Geothermal heating for Homes & Business

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Promotion of geothermal energy in Central America

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As part of the Pacific Rim of Fire, a region characterized by a large by a large number of both active and inactive Volcanoes, Central America has significant Geothermal potential. It is currently estimated at over 6000 Megawatts

Countries: Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama
Lead executing agency: Central American integration system (Sistema de la Integración Centroamericana, SICA)

1_Geothermievorkommen in Ahuachapan_El Salvador_© Deutsche Welle

As part of the Pacific Ring of Fire, a region characterized by a large number of both active and inactive volcanoes, Central America has significant geothermal potential. It is currently estimated at over 6,000 megawatts. Unlike other renewable energy sources such as wind, hydro and solar, geothermal energy can be used at any time and in any weather. Geothermal plants are also based on a climate-resilient infrastructure - they survive storms, sea-level rises, global warming and droughts. Geothermal energy can thus contribute significantly to a stable and secure primary energy supply in the region.

The national governments of Central America have recognized this opportunity and want to further expand the current eight percent installed capacity in the region. However, geothermal energy is still limited in practice, as the current investment climate for the implementation of geothermal projects in the region is unfavorable. The economic use of geothermal energy is constrained by problematic legal framework conditions. The site search and required drilling require high investment and lack specific expertise.


There is increased demand in Central America for geothermal energy, and the climate for investment in promoting geothermal projects is improving steadily.

2_Pilotprojekt zur Kaffeetrocknung von LaGeo_El Salvador_© GIZ

The regional project is part of the Promotion of Geothermal Energy in Central America programme and is being implemented as part of the German Climate Technology Initiative (DKTI). The project cooperates closely with two other projects from the programme: the Geothermal Development Facility (GDF), implemented by Kreditanstalt für Wiederaufbau (KfW Development Bank); and Identification of Geothermal Resources in Central America, implemented by the German Federal Institute for Geosciences and Natural Resources (BGR).

The regional project works in five fields of activity.

  • The project supports decision-makers’ efforts to improve the political and statutory framework.
  • It demonstrates the technical and economic feasibility of using geothermal energy to investors and decision-makers. It promotes implementation of pilot measures and supports investors, project developers and companies with planning and implementing projects.
  • The project strengthens technical expertise and helps to mainstream the training on offer in the region’s institutions.
  • Regional dialogue is also planned as part of the project to allow the initiation of processes in the various countries that will result in further expansion of geothermal energy in the region.
  • Finally, the project aims to set up a specialist network for geothermal energy through information, advice and advertising. This network provides information and advisory services.

During implementation, the project incorporates Germany’s existing expertise in the geothermal energy sector and contributes to technology transfer.

  • The perception of geothermal energy as a stable and climate-resilient energy source and thus as a vital resource in the region has improved.
  • Foundations for the regulatory framework are being laid, both in individual Central American countries and at regional level. Geothermal energy plays a more important role in the updated Central American Renewable Energy Strategy 2030.
  • The project supports project developers with the implementation of pilot projects focusing on direct use of geothermal energy. For example, Salvadorian company LaGeo and the Costa Rican energy supplier ICE are receiving support with making greater use of cascading in existing geothermal power plants. This involves using the residual heat in the steam turbine after power generation. In El Salvador, this heat is used for roasting coffee beans and pasteurising milk, while in Costa Rica, it is used for drying grain. The project is now working with the Ministry of Energy, Natural Resources, Environment and Mines in Honduras to develop a project for direct use of geothermal energy in cheese production. This approach creates green workplaces in the area around the power plants and integrates population groups with lower levels of education.
  • In 2016, the Regional Committee of Central America and the Caribbean of the Regional Energy Integration Commission (CECACIER) took over the role of regional information platform on the use of geothermal energy. The network is identifying knowledge gaps, and these areas are then addressed in face-to-face events, online seminars and publications.
  • Advanced technical courses are offered for in-service and continuing training in geothermal energy in Central America; demand for this is continuously increasing, and more than 200 experts have received training so far (as of July 2019).

Geothermal underdeveloped in Central America

Central America, with more than 1,300 sources of thermal water and 75 volcanos, has an economic geothermal potential estimated at between 3-5GW. However, of this just 650MW of capacity has been developed, providing around 8% of the region’s electricity needs, while a further 7MW provides thermal energy.

The new study from the Central American Integration System (SICA) is part of an initiative to advance the development of geothermal energy and its application in direct uses such as electricity and industry. The use of geothermal energy in the region could satisfy 70% of its energy needs, while reducing greenhouse gas emissions and dependence on fossil fuels, SICA says. In addition, it would create new business, research development opportunities and jobs in the region. As such, SICA believes that Central America could become a global leader in geothermal energy development for direct use exploitation.

Priority areas that are being investigated in the ongoing project include the adaptation of regulatory frameworks for the direct use of geothermal energy in the region and the development of demonstration projects to enable investment decisions in plants and facilities. The development of methodological tools for the management of geothermal projects are another area of focus.

The study reinforces an earlier investigation from the Inter-American Development Bank, which found that geothermal is underdeveloped throughout Latin America and Caribbean with approximately 1.8GW developed out of an up to 70GW estimated potential. The project is being run by the German Ministry for Economic Cooperation and Development (BMZ) and implemented through the German Agency for International Cooperation (GIZ) with collaboration support from the International Geothermal Association, IRENA and World Bank among other organisations. The SICA member countries are Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panamá and the Dominican Republic.

Costa Rica submits geothermal direct use legislation for consultation
Costa Rica submits geothermal direct use legislation for consultation                                            Las Pailas plant, Costa Rica 


Costa Rica has a significant potential of geothermal resources that to date have been partially used, due to barriers to their use, the main one being the lack of a country regulatory framework that allows it. Geothermal resources can be used in a wide variety of productive activities, in industrial, agricultural, commercial and residential sectors among others, with the advantage of being a clean, renewable and national energy, which can contribute to the economic development of various regions of the world. country and reducing greenhouse gas emissions.

In response to this situation and in order to submit for consultation the content of the bill proposal for the direct use of geothermal resources, the Ministry of Environment and Energy (MINAE) held a technical analysis session on the bill for the direct use of geothermal resources on December 2, 2021. Stakeholders participated in the activity, as well as other actors that would eventually be involved in the procedures established in the bill. “We trust that this law will favor not only the process of decarbonization of the national energy matrix, but also the green economic reactivation, especially in rural areas that will be able to take advantage of the resource in many different ways to increase the added value of their products,” contributing to its economic and social development ”, commented the Vice Minister of Energy and Environmental Quality, Rolando Castro.

The proposed law for the direct use of geothermal resources is the result of a process that began in 2019 with the Dialogue Workshop on the use of hydrothermal resources (low temperature geothermal energy). The objective of this workshop was to discuss with different actors about a geothermal policy, taking into account the characteristics of this resource, its potentialities and risks. With the results obtained, a content proposal was prepared for the regulatory framework that served as the basis for conducting a legal study, which generated the inputs that allowed the formulation of the bill for the direct use of geothermal resources. The formulation process was coordinated by the Energy Subsector Planning Secretariat (SEPSE). The next step after this consultation process consists of incorporating the necessary adjustments to the bill in order to present it to the Legislative Assembly in March 2022 for its respective approval process.

Throughout the process, it has had the support of the German Cooperation, specifically the Renewable Energies and Energy Efficiency Program (4E) in Central America, implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) commissioned by the Federal Ministry of Economic Cooperation. and Development of Germany (BMZ).

               Teaser on geothermal bitcoin farm in El Salvador
Teaser on geothermal bitcoin farm in El Salvador          Ahuachapán Geothermal Power Plant by LaGeo in El Salvador 

In a recent tweet, El Salvador President Nayib Bukele teased the first stages of a planned Bitcoin mining facility that uses geothermal power. 

Bukele did not provide any details, showing only a video of a geothermal facility with the text “First steps…” and the #Bitcoin hashtag. Still, this seems to indicate that there has been progress in this project.

Cryptocurrency mining has often been criticized as counter-productive to efforts in reversing the effects of global warming because of how much electricity it consumes. This project in El Salvador can potentially make Bitcoin mining more sustainable. El Salvador is uniquely positioned as the country’s legislators had recently voted cryptocurrency as an official currency to complement the US Dollar. The legislation states that cryptocurrency payments will not have to be accepted by merchants in El Salvador. Cryptocurrency will also be accepted as tax payments and investments. El Salvador currently has a geothermal power capacity of 204 MW with a potential 110 MW additional capacity. State-owned LaGeo operates and develops all geothermal facilities in the country.

When selecting and installing a geothermal heat pump, consider the heating and cooling efficiency, the economics of the system, and your site's characteristics. Be sure to find a qualified installer.

Heating and Cooling Efficiency of Geothermal Heat Pumps

The heating efficiency of ground-source and water-source heat pumps is indicated by their coefficient of performance (COP), which is the ratio of heat provided in Btu per Btu of energy input. Their cooling efficiency is indicated by the Energy Efficiency Ratio (EER), which is the ratio of the heat removed (in Btu per hour) to the electricity required (in watts) to run the unit.

These geothermal heating and cooling units installed in the basement of a new home are tied to a complex array of underground coils to keep indoor temperatures comfortable.

Economics of Geothermal Heat Pumps

Although the purchase and installation cost of a residential GHP system is often higher than that of other heating and cooling systems, properly sized and installed GHPs deliver more energy per unit consumed than conventional systems. For further savings, GHPs equipped with a device called a "desuperheater" can heat household water. In the summer cooling period, the heat removed from the house is used to heat the water for free. In the winter, water heating costs are reduced by about 50%. Depending on factors such as climate, soil conditions, the system features you choose, and available financing and incentives, you may recoup your initial investment in a few years through lower utility bills. And -- when included in a mortgage -- your investment in a GHP may produce a positive cash flow from the beginning. It may also be possible to include the purchase of a GHP system in an "energy-efficient mortgage" that would cover this and other energy-saving improvements to the home. Banks and mortgage companies can provide more information on these loans. 

Available to help offset the cost of adding a GHP to your home. These provisions are available frofederal, state, and local governments; power providers; and banks or mortgage companies that offer energy-efficient mortgage loans for energy-saving home improvements. Be sure the system you're interested in qualifies for available incentives before you make your final purchase
Evaluating Your Site for a Geothermal Heat Pump

Shallow ground temperatures are relatively constant throughout the United States, so geothermal heat pumps (GHPs) can be effectively used almost anywhere. However, the specific geological, hydrological, and spatial characteristics of your land will help your local system supplier/installer determine the best type of ground loop for your site.


Factors such as the composition and properties of your soil and rock (which can affect heat transfer rates) require consideration when designing a ground loop. For example, soil with good heat transfer properties requires less piping to gather a certain amount of heat than soil with poor heat transfer properties. The amount of soil available contributes to system design as well -- system suppliers in areas with extensive hard rock or soil too shallow to trench may install vertical ground loops instead of horizontal loops.


Ground or surface water availability also plays a part in deciding what type of ground loop to use. Depending on factors such as depth, volume, and water quality, bodies of surface water can be used as a source of water for an open-loop system, or as a repository for coils of piping in a closed-loop system. Ground water can also be used as a source for open-loop systems, provided the water quality is suitable and all ground water discharge regulations are met. Before you purchase an open-loop system, be sure your system supplier/installer has fully investigated your site's hydrology, so you can avoid potential problems such as aquifer depletion and groundwater contamination. Antifreeze fluids circulated through closed-loop systems generally pose little to no environmental hazard.

Land Availability

The amount and layout of your land, your landscaping, and the location of underground utilities or sprinkler systems also contribute to your system design. Horizontal ground loops (generally the most economical) are typically used for newly constructed buildings with sufficient land. Vertical installations or more compact horizontal "Slinky™" installations are often used for existing buildings because they minimize the disturbance to the landscape.

Installing Geothermal Heat Pumps
for their listings of qualified installers in your area. Installers should be certified and experienced. Ask for references from owners of systems that are several years old, and check them.

The ground heat exchanger in a GHP system is made up of a closed or open loop pipe system. Most common is the closed loop, in which high density polyethylene pipe is buried horizontally at 4 to 6 feet deep or vertically at 100 to 400 feet deep. These pipes are filled with an environmentally friendly antifreeze/water solution that acts as a heat exchanger. In the winter, the fluid in the pipes extracts heat from the earth and carries it into the building. In the summer, the system reverses and takes heat from the building and deposits it to the cooler ground. Ductwork in the home distributes the heated or cooled air through the house, just like conventional systems. The box that contains the indoor coil and fan is sometimes called the air handler because it moves house air through the heat pump for heating or cooling. The air handler contains a large blower and a filter just like conventional air conditioners.

Benefits of Geothermal Heat Pump Systems

The biggest benefit of GHPs is that they use 25% to 50% less electricity than conventional heating or cooling systems. This translates into a GHP using one unit of electricity to move three units of heat from the earth. According to the EPA, geothermal heat pumps can reduce energy consumption -- and corresponding emissions -- up to 44% compared with air-source heat pumps and up to 72% compared with electric resistance heating with standard air-conditioning equipment. GHPs also improve humidity control by maintaining about 50% relative indoor humidity, making GHPs very effective in humid areas. Geothermal heat pump systems allow for design flexibility and can be installed in both new and retrofit situations. In addition, the hardware may require less space than a conventional HVAC system, thus possibly freeing up space for other uses. GHP systems also provide excellent "zone" space conditioning, allowing different parts of your home to be heated or cooled to different temperatures. The underground piping associated with GHP systems often carry warranties of 25 to 50 years, and the heat pumps often last 20 years or more. In addition, the components in the living space are easily accessible, which increases the convenience factor and helps ensure that the upkeep is done on a timely basis.

GHPs have no outside condensing units like air conditioners, so there's no concern about noise outside the home. A two-speed GHP system is so quiet inside a house that users usually do not know it is operating.

Geothermal Heating Systems
     Grand Prismatic Spring, Yellowstone National Park, Wyoming

                               Geothermal Heating Systems for Homes

Domestic Geothermal heating systems can be a great way to heat a home, replace a furnace, and are labeled as money savers. Question is, are they worth the hype? Here's a quick view first of how they operate.

Starting at depths of between 6 and 10 metres, the temperature of the earth is no longer influenced by variations in surface temperature, and stays relatively constant at around 8 to 10 C. So the underlying principle of geothermal heating and cooling is to use that consistent interior earth temperature to balance our wildly varying North American & Canadian surface temperatures.

With the use of heat pumps, geothermal heating and cooling systems extract heat energy and transfer it into buildings, saving approximately 50 to 60% on heating and cooling costs, depending on the fuel being compared to. In summer months, geothermal cooling functions in a similar way to standard air conditioning, only heat is not simply ejected into the outside air, but rather deposited deep in the ground for future use. The result is guilt-free air conditioning because the heat extracted in summer months is actually used to warm the earth deep below, heat which will increase the efficiency of the ground source heat pump in winter months.

Geothermal home heating systems:

Vertical closed-loop geothermal systems have a sealed U-shaped pipe of high density polyethylene that carries a heat transfer fluid (usually a water / methanol mix) in a continuously circulating loop allowing an exchange of heat by conduction. As the liquid returns to the surface, either heated or cooled depending on the season, the additional or reduced amount of heat in the water is used to condition the home. The required depth for this system is generally 300 feet or more, and the cost is calculated by the foot. Through the nose, but by the foot.

Geothermal vertical loop system 

Horizontal closed-loop geothermal systems function in the same manner as vertical systems, except that pipes are run back and forth 6 to 10 feet underground. Installation involves excavating trenches (at least 300 feet of them), rather than digging a well.

Horizontal ground source heat pump systems can be cheaper to install but require a significant amount of space, and it does some pretty intense damage to any ecosystems that lay in its intended path. For a given length of pipe, horizontal loop systems are a bit less efficient than vertical loop systems, as they can be more easily affected by surface temperatures. The other downside is that if or when there's a leak in the circuit, with a horizontal mat or grid style system the whole garden area has to be dug up again in search of a tiny leak that is losing the system pressure.

Geothermal horizontal loop system 

Open-loop geothermal systems use ground water pumped directly from a supply well (75 to 100 feet deep) in order to draw and inject heat. Water is pumped out of the first well, and after the heat exchange is carried out, it gets injected into the second well.

Geothermal open loop system 

Open-loop systems have a very high thermal efficiency and installation can be up to 50% less expensive than vertical closed loop systems. However, conditions necessary for the proper function of these systems are rarely found in urban areas, as they require an abundant source of ground water and a high water table.

Will geothermal heating save me money?

That truly depends on the size of the project to heat. No geothermal system is cheap to install, and because it offers only a reduction in consumption, the return on investment is really only viable for larger buildings. For this reason geothermal is more suited to commercial or multi-unit residential projects of substantial size.

A home would have to be quite large, and somewhat poorly-insulated to actually make it pay for itself in a reasonable time frame. In many cases, particularly with moderately-sized new homes being built, that large of a financial investment towards energy efficiency could offer much greater returns if put towards heat retention instead - better windows, additional home insulation in new build, insulating existing walls from the outside during a house renovation, or better tapes and membranes for air sealing, etc. 

Ball park pricing for a geothermal system: For an averaged size home (2000 sq. ft.) a GSHP will easily cost $30,000 to have installed, and that is in exchange for a monthly saving of about 50% on the heating bill. So payback for the average single family home is simply too far away to make this a financially competitive option with all but the highest consuming homes - and even then only when the boiler or furnace has failed and needs replacement. 

That same investment of $25,000 (or perhaps less) in a better thermal envelope would likely reduce heating bills easily by 70 or 80%, perhaps more. Geothermal energy is an excellent global technology, but poorly insulated single family homes will get far more bang for the buck if the money is put into insulation instead, or balanced between energy saving renovations and high efficiency heat pumps.

     All You Need to Know About Home Geothermal Heating & Cooling

Have you heard of home geothermal heating and cooling? It’s an HVAC system that can save homeowners serious money on utility bills.

Unfortunately, many people have never heard of home geothermal, or they don’t understand it. A lot of people think it has something to do with capturing heat from volcanoes or geysers.That would be pretty tricky to pull off for most homeowners, and it would seriously limit the number of people who could take advantage of geothermal energy. Thankfully, you don’t have to live anywhere near an active volcano to have an effective, money-saving home geothermal system installed.

Geothermal Heating and Cooling

How does geothermal heating and cooling work?

Geothermal energy utilizes the relatively stable temperature of the earth that is buried and stored a few feet under its surface. Geothermal energy can potentially be harnessed in the front or back yard of your home.

  The geothermal loop, one aspect of geothermal,is being installed in the ground.

Geothermal energy is harnessed from the earth.

One of the three main aspects of a geothermal system, is the series of pipes that are buried in the ground. These pipes store and transfer the relatively constant temperature the lies under the surface of the ground. Regardless of the season or the degree of the outside temperature, the temperature of the earth a few feet underground remains constant.  Where I live in Western Colorado, this temperature is 56 degrees Fahrenheit.  This can differ depending on the latitude and climate of your specific location.

Over time, a substantial energy saving can be gained by using geothermal energy to heat and cool a building.  This is because energy is not used or burned to produce heat, instead, energy is used to move heat through a system.

When compared to the cost of heating and cooling a residence with propane, using geothermal heating and cooling can cut up to 2/3rds of the cost.

   Diagram of a geothermal loop located underground

Both large institutions as well as smaller private residences can benefit from the utilization of geothermal energy as a heating and cooling energy source.

(Side note: Geothermal energy is an extended beneficiary of the passive solar element of the Earth’s ability to store and absorb the sun’s heat in its large planetary mass. Thus, theoretically it can be debated as an extension of passive solar heating and cooling.)

                                 Residential Heat Pump

One of the first large scale geothermal applications at the Oregon Institute of Technology.

Here is an example of a geothermal heating and cooling application at the Oregon Institute of Technology campus

“The Oregon Institute of Technology has been using a geothermal district heating system since 1964, making it the first modern system. Today, the system heats 11 buildings (600,000 square feet), provides domestic hot water, melts snow on 2300 square feet of sidewalk, and even cools five buildings (277,3000 square feet) during the summer. The district heating system saves around $225,000 each year in heating costs, as compared to the previous fuel oil boiler system.”

Three main types of technologies take advantage of Earth as a heat source:

Geothermal energy is considered a renewable resource. Ground source heat pumps and direct use geothermal technologies serve heating and cooling applications, while deep and enhanced geothermal technologies generally take advantage of a much deeper, higher temperature geothermal resource to generate electricity.

                              Ground Source Heat Pumps

A ground source heat pump takes advantage of the naturally occurring difference between the above-ground air temperature and the subsurface soil temperature to move heat in support of end uses such as space heating, space cooling (air conditioning), and even water heating. A ground source or geoexchange system consists of a heat pump connected to a series of buried pipes. One can install the pipes either in horizontal trenches just below the ground surface or in vertical boreholes that go several hundred feet below ground. The heat pump circulates a heat-conveying fluid, sometimes water, through the pipes to move heat from point to point.A commercial-scale ground source heat pump system. This example is a demonstration project at a university.

If the ground temperature is warmer than the ambient air temperature, the heat pump can move heat from the ground to the building. The heat pump can also operate in reverse, moving heat from the ambient air in a building into the ground, in effect cooling the building. Ground source heat pumps require a small amount of electricity to drive the heating/cooling process. For every unit of electricity used in operating the system, the heat pump can deliver as much as five times the energy from the ground, resulting in a net energy benefit.  Geothermal heat pump users should be aware that in the absence of using renewable generated electricity to drive the heating/cooling process (e.g., modes) that geothermal heat pump systems may not be fully fossil-fuel free (e.g., renewable-based).
How It Works

The steps below describe how a heat pump works in “heating mode”—taking heat from the ground and delivering it to a building—and “cooling mode,” which removes heat from the building and transfers it to the ground.

 Heating Mod

  1. Diagram showing a ground source heat pump in heating mode. Components are labeled with numbers that match the text.
    Circulation: The above-ground heat pump moves water or another fluid through a series of buried pipes or ground loops.
  2. Heat absorption: As the fluid passes through the ground loop, it absorbs heat from the warmer soil, rock, or ground water around it.
  3. Heat exchange and use: The heated fluid returns to the building where it used for useful purposes, such as space or water heating. The system uses a heat exchanger to transfer heat into the building’s existing air handling, distribution, and ventilation system, or with the addition of a desuperheater it can also heat domestic water.
  4. Recirculation: Once the fluid transfers its heat to the building, it returns at a lower temperature to the ground loop to be heated again. This process is repeated, moving heat from one point to another for the user’s benefit and comfort.
Cooling Mode
  1. Diagram showing a ground source heat pump in cooling mode. Components are labeled with numbers that match the text.
    1.  Heat exchange and absorption: Water or another fluid absorbs heat from the air inside the building through a heat exchanger, which is the way a typical air conditioner works.
  2. Circulation: The above-ground heat pump moves the heated fluid through a series of buried pipes or ground loops.
  3. Heat discharge: As the heated fluid passes through the ground loop, it gives off heat to the relatively colder soil, rock, or ground water around it.
  4. Recirculation: Once the fluid transfers its heat to the ground, the fluid returns at a lower temperature to the building, where it absorbs heat again. This process is repeated, moving heat from one point to another for the user’s benefit and comfort.

The above-ground heat pump is relatively inexpensive, with underground installation of ground loops (piping) accounting for most of the system’s cost. Heat pumps can support space heating and cooling needs in almost any part of the country, and they can also be used for domestic hot water applications. Increasing the capacity of the piping loops can scale this technology for larger buildings or locations where space heating and cooling, as well as water heating, may be needed for most of the year.

Potential Applications

Direct Use Geothermal
Photo: natural geothermal hot spring
Geothermally heated water reaches the surface at hot springs like this one in Yellowstone National Park 
Direct use geothermal systems use groundwater that is heated by natural geological processes below the Earth’s surface. This water can be as hot as 200°F or more. Bodies of hot groundwater can be found in many areas with volcanic or tectonic activity. In locations such as Yellowstone National Park and Iceland, these groundwater reservoirs can reach the surface, creating geysers and hot springs. One can pump hot water from the surface or from underground for a wide range of useful applications.

How It Works

  1. Diagram showing a direct use geothermal system. Components are labeled with numbers that match the text.
    Pumping: To tap into hot ground water, a well is drilled. A pumping system may be installed, although in some cases, hot water or steam may rise up through the well without active pumping.
  2. Delivery: Hot water or steam can be used directly in a variety of applications, or it can be cycled through a heat exchanger.
  3. Refilling: Depending on the use requirements of the system and the conditions of the site, the ground water aquifer may need to be replenished with water from the surface. In some cases, the movement of ground water might refill the aquifer naturally.

The water from direct geothermal systems is hot enough for many applications, including large-scale pool heating; space heating, cooling, and on-demand hot water for buildings of most sizes; district heating (i.e., heat for multiple buildings in a city); heating roads and sidewalks to melt snow; and some industrial and agricultural processes. Direct use takes advantage of hot water that may be just a few feet below the surface, and usually less than a mile deep. The shallow depth means that capital costs are relatively small compared with deeper geothermal systems, but this technology is limited to regions with natural sources of hot groundwater at or near the surface.

          Deep and Enhanced Geothermal Systems

Deep geothermal systems use steam from far below the Earth’s surface for applications that require temperatures of several hundred degrees Fahrenheit. These systems typically inject water into the ground through one well and bring water or steam to the surface through another. Other variations can capture steam directly from underground (“dry steam”). Unlike ground source heat pumps or direct use geothermal systems, deep geothermal projects can involve drilling a mile or more below the Earth’s surface. At these depths, high pressure keeps the water in a liquid state even at temperatures of several hundred degrees Fahrenheit.

Photo: natural geothermal hot spring
Deep geothermal technologies harness the same kind of energy that produces geysers.
Deep geothermal sources provide efficient, clean heat for industrial processes and some large-scale commercial and agricultural uses. In addition, steam can be used to spin a turbine and generate electricity. Although geothermal steam requires no fuel and low operational costs, the initial capital costs—especially drilling test wells and production wells—can be financially challenging. Steam resources that are economical to tap into are currently limited to regions with high geothermal activity, but research is underway to develop enhanced geothermal systems with much deeper wells that take advantage of the Earth’s natural temperature gradient and can potentially be constructed anywhere. Enhanced systems can use hydraulic fracturing techniques to engineer subsurface reservoirs that allow water to be pumped into and through otherwise dry or impermeable rock.

young family in front of home

Geothermal energy is heat that comes from the subsurface of the earth — a region of the mantel where temperatures range from 45 to 75 degrees Fahrenheit at all times. Geothermal power plants tap into this thermal heat to generate electricity. We can also use this energy to heat or cool homes directly through a residential geothermal energy system.

Residential geothermal systems use a heat pump to exchange heat with the earth to heat a home in the winter and cool it in the summer. These systems have significant environmental advantages. First, geothermal energy is a clean source of energy and the system requires only a small amount of electricity to operate. Also, geothermal energy is accessible 24 hours a day, making it a reliable energy source with an extremely low carbon footprint. Selecting the best geothermal system for your home depends on your local climate, how much land you have available, and soil conditions. If you’re interested in using geothermal energy in your home, it’s essential to understand the different options available, including closed-loop, open-loop, and hybrid systems.

Closed-Loop Systems

This type of geothermal energy system is the most common, and it typically includes two different loops made of plastic tubing. The first is the refrigerant loop, which is installed inside your home. The second is the water loop, which is typically buried underground. As the fluid circulates in the outside tubing, the ground heats it. Then, the fluid goes into the home where it exchanges heat with the refrigerant loop. Of the closed-loop systems, there are three varieties to know:

1. Vertical Loop System

In this geothermal system, you install the tubing vertically in the ground. If your property has limited land available — or you want to minimize the impact on your landscaping — this option may be ideal. However, if you live in an area with rocky ground, digging holes between 100 and 500 feet deep may prove too difficult. Of all the closed-loop systems, vertical systems are considered the most expensive to install. However, the total cost will depend on multiple factors, including environmental factors, regulations, and square footage. Consult with a professional to receive an accurate cost estimate.

2. Horizontal Loop System

For this type of geothermal system, you install the tubing horizontally, which tends to be more effective than vertical installations. However, this requires more land than a vertical system. Plus, with the tubing closer to the surface of the ground — around 3.5 to 6.5 feet — it’s more likely to be affected by weather conditions. Therefore, it’s usually not recommended for homeowners who see long or cold winters.This closed-loop geothermal system is typically cheaper than its vertical counterpart, making the initial installation more affordable. Contact a professional to learn more about specific land requirements and pricing.

3. Pond/Lake Loop System

Do you have a body of water on your land? If so, you can choose this geothermal energy system, where you install the tubing at the bottom of a pond or lake. The tubing is laid in a coil, also called a “slinky” closed-loop at least eight feet under the water’s surface to prevent winter freezing.This geothermal system is ideal when it is a viable option because it tends to be less expensive than other installations. The price varies depending on how close the water body is to your home.

Open-Loop Systems

Similar to a pond/lake loop system, an open-loop system requires water via a well or a surface body of water. The liquid gets directed into the tubing and to the heat pump, where the heat is exchanged with the refrigerant loop. Then the water returns to the ground through the well or surface discharge. This option is best for homeowners who have an adequate supply of clean water and can meet all local codes and regulations. On average, open-loop systems are cheaper to install than closed-loop ones, allowing you to save up to 60 percent on the costs. Keep in mind, however, that these systems also require more maintenance than other geothermal systems, including filter changes, water softening, and well testing.

Hybrid Systems

Hybrid systems aren’t as conventional as closed- or open-loop systems, but they’re still available.They take advantage of a combination of geothermal resources, such as standing column wells and cooling towers. These geothermal systems are primarily used for cooling, rather than heating, making them a viable option for homeowners in warmer regions.

Choosing the Right Geothermal System

If you plan to make the switch to geothermal energy, you can realize many benefits. Geothermal heat pumps typically use 25 percent to 50 percent less electricity than conventional heating and cooling systems. They are also generally quieter, last longer, and need less maintenance than conventional systems. You can save up to 60 percent on heating costs and up to 50 percent on cooling costs each year. Plus, you can take advantage of federal tax credits to bring down the costs of installation. Before you make the switch, do your research and decide which type of system is right for you. Closed-loop, open-loop, and hybrid options all come with pros and cons, but each one delivers key benefits for homeowners. Determining which type of system fits your living situation will lead to long-term contentment.


  1. Environmental impact
  2. Heating and cooling
  3. Unlock potential
  4. No fuel
  5. Renewable
  6. Reliable
  7. Sustainable
  8. New technology

Geothermal AC and heating systems use sustainable resources and provide an excellent option for people or businesses to control their indoor temperature. Geothermal energy has a lot of potential for widespread adoption in the future.

  Icelandic cars running on geothermal power

The number of fully electric cars in Iceland has increased five-fold since January 2014 with ON Power, the operator of Iceland’s two largest geothermal power plants, playing a key role


The number of fully electric cars in Iceland has increased five-fold since January 2014 with ON Power, the operator of Iceland’s two largest geothermal power plants, playing a key role.

Fully electric cars, which many major car manufacturers have introduced in recent years, have been popular with Icelanders and since January 2014, the number of fully electric cars in the country has risen from just above a hundred to over five hundred. Since virtually all electricity in Iceland is generated from renewable sources, the country is viewed as particularly suitable for revolutionising transportation.

Hybrid cars still have the upper hand among Iceland’s population of 320,000 and there are three times as many hybrids as the fully electric cars on the roads.

ON Power operates the geothermal power plants at Hellisheidi and Nesjavellir and has taken a leading role in this development by introducing toll-free fast charging in Iceland’s capital area.

Ten such stations are already in operation and more are on the way. These installations have proven to be a psychological stepping-stone for drivers that have tended to feel unsure whether their environmentally friendly vehicles will reach their destination. Surveys have shown that ON Power’s fast-charging stations in Iceland are used more than similar stations in Norway, which leads the way in the implementation of electric transportation.

ON Power’s geothermal plants are the country’s two largest and their combined electric capacity of around 400 megawatts provides Iceland’s capital Reykjavik with 50 per cent of the geothermal water needed for its district heating.

 Hydrogen Cars and how they Work

How Hydrogen Cars Work

The car of the future is here today. Of course, you can't buy one yet; but if you live in California you can lease one. It doesn't use gasoline and it doesn't pollute the air. In fact, it produces steam instead of exhaust. So what's the mystery fuel? Hydrogen -- the simplest and most abundant element in the universe. And some people think that in 20 to 30 years, we'll all be driving these hydrogen-powered, fuel-efficient vehicles.

Although hydrogen-powered cars have a science fiction quality to them, the idea isn't really new. Actually, the technology for using hydrogen to generate power has been around since the first part of the 19th century -- that's longer than cars have been around. What's new is that you might actually see a hydrogen-powered car on the road, with steam coming out of its exhaust pipe instead of foul-smelling gases. Several hydrogen cars are now in existence, but most of them are concept cars. These eco-friendly driving machines include the Chevrolet Equinox, the BMW 745h and the one that's currently available for lease in California, the Honda FCX.

What makes a hydrogen car possible is a device called a fuel cell, which converts hydrogen to electricity, giving off only heat and water as byproducts. Because it's non-polluting, hydrogen seems like the ideal fuel for the 21st century. A lot of people in the government and the auto industry are excited about its potential. Hydrogen cars have the potential to be fuel-efficient and offer the hope of eco-friendly, green driving. But there are still a lot of problems that need to be overcome and questions that need to be answered before hydrogen becomes the fuel of choice for enough people to make much difference in our current use of fossil fuels. For instance, where will we get the hydrogen? How expensive will these fuel-efficient cars be to purchase? Will you be able to find a hydrogen fuelling station to refill your tank? And, perhaps most importantly, as a fuel, is hydrogen really as non-polluting as it seems?

Hydrogen Fuel Cells

A hydrogen fuel cell powered bus leaves the Connecticut Convention Center in Hartford, Conn., for a demonstration ride.

In 1839, the Welsh scientist Sir William Robert Grove took the familiar electrochemical process of electrolysis, which uses electricity to produce hydrogen from water, and reversed it, generating electricity and water from hydrogen. He called his invention a gas voltaic battery, but today we know it as a hydrogen fuel cell. Much later, in the middle of the 20th century, the technology was further developed by the inventor Francis Bacon. The technology that these two inventors devised is essential to the operation of a hydrogen car.

The first practical fuel cell system was developed in the early 1960s by General Electric for use in orbital space capsules. And then, in the 1990s fuel cells began appearing in city buses. so we know that powering vehicles with fuel cells is feasible. You can think of a fuel cell as a kind of battery, except that while a battery keeps its fuel inside itself, a fuel cell needs to be refilled. The fuel for a hydrogen fuel cell is, as the name suggests, hydrogen. As you might recall from high school chemistry class, hydrogen is the simplest of all elements. An atom of hydrogen consists of a single electron and a single proton. The fuel cell generates electricity by stripping the electrons from the protons and using the electrons to create a pure stream of electricity. The ionized hydrogen atoms then combine with oxygen to form water. The other byproduct of this process is heat, so this water generally takes the form of steam. How's that for eco-friendly driving?

The type of fuel cell used in cars is the polymer exchange membrane (or PEM) fuel cell. PEM fuel cells have the advantage of being light and small. They consist of two electrodes (a negatively charged anode and a positively charged cathode), a catalyst and a membrane. Hydrogen is forced into the fuel cell at the anode in the form of H2 molecules, each of which contains two hydrogen atoms. A catalyst at the anode breaks the molecules into hydrogen ions (the protons) and a flow of electricity (the electrons). The ions pass through the membrane, but the electricity has to go around. While it's doing so, it can be harnessed to do work. Just as hydrogen is forced into the fuel cell at the anode, oxygen is forced in at the cathode. The protons and electrons reunite at the cathode and join with the oxygen to form water, most of which become the fuel cell's exhaust. Fuel cells are designed to be flat and thin, mainly so they can be stacked. The more fuel cells in the stack, the greater the voltage of the electricity that the stack produces.

Many people think that fuel-efficient vehicles like hydrogen-powered cars will be crucial in meeting the energy demands of the 21st century. In 2003, President George W. Bush announced a $1.2 billion Freedom Fuel Initiative in support of the development of fuel cell technology. Fuel cells have two major advantages over fossil fuels. First, they don't deplete the world's finite supply of oil, which helps us preserve the existing supplies and they could also reduce our dependency on foreign oil. Second, the only byproduct from a fuel cell's operation is heat and water, which means fuel cells don't produce pollution. This is vitally important in a time when carbon emissions from cars are believed to be promoting global warming.

Hydrogen Car Production

The Earth has plenty of hydrogen available in the form of water; however, separating it, collecting it and storing it may prove to be quite difficult.

So how do manufacturers actually build fuel-efficient vehicles, like fuel cell cars? Well, hydrogen car production is not vastly different from producing typical cars. Of course, the drive train, for instance, and the electrical systems will be somewhat unique because a fuel cell creates electricity. Therefore, a hydrogen-powered car and electric car have a lot in common in that respect. Perhaps a more important question is how the hydrogen itself will be produced. Given that hydrogen is the most abundant element in the universe, constituting roughly 90 percent of the atoms in existence, you'd think that this wouldn't be a problem. Well, think again. Hydrogen is also the lightest element in the universe and any uncontained hydrogen on the surface of the Earth will immediately float off into outer space. What hydrogen remains on this planet is bound with other elements in molecular form, most commonly in water (H2O) molecules. And there happens to be a lot of H2O on the surface of the Earth.

But how do we separate the hydrogen molecules in the water from the oxygen molecules? And if we don't use water as a hydrogen source, where else can we get hydrogen? The simplest way of getting hydrogen from water is the one that Sir William Grove knew about more than 150 years ago: electrolysis. If you pass an electric current through water, the H2O molecules break down. Similar to fuel cell operation, this process uses an anode and a cathode, usually made from inert metals. When an electric current is applied to the water, hydrogen forms at the cathode, and oxygen forms at the anode. Although this process is slow, it can be done on a large scale.

An alternative source for hydrogen is natural gas, which consists of naturally occurring hydrocarbons. A process called steam reformation can be used to separate the hydrogen in the gas from the carbon. At present, this is the most common method of industrial-scale production of hydrogen and would likely be the first method used to produce the hydrogen for fuel-cell vehicles. Unfortunately, this process uses fossil fuels -- the natural gas -- so if the point of building cars that run on hydrogen is to avoid depleting fossil fuel reserves, natural gas would be the worst possible source of this fuel.

Some experts have suggested that it might be possible to build miniature hydrogen plants that will fit in the average person's garage, so it won't even be necessary to drive to the local fueling station to fill up the car's hydrogen tank. The most extreme form of this idea has been the suggestion that electrolysis could be performed inside the car itself, which would make possible the astounding idea of a car that runs on water! However, the power for the electrolysis has to come from some sort of battery, so a water-powered car would need to be periodically recharged.

So, are green driving machines like fuel-cell equipped vehicles really the cars of the future? Many people hope so, but there are several potential roadblocks on the way to a world where people get around in cars that run on hydrogen.

What is a Hydrogen Fuel Cell?

Although hydrogen is in its infancy as a fuel source, its future is incredibly bright. The technology behind hydrogen fuel cells is improving daily and its viability as a replacement to the internal combustion engine seems likely. Hydrogen is already being used in specialty vehicles such as forklifts and buses, and it’s only a matter of time before infrastructure is in place to serve the consumer automotive market. Why do hydrogen fuel cells have such great appeal? Because their only byproducts are heat and water vapor, making hydrogen fuel cells a truly zero-emission locomotive technology.

What is a Fuel Cell?

A fuel cell is a device that generates electrical power through a chemical reaction by converting a fuel (hydrogen) into electricity. Although fuel cells and batteries are both considered electrochemical cells and consist of similar structure, fuel cells require a continuous source of fuel and oxygen to run; similar to how an internal combustion engine needs a continuous flow of gasoline or diesel.

How Does it Work?

A fuel cell needs three main components to create the chemical reaction: an anode, cathode and an electrolyte. First, a hydrogen fuel is channeled to the anode via flow fields. Hydrogen atoms become ionized (stripped of electrons), and now carry only a positive charge. Then, oxygen enters the fuel cell at the cathode, where it combines with electrons returning from the electrical circuit and the ionized hydrogen atoms. Next, after the oxygen atom picks up the electrons, it then travels through the electrolyte to combine with the hydrogen ion. The combination of oxygen and ionized hydrogen serve as the basis for the chemical reaction.

A polymer electrolyte membrane permits the appropriate ions to pass between the anode and the cathode. If the electrolyte gave free control for all electrons or ions to pass freely, it would disrupt the chemical reaction. At the end of the process the positively charged hydrogen atoms react with the oxygen to form both water and heat while creating an electrical charge.

Within the fuel market there are many different applications with different power requirements. In order to provide adequate power, individual fuel cells can be assembled together forming a stack. A fuel cell stack can be sized for just the right amount of energy for the application.

Where are fuel cells used?

Fuel Cells are used in both stationary and motive power applications for:

  • Cars, trucks, buses, and recreational vehicles
  • Material handling equipment
  • Act as a primary power source for high-volume data centers or commercial, industrial, and residential buildings
  • Backup power source to critical computer and communications networks
  • Generating power on-site