Altprofits

Geothermal Energy - How it works

Applications of Geothermal Energy

Data and Statistics 

Geothermal Energy Status and Trends 

Geothermal Energy Projects & Companies

Geothermal Energy - Research Efforts

Geothermal Energy - Barriers

Introduction

Geothermal energy is energy extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface. It has been used for space heating and bathing since ancient times, but is now known for both heating as well as for generating electricity.

Geothermal power is cost effective, reliable, and environmentally friendly, but has previously been geographically limited to areas near tectonic plate boundaries. Recent technological advances have significantly expanded the range and size of viable resources, especially for direct applications such as home heating.

Geothermal Potential

Geothermal energy has shown   signs of considerable growth over the last few years. Global geothermal   installed capacity (for electricity) has escalated from 7,972 MWe in 2000 to   around 9,700 MWe in the year 2007 (generating about 0.3% of global   electricity demand) and is expected to reach around 13,600 MWe by 2012, with   a CAGR of 7%.

The US continues to be the world leader in terms of total installed capacity of geothermal energy and the generation of electric power from geothermal energy.

By mid 2008, worldwide installed capacity of geothermal energy for electricity generation had crossed the 10 GW mark. Worldwide, about 30 GW of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications. If heat recovered by ground source heat pumps is included, the non-electric use of geothermal energy is estimated at more than 100 GWt (gigawatts of thermal power) and is used commercially in over 70 countries.

Geothermal (ground-source) heat pumps (GHPs) have become a major growth area of geothermal energy use in the United States, Canada and Europe. The number of GHPs has steadily increased over the past 10 years. By 2008, an estimated 800,000 equivalent 12 kW (3.4 ton) units have been installed in the United States and about 50,000 in Canada.

Geothermal Locations

Geothermal energy supplies more than 10,000 MW to 24 countries worldwide and now produces enough electricity to meet the needs of 60 million people. The Philippines, which generates 23% of its electricity from geothermal energy, is the world’s second biggest producer behind the U.S. Geothermal energy has helped developing countries such as Indonesia, the Philippines, Guatemala, Costa Rica, and Mexico. The benefits of geothermal projects can preserve the cleanliness of developing countries seeking energy and economic independence, and it can provide a local source of electricity in remote locations, thus raising the quality of life.

Iceland   is widely considered the success story of the geothermal community. The   country of just over 300,000 people is now fully powered by renewable forms   of energy, with 17% of electricity and 87% of heating needs provided by   geothermal energy. Iceland   has been expanding its geothermal power production largely to meet growing   industrial and commercial energy demand. In 2004, Iceland was reported to have   generated 1465 gigawatt-hours (GWh) from geothermal resources; geothermal   production is expected to reach 3000 GWh in 2009.

According to some experts (Stefansson (2005), for instance), the most likely value for the technical potential of geothermal resources suitable for electricity generation is 240 GWe (This is about 5% of total global installed capacity for electricity in 2008). Theoretical considerations, based on the conditions in Iceland and the USA, reveal that the magnitude of hidden resources is expected to be 5-10 times larger than the estimate of identified resources. If this is the case for other parts of the world, the upper limit for electricity generation from geothermal resources is in the range of 1-2 TWe.

Prominent countries worldwide with geothermal potential:

• Russia
• Japan
• Eastern China
• Himalayan      Geothermal Belt
• The Philippines
• Indonesia
• New Zealand
• Canada
• United States
• Mexico
• Central      American Volcanic Belt
• Andean      Volcanic Belt
• The Caribbean
• Iceland and other Atlantic       Islands
• Northern Europe
• Eastern Europe
• Italy
• Eastern and      Southern Mediterranean
• East Africa Rift System

Geothermal Energy - How it works

There are three main types of geothermal energy in use currently:

• Direct  Use Heating Systems – these use hot water from springs or reservoirs near      the earth’s surface.
• Electricity      from Geothermal Energy – Electricity generation in power plants require      water or steam at very high temperature. Geothermal power plants are      generally built where geothermal reservoirs are located within a mile or      two of the surface. Thus, these plants use the geothermal heat for      generating steam that run a turbine to produce electricity.
• Geothermal      Heat Pumps – These heat pumps use stable temperatures under the ground to heat      and cool buildings.

Applications of Geothermal Energy

• Direct Use Heating Systems – these use hot water from springs or reservoirs near the earth’s surface.
• Electricity from Geothermal Energy – Electricity generation in power plants require water or steam at very high temperature. Geothermal power plants are generally built where geothermal reservoirs are located within a mile or two of the surface. Thus, these plants use the geothermal heat for generating steam that run a turbine to produce electricity.
• Geothermal Heat Pumps – These heat pumps use stable temperatures under the ground to heat and cool buildings. 

Data and Statistics 

Geothermal Energy Status and Trends 

The total installed capacity for electricity worldwide is about 5000 GW (2009. AltProfits estimate). It is considered possible to produce up to 8.3% of the total world electricity with geothermal resources, serving 17% of the world population. Thirty nine countries (located mostly in Africa, Central/South America, and the Pacific) can potentially obtain 100% of their electricity from geothermal resources (Dauncey, 2001).

Geothermal energy currently provides approximately 0.4% of the world global power generation, with a stable long term growth rate of 5%.

The world geothermal electricity production increased by 16% from 1999 to 2004, with an annual growth rate of 3% (In the same period, application of direct use geothermal increased by 43%, with an annual growth rate of 7.5%). The rate of growth of geothermal energy for electricity production has however increased since then; geothermal capacity for electricity is estimated to increase by an annual rate of about 7% for the period 2007-2013.

The United States is the world’s largest producer of geothermal power. Next to the United  States, the Philippines is the second largest producer of geothermal power in the world. Historically, among the country's indigenous resources, it is the largest supplier of electricity and will continue to be a significant source of energy for the country. Based on 2001 data, geothermal generation accounted for 22.2 percent of the power mix for the Philippines, and this share has increased further since then.

GEA’s May 2007 Interim Report: Update on World Geothermal Development named the countries producing geothermal electricity:

• 21 Countries      Generating Geothermal Power in 2000: Australia, China, Costa Rica, El      Salvador, Ethiopia, France (Guadeloupe), Guatemala, Iceland, Indonesia,      Italy, Japan, Kenya, Mexico, New Zealand, Nicaragua, Philippines, Portugal      (Azores), Russia, Thailand, Turkey, United States
• 3 Countries Added      Power Generation by 2005 (for a total of 24): Austria, Germany,      Papua New Guinea
• 22 Potential      New Countries by 2010 (to make a total of 46): Armenia, Canada, Chile,      Djibouti, Dominica, Greece, Honduras, Hungary, India, Iran, Korea, Nevis,      Rwanda, Slovakia, Solomon Islands, St. Lucia, Switzerland, Taiwan,      Tanzania, Uganda, Vietnam, Yemen

Geothermal electricity generation is likely to expand. According to the International Geothermal Association (IGA) in IGA News 72 (April–June 2008), total global geothermal capacity is expected to rise to 11 GW by 2010.

In addition to large power generation, geothermal is also used for direct use purposes worldwide. Geothermal energy is used directly for a variety of purposes, including space heating, snow melting, aquaculture and more.

Source: http://www.geo-energy.org/aboutGE/currentUse.asp#world

In 2005, 72   countries reported using geothermal energy for direct heating, providing more   than 16,000 MW of geothermal energy.

Global Installed Capacity for Geothermal Electricity Production from 1975 Up To End of 2007 and Forecast to 2010

Source: GHC BULLETIN, SEPTEMBER 2007 

Geothermal Future Trends

World Installed Capacity, Electricity Production and Capacity Factor of Geothermal Power Plants 1995 - 2005 and Forecasts for 2010 – 2050

 Source: International Geothermal Association

Countries that Could Meet 100 Percent of Electricity Demand with Geothermal Energy 

¹ Assuming a capacity factor of 90 percent, typical of new geothermal power plants.

Source: Compiled by Earth Policy Institute from Karl Gawell et al., Preliminary Report: Geothermal Energy, the Potential for Clean Power from the Earth (Washington, DC: Geothermal Energy Association, 7 April 1999); and others such as the World Population Prospects: The 2006 Revision Population Database, The World Factbook, U.S. Department of Energy, Energy Information Administration

Geothermal energy as an energy source is prominent in United States, Philippines, Italy, Indonesia, Japan, Mexico, and New Zealand, with additional capacity in several other countries. Iceland gets one-quarter of all its power from geothermal.

Geothermal heating plants (including building-level heat pumps) are now present in over 70 countries. Most of the geothermal power capacity in industrialized countries exists in Italy, Japan, New Zealand, and the United States. Power plants were under construction in several countries. Geothermal direct-heat utilization is growing much faster than geothermal power, with recent growth rates of 30-40% annually. About half of the existing geothermal heat capacity exists as geothermal heat pumps (also called ground-source heat pumps), which are used for both heating and cooling. Over 2 million ground-source heat pumps are used worldwide.

Iceland leads the world in direct heating, supplying some 85% of its total space-heating needs from geothermal.

Source: GHC Bulletin, September 2007

Geothermal Energy - Research Efforts

Geothermal Technology Advancements

Estimated World Geothermal Electricity Potential with Present Technology with Technology Improvement

Source: http://www.ieagia.org/documents/LongTermGeothermElecDevelopWorldBertanioffenburg23Feb09.pdf

As seen from the chart above, with technology improvement, the total electicity generation potential from geothermal increases 100%. The technology improvements are likely to come primarily from innovative concepts such as enhanced geothermal.

Until recently, geothermal power systems have only exploited resources where naturally occurring water and rock porosity is sufficient to carry heat to the surface. However, the vast majority of geothermal energy within drilling reach is in dry and non-porous rock.  Enhanced Geothermal Systems (EGS) are a new type of geothermal power technologies that do not require natural convective hydrothermal resources. EGS technologies "enhance" and/or create geothermal resources in this hot dry rock (HDR) through hydraulic stimulation.

Following are some of the research projects on geothermal energy:

1. Enhanced Geothermal Systems

Geothermal wells in Southern Oregon town of 20,000 mark one of the nation's most ambitious uses of a green energy resource with a tiny carbon footprint, and could serve as a model for a still-fledgling industry that is gaining steam with $338 million in stimulus funds and more than 100 projects nationwide.

A technology known as EGS, for Enhanced Geothermal Systems with support, could be producing 100 gigawatts of electricity equivalent to 1,000 coal-fired or nuclear power plants by 2050, and has the potential to generate a large fraction of the nation's energy needs for centuries to come.

One form of EGS involves drilling thousands of feet down to reach hot rock, pumping water down to fracture the rock to create reservoirs, and then sending down water that will come back up another well as hot water or steam that can spin a turbine to generate electricity.

The system can be dropped in practically anywhere that hot rocks are close enough to the surface to make drilling economical. The major problem with EGS is the potential to create earthquakes.

Pumping water into the ground to open numerous tiny fractures in the rock for a reservoir makes the earth move — what scientists call induced seismicity. Earthquakes stopped an EGS project in the middle of Basel, Switzerland, last year, and an international protocol has been developed for monitoring and mitigating earthquake problems.

The centerpiece is $25 million to AltaRock Energy, Inc., of Seattle and Sausalito, Calif., to demonstrate EGS can produce electricity economically and without producing earthquakes just outside the Newberry Craters National Monument in central Oregon. Investors, Google among them, put in $60 million.

The city is stepping beyond heat to electricity, building a geothermal generator like the one at Oregon Institute of Technology with the help of an $816,000 stimulus grant.

(March 2010)

Source: http://climatesolutions.org/news/oregon-town-uses-geothermal-energy-to-stay-warm

2. The KAPS technology

Kaldara Green Energy, a Norwegian manufacturer of geothermal electrical power production equipment has developed KAPS ('Kaldara Power System') geothermal power plant.

Features & Benefits

• KAPS are container based 5 MW geothermal power plants that can operate stand-alone and are also capable of working together in power farms.
• Because of small sizes KAPS can be more easily adopted to the environment than large power plant structures. KAPS on-surface units can be used for all types of Wet/Dry and Binary/Flash geothermal Systems.
• The containers could be placed hidden into hillside areas or placed underground to avoid offensive structures in the environment, in full reconciliation with environmental groups. Using KAPS could therefore extend the reach of environmentally friendly exploitation for electrical power production worldwide.
• With the KAPS approach, boreholes can be harnessed at an earlier stage or within weeks after drilling is completed, whereas the conventional approach requires borehole evaluation period of 3-5 years before power production. Thus the earlier income alone can in most cases pay majority of the KAPS investment.
• KAPS units can be organized in power farms of same capacity as large geothermal power plants and even larger.
• Outstanding efficiency is only to be compared with 30-50 MW highly advanced conventional geothermal power plants. By advanced technology and size standardization KAPS compares in cost effectiveness pr MW with the larger conventional geothermal power plants.
• The KAPS technology lowers barriers of entry into the realm of geothermal power production, until now restricted by the number of production boreholes necessary to make sufficient energy for an economical version of conventional geothermal power plants.
• KAPS power plants are factory installed in containers. This flexible approach allows for reallocation in case of failing yield of boreholes.

Source: http://global-renewables.com/a389119-green-energy-made-feasible-with-innovations.cfm

Geothermal Energy - Barriers

The key problems of geothermal energy are listed below:

• Constraints on locations – One key problem with geothermal is that there are not many places where you can build a geothermal power station.

• Drilling related problems - Drilling very deep holes can pose problems, because this can cause tremors in the earth and can be hard to do, especially if drilling is done through hard rocks.
• Water loss - One problem is that some water used in geothermal energy systems gets lost, as evidenced by the results of various tests showing that only a third of the water comes back to the surface.
• Water pollution - Hot water coming from geothermal sources can also contain trace amounts of dangerous elements such as arsenic, mercury, and antimony. In case water containing these elements is disposed of into lakes, rivers, or other bodies of water, it can make the water unsafe to drink.

• Risk of other pollutants – In some geothermal locations, hazardous gases and minerals may come up from underground, and can be difficult to safely dispose of. Some events at locations near geothermal plants suggest that the plants could contribute to increased levels of H₂S near the location.

Financial Challenges:

One of the most important aspects is the higher costs of the provision of heat and/or electricity from low enthalpy geothermal energy compared to energy production from fossil fuel energy.

In most countries, geothermal electricity production faces huge financial challenges. The generation of electricity from geothermal resources is not competitive without significant financial support under the existing energy price conditions.

Private financing of geothermal power and/or CHP plants can be achieved through credits from banks or other financing institutions. However, such credits from commercial companies with acceptable conditions are not easy to obtain due to given technical and non-technical uncertainties and challenges due to e.g. changes in the economic efficiency of the plant.

Small players continue to find it extremely difficult to attract financing for their projects.

Other Challenges:

• Dropping electricity prices could also hit geothermal developers, despite the increase in financing cost, effectively hitting the return for players and investors.

• Current press on EGS and earthquake fears could reflect negatively on the overall sector and also affect conventional geothermal projects. Therefore the industry still has to work on promoting and educating the general public, politicians and the market place.

• The short term for some of the stimulus legislation elements are extremely short for geothermal developers and will be too short for the majority of projects. This applies particularly to loan guarantees.

• Oil and gas sector players entering the market, which could prove competition for some players in the market.

• The increased number of geothermal projects also means an increase in competition for rare expertise and personnel, meaning effectively a shortage in people.

• The US is missing mitigation tools covering drilling risk.

Case studies

Geothermal District Heating Systems at Klamath Falls, Oregon (USA)

Location: Klamath County, Oregon

Owner: City of Klamath Falls

Capacity: 16 MBtu/hr (4.7 MW)

Temperature: 210°F (99°C)

Startup date: March 20, 1984

Developer: the city of Klamath Falls

Cost: $ 2,580,000 (for the initial construction)

The city of Klamath Falls, Oregon, is located near a geothermal resource that has provided heating for homes, businesses, schools and institutions for many years.

The district heating system was constructed in 1981 to initially serve 14 government buildings and 120 residents with some limited capacity for expansion. Total cost of the project was $2.58 million, consisting of 65% federal funds and the remainder from city, county and state funds.

The district heating system was originally designed for a thermal capacity of 20 million Btu/hr (5.9 MW thermal). At peak heating, the buildings on the system utilized only about 20% of the system thermal capacity and revenue from heating those buildings was inadequate to sustain system operation. This led the city to begin a marketing campaign in 1992 to add more customers to the system.

The city developed a flat rate for heat customers, which for most is about 50% of the costs for gas heat. New customers are connected directly into the distribution system with district loop water used as the building heating medium. This eliminates the customer’s need for a heat exchanger, thus reducing potential retrofit costs to participate.

As well as being used to heat buildings, geothermal water is also piped under Klamath City’s roads and sidewalks to keep them from icing. The snowmelt systems have been incorporated into a downtown redevelopment project along Main Street which started in 1995. The heated sidewalk and crosswalk area currently served by the systems is over 60,000 ft2.

Feather River College Geothermal Heat Pump System (USA)

Quincy, California

Location: Quincy, California

Owner: Feather River College

Temperature: 190°F (88°C)

Startup date: 1998

Developer: Princeton Development

Cost: $512,000

Feather River College in Quincy, California, significantly cut their energy costs by switching from antiquated air conditioners to a geothermal heat pump (GHP).

Designed and engineered through a partnership with the California Energy Commission (CEC) and private groups, the innovative GHP project has enabled the college to significantly reduce its heating and cooling energy costs. The GHP was installed in January 1998 by Heat Transfer Systems.

To cut $190,000 of annual heating and cooling costs, the college decided to employ GHP technology to four buildings containing a library, classrooms, offices and a gymnasium. The 135-ton system relies on 24 individual GHPs strategically located throughout the buildings. The GHPs allow separate areas to be heated and/or cooled simultaneously and independently, based on need.

In 1996, Princeton Development Corporation, Guttman & Blaevoet and engineers and technical experts from the CEC assisted the college administration with choosing the GHP system.

Princeton Development underwrote 100 percent of the project's costs. Funding for the project came from various sources, including the CEC, the California Community Colleges, the National Geothermal Heat Pump Consortium, long-term debt financing and third party equity financing. As a Geothermal Heat Pump Demonstration Project, the College received assistance in engineering, commissioning and monitoring of the ground loop installations.

The entire project cost was $512,000, roughly $218,000 more than the base price of air source heat pumps. The in-ground heat exchange loop is responsible for most of the cost differential that will be paid back many times over during the system's life cycle.

Since its start-up in 1998, the GHP system has saved the college about $50,000 in energy costs each year. The college also benefits from the quieter operation of the GHP system, which is important to their educational environment.