Geothermal Energy Information, Geothermal Power Facts - National Geographic Geothermal Energy Tapping the Earth's Heat Here's what you need to know about ​the warming planet, ho​​w it's affecting us, and what's at stake. This Ggeothermal power plant in Reykjavik, Iceland, is using their underground reservoirs of steam and hot water to generate electricity and to heat and cool buildings directly. Photograph by Medford Taylor Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.This thermal energy is contained in the rock and fluids beneath Earth's crust. It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma. These underground reservoirs of steam and hot water can be tapped to generate electricity or to heat and cool buildings directly. A geothermal heat pump system can take advantage of the constant temperature of the upper ten feet (three meters) of the Earth's surface to heat a home in the winter, while extracting heat from the building and transferring it back to the relatively cooler ground in the summer.

Geothermal water from deeper in the Earth can be used directly for heating homes and offices, or for growing plants in greenhouses. Some U.S. cities pipe geothermal hot water under roads and sidewalks to melt snow. To produce geothermal-generated electricity, wells, sometimes a mile (1.6 kilometers) deep or more, are drilled into underground reservoirs to tap steam and very hot water that drive turbines linked to electricity generators. The first geothermally generated electricity was produced in Larderello, Italy, in 1904. There are three types of geothermal power plants: dry steam, flash, and binary. Dry steam, the oldest geothermal technology, takes steam out of fractures in the ground and uses it to directly drive a turbine. Flash plants pull deep, high-pressure hot water into cooler, low-pressure water. The steam that results from this process is used to drive the turbine. In binary plants, the hot water is passed by a secondary fluid with a much lower boiling point than water. This causes the secondary fluid to turn to vapor, which then drives a turbine. Most geothermal power plants in the future will be binary plants. Geothermal energy is generated in over 20 countries.

The United States is the world's largest producer, and the largest geothermal development in the world is The Geysers north of San Francisco in California. In Iceland, many of the buildings and even swimming pools are heated with geothermal hot water. Iceland has at least 25 active volcanoes and many hot springs and geysers. There are many advantages of geothermal energy. It can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces. Binary plants release essentially no emissions. Unlike solar and wind energy, geothermal energy is always available, 365 days a year. It's also relatively inexpensive; savings from direct use can be as much as 80 percent over fossil fuels. But it has some environmental problems. The main concern is the release of hydrogen sulfide, a gas that smells like rotten egg at low concentrations. Another concern is the disposal of some geothermal fluids, which may contain low levels of toxic materials. Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down.

Reykjavik: The ground heats the city - Danish Architecture Centre The city of Bristol in southwest England has an innovative approach to sustainable urban development and citizen involvement, for example via social media and interactive websites. That meant that on 14 June 2013 the city beat Brussels, Glasgow and Ljubljana in contention for the title of European Green Capital 2015. Reykjavik: The ground heats the city Reykjavik, the capital of Iceland, has been very lucky with its geologic location. Every day, geothermal energy from underground hot springs is used to generate electricity and to heat 95% of all buildings in the city. In terms of CO² emissions, Reykjavik is now one of the cleanest cities in the world. Geotermisk borehuls hus, 14. marts 2008, Af Lydurs, Flickr, Creative Commons Reykjavik has, for a long time, held the title of the world's largest and most sophisticated geothermal heating user, drawing up hot water from natural springs to heat its buildings as early as 1930.

Today, geothermal energy powers the entire city - with an electricity network harnessing 750 MW of thermal power from steam, and a hot water distribution system generating 60 million cubic meters of hot water annually. In 2006, 26.5% of electricity in Iceland was derived from geothermal energy, 73.4% from hydro power, and only 0.1% from other sources. As the figures clearly illustrate, the use of this natural resource has massively reduced Reykjavik's dependence on fossil fuels and made it one of the cleanest cities in the world. The city's use of geothermal energy has prevented as much as 110,000,000 tons of CO² from entering the atmosphere between 1944 to 2006 and presently saves up to 4 million tons from being emitted annually. Geothermal energy has also contributed to Iceland's transformation from a relatively poor country to one that enjoys a very high standard of living. The special geological condition of Iceland that allows it to take such a huge advantage of geothermal energy is its location along the Mid Atlantic ridge - a deep sea mountain range with a high concentration of volcanoes.

Specifically, Iceland gets most of its heating and electricity from five power/heating plants that are located 30 km east of Reykjavik in a particularly geothermal energy-rich area. Geothermal heat originally comes from the Earth's core, where temperatures may reach 4,000-7,000°C. This heat can come to the surface in the form of hot water that seeps through fissures, cracks and permeable rock. A number of countries and continents, including Iceland, sit over terrain with a lot of these fissures and cracks, allowing them to easily take advantage of these naturally occurring heat supplies. Over the years, the United Nations University Geothermal Training Program and Iceland's National Energy authority were established in order to help developing countries meet their potential for geothermal energy use. Presently, the company Reykjavik Energy serves about 170,000 people, drawing up 63 million cubic meters of hot water for thermal use annually. Space heating accounts for 85% of this water, while bathing and washing account for 15%.

The "space heating" category includes the heating of houses, swimming pools, some greenhouses, and (increasingly) roads and sidewalks that accumulate snow. Typically, Reykjavik Energy draws up water from low temperature fields (with temperatures below 150°C located roughly 1000 m below the surface) as well as high temperature fields (with temperatures above 200°C located far below the 1000 m depth line). Water from low temperature fields can be used as hot tap water or can directly space heat buildings after it is sent into the city's distribution system consisting of over 1,300 km of piping. Water from high temperature fields is used for electricity generation and must pass through heat exchangers and treatment facilities before it can enter the city's distribution system. In this system, water that has cooled is either re-circulated and reheated by adding hotter water, or drains directly into the sewer system. Geothermal Energy 1. What Is Geothermal Energy? Geothermal energy comes from the heat within the earth.

The word "geothermal" comes from the Greek words geo, meaning earth," and therme, meaning "heat." People around the world use geothermal energy to produce electricity, to heat buildings and greenhouses, and for other purposes. The earth's core lies almost 4,000 miles beneath the earth's surface. The double-layered core is made up of very hot molten iron surrounding a solid iron center. Estimates of the temperature of the core range from 5,000 to 11,000 degrees Fahrenheit (F). Heat is continuously produced within the earth by the slow decay of radioactive particles that is natural in all rocks. Surrounding the earth's core is the mantle, thought to be partly rock and partly magma. The mantle is about 1,800 miles thick. The outermost layer of the earth, the insulating crust, is not one continuous sheet of rock, like the shell of an egg, but is broken into pieces called plates. These slabs of continents and ocean floor drift apart and push against each other at the rate of about one inch per year in a process called continental drift.

Magma (molten rock) may come quite close to the surface where the crust has been thinned, faulted, or fractured by plate tectonics. When this near-surface heat is transferred to water, a usable form of geother- energy is created. Geothermal energy is called a renewable energy source because the water is replenished by rainfall, and the heat is continuously produced by the earth. 2. History of Geothermal Energy Many ancient peoples, including the Romans, Chinese, and Native Americans, used hot mineral springs for bathing, cooking, and heating. Water from hot springs is now used world-wide in spas, for heating buildings, and for agricultural and industrial uses. Many people believe hot mineral springs have natural healing powers. Using geothermal energy to produce electricity is a relatively new industry. It was initiated by a group of Italians who built an electric generator at Lardarello in 1904. Their generator was powered by the natural steam erupting from the earth. The first attempt to develop geothermal power in the United States came in 1922 at The Geysers steam field in northern California.

The project failed because the pipes and turbines of the day could not stand up to the abrasion and corrosion of the particles and impurities that were in the steam. Later, a small but successful hydrothermal plant opened at the Geysers in 1960. Today 28 plants are operating there. Electricity is now produced from geothermal energy in 21 countries, including the United States. 3. Where Is Geothermal Energy Found? What does geothermal energy look like? Some visible features of geothermal energy are volcanoes, hot springs, geysers, and fumaroles. But you cannot see most geothermal energy. Usually geothermal energy is deep underground. There may be no clues above ground to what exists below ground. Geologists use many methods to find geothermal resources. They may study aerial photographs and geological maps. They may analyze the chemistry of local water sources and the concentration of metals in the soil. They may measure variations in gravity and magnetic fields. Yet the only way they can be sure there is a geothermal resource is by drilling wells to measure underground temperatures. The earth is a hotbed of geothermal energy.

The most active geothermal resources are usually found along major plate boundaries where earthquakes and volcanoes are concentrated. Most of the geothermal activity in the world occurs in an area known as the "Ring of Fire." The Ring of Fire rims the Pacific Ocean and is bounded by Japan, the Philippines, the Aleutian Islands, North America, Central America, and South America. 4. Today's Geothermal Energy There are four main kinds of geothermal resources: hydrothermal, geopressured, hot dry rock, and magma. Today hydrothermal resources are the only kind in wide use. The other three resources are still in the infant stages of development. Hydrothermal resources have the common ingredients of water (hydro) and heat (thermal). These geothermal reservoirs of steam or hot water occur naturally where magma comes close enough to the surface to heat ground water trapped in fractured or porous rocks, or where water circulates at great depth along faults. Hydrothermal resources are used for different energy purposes depending on their temperature and how deep they are.

Low Temperature: "Direct Use" or Heating When the temperature of a hydrothermal resource is around 50F and up, it can be used directly in spas or to heat buildings, grow crops, warm fish ponds, or for other uses. Hydrothermal resources suitable for heating occur throughout the United States and in almost every country in the world. Most of the people in Iceland and over 500,000 people in France use geothermal heat for their public buildings, schools, and homes. In the United States, geothermal heat pumps are used in 45 states to heat and cool homes and buildings. Idaho, Oregon, Nevada, and some other states use geothermal energy to heat entire districts. Heat from geothermal resources is also used to dry ceramics, lumber, vegetables, and other products. High Temperature: Producing Electricity When the temperature of a hydrothermal resource is around 220F and up, it can be used to generate electricity. Most electricity-producing geothermal resources have temperatures from 300 to 700F, but geothermal reservoirs can reach nearly 1,000F.

Two main types of hydrothermal resources are used to generate electricity: dry steam (vapor-dominated) reservoirs, and hot water (liquid-dominated) reservoirs. Dry steam reservoirs are rare but highly efficient at producing electricity. The Geysers in California is the largest and best known dry steam reservoir. Here, steam is obtained by drilling wells from 7,000 to 10,000 feet deep. In a dry steam reservoir, the natural steam is piped directly from a geothermal well to power a turbine generator. The spent steam (condensed water) can be used in the plant's cooling system and injected back into the reservoir to maintain water and pressure levels. Hot water geothermal reservoirs are the most common type. In a liquid-dominated reservoir, the hot water has not vaporized into steam because the reservoir is saturated with water and is under pressure. To generate electricity, the hot water is piped from geothermal wells to one or more separators where the pressure is lowered and the water flashes into steam. The steam then propels a turbine generator to produce electricity. The steam is cooled and condensed and either used in the plant's cooling system or injected back into the geothermal reservoir.

A binary cycle power plant is used when the water in a hot water reservoir is not hot enough to flash into steam. Instead, the lower-temperature hot water is used to heat a fluid that expands when warmed. The turbine is powered from the expanded, pressurized fluid. Afterwards, the fluid is cooled and recycled to be heated over and over again. 5. Geothermal Energy Production and Economics Geothermal energy is put to work in many places around the world. The best known geothermal energy sources in the United States are located in western states and Hawaii. Some moderately hot geothermal resources also exist in the Dakotas, along the Atlantic coast, and in Arkansas and Texas. Someday we may be able to use these resource too. Most geothermal energy is produced in four states--California, Nevada, Utah, and Hawaii. Today the total installed capacity of geothermal power plants in the United State is 3,200 megawatts (MW) That's the energy equivalent of three nuclear power plants. American geothermal power plants range in size from a few hundred kilowatts to more than 130 megawatts.

In 1994, geothermal energy produced 18 billion kilowatt hours (kWh) of electricity, or 0.3 percent of the electricity used in this country. Still, this was enough to serve the electrical energy needs of over three million households. California gets six percent of its electricity from geothermal energy, more than any other state. Geothermal supporters say geothermal energy production will grow in the 1990s despite the fact that geothermal energy production peaked in 1987 and has since declined. Geothermal supporters say at least 400 MW more capacity is planned for the next five years and estimate that geothermal energy could provide 10 percent of the electrical capacity of the western United States by the turn of the century. Economics of Geothermal Energy Geothermal power plants can produce electricity as cheaply as some conventional power plants. It costs 4.5 to seven cents per kWh to produce electricity from hydrothermal systems. In comparison, new coal-fired plants produce electricity at about four cents per kWh. Initial construction costs for geothermal power plants are high because geothermal wells and power plants must be constructed at the same time.

But the cost of producing electricity over time is lower because the price and availability of the fuel is stable and predictable. The fuel does not have to be imported or transported to the power plant. The power plant literally sits on top of its fuel source. Geothermal power plants are also excellent sources of baseload power. Baseload power is power that electric utility companies must deliver all day long. Baseload geothermal plants sell electricity all the time, not only during peakuse times when the demand for electricity is high. Until recently, utilities were required to buy the least-cost electricity, without regard to environmental impacts. Federal and state energy and environmental agencies are studying ways to give preference to nonpolluting energy sources such as geothermal energy. 6. Geothermal Energy and the Environment Geothermal energy is a renewable energy source that does little damage to the environment. Geothermal steam and hot water do contain naturally occurring traces of hydrogen sulfide (a gas that smells like rotten eggs) and other gases and chemicals that can be harmful in high concentrations. Geothermal power plants use "scrubber" systems to clean the air of hydrogen sulfide and the other gases. Sometimes the gases are converted into marketable products, such as liquid fertilizer.

Newer geothermal power plants can even inject these gases back into the geothermal wells. Geothermal power plants do not burn fuels to generate electricity as do fossil fuel plants. Geothermal power plants release less than one to four percent of the amount of carbon dioxide (C02) emitted by coal plants. Emissions of sulfur compounds from motor vehicles and fossil fuel plants are also major contributors to acid rain. Geothermal power plants, on the other hand, emit only about one to three percent of the sulfur compounds that coal and oil-fired power plants do. Well-designed binary cycle power plants have no emissions at all. Geothermal power plants are compatible with many environments. They have been built in deserts, in the middle of crops, and in mountain forests. Geothermal development is often allowed on federal lands because it does not significantly harm the environment. Before permission is granted, however, studies must be made to determine what effect a plant may have on the environment. Geothermal features in national parks, such as the geysers and fumaroles in Yellowstone and Lassen National Parks, are protected by law, so geothermal energy is not tapped in these areas.

Geothermal Energy in Developing Countries and the MDGs - United Nations University Geothermal Energy in Developing Countries and the MDGs Ingvar Birgir Fridleifsson and Málfrídur Ómarsdóttir Hellisheidi Geothermal Power Plant (Iceland). UN Photo/Eskinder Debebe The United Nations designation of 2012 as the Year of Sustainable Energy for All, coupled with the UN Secretary-General’s launch of his Sustainable Energy for All initiative, arguably set high expectations for energy achievements last year. According to the International Energy Agency (IEA), the year indeed saw a “new focus, new commitments and new actions towards a goal of achieving universal energy access by 2030”. But despite advancements and this new focus, 1.3 billion people today still do not have access to modern energy sources; double that number rely on wood, coal, charcoal or animal waste for cooking, thus exposing themselves to harmful smoke. A key factor in improving standards of living to achieve the Millennium Development Goals (MDGs), while at the same time ensuring environmental sustainability, is making clean energy widely available and, more importantly, affordable.

This is echoed by the World Energy Council’s (WEC) development of a framework to help address the challenges of energy sustainability, the WEC’s definition of which “is based on three core dimensions — energy security, social equity, and environmental impact mitigation”. Geothermal is a clean and renewable energy source. Almost 70 percent of the countries where geothermal utilization has been recorded are developing or transitional countries. The potential for geothermal energy use to improve living standards in those countries is thus very high. However, geothermal has high upfront investment costs. Therefore, in order to attain the MDGs and improve poverty conditions globally, much effort is needed to increase capacity building in renewable energy technologies like geothermal in developing countries. For though the technologies for exploiting the main renewable energy sources — hydro, biomass, wind, geothermal, solar and wind — have been developed, the experience is mainly confined to industrialized countries. World energy sources Over the coming years, rapid population growth is expected in the global south, while populations in developed countries will diminish as a share of the world’s total.

Consequently, recent forecasts project that by 2040 energy demand in the developing world will rise by 65 percent (compared to 2010), which is twice the increase foreseen for developed countries. When assessing future global energy needs, it therefore is essential to establish which energy services are best suited to supporting the MDGs, and to look at the roles different forms of energy can play in providing these services to reinforce human development and to combat climate change in the most practical and affordable way. It is also important to consider that economic development over the next century will seemingly be constrained less by geological resources than by environmental concerns, and financing and technological constraints. Oil and gas will continue to be important energy sources, but renewable energy is on the rise. In its World Energy Outlook 2012, the IEA notes that “a steady increase in hydropower and the rapid expansion of wind and solar power has cemented the position of renewables as an indispensable part of the global energy mix”. By 2035, the IEA predicts , renewable energy will account for almost one-third of total electricity output.

With annual consumption of primary energy in the world currently at about 510 exajoules, there is no question that the technical potential (how much energy can be produced, independent of cost) of renewable energy is sufficiently large to meet future world energy requirements, as shown in Table 1. Table 1: Ranges of technical potential (yearly availability) of renewable energy sources Source Source: IPCC (2011). Note: EJ = exajoules. However, the question is: How large a part of the technical potential can be harnessed in an economically, environmentally and socially acceptable way? That will probably vary between the energy sources. In favour of geothermal The number of hours a power plant can produce per 24-hour period (i.e., the capacity factor) varies quite widely depending on the renewable source . The capacity factors are: geothermal energy, 72 percent; bioenergy, 55 percent; hydropower, 44 percent; wind energy, 23 percent; and solar energy, 13 percent.

Not only is the capacity factor of geothermal by far the highest, and not dependent on weather conditions, but geothermal has an inherent storage capability and can be run continuously to meet demand during “normal” use periods and at “peak demand” when there is additional need (e.g., on hot days when air conditioners are used more intensively). The need for drilling wells, and constructing power plants, transmission lines and/or insulated pipelines, typically generates high upfront investment costs for geothermal projects. However, they have relatively low operating costs. Geothermal resources have been identified in around 90 countries, and 79 of those have quantified records of geothermal utilization. Electricity is produced from geothermal sources in 24 countries, of which nine obtain 5–26 percent of their national electricity from geothermal. To date, geothermal potential has been developed to a very small extent, and there is ample space for accelerated use of geothermal energy both for direct applications (such as ground-source heat pumps for space and water heating) and for electricity generation. Table 2 lists the top 16 countries in the world in geothermal electricity production and in direct use.

Table 2: Top 16 countries producing and using geothermal energy Geothermal electricity production, 2010 Switzerland 2,143 Sources: Data on electricity from Bertani (2010) and on direct use from Lund et al. (2010). Notes: GWh/year = gigawatt hours per year. The World Bank divides the world’s economies into the following groups: low-income countries (LIC), lower-middle-income countries (LMC), upper-middle-income countries (UMC), and high-income countries (OECD and non-OECD countries). Table 3 shows the number of geothermal countries in each of these groups and also compares that number to the number of the top 16 countries using geothermal for electricity production and direct use (heating and cooling), respectively. When tables 2 and 3 are compared, it is clear that electricity production with geothermal is relatively evenly spread between countries in the different economic categories.

This is in contrast to the top 16 countries making direct use of geothermal, where there are 14 high-income OECD countries, 1 UMC (Turkey) and 1 LIC (China) — the latter actually figuring at the top of the list of direct use. Table 3: Number of countries in different economic categories using geothermal for electricity production and direct use, in 2010 (from Fridleifsson, 2012). Top 16 countries utilizing geothermal Economic category* 1 *As defined by the World Bank. This kind of categorization can signal in which areas lie the most scope for capacity development initiatives in developing countries. Direct utilization During the past decade, the main growth in the direct use sector has been in ground-source heat pumps (GHPs). The reason is, in part, because GHPs can utilize groundwater or ground-coupled temperatures anywhere in the world for space heating and/or cooling. For developing countries, it is this sector in which there is the most potential for development as space and water heating form significant parts of the energy budget in many parts of the world.

(In industrialized countries, 35–40 percent of total primary energy consumption is used in buildings.) However, potential in this sector has remained largely untapped. Apart from China, developing countries have, as yet, shown very limited interest in the installation of GHPs. The direct use of geothermal is very important in many developing and transitional countries, as activities such as washing and bathing, and greenhouse cultivation and fish farming significantly improve people’s quality of life. In addition, tourism is often a substantial source of income at geothermal locations. The direct use of geothermal can even replace fossil fuels in densely populated areas where space heating and/or cooling is needed. The potential is very large because space heating and water heating are significant parts of the energy budget in large parts of the world. Industrialized countries can assist developing countries to achieve their energy goals in this area in the form of both technology transfer and financial support for energy projects. One flexible, market-based mechanism is the Clean Development Mechanism (CDM). The CDM provides the opportunity for developing countries to earn certified emission reduction credits (through sustainable energy projects), which can be sold to industrialized countries to contribute to their emission reduction targets under the Kyoto Protocol.

The CDM can potentially deliver renewable energy to developing countries, with geothermal energy being one of the contributors to the carbon credit market. The potential of carbon finance has attracted several geothermal projects to be registered under the CDM. As of January 2012, two direct use projects are presently under evaluation for eligibility to receive carbon credit revenues. Both are geothermal district heating projects, one in China and one in the Republic of Korea (UNFCCC, 2012). Electricity generation The countries with geothermal fields suitable for electricity production are mainly confined to the active plate boundaries or regions with active volcanoes (see table 2). Many developing countries that have suitable geothermal fields are not able to harness the potential, mainly due to the high investment costs and lack of funds. Even the ones that are able are harnessing only a very small portion of their potential for the same reasons. Figure 1 shows the top 14 countries with the highest percentage share of geothermal in their national electricity production. Geothermal power stations provide about 12 percent of the total electricity generation of Costa Rica, El Salvador, Guatemala and Nicaragua, with potential for harnessing much more.

With the large untapped geothermal resources and the significant experience in geothermal as well as hydro development in the region, Central America may become an international example of how to reduce overall emissions of greenhouse gases in a large region and address the MDGs. Similar developments can be foreseen in the East African Rift Valley and other countries and regions rich in high-temperature geothermal resources. There are examples from many developing countries of how the development of geothermal resources has enabled rural electrification, safe drinking water, schools and medical centres. Such projects are in line with the MDGs. Figure 1: The 14 countries with the highest percentage share of geothermal energy in their national electricity production. Notes: Numbers in parentheses give annual geothermal electricity production in GWh in 2010. The numbers on the x axis (bottom) of the graph show the percentage of the national electricity production that geothermal provides in the respective countries. The number of UNU-GTP graduates from each country is shown to the right of the graph bars. Cooperating for climate and living standards Global warming due to greenhouse gas emissions is one of the major concerns faced by humanity today.

It is an unsettling fact that the poorest people in the world — those who have done the least to bring about changes to the climate — will be most impacted due to a lack of infrastructure, preparedness and resources for adaptation measures. Reducing fossil fuel use, therefore, is essential, and a key solution is to increase the sustainable use of renewable energy sources such as geothermal. More and more countries are now seriously considering how they can use their indigenous renewable energy resources. For instance, most of the EU countries, as well as the United States and Canada, already have some geothermal installations. However, with limited economic resources, mitigation of climate impacts through a reduction of CO2 emissions has not been among the top priorities of developing nations. This is why it is imperative for industrialized countries to make significant contributions by assisting developing countries in this field. Capacity building and the transfer of technology are key issues in the sustainable development of renewable energy resources. Many industrialized and developing countries have significant experience in the development and operation of renewable energy installations for direct use and/or electricity production. It is important that they share that knowledge with newcomers in the field.

An example of how capacity building in renewable energy technologies in developing countries can be done effectively is the innovative training programme for geothermal energy professionals developed in Iceland under the United Nations University. With strong international cooperation and support from industrialized countries, geothermal energy can play a great part in helping developing nations to achieve the MDGs by simultaneously battling climate change and improving living standards. Geothermal provides energy services from a clean source, is secure, and is free from fuel price fluctuations, thus increasing the amount of financial resources available for economic development and the attainment of the MDGs. RELATED ARTICLES Geothermal | energy4me Geothermal Geothermal Geothermal energy comes from the heat stored in the Earth’s core, about 4,000 miles/ 1,609 kilometers below the surface, and heat from the sun warming the Earth. The word geothermal originates from the Greek words geo (earth) and therme (heat). The ground is a good insulator and stores the heat as energy. Pipes are run through a large area several feet underground. Water is heated as it passes through these pipes. New drilling technologies are being researched and developed to capture the heat in deeper areas.

How Geothermal Energy is Formed Magma (layers of melted rock from the Earth’s crust) deep in the Earth’s core heats nearby rock and rainwater that has seeped into the ground. Some of this hot water reaches the Earth’s surface in the form of geysers or hot springs. But most stays trapped in porous rocks and cracks underground in what are called geothermal reservoirs. Geothermal specialists drill into these reservoirs to access the hot water and steam and use it to generate electricity at geothermal power plants. The heated water and steam produces enough power to spin turbine generators that make electricity. Geothermal heat pumps use the Earth’s relatively stable underground temperature to heat and cool buildings with very little energy use or environmental impact. The pumps, which use pipes buried next to buildings, circulate water or other liquids to either heat the buildings using energy from the Earth’s crust or cool the buildings by pulling heat from them and transferring it to the Earth. This form of heating and cooling is used in the US, Sweden, Romania, Japan and other countries around the globe. History of Geothermal Energy People have used geothermal power for thousands of years. The ancient Romans used geothermal water for medicinal purposes, from bathing in hot springs to treating skin ailments.

Native Americans and New Zealand’s Maori people have used the Earth’s hot water for cooking for centuries. In the last 50 years, people have improved the techniques and technology used to harness geothermal power for electricity and heating. 10,000+ years ago – Ancient peoples use hot springs or bathing and heating. 1904 – The first dry steam geothermal power plant was built in Laderello in Tuscany, Italy. The Larderello plant today provides power to about 1 million households. 1922 – The first geothermal power plant in the United States produces 250 kilowatts, capable of lighting area buildings and streets. 1960s – The United States’ first large-scale industrial geothermal energy power plant is built, producing 11 megawatts of geothermal electricity. 1972 – Deep well drilling technology improvements led to deeper reservoir drilling and to access to more resources. 1974 – Scientists begin to develop the first hot dry rock (HDR) reservoir at Fenton Hill, N.M. An HDR power facility was tested at the site in 1978 and started to generate electricity two years later.

1982 – Geothermal (hydrothermal) electric generating capacity reached a new high of 1,000 megawatts. 1991 – The world’s first magma exploratory well was drilled in the Sierra Nevada Mountains to a depth of 7,588 feet. 1995 – Worldwide geothermal capacity reaches 6,000 megawatts. At Empire, Nevada, a food-dehydration facility processes 15 million pounds of dried onions and garlic a year, using geothermal resources. A DOE low-temperature resource assessment of 10 Western states identifies nearly 9,000 thermal wells and springs and 271 communities with a geothermal resource greater than 50ºC. 2006 – The US geothermal industry becomes a $1.5 billion a year business that involved electricity generation and thermal energy in direct use such as indoor heating, greenhouses, food drying and aquaculture. 2008 – Idaho’s first commercial geothermal power plant begins operating. Today – Geothermal power is generated in more than 20 countries.

While it currently makes up less than 1% of the world’s energy, geothermal power is on the rise, with six new plants going online in the United States in 2009. Uses for Geothermal Energy Geothermal energy can be used directly to: heat buildings aid aquaculture, such as breeding fish spin a turbine to generate electricity Stable temperatures near the surface of the Earth can also be used to heat and cool buildings. Creative Uses for Geothermal Energy Geothermal energy is also used creatively all over the world. Hot springs are used in health spas to relieve sore muscles, and geothermal water is used to heat buildings. In some cold climates, geothermal water is routed under sidewalks and roads to keep them from icing up in the winter! Demand for Geothermal Energy More than 20 countries around the world use geothermal power in some capacity. The countries currently producing the most electricity from geothermal reservoirs include the US, New Zealand, Italy, Iceland, Mexico, the Philippines, Indonesia and Japan. These natural reservoirs can be found in places where magma has risen near the Earth’s surface (and where it has even broken through the surface in the form of lava).

Geothermal heat pumps can be used virtually anywhere, since the temperature just under the Earth’s surface stays relatively constant everywhere. Technology is being developed to expand the use of geothermal energy. For example, many areas of the planet sit atop hot dry rock—no water, but plenty of heat. Scientists are working on “ enhanced geothermal systems ” that would pump water into this rock, break it up and produce steam to power turbines and produce electricity. And as advanced drilling capabilities are discovered, more and more geothermal energy may become available. Potential for geothermal energy also lies in oil and gas fields already in production. Many existing oil and gas reservoirs contain hot water that could be used to produce electricity and fuel at the same time! In the US, 2009 legislation allocated $400 million for the Department of Energy’s Geothermal Technologies Program, which will go toward exploring new geothermal capabilities for the future.

FAO - News Article: For developing countries, new opportunities in geothermal energy For developing countries, new opportunities in geothermal energy New report explores uses of natural heat for food production and processing For developing countries rich in geothermal activity, using the earth's heat offers new possibilities for agriculture 7 April 2015, Rome -- Geothermal energy, the flow of heat energy radiating from the earth’s core, provides unique opportunities for cost efficient, sustainable food production and processing in developing countries, says a new report published by FAO today. In some developing economies, as much as half of all food produced is lost post-harvest – that's due in part to a lack of affordable energy for food processing, according to “Uses of Geothermal Energy in Food and Agriculture” . This makes the use of heat energy for drying foods, pasteurizing milk and sterilizing produce especially interesting for developing countries, where increased food processing can give a boost to food security. Food drying can prolong the shelf life of nutritious foods like fish and vegetables and make them available year-round, including in times of drought. Geothermal energy is also a prime source for heating greenhouses, soils, and water for fish farming, the report says.

Developing countries that have much to gain from harnessing heat energy for agriculture include those in the so-called Ring of Fire along the Pacific Plate, such as Mexico, Indonesia, the Philippines and various countries along the Pacific Coast of South America. So do Ethiopia and Kenya in Africa’s Rift Valley, and transitioning economies in Eastern Europe, including Romania and Macedonia. The case for geothermal “It’s an energy source that’s renewable, clean and low-cost once you’ve made the initial investment to harness it,” says Carlos da Silva, Senior Agribusiness Economist in FAO’s Rural Infrastructure and Agro-Industries Division . “By using a clean energy source, you’re not only addressing cost but also the environmental impacts of food production and processing,” according to da Silva. Agriculture both consumes energy and emits greenhouse gases that contribute to global warming. Research suggests that using geothermal heating for greenhouses decreases fungus infections and cuts fuel costs by up to 80 percent, providing significant savings to operating budgets.

And while oil and gas can be costly and scarcely available in parts of the world, the estimated 42 million megawatts (MW) of power that radiates from the earth’s 5000-degrees-celsius core won’t run out for billions of years. “Geothermal energy for agriculture can be done even at small-scales and can significantly contribute to income generation, providing employment and improving food and nutrition security in developing countries,” adds Divine Njie, AGS Deputy Director and co-editor of the report. From electricity to agriculture Worldwide, 38 countries currently use geothermal energy for direct application in agricultural production and some 24 countries harness it to generate electricity, with Iceland, Costa Rica, El Salvador, Kenya, New Zealand and the Philippines deriving more than 10 percent of their electricity needs from natural heat sources. Of the 23 developing countries that are using geothermal, the majority currently apply it to space heating and recreational purposes like bathing only, leaving its significant potential for agricultural uses untapped. Still, successful geothermal agricultural projects are underway in just under half of those countries, including in aquaculture, farming and processing.

Success stories A government-funded project in Algeria is supporting the building of fish farms that utilize hot water from drill holes to heat Tilapia ponds. The three farms built so far produce an average 1700 tonnes of Tilapia per year. Iceland – which derives most of its heating and electricity from geothermal power -- has been a leader in the use of geothermal power for agriculture since the 1920s. In addition to greenhouse heating, some 20 companies across Iceland dry between 2000 and 4000 tonnes of fish each year, while an emerging industry for geothermal pet food drying is currently producing 500 tonnes of animal feed annually. Challenges Start-up costs remain the main barrier to developing countries’ exploring geothermal energy uses on a larger scale, making it all the more necessary for governments to take a leading role in attracting investment and creating policy environments that support the sector, according to FAO. “You can invest in ground proofs and not find any economically viable heat sources,” says da Silva, adding that even in successful cases, selling energy at a low cost can be a challenge when having to recover start-up costs.

Nevertheless, various projects outlined in the FAO report show that these obstacles are not insurmountable and investments worth exploring in the larger effort of making agriculture more sustainable. Indeed, “the FAO report also shows that there are direct-use opportunities which do not require high-cost exploration and exploitation”, says Njie. An example of geothermal energy use: Drying chilies and garlic in Thailand Chillies and garlic are highly popular in Thailand, where people eat them both fresh and dried. In one project there, waste heat from a geothermal power plant is being used to dry these important food products in compartments that can hold 450 kg of chilies or 220 kg of garlic at a time. The required air temperatures are 70 °C for chillies and 50 °C for garlic. The total energy consumed is just 13.3 megajoules per kilogram of water evaporated for chillies, and 1.5 mj/kg of water for garlic. This type of dryer has relatively low running costs and can be used in any weather conditions. Share this page

Question: What country heats most of its buildings with geothermal energy?
Answer: Iceland