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NexPlan Recycling & Renewable Energy
Geothermal Power | Geothermal Energy
Geothermal power is energy generated by heat stored beneath the Earth's surface or the collection of absorbed heat in the atmosphere and oceans. The name "geothermal" comes from two Greek words: "geo" meaning, "earth" and "thermal" which refers to "heat". Geothermal energy offers a number of advantages over traditional fossil fuel based sources. From an environmental outlook, the energy harnessed is clean and safe. It is also practicable because the hot water used in the geothermal process can be re-injected into the ground to produce more steam. In addition, geothermal power plants are unaffected by the change in weather conditions. Geothermal energy uses steam or hot water in the earth's crust to power turbines or to heat buildings or heat water. The earth's crust contains a vast amount of energy. Hot water from within the earth can heat buildings with no conversion. Geothermal earth energy can provide heating in winter, cooling in summer, and year-round hot water for home use. Geothermal energy has been used for thousands of years in certain places around the world for heating and cooking.
Geothermal power stations are able to provide an excellent source of clean, cheap and simple renewable power. Geothermal energy is one of the best natural energies around. No fuel is used to generate the power, which means the running costs for the plants are very low as there are no costs for purchasing, transporting, or cleaning up of fuels that are used to generate the power. Heating and cooling buildings using geothermal energy is the primary use of the Earth's heat energy. Much energy is placed into moderating the temperature inside buildings, especially during periods of extreme heat or cold. Using geothermal energy as a way of controlling temperatures in buildings is one way to continue to provide that comfort but reduce the use of energy sources that are more harmful to our climate. Geo thermal energy is free and efficiently a renewable resource that does not consume any fuel or produce significant emissions.
One megawatt, which equates to 1 million watts, can meet the power needs of about 1,000 people. The geothermal energy resources used throughout the United States today meet the requirements of 2.8 million households. Geothermal energy today meets the total electricity needs of some 60 million people around the world. Since 2000, geothermal generation has tripled in France, Russia, and Kenya. Countries such as the Philippines, Iceland, and El Salvador generate an average of 25 percent of their electricity from geothermal sources. According to the Geothermal Energy Association, the United States continues to produce more geothermal electricity than any other country, encompassing approximately 32 percent of the world total. In 2005, 72 countries reported utilizing geothermal energy for direct uses, providing over 16,000 MW of geothermal energy. Geothermal energy is used directly for a variety of functions including space heating, greenhouse production, aquaculture, and more. However we have a ways to go in making geothermal energy a mainstream source. According to the International Energy Agency, as of 2008, geothermal power supplies less than 1% of the world's energy.
How is Geothermal Power Produced:
There are three main uses of geo thermal energy. One is direct use and district heating systems, which use hot water from springs or reservoirs near the surface. Electricity generation in a power plant requires water or steam at very high temperature (150-370 degrees Celsius). Geothermal power plants are normally built where geothermal reservoirs are located within a mile or two of the surface. Geothermal heat plants use stable ground or water temperatures near the earth's surface to control building temperatures above ground.
The centre of the earth is around 6000 degrees Celsius, which is easily hot enough to melt rock. Even a few kilometers down, the temperature can be over 250 degrees Celsius. Hot rocks underground heat water to produce steam. Holes are drilled down to the hot region, steam comes up, and then the steam is purified and used to drive turbines, which power electric generators. There may be natural groundwater in the hot rocks anyway, or we may need to drill more holes and pump water down to them. Water is then pumped down an injection well and filters through the cracks in the rocks in the hot region, and comes back up the recovery well under pressure. It then flashes into steam when it reaches the surface. The steam may be used to power a turbo generator, or passed through a heat exchanger to heat water to warm houses.
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 the Pacific Ocean rim.
Geothermal Heating:
Geo thermal heating is a fairly old concept that has gained a new life through advances in modern technology and materials. Geo thermal energy is the use of ground temperatures to heat and cool homes. Geothermal power takes advantage of the inherently stable temperature of the ground. Regardless of temperature fluctuations on the surface of the ground, soil below five feet remains at a fairly constant temperature range of 10-13 degrees Celsius. (50-55 Fahrenheit). During the winter, this temperature can be used to create geothermal heating for a home or building. To produce heat, plastic piping loops are dug into the ground to create a circuit for heat transfer. Depending on the season, liquid is run through the system to exchange heat or cold with the ground and suck up the opposite. The reconstituted liquid is then run through a refrigerant process to produce cold air that it circulated in the home during the hot summer. In winter, the process runs backwards and the cold air in the home is forced into the ground where it circulates and is subsequently compressed. The compression warms the fluids to well over 100 degrees, which is transformed into heat for the home through air ducts.
A geothermal heat pump moves heat into or out of the earth to heat or cool your home. A heat pump is usually an electrically powered system that can heat or cool a space by transferring heat from one place to another. During the heating season, a heat pump gathers heat from the air, ground or water outside the house, and transfers it indoors. In the summer the direction of the heat flow is the opposite, extracting heat from indoors and transferring it outdoors, to provide air conditioning. The heat pump system has three main components. The first component is the ground loop system of polyethylene pipes that extract heat from soil beneath the frost line. In cooling mode, the pipes return heat to the earth. Next, the heat pump furnace unit and distribution system are located inside your home. Heat is transferred from the ground loop system to the furnace unit. Once inside the furnace unit, the heat is moved to the distribution system to heat your home. The system operates in reverse to cool your home. Rural residences and new home construction are ideal for installation of geothermal heat pumps.. They normally have less physical barriers, so installation is more cost-effective. Replacing an older heating system with a geothermal technology may mess up landscaping and is often expensive. Home renovations may also be needed to install the interior geothermal units.
When installed properly, geothermal systems generally require very little repair for over 20 years. It is recommended strongly that a qualified and certified contractor design and install the system and do any major repairs. Any mistake in system design or installation can drastically jeopardize reliability and performance.
Geothermal Power Plants:
There are three geothermal power plant technologies being used to convert hydrothermal fluids to electricity. The conversion technologies are dry stream, flash, and binary cycle. The type of conversion used depends on the whether the fluid is steam or water and its temperature. Dry steam power plants systems were the first type of geothermal power generation plants built. They use the steam from the geothermal reservoir as it comes from wells, and route it directly through turbine/generator units to produce electricity. Flash steam plants are the most common type of geothermal power generation plants in operation today. They use water at temperatures greater than 182°C (360°F) that is pumped under high pressure to the generation equipment at the surface. Binary cycle geothermal power generation plants differ from Dry Steam and Flash Steam systems in that the water or steam from the geothermal reservoir never comes in contact with the turbine/generator units.
The largest group of geo thermal power plants in the world is located in the Geysers, a geo thermal field in California. California has 33 geo thermal power plants that produce almost 90 percent of the geo thermal electricity in the United States. There are also geo thermal power plants in Alaska, Idaho, Hawaii, New Mexico, Nevada and Utah.
As start-up costs for geothermal fall, geothermal energy is gaining favor in Europe with the rapid price increases of oil and greenhouse gas emission worries. Potential areas for geothermal generation capacity are in the northwestern and central western coast of Italy, western part of Turkey, and parts of Portugal, Spain, France and Germany. Australia's government announced AU$50 million ($43 million) in funding for the geothermal industry to help make the technology viable for energy production. In Asia, there are geothermal power plants in Thailand, Philippines and Russia
Advantages to Geothermal Energy:
Geothermal energy does not produce any pollution and produces less carbon dioxide and does not contribute to greenhouse gases. The power stations do not take up much room, so there is not much impact on the environment. By using the Earth's own heat and water, energy can be created that can be used on a small or large scale. This renewable resource is also cleaner and safer than many other types of energy, making it a great type of energy source that is environmentally friendly. Once you've built a geothermal power station, the energy is almost free as no fuel is required. Geothermal energy can provide at least two thirds of the energy required to heat a home. This can lead to savings of 30 to 70 per cent of homeowners heating costs.
In both commercial and residential installations, geothermal heat pump systems typically have lower maintenance costs than conventional systems as all equipment is installed inside the building or underground. This means that there is no outside equipment exposed to weather and vandalism. All refrigerant systems are sealed, similar to household refrigerators. Geothermal systems are very flexible. They can be easily and inexpensively subdivided or expanded to fit building remodeling or additions. In commercial installations, systems can save money by recovering excess heat from building interior zones and moving it to the perimeter of the building. They can also save money by allowing management to isolate and shut down unoccupied areas of the building.
While geothermal systems may be more expensive to install than conventional systems, long-term energy savings can be significant. The payback period for each system will vary depending on the cost of the system and the existing energy expenses. Depending on where you live, you may be able to receive government rebates for installing geothermal systems in your home or business. Many world governments offer incentives to those who switch to green energy technologies including geothermal. Heat pump incentives are available in the U.S., Canada, Australia, The United Kingdom, and many parts of Europe.
Disadvantages to Geothermal Energy:
A huge issue is that there are not many places where you can build a geothermal power station. You need hot rocks of a suitable type, at a depth where we can drill down to them. It is possible that a geothermal site may run out of steam for a long period of time. Hazardous gases and minerals may come up from underground, and can be difficult to safely dispose of as well. Geothermal heating systems for houses use liquid to transfer heat to and from the ground. This liquid is often a refrigerant of some type, which can be toxic geothermal systems. Although prices vary by brand and location, installing a geothermal system in a building or residence will usually cost more than a traditional heating and cooling system. A geothermal system is unique, so if it breaks or has problems, getting it repaired can be difficult and expensive.
To utilize this energy, however, there are capital and operating costs that have to be taken into account. The capital costs are generally somewhat higher than conventional heating systems, but the operating costs are usually significantly lower. Another disadvantage of geothermal heat is that it is extracted from deep within the earth's surface, and it is difficult finding a suitable build location.
Geothermal Energy & the Environment:
There are many different types of energy available to power our world. For years, people have used the power of burning fossil fuels, such as coal to create energy. Recently there has been a shift to using renewable energy resources to create the energy we need. These resources include hydroelectric power, solar power, wind power, biomass energy and geothermal energy. All of these energy sources reduce pollution and global warming emissions, contribute to energy security and stand to benefit our global energy system. The world's energy system has to undergo significant changes in order to urgently meet the demands for modern energy services for the over 2 billion people without access in developing countries while preserving our global climate, ecosystems and human health. Renewable energies can contribute considerably to meeting these needs. Geothermal energy is a renewable energy source and is something we need to utilize more in order to lesson the impact on climate change and global warming.
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