricity. All remaining geothermal fluids are injected back into the reservoir for reuse. Under its own pressure, superheated fluid from geothermal resource flows naturally to the surface through production wells. As the liquid flows toward the surface, the pressure decreases, causing a small portion of the fluid still within the well to separate into steam.

Geothermal energy production well.

At the surface, the superheated fluid and steam mixture flows through surface pipelines and into a wellhead separator. Inside the separator, the pressure of the superheated fluid is reduced. This causes a large amount of the superheated fluid to rapidly vaporize and flash into high-pressure steam. The geothermal fluid that is not flashed into steam in the wellhead separator flows to a second vessel, called a standard-pressure crystallizer, where an additional amount of standard pressure steam is produced. The flash process continues in the low-pressure crystallizer. The remaining fluid is again flashed, this time at a lower pressure, to produce low-pressure steam. All of the low-pressure, standard-pressure and high pressure steam is delivered into a turbine. The fluid that is not flashed into steam flows into the reactor clarifier system and is then returned to the geothermal reservoir through injection wells.

Turbines are the primary piece of equipment used to transform geothermal energy into mechanical energy. Pressurized steam created from the geothermal superheated fluid flows through pipelines to large steam turbines. The force and energy in the steam is used to spin the turbine blades. Turbines turn a shaft directly connected to an electrical generator. An electrical charge is created when magnets rotate within the generator. Large copper bars carry the electrical charge to a step-up transformer outside the plant. Within the transformer, the voltage is increased before the power is sent to the power lines that carry it to homes and businesses.

Geothermal energy is a sustainable resource because, with proper management, a geothermal resource can remain a renewable source of energy. Water trapped deep within the earth will naturally replace the superheated fluid that is drawn from the geothermal resource through surface wells. However, it is possible to deplete the geothermal resource by removing fluids faster than it can be naturally replaced. To help prevent this, the steam used in the geothermal power plant passes through a condenser that turns it back into fluid. At this stage, it is possible to recover minerals from the geothermal fluid before it is injected back into the earth. This condensed fluid, along with the fluid that did not flashed into steam, is injected back into the underground reservoir. Magma naturally reheats the fluid so it can be used again.

Source: video from youtube.

Montana - Geothermal energy state?

Geothermal energy projects, as well as the renewable energy projects in general, are lately getting lot more attention that they used to do, and many areas across the U.S. want to fully utilize their natural advantages by developing different renewable energy projects to not only satisfy ever-growing energy demand but also to work on ecologically acceptable fuels, especially now when climate change problem looks to be so big. One of these projects is geothermal energy project in Montana, to be more precise in Lake County, and if all goes well Montana will soon become one of the leading state in total U.S. geothermal energy sector.

Montana looks to be starting this project as soon as possible by using its natural advantages in form of hot springs to give enough power to homes around the lake county. Montana's based company Flathead Electric Co-Op is now working on a project that plans to use hot water from the ground to produce geothermal energy, and satisfy demands of many households in this territory.


This geothermal energy project could be a first of its kind in Montana and is only being made possible after Flathead Electric was granted almost half a million ($491,000) in federal funds to test the groundwater of hot springs in Lake County to see whether it was hot enough to be used as geothermal energy source.

This company plans to plan to drill about 2,000 feet into shallow wells to see if the water is hot enough to produce energy, and if it turns out to be positive we could soon see room being made for large geothermal energy project. Many energy experts believe that geothermal energy potential of this are is definitely worth to be fully explored as hot springs are usually great sources of geothermal energy.

If everything goes well this could be giant step for Montana to be looked like geothermal energy state. Currently when people think geothermal energy they usually think of states like Nevada, Oregon and California, and with little luck Montana could soon use geothermal energy as the viable and dependable energy source.

If all goes as planned, the geothermal energy project in Montana could begin with preliminary drilling as early as in spring 2010. It will be really interesting to see what drilling results will show in the end.

Most geothermal power plants in U.S. are located in the west, and currently geothermal energy is third largest renewable energy sector in the United States, behind hydroelectricity and biomass. Some studies have even reported that nine western states together have the geothermal potential to provide over 20 percent of national electricity needs, one of them being Montana too.

Monrtana Geothermal Energy Sites. Source and details: US Department of Environmental Quality.

Many of people also do not know that exploiting geothermal energy in United States isn't something new but something that almost have 50 years long history as first geothermal energy power plant was opened at The Geysers in California in 1960, and perhaps a bit surprisingly it still continues to operate successfully, despite being almost 50 years old.

This is really an evidence that geothermal energy is really dependable energy source that could provide lots of energy to homes across the western U.S. Currently there are 3,040.27 MW of installed geothermal capacity but energy experts this number to b lot bigger in years to come as many other projects like this one in Montana are already underway with lot more to come in years ahead.

Geothermal energy - Technology and power plants

There are two basic types of geothermal power plants currently in use, steam plants and binary plants. Steam plants use the hot water and very hot steam (with temperatures over 300F) to power a turbine that feeds a generator directly (if this is a "dry steam" principle) or they can depressurize the very high-pressure and temperature water to create steam ("flash steam" principle). Currently steam plants can generate electricity for about 4 cents to 6 cents per kWh.

Binary plants have one advantage over steam plants, namely that they can operate at locations with lower temperatures ((100 F to 300 F), which makes them available at much more places than steam plants. This is also the reason why there are much more binary plants than steam plants Hot water passes through a heat exchanger along with a working fluid that has a lower boiling point (such as isobutene). The working fluid vaporizes, moving the turbines and powering the generators.

Geothermal power station. Click on the picture for full size.

As said before geothermal energy can also be used a direct heat source. If we take a look at Iceland we can see that all the houses in Iceland are heated with water from hot springs, and Iceland currently generates more than half its energy from geothermal sources.

We should also mention underground heat pumps that are also a form of geothermal energy. Underground heat pumps have very interesting working principle, namely they work like refrigerators in reverse. Heat pumps use pipes (that circulate a refrigerant through a cycle of condensing and evaporating between two heat exchangers. One heat exchanger evaporates at low pressure and absorbs heat. A compressor pushes the refrigerant vapour, now at high pressure, to other coil where the refrigerant condenses and releases the heat. Unlike refrigerators and air conditioners, heat pumps can be used for both heating and cooling.

Conclusion

Geothermal energy is definitely one of the energy sources we should be using more in years to come. Of course, in order for this energy source to become cost competitive there are still lot of researches needed to decrease currently high installation costs, and to find methods to improve efficiency. Given that is environmentally friendly energy source we should be definitely working more on methods to exploit it as much as possible. Many positive examples have so far proved that this energy source has huge potential and it would really be a shame if we won't do anything to expand its use, especially now when world seeks for alternative energy sources to combat climate change and pollution.

Geothermal energy overview:
1. Geothermal energy - Quick overview
2. Geothermal energy - How to use
3. Geothermal energy - Advantages and disadvantages (previous)
4. Geothermal energy - Technology and power plants (current)

Geothermal energy - Advantages and disadvantages

In order to better understand the whole geothermal energy concept we also need to point out advantages and disadvantages of this renewable energy source. First we'll start with the geothermal energy advantages.

Direct use of geothermal energy is definitely one of geothermal energy advantages. Since ancient times, people have used geothermal power directly for purposes of taking baths, preparing meals, and today this renewable source of energy is primarily used for heating homes or buildings mostly through the use of district heating systems. These heating systems pipe hot water into buildings from the surface of the earth, and are available for immediate use.

Geothermal energy is ecologically acceptable renewable energy source because of low greenhouse gas emissions. The biggest problem with fossil fuels is that they during combustion release harmful emissions to our environment. This results in not only climate change problem, but also in acid rain and other pollutants. Geothermal energy releases negligible emissions compared to fossil fuels. In most cases, the "geothermal fuel" is free, although with the "hot rock" method water must be used, and may have to be transported there. Once the power stations are built they cost very little to operate.

Ground-based heat pumps can be used almost anywhere. For instance even snowy Canada uses them.

Geothermal energy advantages - cheap cooling.

Geothermal energy advantages - cheap heating.

Geothermal energy is also renewable energy source, and this means that this energy source won't disappear after some time. Geothermal energy can constantly be at our disposal because the earth continually replenishes our water supply through rain, and the earth's interior is in a constant state of producing heat. When we combine this we get the energy source capable of both heating as well as cooling homes that is constant and is doing no damage to environment.

Like with all other energy source geothermal energy also has some disadvantages that we should be mentioning. So here are few of them.

Geothermal energy isn't widely spread source of energy and most countries do not make use of geothermal energy, which in many cases results in difficulties during the geothermal system installation in your home or office because it is hard to find qualified personnel for the job, and even if you find them they cost you lot.

There are also some difficulties during the installation process because in order to install geothermal system requirements are usually wide spaces and long pipes. This of course can be quite tricky to do in areas with very dense population.

Geothermal sites can run out of steam, as their temperatures drop to low. This can happen naturally or if a "hot rock" extraction method is mismanaged, and the water injected cools the rocks.

Not every area has accessible geothermal sources. The hot rocks and water must be within drilling range (except in the case of natural geysers).

There is no guarantee a given site, regardless of its location, will produce enough energy to offset the capital expenditure and operating costs.

Geothermal energy overview:
1. Geothermal energy - Quick overview
2. Geothermal energy - How to use (previous)
3. Geothermal energy - Advantages and disadvantages (current)
4. Geothermal energy - Technology and power plants (next)

Geothermal energy - How to use

Using geothermal energy has very long tradition in human history. For instance people in ancient times have used geothermal energy for hot springs, cooking, bathing and heating purposes. Basically there are three primary ways to use geothermal energy:

• The heat from the Earth could be used directly for heating systems in houses or buildings. The hot water close to the Earth's surface can be directly pumped into heating systems ensuring adequate supply.
• Generators in power plants require steam at extreme temperatures to operate. Therefore geothermal power plants are built near reservoirs to ensure better efficiency. Geothermal power plants use steam or hot water close to the surface to increase efficiency of standard thermal power plant, and this is how electricity is generated.
• Geothermal heat pumps are also used in exploiting geothermal energy. These pumps use water near the Earth's surface to control building temperatures.

Geothermal heat pump system. Click on the picture for detailed view.

Country that uses geothermal energy the most is Iceland. For instance in Reykjavik, Iceland's capital, 95 percent of the buildings is heated with geothermal district heating systems. Of course this can't be achieved anywhere in the world and Iceland is really using tremendous geothermal energy potential to ensure enough heat for both households, as well as buildings and industries.

Geothermal energy overview:
1. Geothermal energy - Quick overview (previous)
2. Geothermal energy - How to use (current)
3. Geothermal energy - Advantages and disadvantages (next)
4. Geothermal energy - Technology and power plants

Geothermal energy - Quick overview

As the energy demand keeps on growing many people have started looking for more and more ways to find different renewable energy sources. Despite growing popularity of geothermal energy over the years many people still don't realize they are standing on top of one of the greatest energy resources on the planet. The Earth's core is full of heat, and heat builds up tremendous pressure in the Earth's core that simply has to be released in some way. These energy releases from Earth's core are known as geothermal energy, usually in form of hot water and hot steam. The hot water and steam from the Earth can be used in a variety of different ways to create energy. Geothermal energy is called renewable energy because the heat in the Earth's core is constant.

Geothermal spring - water and steam from the Earth can be used in a variety of different ways to create energy.

Today people have started talking much more on possible ways to save fuel and how to find more energy efficient ways to satisfy our daily energy demand. Geothermal heat and energy are definitely one of the renewable sources with biggest potential because of its natural origin. By using geothermal energy we are basically using the natural energy stored in the earth's core to power our homes and buildings. Geothermal energy also has many positive environmental effects such as it helps reduce global warming but we will talk more about it later.

Geothermal energy overview:
1. Geothermal energy - Quick overview (current)
2. Geothermal energy - How to use (next)
3. Geothermal energy - Advantages and disadvantages
4. Geothermal energy - Technology and power plants

Importance of renewable energy sources

Renewable energy systems - General info

Lately there has been some problems in the supply of conventional energy sources (those that come from fossil fuels) so it is really no wonder that more and more nations are interested to use different renewable energy systems in order to satisfy their growing energy demand. All renewable energy systems have one thing in common, namely the fact that there are harnessed from nature. This means that they are constantly replenished unlike the fossil fuels that are likely to run out in years to come. These advantages are making them more and more popular compared to conventional energy sources.

Renewable energy sectors are all about using natural sources to create energy. These natural sources usually include the sun, water, wind, and geothermal sources. The science and technology are constantly developing so it is logical to expect even more renewable energy sources in years to come, as well as the highly improved efficiency of existing ones.

Many people think of the sun, or to be more precise solar energy as the main future energy source. Throughout the history of the humanity Sun has been used to give light and heat but Sun's almost unlimited potential can provide electricity enough for the whole planet. Different methods have been used to harness energy from Sun, and the simplest method is through the use of a photovoltaic cells. Photovoltaic cells contain a special technology that traps the sun's energy and converts it into electricity.

Water is also one very important source for clean renewable energy. The most common form of using water to get electricity is hydroelectric energy that is acquired from large river dams. Hydroelectric power stations are usually built in large river systems that have big quantifies of water. The more water there is, the easier it is to produce kinetic energy, which is then used to produce electricity. Beside hydroelectric energy there are also some other energy sources that harness water to get electricity such as wave and tidal power.

Wind power is also one renewable energy sector in the rise, especially in some European countries like Denmark and Germany. Basically wind power uses the same principle found in hydroelectric dams to convert the wind kinetic energy to electricity. There are lots of windy areas across the globe, and in many parts of the world people are trying to harness wind energy as much as possible, though efficiency of this energy source still remains a big problem, largely because of inconsistency of wind blowing.

Geothermal power is another excellent form of renewable energy system. Geothermal energy uses the heat from deep inside the earth to produce electricity. Various methods have been developed to do this, and the most common method is harnessing the steam that naturally comes out of fissures on the ground. Geothermal energy is mostly used on Iceland.

It is not very had to conclude that if science and technology continue their development, renewable energy systems could be more than enough to satisfy world energy demand in years to come. If this happens this will have very positive effect by eliminating our dependence on fossil fuels, which has blamed as the main factor contributing to climate change problem.

Main advantage of using renewable energy sources

Though there are some significant advantages in using renewable energy sources fossil fuels still remain dominant energy sources in many parts of the world. For instance statistical data shows that the United States still gets 90% of its electricity from fossil fuels and nuclear power plants. Despite recent "go green" strategy in United States coal-burning power plants are still dominant sources for producing electricity. Of course these power plants are also the country's largest emitter of carbon dioxide, a greenhouse gas that is mostly responsible for climate change and global warming problem. Coal is really the main source of pollution and greenhouse gases around the world, mainly because this fossil fuel is cheap and easily available which makes its use justifiable from economic point of view.

Obama and the federal government are working hard to decrease country's reliance to coal power by providing at least 20% of country's total energy demand from renewable sources of energy by 2020. Generally speaking ever-increasing use of fossil fuels has done big damage to our environment and now we have to take care of that before it is too late. With this in mind technology and science are working hard to introduce highly improved renewable energy sources such as wind, solar, geothermal to lessen our dependence on coal and other fossil fuels.

Many energy experts agree that a very good start would be utilizing the power of the sun. This is the oldest energy source that has vast potential so it is really a surprise why this technology has not been used earlier. As the world energy demand keeps on growing there is also the need to convert the sun's energy to electricity on a much larger scale. Solar power has potential to become one of the most cost-effective renewable energy sources, with a little more investments on solar panels and generators needed to really make the difference. Solar panels that are created nowadays can be very easy adapted with the architectural design of modern-day homes and office buildings. The negative factor are high installation costs that are still more expensive than simply buying power from utility companies, but the benefits can soon bring back that bit more money invested in it.

Wind energy is a cheaper alternative to solar power. There are growing number of people that install do-it-yourself windmills on their lands to generate enough electricity for their homes, ranches, and farms. Windmills of course have long history and tradition of using it, and if you're on a windy location you should definitely consider using this renewable energy source. Some countries like Denmark, Spain, Portugal and the Great Britain are utilizing wind farms to power large portions of their communities. Modern-day wind turbines still haven't been used to their full potential in United States, though there is significant progress in some U.S. states.

Geothermal energy is definitely a renewable energy source to consider. The trapped heat in earth's core can be greater than 9,000 degrees Fahrenheit. By harnessing its steam we can turn this heat into electricity. Besides this we can also use the energy from the underground directly by installing geothermal heat pumps to generate home heating and cooling provisions for both households as well as industrial facilities.

Sustainable energy future can be only done with the help of renewable energy sources and this really is the main advantage that these energy sources have over traditional fossil fuels. World has come to a point where it has to not only satisfy ever-growing energy demand but also to do this on ecologically acceptable way in order to save our environment, and this can't be done without the renewable energy sources.

Why is renewable energy sector so important?

Many energy experts believe that we are using negligible percentage of currently available renewable energy, and that energy sector should be much more exploited than it is today. If we could only be using a small part of currently available Sun's energy for instance that would be more than enough to satisfy global energy demand couple of times.

Using renewable energy sources is not only highly beneficial from energetic point of view but also from ecological point of view because by utilizing the renewable energy we can save our environment for our future generations. Currently the most talked about renewable energy sources are wind and sun, and many people see these two energy sources dominant in years to come.

Our world needs quick awakening and much better use of renewable energy sources if we want to save our planet. Fossil fuels are not only sources of tremendous pollution but also sources of heat trapping gases, most notably CO2, responsible for climate change problem. Therefore it is of vital importance to continue development in science in technology to improve efficiency and cost-competitiveness of renewable energy sources so they'll be able to put fossil fuels aside.

There are certain drawbacks in using renewable energy. For instance the solar power is significantly less effective in cloudy weather and the wind power highly ineffective to use during calm days. But combining couple of renewable energy sources can hide these drawbacks. For instance a home solar power has the ability to generate power all day while a home wind power can generate power only when strong wind blows, so these systems can compliment each other and make up for each others weaknesses.

Unless we choose renewable energy future as the "energy go guide" the world will not only have problems with future energy demand but we'll be also creating tremendous environmental mess that will make life of future generations very difficult.

Why go for geothermal energy?

When it comes down to renewable energy, most people think only of wind turbines, and solar panels, because most people think how solar and wind power are the two only renewable energy sources. But this is far from truth, there is also geothermal energy that can be quite useful energy source but many people know very little about this energy source. Maybe this has to do with the fact that oil companies want us to think of solar and wind power as the only renewable energy sources, because solar and wind power doesn’t directly affect oil and propane use.

The golden “oil age” is far behind, going down to a strong political campaign that brought geothermal, a very important renewable energy source, well up front. The new administration gave its full blessing to geothermal energy in form of substantial tax credits enabling just about everyone to take advantage of geothermal energy.

Geothermal energy map of United States. Click on picture for full size.

There are some already claiming how geothermal energy should be the first choice to reduce nation's dependence on fossil fuel. But how can the average home save a significant amount of money every year by replacing fossil fuel with geothermal? Well you are probably already familiar with fluctuations in fuel prices that have potential to go out of control in the matter of days. The cost of heating homes is no longer negligible and has become an expensive proposition, despite today’s "seemingly low" fossil fuel prices. It is really only matter of time before fossil fuel prices will go up, reaching very high levels. Just to remind you in July 2008, the price of oil doubled in less than 30 days. Who can guarantee us that this scenario won't happen once again?

Geothermal energy can provide not only 100 percent of home heating, but also air conditioning and hot water, and it require no additional use of oil, natural gas or any other fossil fuel. And the payback on geothermal is more than acceptable. If you consider the 30 percent federal tax credit, payback usually takes less than five years in new construction and somewhere around seven years for retrofits. This translates to gigantic 15 percent annual return on investment simply by installing a geothermal system, which is really a number from which many other energy sources are still far off. The logic in this whole story is quite simple, namely homeowners pay back the investment with the money they would have paid to oil or gas company. After payback, the savings continue with an average return of more than 65 percent – percentage that is likely to be even higher as fossil fuel prices are very likely to increase after recession is over.

Geothermal power technologies. Click on picture for full size.

And geothermal can be retrofitted into most existing structures. According to the U.S. Department of Energy, geothermal heat pumps are far more efficient and reliable than any fossil fuel furnace or boiler so it is really no surprise that hundreds of homes throughout the Catskills and Hudson Valley are now getting all their heating, cooling and hot water from geothermal energy. The other huge benefit is that geothermal energy can be easily adapted into most existing structures.

How to calculate cost of geothermal system needed for your household? Cost to professionally install a geothermal system is computed based on total heating load required by the specific needs of your home. Professional geothermal installers, even before sizing a system, will recommend ways to reduce energy use. For an average 3,000-square foot Colonial, that’s five years old, geothermal air heating and cooling with appropriate energy efficiency measures would cost under $38,000 and provide all heating, cooling and hot water needs. With tax credits, the out-of-pocket costs are about $26,000. This is really a bargain price when you look at the all advantages.

Geothermal energy and EIS in US

While there is no doubt (apparently) between both politicians and experts that world needs more energy from renewable energy sources, in order to avoid the dependence on fossil fuels that have negative impact on environment by causing global warming and climate change, so far very few people believed in the potential of geothermal energy as one of the leading renewable energy sectors, especially in United States. But things are starting to look more brightly for geothermal energy because many new investors and it seems like geothermal energy isn't anymore underdog in renewable energy sector.

Growth in geothermal energy sector in the last few years, and different new technological innovations have done a great deal to sudden enthusiasm for this renewable energy sector. This sudden enthusiasm is encouraging faster rates of conventional development as well as interest in new technologies that will greatly expand the amount of exploitable resources, giving additional boost to geothermal energy sector.

Energy from the Earth. Geothermal energy potential is huge.

United States have 2,957 megawatts (MW) of capacity online today, which makes U.S. the global leader in geothermal capacity. Although capacity looks good geothermal energy sector still represents an almost negligible energy ratio compared to dominant fossil fuels. There are plans according to which in the next 5 years or so, the industry will add around 3,979 MW of capacity that would be enough to more than double existing capacity.

Focus is especially on large-scale, high temperature engineered geothermal systems (EGS), but smaller, more quickly deployable modular units are also showing signs of rapid expansion, as geothermal energy attract more investors not only in US, but worldwide also. EGS have significant advantage over traditional projects by using the heat from rocks deep beneath the earth's crust instead of just using hot water close to the earth's surface like the old geothermal systems use to do. By drilling into these hot rocks and cycling water through the bore hole to create steam and run a turbine, developers can create an “artificial” resource. If developed, these engineered resources could create an exponential increase in U.S. geothermal capacity.

One of the latest major investors in geothermal energy sector will be the web giant Google that announced that it would invest US $10.7 million in the EGS in order to additionally boost US geothermal energy sector.

However story with EGS is still not fully told, there is this undoubted great potential that these geothermal projects have, but it will take some time for further development before these innovative EGS projects become competitive on commercial scale. The main problem so far with cost-effectiveness is the fact that bore holes need to be very deep in order to access rock with temperatures high enough - in some cases up to a mile and a half, which makes conventional drilling technologies inadequate.

There has been some companies, most notably «Potter Drilling» that started using a thermal fragmentation technique called “spallation” for EGS projects. This technique isn't new, and has been used by the rock quarry industry for many years now. Instead of relying on drill bits, which typically only last around 200 feet in hard rock, the company uses superheated water to carve through the earth, because the deeper the drilling, the more difficult it is to drill. According to current estimations spallation can significantly reduce the cost of drilling.

This technique is still not ready for field action but latest financial injection from Goggle worthy over $4 million should accelerate commercialization of this technique. Given the estimation how EGS should be commercially viable within the next five years geothermal energy sectors looks to be heading to a bright future, as one of the leading renewable energy sources with great potential for use in years to come.

Geothermal energy - Use and working principle

Geothermal energy is energy that is gained thanks to an intensive heat that continuously flows outward from deep within the Earth. Word “geothermal” has its roots in two Greek words, “gheo” which means Earth and “thermal” which means heat. This energy is mainly generated from Earth's core since temperature of Earth's center is reaching temperatures above 6000 degrees Celsius which is even hot enough to melt a rock. Lesser part of this energy is gained from the crust, the planet's outer layer by decay of radioactive elements which are present in all the rocks. In nature this energy is usually shown in the form of the volcanoes, hot water springs and geysers, which are all areas on which heat is concentrated near the earth’s surface.

Geothermal energy was for centuries used in some countries in the form of hot springs that provided recreational and medical bathing, not to mention that positive therapeutic effects of hot springs were known in ancient times by many nations like ancient Romans. However, progress in science didn't stop only in exploring healing effects of geothermal energy and has pushed use of geothermal energy in many different ways of which two take special place, namely its use in generating the electricity and its use in heating of households and industrial facilities. Uses of geothermal energy for central heating of the buildings and for generating electricity are the main ways of its exploration, but not the only ones.

One of many geysers on Iceland. Click on picture for full size.

Geothermal energy can be also used in many other ways and it's used for pasteurizing milk, paper manufacturing, in swimming pools, drying timber and wool, animal husbandry etc. Main advantage of geothermal energy lies in the fact that this is renewable energy source since heat of Earth's core is constantly radiating from within, and the main flaw is the fact that the best geothermal resources are located in areas where volcanic activity is increased which means that this energy source is not widely distributed. Geothermal power plants have almost negligible negative effect on environment and they can be successfully implemented in different environmental surroundings, from farms, sensible desert environments and forest recreation centers.

It's also important to mention that use of geothermal energy isn't expensive and has significantly smaller operational costs than many other energy sources and geothermal water is source of many minerals and other chemical elements which have healing effects on many skin diseases. First geothermal power station was built more than hundred years ago, at Landarello, Italy in 1904, and second one was built in Wairekei in New Zealand. Largest geothermal system that is used for central heating is located in Iceland's capital Reykjavik, city in which almost all buildings use geothermal energy heat and 89 % of all households in Iceland are heated this way.

Geothermal energy – Working principle

Through this article I will present geothermal energy working principle used for building heating and generating electricity (simplified version). First step needed is to extract the geothermal energy from steam, hot water and hot rocks from Earth's crust. The success of this process depends on how hot the water gets, and water temperature depends on how hot were rocks to start with, and how much water is pumped down to these rocks. The water is pumped down through an „injection well“, it passes through the cracks in these rocks and then comes back up again through a „recovery well“ towards the surface, and because of the great pressure water is transformed into a steam when getting to the surface.

Geothermal energy working principle used for generating electricity. Click on picture for full size.

This created steam then needs to be separated from brine what is usually done in central separation chamber. After this process of separation is over, complete steam is transferred to heat exchangers which are located inside the power plant. After steam is transferred to heat exchangers it’s possible to transfer it even further to the steam turbines where it can be generated into electricity, and in the same time through the exhaust pipes unused energy is being released.

In heat exchangers steam is being cooled under the pressure in condensate and after that heat is transferred into cold water in condensate heat exchangers. This cold water that is gained on this way gets pumped from wells to storage tanks from which is transferred to heat exchangers where water's temperature gets increased and then passes through deaerators where it boils and where released oxygen and other gases that could cause corrosion (when being heated) are removed by final water cooling.

Speaking in simple term it's all in the process of water heating and its transfer to steam which can be then used to drive a turbo-generator that generates electricity or this steam passes through heat exchangers and heats water creating necessary heat for central heating of households and industrial facilities.

Location of geothermal power plants around the world. Click on picture for full size.

Geothermal energy facts

Geothermal energy is energy generated by heat stored beneath the Earth's surface.

Geothermal energy is often referred to as geothermal power.

Geothermal energy supplies less than 10 % of the world's energy.

Geothermal energy is clean and safe for the surrounding environment.

Geothermal energy is sustainable because hot water can be re-injected into the ground.

Geothermal energy is extremely price competitive in suitable areas.

Geothermal energy suitable areas aren't widely spread.

Geothermal energy is main energy source in Iceland.

Geothermal energy is very important energy source in volcanically active places such as new Zealand and Iceland.

Geothermal energy source (click on picture to enlarge).

Geothermal energy can be found in the form of volcanoes, hot springs and geysers.

Geothermal energy has three main uses: Heating, Electricity generation and Geothermal heat pumps.

Geothermal energy is used since ancient times in form of hot water.

Geothermal energy exploit uses three basic types of geothermal power plants: Dry steam, Flash steam and Binary power plant.

Geothermal energy use has very low emissions of greenhouse gases to about three percent of the carbon dioxide emissions of a fossil power station.

Geothermal energy is widely used in California with more than 30 geothermal power plants that are producing more than 90 % of the geothermal electricity in the USA.

Geothermal energy's amount of electricity is less than 1 percent of total electricity produced in the USA.

Geothermal energy is also widely used in the state of Nevada.

Geothermal energy got its name from Greek words: geo (earth) and therme (heat), and therefore geothermal energy is in fact Earth's heat..

Geothermal energy has minimum negative environmental impact.

Geothermal energy is giving 18 % of Iceland's total electricity.

Geothermal principle (click on picture to enlarge).

Geothermal energy could produce 10 percent of US electricity by the year 2050.

Geothermal energy could supply US with more than 30,000 MW of power by 2025.

Geothermal energy doesn't depend on the sun like other renewable energy resources.

Geothermal energy widely exploited in Iceland, New Zealand, Japan, Italy, Philippines and in USA mostly in California and Nevada.

Geothermal energy is taken from Earth with the help of geothermal heat pumps.

Geothermal energy can be easily found and exploited along the "Ring of Fire" region.

Geothermal energy is extremely efficient (almost 100 %) energy source where only real source of losing energy is from turbine friction.

Geothermal energy has only one real problem and that is lack of easily accessible sites.

Geothermal energy's advantage is also the fact that geothermal power plants run continuously day and night with an uptime typically exceeding 95%.

Geothermal energy's advantage is also the fact that geothermal power stations are relatively small, and have a lesser impact on the environment than for instance hydroelectric plants.

US geothermal map (click on picture to enlarge)