A SEMINAR REPORT SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE DEGEREE OF

Bachelor of TechnologyIn

Electrical and Electronics Engineering

By AJIT KUMAR PATRAREGD NO-0801402109

Under the guidance Of

Prof. Rupali Mohanty

Department of Electrical&Electronics EngineeringGandhi Institute for technology,

Bhubaneswar

1

GANDHI INSTITUTE FOR TECHNOLOGY BHUBANESWAR

CERTIFICATE

This is to certify that the Report of the seminar entitled “Geothermal energy” has been

carried out and submitted by Ajit kumar patra under my guidance in partial fulfillment of

the requirements for the award of Bachelor of Technology degree in Electrical&Electronics

Engineering at the Gandhi Institute for Technology, Bhubaneswar is an authentic work

carried out by him under my supervision and guidance. To the best of my knowledge the

matter embodied in the report has not been submitted elsewhere for the award of any other

degree.

H.O.D(EEE) GuideProf Srikant Das Prof. Rupali Mohanty

2

ACKNOWLEDGEMENT

I would like to articulate our deep gratitude to my seminar guide Prof.Rupali Mohanty for his

invaluable guidance and blessings. I express my gratitude to Prof. Srikant Das, Professor and

Head of the Department, Electrical&Electronics Engineering for his invaluable suggestion and

constant encouragement all through the work.

I would also like to convey our sincerest gratitude and indebtedness to all other faculty members

and staff of Department of Electrical & Electronics Engineering, Gandhi institute for technology,

Bhubaneswar who bestowed their great effort and guidance at appropriate times without which it

would have been very difficult on my seminar work.

An assemblage of this nature could never have been attempted with my reference to and

inspiration from the works of others whose details are mentioned in references section. I

acknowledge my indebtedness to all of them. Further, I would like to express our feeling towards

our parents and God who directly or indirectly encouraged and motivated us during this

dissertation.

Ajit kumar patra

3

GEOTHERMAL ENERGY

ABSTRACT

Among the various new and renewable energy sources, geothermal energy is known to be one of

the clean energy without smoke and also without environmental hazards. Although it’s

importance is realised long back inother countries, it’s exploitation is still far away in our

country mainly due tolack of knowledge on the deep subsurface structure and deep

drillingtechnology in high pressure, high temperature regions. GSI and NGRI have made

concerted efforts in identifying these resources in different parts of our country for possible

exploitation of the energy source. In the present paper,

the details of geothermal energy, it’s importance and usage in other countries are

discussed with estimated potential in our country.

4

Geothermal Energy: An Alternate Source of Energy

 

Summary  : This report highlights the available technologies world over for utilisation of

Geothermal Energy. It also identifies areas in India where maximum benefit can be derived

from Geothermal Energy. Considering the fact that fossil fuels are limited in quantity and

fast depleting, as more than 90% of the world\'s energy needs are being met by fossil fuels

Geo Thermal Energy is a very attractive alternate source of energy. With an objective of

looking ahead at technologies, it is a report on Geothermal Energy, which deals in depth the

present status of technologies for exploration & utilization of geothermal energy in India and

abroad. Geothermal resource base for India has been estimated as 3.8X105 Quads (1Quad

=2.93X1011Kwhth) whereas the generation of electricity in India in 1997-98 stood at 4.2

Quads which reflects the enormous potential of this energy. The report also details the

different uses of geothermal energy in different parts of the world such as power generation,

agriculture, aquaculture etc. The report also identifies areas in India where maximum benefit

can be derived from Geo Thermal energy, such as Puga valley in Laddakh, Tattapani in

Sarguja district in M.P, Tapoban in U.P etc and its utilities in these regions.

5

INTRODUCTION

The Techno-Market Survey "Geothermal -An alternate source of energy" focuses on the

present status of exploration & utilization of this energy resources in India and world over.

The exploration and exploitation of geothermal resources got a boost following the 1973 oil

crisis world over. R & D activities were directed towards exploration & exploitation of

various types of geothermal resources such as hydrothermal, geopressurised, hot dry rock,

magma. In India also lot of efforts have been put up by Geological Survey of India in

identification and exploration of various sources of geothermal energy which mainly include

hydrothermal sources. The estimated energy in only one third of known thermal spring areas

is 10,600 MWth. Geothermal energy has been put to varied uses in different parts of the

world. The uses include power generation, direct use of heat for space heating, agriculture,

aquaculture industrial processes, balneology, tourism etc. The geothermal fluid has also been

used for mineral extraction & water resources. The status of utilization of geothermal energy

in India at present is on symbolic level only as compared to the availability of the resources.

Efforts are required to be directed for utilization of the resources, which have been identified

for development, in backward, hilly and tribal regions in India, where maximum, benefit

from geothermal resources can be derived as cost of energy sources through conventional

means is also high there e.g. Puga - Chhumathang in Ladakh. (J&K), Tattapani in Surguja

District (M.P.), Tapoban (U.P.) etc. Technology for utilization of geothermal energy at such

a scale is available in our country.

As far as the status of utilization of geothermal resources world over, the electric utilization

is nearly 8000 MW by the end of year 1997; the leading countries are Italy, New Zealand,

USA, Japan, Philippines, Indonesia, Mexico, etc. In non electric utilization of geothermal

energy the countries leading in use of geoheat for space heating, agricultural & industrial

usages are Iceland, France, China, Japan, Hungary, USSR, USA, New Zealand, etc. World

over utilization of geothermal energy for non-electric applications was to the tune of 12,000

MWth in the year 1991, Advanced technology is available for large scale utilization of

geothermal energy in developed countries e.g. USA, Italy, Japan, France, New Zealand etc.

 

6

Scope and Objective of the Study

The scope and objective of the study as given by TIFAC is to address the following aspects

in the context of the topic under study.

Relationship and the importance of the topic to the broad area to which it belongs.

The current status of the technology in the world and in India, Market sizes and their

potentialities.

Assessment of technology, resource parameters such as energy, raw material, infrastructure

etc., to arrive at preferred technology options available in the country.

Short term and long term economic aspects of preferred options along with their feasibilities.

Impact of preferred options and its spin-offs.

Recommendations :

For implementation of preferred technology options - identifying critical inputs such as

occurrence and availability of raw material, capital goods and human resources required and

their, expected benefits etc.

For R & D/technology development-identifying the requirements of inputs and expected

benefits.

Action plan for implementation of recommendations alongwith identification of :

List of available technology for Indian Industry and

The agencies/group/individuals for implementation.

Expected impact of recommendations; if implemented.

 

7

Importance of Topic

Geothermal energy is contained in underground reservoirs of steam/water and hot dry rocks.

Man’s appetite for energy is increasing day by day. World Energy conference Survey of

Energy Resources estimated in 1980 that proved recoverable reserves of fossil fuels to last

131 years at world consumption level of 1972. To avert the situation new energy sources are

to be found and to reduce the growth rate of energy demand to zero, or even reverse it.

‘Non-fuel’ energy sources becoming important, gone are the days of cheap energy.

Reduction in growth rate of population will go a long way to reduce the growthrate of

energy demand. As per energy consumption scenario in India, the per capita energy

consumption is low but the growth rate of energy consumption is high in India, being a

developing country utilisation of geothermal energy is one of the options. With energy

demand multiplying, none of the reasonably accessible source can be allowed to go waste.

The probable shape of things to come in future world energy supply will be ultimately

limited to renewable sources alone.

Gigantic efforts have already been made by GSI in close ordination with NGRI, ONGC,

MECL, CEA, BARC, UOR, IIT Delhi in the field of exploration of geothermal resources in

India and the estimated energy in only one third of known thermal spring areas in the

country is 10,600 MWth. If this energy is exploited for the benefit of society, development

of backward, hilly & tribal areas can get a boost.

 Methodology

The Techno-Market Survey was conducted through extensive literature survey on the subject

relating to the exploration, electric and non-electric utilization of geothermal resources in

India and the world over and the constraints in the system approach for its exploration &

exploitation. The various possibilities of its utilisation have been explored. Present

technological statues of exploration & utilization scenario in India as well as in world has

been synthesised and evaluated in the light of ongoing R & D work towards optimum

utilisation of the resources in the world. This desk work was followed by:

Mail survey through structured and open ended questionnaires. Efforts were made to get

8

back replies through reminders and even telephonic discussion, wherever required.

The questionnaires covered all possible segments in private and Govt. Sectors, Research

Institutes and other related organisations in India. A number of agencies were also contacted.

Personal interviews and discussions were held with several persons active in the field of

geothermal energy resources to gather further information and clarifications.

Discussions with the experts in various field were held and obtained literature on request.

Compilation, analyses and synthesis of data was carried out in accordance with the guideline

of TIFAC.

The draft report would be finalised in accordance with the comments and suggestions, that

would be received from TIFAC.

Technology

Mile-or-more-deep wells can be drilled into underground reservoirs to tap steam and very hot water that drive

turbines that drive electricity generators

Four  types of power plants are operating today:

Flashed steam plant: The extremely hot water from drill holes when released from the deep

reservoirs high pressure steam (termed as flashed steam) is released. This force of steam is used to

rotate turbines. The steam gets condensed and is converted into water again, which is returned to

the reservoir. Flashed steam plants are widely distributed throughout the world.

9

Dry steam plant: Usually geysers are the main source of dry steam. Those geothermal reservoirs

which mostly produce steam and little water are used in electricity production systems. As steam

from the reservoir shoots out, it is used to rotate a turbine, after sending the steam through a rock-

catcher. The rock-catcher protects the turbine from rocks which come along with the steam.

Binary power plant: In this type of power plant, the geothermal water is passed through a heat

exchanger where its heat is transferred to a secondary liquid, namely isobutene, isopentane or

ammonia–water mixture6 present in an adjacent, separate pipe. Due to this double-liquid heat

exchanger system, it is called a binary power plant.The secondary liquid which is also called as

working fluid, should have lower boiling point than water. It turns into vapour on getting required heat

from the hot water. The vapour from the working fluid is used to rotate turbines. The binary system is

therefore useful in geothermal reservoirs which are relatively low in temperature gradient. Since the

system is a completely closed one, there is minimum chance of heat loss. Hot water is immediately

recycled back into the reservoir. The working fluid is also condensed back to the liquid and used over

and over again.

10

Hybrid power plant: Some geothermal fields produce boiling water as well as steam, which are also

used in power generation. In this system of power generation, the flashed and binary systems are

combined to make use of both steam and hot water. Efficiency of hybrid power plants is however less

than that of the dry steam plants.

Enhanced geothermal system: The term enhanced geothermal systems (EGS), also known as

engineered geothermal systems (formerly hot dry rock geothermal), refers to a variety of engineering

techniques used to artificially create hydrothermal resources (underground steam and hot water) that

can be used to generate electricity. Traditional geothermal plants exploit naturally occurring

hydrothermal reservoirs and are limited by the size and location of such natural reservoirs. EGS

reduces these constraints by allowing for the creation of hydrothermal reservoirs in deep, hot but

naturally dry geological formations.EGS techniques can also extend the lifespan of naturally

occurring hydrothermal resources. Given the costs and limited full-scale system research to date,

EGS remains in its infancy, with only a few research and pilot projects existing around the world and

no commercial-scale EGS plants to date. The technology is so promising, however, that a number of

studies have found that EGS could quickly become widespread.

 

Limitations

During the survey a few difficulties were experienced in collecting information particularly

on detailed aspects of technology and economics. Only a few organisations/individuals were

willing to part with the detailed information. However, some insight could be obtained

during personal meetings and persuasions. Thus, the report may be read in conjunction with

the following limitations :

The study is based on published literature, mail survey, a limited number of personal visits

11

and interviews.

No interview could be possible with foreign experts. The details of technical and economic

parameters are limited to the extent of information that could be gathered during the survey.

The information of world scenario and evaluation thereof is based upon the published

literature and the information collected through survey & literature requests.

The information on commercial aspects of the technologies were provided only by a few.

 

Market Survey Response

The response to market survey was not very encouraging. We got about 10% response from

Indian organisations and about 70% response from foreign agencies (including embassies). It

includes the response in reply to our reminders and also collection of information during

personal meetings and interviews.

The information regarding technologies and commercial aspects was provided only by a

few. Most of the respondents have sent published literature and literature the performance of

utilization plants.

 

Findings of study/survey analysis

Earth is a reservoir of natural heat. Major geothermal fields are situated in circum-Pacific

margin, rift zones of East Africa, Mediterranean basin Europe, mid-Atlantic rift, North

Africa, across Asia to pacific. Geothermal resources are of four types; hydrothermal,

geopressurised brines, hot dry rocks and magma. Geothermal reserves upto depth of 3 km

have been estimated at 41.04 X 106 Quads, this figure for depth upto 10 km is 403 X 106

Quads. Where as the annual world energy consumption was 306 Quads in the year 1995.

12

Thermal anomalies are generally associated with tectonic plates. Average thermal gradient

below earth is 25-300C per km, but thermal gradient as high 200-8000C has been recorded.

The world average of geothermal heat flow is 0.06 watt/m2 where as this figure is 30

Watt/m2 in Wairakei New Zealand. Geothermal electrical power plants are economically

successful. Hydrothermal energy is being commercially used for electric & non-electric

uses, in many parts of the world. Efforts are on to use geopressurised, hot dry rock & magma

sources of geothermal energy.

Geothermal resources in India are under active study since 1970 and there are more than 340

known thermal spring localities in India. Temperature gradient in excess of 1000C/km and

heat flow in excess of 200 mW/m2 has been recorded. Geofluid temperature upto 980C

(boiling point at the altitude of occurrence) and bottom hole temperature of 1400C-2000C

has been recorded. Ten geothermal provinces have been identified in India.

Exploration of geothermal resources requires skills of geology, geochemistry, geophysics,

seismology, hydrology, reservoir engineering. In early stages of exploration low cost

techniques are employed followed by expensive techniques for economic extraction of

geothermal energy. Important sites being explored in India include Puga Chhumathang,

Manikaran, Tapoban, Cambay, Tattapani, Bakreshwar, Tantloi, Tatta-Jaron, Athmallik,

Unkeshwar. Physical and chemical properties of geothermal water, isotopic composition

trace elements, and gases are analysed. Temperature-depth curves, isotherms, heat flow

studies etc. are the basic tool deployed during exploration. Puga, Manikaran, Tattapani have

been found suitable for electric generation.

Exploratory wells are drilled and these can be upto the depth of 500m-2000m, various data

are recorded including pressure, temperature & flow of geofluid. Chemical & other physical

properties are also recorded. Subsequently reservoir model is constructed. Bore hole drilling

techniques are similar as followed in oil & gas drilling. A case study of geothermal drilling

and drilling hazards is included in chapter IV. After geothermal drilling borefluid

characteristics e.g. temperature, pressure, flow, enthalpy, quality, heat/power capacity,

corrosiveness etc. are checked. A conceptual model of reservoir is constructed. Performance

prediction, reservoir behaviour for a given rate of production, pressure transient analysis of

geothermal well, permeability of reservoir are important parameters to be checked. Once

optimum level of production of a reservoir is established geothermal fluid can be put to

13

commercial use.

For collection controlling of geofluid well head gear is used. Arrangements for separation of

water/steam, girt are made. Silencers, steam-mains, steam branch-lines, expansion bellows,

loops, thermal legging, safety valves etc. are the important components of fluid collection.

Transmission of two phase geofluid has also been used.

Electricity generation is the most attractive use of geothermal energy as transmission of

electric energy to the users is simple as compared to transmission of heat energy. Also

electric energy can be put to various applications. Geothermal electric generation was started

in the beginning of this century in Italy at Larderallo. The world’s generating capacity of

geothermal electricity at the end of 1997 was around 8000 MW. Italy, New Zealand, USA,

Japan, Mexico, Philippines, Indonesia, Russia, El Salvador are the leading countries in the

geothermal electric utilization apart from many other countries. Technology for electric

generation from geofluid has been perfected these include condensing, non-condensing

single/multi flashing, binary, single/double fluid cycles. Total flow system, hybrid

combustion-geothermal system have also been tried. Reinjection of geofluid has been

adopted due to environmental consideration and to prolong the life of reservoir. Various

systems & subsystems of geothermal electric power plant are covered in chapter VI and

Appendix I to IV.

Non-electric utilization of geothermal energy include space heating air conditioning

agricultural usages; green house farming, horticulture, aquaculture, animal husbandry,

industrial applications, chemical industry, extraction of mineral, food processing, pulp &

paper manufacturing, balneology, tourism, bottled mineral water etc. The leading countries

in non-electric use are China, Iceland, Japan, France, Hungary, CIS (formerly USSR), USA,

New Zealand. Geothermal heat pump are popular in USA for space heating/cooling. In India

direct application of geofluid include tourism (hot bath-balneology), mineral water and

beginning has been made in space heating, green house farming, cold storage, poultry

farming, mushroom cultivation, sulphur and borax extraction. Direct use of geothermal

energy was to the tune of 12,000 MWth in the year 1991.

For efficient utilization of geothermal energy dual and multipurpose projects can play an

important role. There are wide spectrum of possibilities. The main problem of utilization of

geothermal energy in cascaded manner is mainly of demand balancing for various uses.

14

Control system safety equipment and safety precautions required to be adopted in

geothermal installations for efficient & safe (both for human & machinery) operation are

covered in chapter IX. Environment issues; impact on land air, water, and thermal

discharges, noise, odour have been covered in chapter X including Methods of H2S

abatement and impact on ecology are also covered. As compared to conventional sources of

energy the environmental pollution & effect on ecology is very small in the case of

geothermal utilization plants. Chapter No. XI covers the chemical & metallurgical problems

faced in geothermal utilization plants and solution thereof.

Cost is always important but due consideration is also required to given to national self-

sufficiency environmental impact, energy conservation & future source of non-fuel energy.

Cost of geothermal energy includes exploration cost; land acquisition & drilling costs, fluid

gathering & transmission cost, cost of plant and conversion equipment, man power,

efficiency of the plant etc. Exploration costs are unpredictable and there are late returns on

investments, as such exploration costs are to be supported by government and or

international agencies UNDP/UNITAR. R&D is being done in USA, Japan, UK, Germany &

Russia for utilization of hot dry rock type geothermal resources, geopressurised and magma

resources. R&D is also directed towards improvement of drilling techniques for deep drilling

upto 10 kms economically with reasonable speed.

 

Recommendations, Action Plan & Impact

Relevance of geothermal resources utilization to India is covered in chapter XV wherein it

has been brought out that in view of gigantic exploration effort put in by GSI, and successful

pilot projects for geothermal resources utilization, India should speed up utilization of

geothermal resources. The recommendations for proper and effective utilization of

geothermal resources include :

Formation of independent centralized body by MNES to co-ordinate all aspects of

exploration, evaluation and exploitation of geothermal resources. It will be worth while to

award few projects on turnkey basis to multinational companies.

Immediate steps should be taken to create proper infrastructure, which should include inter

alia provision of deep drilling rigs to pursue the programme of establishing the potential

15

geothermal resources.

In the areas where exploration has ben carried out by GSI and pilot utilization projects have

been successfully completed. Actions are required to be initiated. MNES should encourage

state agencies, entrepreneur for utilization of the resources for direct/electric application or

mineral/elements or gas extraction.

A programme of advance training of Indian Earth Scientists and Engineers in specific area of

interpretation of geoscientific data, reservoir modelling, drilling, monitoring of reservoirs,

electric & non-electric utilization of geothermal energy to be chalked by MNES by

establishing national or regional scientific technological research centres. Facilities of

already established centres in New Zealand, Italy, Japan, Iceland, UK, USA and United

Nations University in Japan/Iceland can also be availed.

Experimental use of geothermal heat pumps be introduced in selected areas.

Government should allow tax (excise, custom, sales, electricity etc.) holidays for geothermal

exploration & exploitation projects. Allotment of land on concessional rates and subsidy on

appliances used for exploration & utilization of geothermal energy be allowed.

Appropriate modifications be made in the administrative and legislative rules, and

regulations governing mining/ground water resources and their utilization, so that it should

not hinder the process of exploration and utilization of geothermal resources.

The already developed techniques of exploration and utilization of geothermal energy viz

green house farming, poultry farming, mushroom cultivation, balneology, cold storage,

power generation from low enthalpy resources, by different R&D Institutes/Organisations

should be commercialized even by providing financial subsidies and other incentives to the

industrial entrepreneurs.

R&D work of deep exploration of geothermal resources and large scale utilization in fields

agricultural, industrial and electrical be encouraged. R&D work in exploration &

exploitation of HDR, geopressurised and magma resources is also required to be initiated.

Incentives should be given by the government to agencies engaged in exploration of

geothermal energy.

16

Active role of following agencies is crucial for advancing the cause of utilization of

geothermal resources (the non-fuel energy resource of future) MNES, GSI, TIFAC (Ministry

of Science & Technology), ONGC, NGRI, MECL, Central Ground Water Board, CEA,

BHEL. The impact & spin offs, if all the recommendations are implemented are covered in

chapter XVI.

 

REFERENCE

1. Assessment of Geothermal Resources of the United States – 1978, USGS Circular 790 (p. 41 and 157).

Includes identified and unidentified resources; 2015 and later estimates are a consensus of the experts at the

workshop. Estimated accessible figure includes identified (~30,000 MW) and unidentified (~120,000 MW)

(i.e., hidden or showing no surface manifestations) hydrothermal resources.

2. “Geothermal Electric Power Supply Possible from Gulf Coast, Midcontinent Oil Field Waters,” Oil and

Gas Journal, September 5, 2005, and SMU Geothermal Laboratory Geothermal Energy Generation in Oil

and Gas Settings Conference findings, March 13 – 14, 2006, and USGS Circular 790.

3. Based on Mafi Trench Unit on offshore platform now in operation.

4. Energy Recovery from Enhanced/Engineered Geothermal Systems (EGS), Massachusetts Institute of

Technology (MIT), September 2006.

5. OIT Geo-Heat Center, using analysis based on USGS Circulars 790 and 892.

6. Geothermal Heat Pump Consortium, based on Energy Information Administration data and projections.

The ‘avoided power’ figure represents the peak power not required or offset through use of GHPs. Thus,

GHPs act as a proven demand and growth management option for utilities.

17

18