Presented By :-Prateem

Chakraborty(66)Sagar Panja(81)Shubham

Bardhan(98)Department :- EE_2_X

-:INDEX:--:INDEX:- IntroductionIntroduction What is geothermal energy?What is geothermal energy? Power generationPower generation Types of power plantTypes of power plant Area available for plantArea available for plant EconomicsEconomics conditioncondition Advantages and limitationsAdvantages and limitations Environmental impact Environmental impact Present statusPresent status ConclusionConclusion

Introduction

Non-Conventional Energy Source (NECS) which comprise both renewable and non renewable source should play an increasingly important role in the coming periods in view of fast depleting fossil fuel reserves and growing concerns for environment protection.

A geothermal power plant uses the geothermal activity to generate power. This type ofnatural energy production is extremely environment friendly and used in many geothermal hot spots around the globe.

What is geothermal energy ?What is geothermal energy ?Geothermal energy is defined as heat from the Earth. It is a clean, renewable resource that provides energy in around the world in a variety of applications and resources. Although areas with like hot springs are more obvious and are often the first places geothermal resources are used, the heat of the earth is available everywhere, and we are learning to use it in a broaderdiversity of circumstances.

It is considered a renewable resource because the heat emanating from the interior of the Earth is essentially limitless. Accessible geothermal energy from the Earth’s interior supplies heat for direct use and to generate electric energy.

The heat continuously flowing from the Earth’s interior, which travels primarily by conduction, isestimated to be equivalent to 42 million megawatts (MW) of power, and is expected to remainso for billions of years to come, ensuring an inexhaustible supply of energy.

Types of power plantTypes of power plant

All geothermal power plants use steam to turn large turbines, which run electricalgenerators. In the Geysers Geothermal area, dry steam from below ground is used directly in the steam turbines. In other areas of the state, super-hot water is "flashed“ into steam within the power plant, and that steam turns the turbine.

Steam plants use hydrothermal fluidsthat are primarily steam. The steam goes directly to a turbine, which drives a generator that produces electricity. The steam eliminates the need to burn fossil fuels to run the turbine. (Also eliminating the need to transport and store fuels!)This is the oldest type of geothermal power plant. It was first used at Lardarello in Italyin 1904. Steam technology is used today at The Geysers in northern California, theworld's largest single source of geothermal electricity. These plants emit only excesssteam and very minor amounts of gases.

Hydrothermal fluids above 360°F(182°C) can be used in flash plants to make electricity.

Fluid is sprayed into a tank held at a much lower pressure than the fluid, causing some of the fluid to rapidly vaporize, or "flash." The vapor then drives a turbine, which drives a generator.

If any liquid remains in the tank, it can be flashed again in a second tank (double flash) to extract even more energy.

Most geothermal areas containmoderate-temperature water (below 400°F). Energy is extracted from these fluids inbinary-cycle power plants.

Hot geothermal fluid and a secondary (hence, "binary") fluid with a much lower boilingpoint than water pass through a heat exchanger. Heat from the geothermal fluid causes the secondary fluid to flash to vapor, which then drives the turbines.

Because this is a closed-loop system, virtually nothing is emitted to the atmosphere.Moderate-temperature water is by far the more common geothermal resource, andmost geothermal power plants in the future will be binary-cycle plants. The thermalefficiency of this type station is typically about 10–13%.

available Area for plantavailable Area for plantGeothermal energy is present over the entire extent of the earth's surface. It varies only in its ease and cost of extraction. The need for developing the least expensive resource first has resulted in the exploration of geothermal resources primarily in these areas which have associated volcanic activity. However, by no means is the resource restricted only to volcanic areas.

Geothermal fields such as geysers require a combination of 3 geological factors-

I) a natural underground source of water. 2) an impermeable layer that traps the water and

permits formation of steam. 3) a mass of hot rock near the natural water system.

In Pacific Ocean lies the richest belt of geothermal energy known as 'RIM OF FIRE‘ stretching from New Zealand up through New Guinea, Philippines, Japan, Western Siberia and then down through Western United States, Mexico, Central America.

Economics conditionGeothermal power requires no

fuel; it is therefore immune to fuel cost fluctuations. However, capital costs tend to be high.

Drilling accounts for over half the costs, and exploration of deep resources entails significant risks.

A typical well doublet in Nevada can support 4.5 megawatts(MW) of electricity generation and costs about $10 million to drill, with a 20% failure rate. In total, electrical station construction and well drilling costs about 2–5 million € per MW of electrical capacity, while the levelised energy cost is 0.04–0.10 € per kWh.

Advantages of Geothermal Power Advantages of Geothermal Power PlantPlantSignificant cost saving : Geothermal energy generally

involves low running costs since 80% costs over fossil fuels and no fuel is used to generate the power.Reduce reliance on fossil fuels: Dependence on fossil fuels decreases with the increase in the use of geothermal energy. With the sky-rocketing prices of oil, many countries are pushing companies to adopt these clean sources of energy.Environmental benefits: Being the renewable source of energy , geothermal energy has helped has in reducing global warming and pollution. Moreover, geothermal system systems does not create any pollution as it releases some gases from deep within the earth which are not very harmful to the environment.

Limitations of Geothermal Power PlantLimitations of Geothermal Power Plant

High Installation Costs: To get geothermal energy, requires installation of power plants, to get steam from deep within the earth and this require huge one time investment and require to hire a certified installer and skilled staff needs to be recruited and relocation. Moreover, electricity towers, stations need to set up to move the power from geothermal plant to consumer.Suited To Particular Region : It is only suitable for regions where temperature below the earth are quite low and can produce steam over a long period of time. For this great research is required which is done by the companies before setting up the plant.May Release Harmful Gases : Geothermal sites may contain some poisonous gases and they can escape deep within the earth , through the holes drilled by the constructors.

1. Fluids drawn from the deep earth carry a mixture of gases, notably carbon dioxide (CO2), hydrogen sulfide (H2S), methane (CH4), and ammonia (NH3). These pollutants contribute to global warming, acid rain, and noxious smells if released.

2. The greenhouse gas emissions of geothermal electric stations are on average 45 grams of carbon dioxide per kilowatt-hour of electricity, or less than 5 percent of that of conventional coal-fired plants.

3. Stations that experience high levels of acids and volatile chemicals are usually equipped with emission-control systems to reduce the exhaust. Geothermal stations could theoretically inject these gases back into the earth, as a form of carbon capture and storage.

4. In addition to dissolved gases, hot water from geothermal sources may hold in solution trace amounts of toxic chemicals, such as mercury, arsenic, boron, antimony, and salt. These chemicals come out of solution as the water cools, and can cause environmental damage if released. The modern practice of injecting geothermal fluids back into the Earth to stimulate production has the side benefit of reducing this

environmental risk.

Environmental impact

Present Present statusstatusThe International Geothermal Association (IGA) has reported that 10,715 megawatts (MW) of geothermal power in 24 countries is online, which is expected to generate 67,246 GWh of electricity in 2010.[1] This represents a 20% increase in geothermal power online capacity since 2005. IGA projects this will grow to 18,500 MW by 2015, due to the large number of projects presently under consideration, often in areas previously assumed to have little exploitable resource.

As of 2015, worldwide geothermal power capacity amounts to 12.8 gigawatts (GW), of which 28 percent or 3,548 megawatts are installed in the United States. International markets grew at an average annual rate of 5 percent over the last three years and global geothermal powercapacity is expected to reach 14.5–17.6 GW by 2020.Based on current geologic knowledge and technology, the Geothermal Energy Association (GEA) estimates that only 6.5 percent of total global potential has been tapped so far, while the IPCC reported geothermal powerpotential to be in the range of 35 GW to 2 TW.Countries generating more than 15 percent of their electricity from geothermal sources include El Salvador, Kenya, the Philippines, Iceland and Costa Rica.

Country Capacity(MW)2007

Capacity(MW)2010

Capacity(MW)2013

CapacityCapacity(MW)(MW)20152015

PercentagePercentageOf NationalOf NationalProductionProduction

USAUSA 26872687 30863086 33893389 34503450 0.30.3PhilippinesPhilippines 1963.71963.7 19041904 18941894 18701870 27.027.0IndonesiaIndonesia 992992 11971197 13331333 13401340 3.73.7MexicoMexico 953953 958958 980980 10171017 3.03.0New New ZealandZealand

471.6471.6 628628 895895 10051005 14.514.5

ItalyItaly 810.5810.5 843843 901901 916916 1.51.5IcelandIceland 421.2421.2 575575 664664 665665 30.030.0KenyaKenya 128.8128.8 167167 215215 594594 51.051.0JapanJapan 535.2535.2 536536 537537 519519 0.10.1Costa RicaCosta Rica 162.5162.5 166166 208208 207207 14.014.0El SalvadorEl Salvador 204.4204.4 204204 204204 204204 25.525.5

Installed geothermal electric capacity

ConclusionConclusionGeothermal power can become a valuable source of energy if properly harnessed. Continued energy shortages have created added interest in geothermal energy for both power generation and direct applications. Geothermal power is considered to be a sustainable, renewable source of energy because the heat extraction is small compared with the Earth's heat content, but extraction must still be monitored to avoid local depletion.

Geothermal power is highly scalable: a small power station can supply a rural village, though initial capital costs can be high.

The development of binary cycle power plants and improvements in drilling and extraction technology may enable enhanced geothermal systems over a much greater geographical range.

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