The evaluating of the cost of electric power generation from the first geothermal power plant in Iran (Case Study: Meshkin-Shahr Geothermal Field)

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International Journal of Advanced Biotechnology and Research (IJBR) ISSN 0976-2612, Online ISSN 2278–599X, Vol-7, Special Issue-Number5-July, 2016, pp867-876

http://www.bipublication.com

Case Report

The evaluating of the cost of electric power generation from the first

geothermal power plant in Iran

(Case Study: Meshkin-Shahr Geothermal Field)

Mousazadeh1, B. And Monfaredi1, Kh.

Department of electrical engineering,

Malekan Branch, Islamic Azad Univerity,

Malekan, Iran. Bh_mosazade@yahoo.com

Khmonfaredi@malekaniau.ac.ir

ABSTRACT

Iran has fourteen vast areas with good potential for geothermal utilization. One such area is the Meshkin-Shahr geothermal field. Ten exploration wells and one injection well have been drilled to determine the parameters of the reservoir. In this paper, we considered the possibility of installing 55 MW geothermal power plant in Meshkin-Shahr near Sabalan Mt in the north-west of Iran.

The Renewable Energies Organization of Iran (SUNA) are trying to develop Meshkinshahr geothermal field to start-up the first double flash geothermal power plant. In this pape, the technical and economical parameters due to installing 55 MW geothermal power plant was considered for meshkinshahr geothermal field.

Three scenarios; minimum, mean, maximum have been explored respectively to estimate the cost of power generation in Meshkin-Shahr geothermal power plant. The results of these calculations have been classified in some tables and shows that it will be economical to generate 55 MWe from Meshkin-Shahr geothermal power plant.

Keywords: GeothermalPower Plant , Double Flash Cycle, Meshkin-Shahr, Scenario

1. INTRODUCTION

Electricity generation from geothermal reservoirs for last recent years has been increased significantly all over the world. Geothermal activities in Iranian ministry of energy were started in 1975 with co operation of Italian ENEL Company and Iranian Tehran Berkley Co.

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The evaluating of the cost of electric power generation from the first geothermal power plant in Iran

Behnam mousazadeh and Khalil monfaredi 868

Organization of Iran (SUNA) have been defined 10 more prospect area in other parts of country [1].

In 1995, studies and development of Sabalan area (one of those 14 areas), which it was in first priority according to several studies, has been started. The aim of the project is considering the possibility of installing first Iranian geothermal

power plant (100 MWe) and it is funding by Iranian Ministry of Energy.

fourteen vast areas with good potential for geothermal of Iran have been shown in Figure 1.

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2. PARAMETERS AFFECTING

TECHNOLOGY OF GPP1CHOICES AND

POWER SYSTEMS

In this paper, effective parameters are classified into two groups: technical and economical parameters.

Technical parameters include geothermal field, power plant, environmental parameters. Economical parameters are classified into three subgroups: capacity factor(%), installed capacity(MW), financial factors(interest rate and tax rates), capital investment and operation and maintenance (O&M) costs [3]

Various kinds of technologies may be used to deal with particular problems, the optimum choice is usually dictated by the resource characteristics (temperature, chemistry, the mass flow rate, etc.) and power plant environment (weather conditions, water availability, etc.) [3].

3. CHOOSING THE TECHNOLOGY

OF GPP

Most geothermal resources are unique in terms of site and resource characteristics. As a result, most power plants currently in operation are equally unique. Choosing the best suited technologies

deal with resource characteristics is an important decision making in early stages that aims to minimize both construction and operation & maintenance costs in a long-term perspective[4].In 2005, DiPippo provided technology choices for various resource characteristics such as the mass flow rate and temperature of the geothermal resources.

The information displayed in the following table corresponds to 150, 200 and 250 °C resource temperature for the mass flow rate needed to dealing with geothermal technologies[5]. The Lifetime of the geothermal power plants varies between 25 to 30 years. Valuable geothermal resources are not always located in areas furnished with transmission facilities. Some projects thus include the cost of building a new transmission line to connect the power plant to the grid.

Transmission lines are quite expensive and their cost may be a hurdle to a project's competitiveness. The construction cost of a new transmission line is linked to its length but is also affected by the topography, slope stability, and accessibility of the site considered[4].

Table (1) Various kinds of technologies deal with the Mass Flow rate (kg /s) and temperature of the resource [5].

Resource temperature (degree centigrade) Type of Geothermal power

plant 150 200 250

10-20 -

- Direct Dry Steam

(without upstream reboiler)

6-9 -

- Direct Dry steam

(with upstream reboiler)

50 80

150 Single Flash

30 60

130 Double Flash

- 70

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Case Report

4. MESHKIN-SHAHR GEOTHERMAL

PROJECT

The Meshkin-shahr geothermal prospect lies in the Moil valley on the western slopes of Mt. Sabalan, approximately 16 km SE of the town of Meshkinshahr, in the province of Ardabil in northwest Iran. Mt. Sabalan has been previously explored for geothermal resources in 1978, with geological, geochemical and geophysical surveys being undertaken [5]. Renewed interest in the area resulted in further geophysical, geochemical and geological surveys being carried out in 1998. These have identified a number of prospects associated with Mt. Sabalan. The Meshkinshahr prospect has been

identified as the best of these prospects. The exploration phases of project including geological, geochemical, geophysical and hydrological studies with cooperation of Renewable Energy Organization of Iran and Sinkler Night Merz (SKM) Co. from New Zealand have been finished in 1999[6].

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Case Report

Figure (2) location of Meshkin-shahr geothermal field in North western Iran

5. GEOTHERMAL POWER PLANT

TECHNOLOGIES SUITABLE FOR

MESHKINSHAHR 6.

5.1. Overview of power plant technologies The characteristics of a geothermal field are crucial in determining the appropriate type of power plant suitable for the field. In designing a flash steam plant (either single or double flash), it

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towards the inlet of a turbine for electricity generation.

The water phase from the separator may be flashed again for a low pressure turbine, making the cycle a double-flash power plant. Double-flash power plants are normally associated with high-enthalpy geothermal fields where resource temperatures are above 150°C[9].

The range of operating enthalpy is different for the different types of geothermal plants. The Single flash plants operate at a wider range of enthalpy (from ~800-2800 kJ/kg), while double flash operate at smaller range (from ~750-1900 kJ/kg). This is because as enthalpy increases the reservoir will dry up and there will be less produced water to justify a second flash. At the same time, the wellhead pressure will significantly reduce, not permitting a second flash[11]. Experience has shown that the binary plants can generate electricity from water as low as 73 ºC (306 kJ/kg) to up to 1100 kJ/kg. However, generation from higher enthalpy fluid is also possible, while for an enthalpy higher than ~1900 kJ/kg only single flash/dry steam plants is recommended[5,10].

5.2. Meshkin-Shahr geothermal power plant According to the data from well testing in Meshkin-Shahr field, the anthalpy is about 1200 kJ/kg and resource temperaturevaries between 130-170 °C. As a result, Double flash cycle is the best suited technology for generation electricity[11]. Figure 3 shows a schematic of Double flash cycle geothermal power plant.

Figure (3) Schematic of Double flash Cycle Geothermal Power Plant

7. ECONOMICAL PARAMETERS

AFFECTING COSTS OF GEOTHERMAL POWER GENERATION

Major parameters affecting costs of geothermal electricity generation presented below [3]:

- Upper hand costs of site development

- Capital investment costs

- Operation and Maintenance (O&M) costs

6.1. UPPER HAND COSTS OF

GEOTHERMAL POWER DEVELOPMENT Developing a new geothermal resource is a long and expensive process. Initial development steps are risky and upper handcapital costs are important Note that geothermal development occurs sequentially and that the distinction between exploration, confirmation and the early drilling phase are sometimes difficult to make. This is particularly true for small projects that do not require many production wells. Should exploration and confirmation be considered together[3, 12]

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generating capacity of the reservoir (confirmation) and build the power plant and associated structures (site development)[13]. The confirmation phase mainly consists of drilling additional production wells and testing their flow rates until approximately 25% of the resource capacity needed by the project is confirmed. It also involves reservoir design and engineering and the drilling of some injection capacity to dispose of fluids from production well tests[5,10].

The steam gathering cost includes the cost of the network of pipes connecting the power plant with all production and injection wells. The cost for these facilities varies widely depending on the distance from the production and injection wells to the power plant, the flowing pressure and chemistry of the produced fluids [13].

The overhead costs of geothermal power plant development and ranges of them are summarized in table 2 [3,4].

Table(2) upper hand GPP development cost components and unit cost range

Upper hand costs of geothermal power plant development Cost ranges Unit

Cost components

100-300 KW

Surface exploration

500-2500 Meter

Exploration drilling(early drilling)

Vapour dominated systems 4000-7000 Well

Well testing

Water dominated systems 8000-15000

Vapour dominated systems 200000-270000 Well

wellhead Gathering Systems

Vapour dominated systems 70-170 Meter

Reinjection fluid back into the geothermal system

6.1.1.Factors affecting the upper hand costs of GPP power plants

Drilling expenses usually account for eighty percent (80%) of total confirmation costs. Two major factors will affect total drilling costs: (1) the cost of drilling individual wells and, (2) the number of wells to drill. The cost of an individual well is mainly related to the depth and diameter of the well as well as the properties of the rock formation[4]. The cost of drilling individual well for Vapour or water dominated systems are nearly the same and varies average values range 1500-2500 US$ per meter[3,4]. The number of wells to drill is determined by the average well productivity and the size of the project.

Well productivity directly depends on the resource temperature and the rock permeability. For low temperature systems (212-400°F), GeothermEx (2004) established a roughly linear correlation between well productivity and temperature:

Well productivity (MW) = resource temperature (°F) /50 - 3.5 (1)

The productivity of a geothermal well varies even more (1-2 MW to 25-50 MW/well) but average values range 3-5 MW.The drilling success rate improves throughout the development phases and site development drilling success rate is expected to average 70 to 80% [12,13].

6.1.2. Calculation of the upperhand costs of development of Meshkin-Shahr geothermal power plant

The temperature of diverse layers of Meshkinshahr resource is between 130-250 degrees centigrade. As a result, The productivity of a wells varies between 1.8 - 6.1 Watts. The drilling success rate averages 75% [11]. It has been calculated at least 9 to 30 wells needed available to compensate any steam supply problem for the 55 MW Meshkin-Shahr geothermal power plant[11,14].

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between salinity and diatomite concentration caused increased of K+_{contain under salinity}

levels table (5).

Table (3) Upper hand costs of geothermal development in Meshkin-Shahr GPP (US$)

Scenarios

Min value of cost Mean value of cost

Max value of cost Cost parameters

100 200

300 Surface exploration per Kw

1500 2000

2500 Exploration drilling per meter

100000 125000 150000 well testing 400000 450000 500000 On wellhead 130 190 250 Reservoir’s temperature (°C)

6.1 3.9

1.8 Well Productivity (W)

9 14.1

30.5 Number of Wells

45000000 92050000

244500000 Upper hand of investment cost(US$)

8. CAPITAL INVESTMENT COST OF

GEOTHERMAL POWER TECHNOLOGIES Power plant design is a complex activity that aims to minimize both construction and operation & maintenance costs in a long-term perspective. It thus consists of choosing the best suited technologies and construction materials to deal with site and resource particularities. Table 4 suggests that capital costs of geothermal power technologies.

Table 4. Capital cost of geothermal power technologies [4,13].

Capital Cost Range ($/ kWh) Power plant type

750-1300 Dry steam (without

upstream reboiler)

1100-1700 Dry steam (with upstream

reboiler)

1162-2500 Flash Cycle

1700-2700 Binary Cycle

According to the above table, the total capital cost to build a flash plant, varies from $1162/kWh to $2500/kWh. The capital costs of developing a binary plants range from $1700/kWh to $2700/kW.

7.1.The investment cost of Meshkin-Shahr geothermal power plant

Compared to the cost figures appearing in the above table, estimates from flash projects currently under development show significantly higher cost values. According to the well test data for the seven production wells, each well of Meshkin-Shahr field has 5 to 7 MWe potential for generation of electricity . The geothermal department in the Renewable Energy Organization of Iran (SUNA) explored tender documents for the geothermal power plant. It is possible to choose between a double flash condensing geothermal power plant (GPP) with 55 MWe capacity. The investment cost of flash cycle is therefore between 1162 to 2500 $/KWh. Thus the power plant installed capacity is the reference for the investment cost calculations, Therefore, the capital cost for Meshkin-Shahr project averaged 96 million US$ for 55 kW installed. Table 5 shows the results of estimated three scenarios of minimum, mean and maximum values of investment cost for case study geothermal field.

Table (5) Evaluation of Capital Investment Cost of Meshkin-shahr Gpp(USD)

Scenarios

Min Value of cost Mean Value of

cost Max Value of

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1162 1750

2500 Cost of Capital Investment of GPP($/KWh)

63910000 96250000

137500000 Cost of Capital Investment of 55 MW Double flash

GPP($)

9. OPERATION AND MAINTENANCE

COSTS(O&M)

Operation and Maintenance (O&M) costs consist of all costs incurred during the operational phase of the power plant. Economic analysis usually distinguishes fixed and variable O&M costs, but in the case of geothermal power production, variable costs are relatively low and the marginal cost of power production increase is thus considered to be minimal [4]. Consequently, geothermal power plant operators will keep capacity as high as possible in order to minimize the cost of each kWh produced. O&M costs are not constant during the lifetime of the power plant. During the first years of operation, O&M costs are expected to be relatively low but climb progressively as equipment ages and needs more maintenance or replacement. In the study of Vorum and Fritzler (2000), O&M costs were taken as 5% of the initial capital investment cost[15]. Also in 2001, EPRI estimated the annual cost of power plant maintenance as 5% of the initial capital costs.

8.1.Factors affecting Operation and Maintenance (O&M) costs

Each power plant has specific O&M costs that depend on the quality and design of the power plant, the characteristics of the geothermal resource, the environmental regulations and requirements applicable to the site, and the structure and efficiency of the company. Major parameters affecting O&M cost are related to the plant labor requirement, the amount of chemicals and other consumables used during operation, the extent of make-up drilling requirements, and the cost of the equipment that has to be replaced throughout the years. The variability of many of these cost components is also related to trade-offs that may apply between initial capital cost and O&M costs [13].

8.2. Operation and Maintenance (O&M) costs of Meshkin-Shahr geothermal power plant Based on study of Vorum and Fritzler (2000) and EPRI (2001), average O&M costs for three scenarios, range from 0.03 to 0.08 of initial capital investment costs of Meshkin-shahr project. According to the available data presented by in table 6, O&M cost approximately changes from 7 to 12 million US$/year and average costs are approximately 10 million US$ per year.

Table (6) Evaluation of O&M costs for Meshkinshahr GPP(USD/year)

Scenarios

Min Value of cost Mean Value of

cost Max Value of

cost Components of Operations and Maintenance

Cost

0.03 0.05

0.08 Rate of O&M

3600000 4602500

723500 Upper hand O&M Costs

4112500 4812500

5112800 O&M costs of GPP

7712500 9415000

12447800 Total cost ($/ year)

10. GEOTHERMAL POWER

PRODUCTION COSTS (CAPITAL AND O&M) OF MESHKINSHAHR PROJECT The resource temperature, depth, chemistry, permeability and capacity factor are the major factors affecting the cost of the geothermal power production. The site accessibility and topography,

local weather conditions, land type and ownership are additional parameters affecting the cost and time required to bring the power plant online[4]. Table 7 shows the results of calculation of unit cost of electricity production in Meshkin-shahr 55MW geothermal power plant (US$ per KWh).

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Scenarios

Min Value of cost Mean Value of

cost Max Value of

cost Cost Parameter

1.3 2.5

8 Overhead Capital Investment costs

1.1 2.2

3.3 Capital Investment costs of GPP

0.33 1.2

2.3 Upper hand O&M costs

0.63 1.1

2.6 O&M costs of GPP

4.3 7

16.2 Total (¢/ kWh)

11. CONCLUSION: From the results of this paper, unit cost of electricity generation in 55 MW Meshkin- shahr geothermal power plant were estimated 4.3 and 7 and 16.3 ¢ per kWh based on three scenarios of min, mean, max values of cost. The parameters of cost of capital investment and the rate of O&M have been assumed 1162, 1750 and 2500USD$ per KWh and 0.03 , 0.05 and 0.08 respectively. In addition, in this report, the entire lifetime of the power plant is about 30 years, capacity factor varies between 85 to 95 percent and interest rate is assumed 10 percent. These calculations for the geothermal power plant with 50MWe capacity show Installing a 50MWe geothermal power plant in Meshkin-shahr will be more economic than the fossil fuel fired power plant, specially The geothermal are environmentally benign energy sources, with low CO2 emissions.

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