Climate Change and Hydropower Planning in the Middle East: Implications for Iran’s Karkheh Hydropower Systems

Abstract

Given the important role of hydropower in peak electricity management, Middle Eastern countries are actively pursuing development of more hydropower resources by construction of large dams. Nonetheless, climate change is expected to affect the future productivity of hydropower by influencing the hydrologic cycle and different climate variables in the region. Although reactive plans to minimize climate change impacts on hydropower production have been implemented in the developed world, the developing world can still benefit from proactive actions. Studies of climate change impacts before and during implementation of hydropower projects can result in timely responses
and adaptation to climate change with a potential of considerable cost savings. This study investigates the potential impacts of climate change on the hydropower systems in the Karkheh River Basin—the third largest river basin in Iran—in terms of potential for hydroelectricity generation. A simulation model is developed to examine how hydropower generation levels vary for different future climate change scenarios in this representative Middle Eastern basin. The obtained results suggest that the existing operation rules and design specifications, developed based on the historical climatic conditions, can lead to inefficient operations of the hydropower in the basin. Because of insignificant streamflow reductions in the short term, hydropower production may not change considerably in the near future. However, a serious hydropower
generation deficit is expected in the midterm and long-term horizons in the Karkheh River Basin. Therefore, adaptation to the future climate change conditions and revision of the operation rule curves and design specifications are essential to optimal hydropower operations in this basin.

Full text

Climate Change and Hydropower Planning in the Middle
East: Implications for Iran’s Karkheh Hydropower Systems
Saeed Jamali, Ph.D.1; Ahmad Abrishamchi, M.ASCE2; and Kaveh Madani, A.M.ASCE3
Abstract: Given the important role of hydropower in peak electricity management, Middle Eastern countries are actively pursuing develop-
ment of more hydropower resources by construction of large dams. Nonetheless, climate change is expected to affect the future productivity
of hydropower by influencing the hydrologic cycle and different climate variables in the region. Although reactive plans to minimize climate
change impacts on hydropower production have been implemented in the developed world, the developing world can still benefit from
proactive actions. Studies of climate change impacts before and during implementation of hydropower projects can result in timely responses
and adaptation to climate change with a potential of considerable cost savings. This study investigates the potential impacts of climate change
on the hydropower systems in the Karkheh River Basin—the third largest river basin in Iran—in terms of potential for hydroelectricity
generation. A simulation model is developed to examine how hydropower generation levels vary for different future climate change scenarios
in this representative Middle Eastern basin. The obtained results suggest that the existing operation rules and design specifications, developed
based on the historical climatic conditions, can lead to inefficient operations of the hydropower in the basin. Because of insignificant stream-
flow reductions in the short term, hydropower production may not change considerably in the near future. However, a serious hydropower
generation deficit is expected in the midterm and long-term horizons in the Karkheh River Basin. Therefore, adaptation to the future climate
change conditions and revision of the operation rule curves and design specifications are essential to optimal hydropower operations in this
basin. DOI: 10.1061/(ASCE)EY.1943-7897.0000115.© 2013 American Society of Civil Engineers.
CE Database subject headings: Climate change; Hydro power; Simulation; Models; River basins; Middle East.
Author keywords: Climate change; Hydropower; Operations; Simulation; Modeling; Adaptation; Karkheh River Basin; Iran.
Introduction
Accounting for 16% of the electricity production worldwide,
hydropower is one of the most popular energy resources because
of its low cost, near-zero greenhouse gas emissions, and the flex-
ibility it provides in operations (Madani and Lund 2009). Despite
its great advantages over other electricity sources, hydropower is
among the most vulnerable energy sources to changes in global
and regional climates because of its direct dependence on the mag-
nitude and timing of streamflows. Therefore, the availability of hy-
dropower at its current or planned levels remains in question under
the expected climatic changes and associated spatial and temporal
streamflow changes [Intergovernmental Panel on Climate Change
(IPCC) 2007].
Climate warming can exacerbate the situation of water resources
in the semiarid and arid regions of the world (IPCC 2007). These
effects are of particular importance for the Middle East countries,
which are already experiencing stressed water resources because of
the limited water availability and growing water demand (Sowers
et al. 2011). Temperature is expected to increase up to 4.5°C in the
Middle East by the end of the century, which with the expected
25% decrease in average annual precipitation and the changing
precipitation patterns (Zereini and Hotzl 2008) can create serious
challenges to water resources management in the region. Although
considerable effects on water resources systems are expected in the
region, adaptive measures do not have a high priority in planning in
the Middle Eastern countries (Sowers et al. 2011). These countries
pursue their aggressive development plans, relying on historical
conditions with no climate change effects.
In Iran—the second largest country in the Middle East—
hydropower production has a key role in supplying the peak power
demand. The first Iranian hydropower plant was built in 1961 on
the Dez River. Since then, Iran has been actively developing hydro-
power projects. Depending on the hydrologic conditions, hydro-
power represents 6–15% of the nation’s electricity and is the
largest renewable energy source in Iran. The present installed
hydropower generation capacity is approximately 9,000 MW and
is expected to reach 28,000 MW in the next two decades based
on the development plans of the Iran Water and Power Resources
Development Company (IWPCO), a state agency that is respon-
sible for construction of dams and hydroelectric power plants
in Iran.
Most of Iran’s hydroelectric generation capacity is concentrated
in three major river basins, namely, the Karun, Dez, and Karkheh
River Basins. The Karkheh River Basin is the third most productive
basin in Iran in terms of total surface water flow and potential
for hydropower generation. The current total available surface
water storage capacity accounts for only 40% of the potential
surface water storage capacity of 15,000 million cubic meters
(MCM). Therefore, IWPCO is in the process of expanding the
1Assistant Professor, Dept. of Engineering, Islamic Azad Univ., Central
Tehran Branch, Tehran 1965916954, Iran (corresponding author). E-mail:
sae.jamali@iauctb.ac.ir
2Professor, Dept. of Civil Engineering, Sharif Univ. of Technology,
Tehran 1136511155, Iran. E-mail: abrisham@sharif.edu
3Alex Alexander Assistant Professor, Dept. of Civil, Environmental and
Construction Engineering, Univ. of Central Florida, Orlando, FL 32816.
E-mail: kaveh.madani@ucf.edu
Note. This manuscript was submitted on November 5, 2011; approved
on January 15, 2013; published online on January 17, 2013. Discussion
period open until February 1, 2014; separate discussions must be submitted
for individual papers. This paper is part of the Journal of Energy Engi-
neering, Vol. 139, No. 3, September 1, 2013. © ASCE, ISSN 0733-9402/
2013/3-153-160/$25.00.
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hydroelectricity generation capacity in the basin by 2,000 MW by
constructing six new large dams.
Development plans that ignore the potential climate change
impacts are associated with a considerable risk of failure, especially
in developing nations located in water-stressed areas (Brown et al.
2010,2011). Thus, considering the potential effects of climate
change is essential in designing large dam and hydropower projects
to develop systems that are resilient to climate change and its as-
sociated extreme events. Whereas in developed countries adapta-
tion capacity of water resources systems to climate change may
be limited by the design conditions of the existing systems, devel-
oping countries still have a chance to design water resources sys-
tems that provide high flexibility in operations and reasonable
adaptation capacity to cope with climate change. Nevertheless,
timely and early consideration of climate change impacts is neces-
sary to designing and developing systems that are less vulnerable to
climate change.
Given the value of hydropower, both developing and developed
countries have a serious need to study climate change effects on
hydropower production to prepare for future climatic and socioeco-
nomic changes. Therefore, several researchers have studied the
climate change effects on different aspects of hydropower sys-
tems at different scales around the world. Example studies include
studying the climate change impacts on hydropower production in
New Zealand (Garr and Fitzharris 1994), eastern United States
(Robinson 1997), Switzerland (Westaway 2000;Schaefli et al.
2005), Sweden (Bergström et al. 2001), Nepal (Agrawala et al.
2003), the Colombia River Basin (Payne et al. 2004), the Colorado
River Basin (Christensen et al. 2004), United States Pacific north-
west (Markoff and Cullen 2008), California (Medellin-Azuara et al.
2008;Vicuna et al. 2008;Madani and Lund 2010;Connell-Buck
et al. 2011;Guégan et al. 2012a,b), and Canada (Minville et al.
2009,2010); studying the effects of climate change on financial
aspects of hydropower projects (Harrison and Whittington 2001;
Harrison et al. 2003); and studying the climate change impacts
on legal aspects of hydropower systems (Madani 2011;Viers
2011). Reviewing the existing literature reveals the limited concern
of developing countries, especially the Middle Eastern countries,
about the vulnerability of hydropower systems to climate change
because most studies of the subject belong to researchers in western
countries. Climate change has become an issue of concern after
development of hydropower projects in the developed world,
whereas the developing countries ignore climate change effects
during hydropower design and development phases. This is despite
the fact that developing countries can benefit more from proactive
assessment of climate change effects on hydropower projects
than reactive assessment because the former can reduce the cost
of climate change to such countries and modify irreversible devel-
opment plans early on, before the massive hydropower projects are
implemented.
Given the value of hydropower and its current development
status in the Middle East, the objective of this study is to assess
potential vulnerability of an example Middle Eastern hydropower
system to climate change. Iran’s Karkheh River Basin hydropower
system has been selected for the Middle East and developing world
as an example to underline the value of proactive assessment of
climate change impacts on hydropower to minimize the potential
costs of climate change to hydropower systems.
The paper is structured as follows. The next section describes
the study basin and provides some information on previous regional
climate change studies. Details of the developed simulation model
are presented in “Hydropower Operations Model”section. The
“Results and Discussion”section presents the obtained simulation
results under a range of climate change scenarios and reflects how
climate change can affect hydropower production in the basin. The
last section concludes.
Karkheh River Basin
The Karkheh River originates from the Zagros Mountains in west
Iran. After a journey of approximately 900 km, the Karkheh River
discharges in the Hoor-Al-Azim Swamp at the Iran-Iraq border.
The Karkheh River Basin (Fig. 1), with a catchment area of
48,000 km2, is located in southwest Iran (between 30–35° northern
latitude and 46–49° eastern longitude). Elevation of the Karkheh
Basin ranges from a few meters above sea level (m.a.s.l.) in the
south to more than 3,500 m.a.s.l. in the northeast. The basin has
a Mediterranean climate and more than 64% of annual water flow
occurs from January to May. The basin experiences high spatial and
temporal variation in precipitation (Muthuwatta et al. 2010).
Whereas the Khuzestan plain and southern area of the catchment
is semiarid with mild winters and long hot summers, the northern
parts and the alpine regions have cold winters and mild summers.
Temperature in this area ranges from −25 to 50°C. The average
annual rainfall in the basin varies from 150 mm in the south to
1,000 mm in the north and the east upper Karkheh River. The aver-
age annual flow of the Karkheh River is 5,916 MCM.
The Karkheh River Basin includes approximately 9% of the
total irrigated area of the country and provides 10% of the total
nationally produced wheat (Marjanizadeh 2008;Muthuwatta et al.
2010). Agriculture production, urban water, and fish farming are
the most important water consuming activities in the basin. In
the upper basin, areas with both rainfed and irrigated agriculture
are practiced, but in the lower basin, only irrigated agriculture is
possible because of the drier conditions.
Karkheh River Basin
Dam
Hydropower Plant
River
Karkheh River
Kashkan River
Saymareh River
Qarasou and Gamasiab catchments
Koran Bozan Dam and Hydropower
Saz Bon Dam and Hydropower
Saymareh Dam and Hydropower
Karkheh II Dam and Hydropower
Garsha Dam and Hydropower
Tangeh Mashoureh Dam
and Hydropower
Karkheh Dam and Hydropower
Hoor Al Azim Swamp
Fig. 1. Schematic of the Karkheh River Basin
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The Karkheh Reservoir with the storage capacity of 5,600 MCM
(active storage capacity of approximately 4,600 MCM) and the
Karkheh hydropower station have been in operation since 1999.
Given the great potential of the Karkheh River Basin for hydroelec-
tric generation, five additional large hydropower dams are already
under study, and one dam is under construction. Characteristics of
these dams and their tentative locations are shown in Table 1and
Fig. 1, respectively.
Average annual flow of the Karkheh River is approximately
36% of the total planned storage capacity. The high ratio of storage
capacity to river flow may make the system vulnerable to natural
climatic changes that are expected to affect water availability in the
basin. Jamali et al. (2012) studied the hydrologic effects of climate
change on the Karkheh River Basin by downscaling the results of
two general circulation models, namely CGCM3 and HadCM3,
under three emission scenarios, i.e., A1B, A2, and B1. Results were
obtained for three 20-year horizons, i.e., 2020s (2011–2030),
2050s (2041–2060), and 2080s (2071–2090). Both CGCM3 and
HadCM3 outputs for all emission scenarios showed an increase
in downscaled monthly mean temperature over all months in all
considered time horizons. An average temperature increase of ap-
proximately 0.9, 2.0, and 2.5°C are expected in the basin under the
future climate change scenarios in the 2020s, 2050s, and 2080s,
respectively. The projected increase in mean temperature is higher
Table 1. Karkheh River Basin Reservoirs
Reservoir Current condition
Normal level
(m.a.s.l)
Normal storage
(MCM) Purpose
Installation
capacity (MW)
Karkheh Under operation 220 4,616 Hydropower/Agriculture 400
Saymareh Under construction 720 2,474 Hydropower 480
Garsha Under study 1,245 1,385 Hydropower 280
Koran Bozan Under study 1,090 3,350 Hydropower 330
Saz Bon Under study 850 1,576 Hydropower 360
Tangeh Mashoureh Under study 1,400 1,640 Hydropower/Agriculture 154
Karkheh II (Run of the River Karkheh) Under study 375 317 Hydropower 300
za
S
nazoBnaroK
a
hsra
GBon Saymareh
Mean Monthly Inflow (MCM)Mean Monthly Inflow (MCM)Mean Monthly Inflow (MCM)
0
200
400
600
800
1000
1200
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
0% 20 % 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20 % 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20 % 40% 60% 80% 100%
Exceedence Probability (%)
0
200
400
600
800
1000
1200
1400
0% 20% 40% 60% 80% 100%
Exceedence Probability (%)
Historical
HadCM-A1B HadCM-A2 HadCM-B1
CGCM-A2 CGCM-B1
CGCM-A1B
Fig. 2. Inflow exceedence probability curves for each dam in different time periods
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in the months of June, July, and August in comparison to other
months. The annual amount of rainfall is not expected to change
considerably, but rainfall timing will change. As a result, peak rain-
fall will shift from spring to winter. Climate change can lead to
considerable reduction in streamflow. Average streamflow reduc-
tion of 5, 15, and 27% are expected in the basin under the future
climate change scenarios in the 2020s, 2050s, and 2080s, respec-
tively. Currently, the hydropower systems of the basin are fed by
the streamflow resulting from precipitation in winter and spring
months and snowmelt during the spring. Under climate change,
peak streamflow shifts to earlier months because of earlier snow-
melt and more precipitation in the form of rain rather than snow
(Jamali et al. 2012).
The expected changes in the magnitude and timing of stream-
flows can affect hydropower operations in the basin. Therefore,
early investigation of the potential effects can help the decision
makers of the basin in revising their hydropower development
plans to prevent inefficient operations in the future.
Hydropower Operations Model
In this study, MODSIM (Shafer and Labadie 1978) is used to de-
velop a hydropower operations model that can provide useful in-
sights into hydropower planning and management in the basin. The
MODSIM model facilitates modeling complex water systems
through transforming the river basin to a network of nodes and
Mean Monthly Inflow (
MCM
) Mean Monthly Inflow (
MCM
)Mean Monthly Inflow (
MCM
)
0
400
800
1200
1600
2000
0%
0
400
800
1200
1600
2000
0
400
800
1200
1600
Karkheh II
20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100%
0% 20% 40% 60% 80% 100%
0% 20% 40% 60% 80% 100%
0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100%
Exceedence Probability (%) Exceedence Probability (%)
Exceedence Probability (%) Exceedence Probability (%)
Exceedence Probability (%) Exceedence Probability (%)
0
500
1000
1500
2000
2500
0
500
1000
1500
2000
2500
0
400
800
1200
1600
2000
Karkheh
Historical
HadCM-A1B HadCM-A2 HadCM-B1
CGCM-A2 CGCM-B1
CGCM-A1B
Fig. 2. (Continued.)
(a)
(b)
(c)
0
1000
2000
3000
4000
5000
6000
7000
8000
1979 1982 1985 1988 1991 1994 1997 2012 2015 2018 2021 2024 2027 2030
Hydropower Production (GWh)
Year
2020s
0
1000
2000
3000
4000
5000
6000
7000
8000
1979 1982 1985 1988 1991 1994 1997 2042 2045 2048 2051 2054 2057 2060
Hydropower Production (GWh)
Year
2050s
0
1000
2000
3000
4000
5000
6000
7000
8000
1979 1982 1985 1988 1991 1994 1997 2072 2075 2078 2081 2084 2087 2090
Hydropower Production (GWh)
Year
2080s
Control Period Pessimistic Scenario Optimistic Scenario
Fig. 3. Comparison of the annual mean hydropower production during
the control period with historical climate and during different time hor-
izons for optimistic and pessimistic climate change scenarios: (a) 2020s
(HadCM B1, CGCM A1B); (b) 2050s (HadCM A2, HadCM A1B);
(c) 2080s (CGCM B1, CGCM A2)
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
CGCM-A1B CGCM-A2 CGCM-B1 HadCM-A1B HadCM-A2 HadCM-B1
%
Change in Annual Mean Hydropower Production
2020s
2050s
2080s
Fig. 4. Estimated changes in Karkheh River Basin’s average annual
hydropower production for different climate change scenarios in the
2020s, 2050s, and 2080s with respect to the historical conditions
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links. To find the optimal decision, MODSIM employs a minimum
cost network flow algorithm that solves a linear optimization
problem in a specified time step over a desired planning horizon.
This model uses a capable network flow optimization algorithm,
combining simulation with optimization to determine optimal
flows within the network. Detailed information about MODSIM
can be found in Labadie (2010a,b).
Reservoir operation rules, suggested by the Karkheh River
Basin’s integrated water resource planning study (IWPCO 2011),
are used in developing the hydropower operations model that sim-
ulates the Karkheh River Basin operations under any given climate
scenario. These standard operation policy (SOP)-based reservoir
operation rules suggest matching release to demand as long as the
available storage (AS) exceeds the demand (assuming there is
enough storage capacity and spillage is not required) and releases
the AS otherwise.
The developed model is used to examine the potential climate
change impacts on hydroelectricity production in the basin. The
MODSIM model applies the following equation to calculate hydro-
power generation in high-head power plants:
Pi;t¼MIN½K·Qi;t·¯
Hi;t·eiðQi;t;¯
Hi;tÞ;Pi;maxð1Þ
where for powerplant iduring period t,Pi;t=power output; Qi;t=
water flowing through the turbine (release rate); ¯
Hi;t=mean
effective head; eiðQi;t;Hi;tÞ=plant efficiency as a function of Qi;t
and ¯
Hi;t;K=water-to-electricity conversion ratio; and Pi;max =
maximum generation capacity of the power plant.
On-peak hydroelectricity generation can be calculated as
EP
i;t¼Pi;t×ΔTP
i;tð2Þ
where ΔTP
i;t=total hours of on-peak generation of powerplant iin
time period t. Off-peak hydropower generation of the same power-
plant is then calculated as
Table 2. Average Change in Annual Hydropower Production for Different
Climate Scenarios in the 2020s, 2050s, and 2070s with Respect to
Historical Climate Conditions during the Control Period
Hydropower
plant
CGCM3 HadCM3
Decade
A1B
(%)
A2
(%)
B1
(%)
A1B
(%)
A2
(%)
B1
(%)
Garsha 2020s −18 −12 −14 −11 210
2050s −30 −36 −17 −21 −1−18
2080s −32 −39 −24 −53 −29 −25
Koran
Bozan
2020s −18 −11 −14 −11 210
2050s −30 −37 −16 −26 −1−17
2080s −33 −38 −25 −49 −31 −27
Saz Bon 2020s −13 −6−11 −749
2050s −25 −30 −14 −25 0−18
2080s −29 −32 −23 −33 −30 −23
Saymareh 2020s −13 −6−26 −64−17
2050s −23 −23 10 −28 1−39
2080s −26 −30 −43 −31 −28 −46
Karkheh II 2020s −5−1−4−228
2050s −11 −13 −9−13 −2−11
2080s −16 −16 −11 −14 −15 −14
Karkheh 2020s −4−1−3−208
2050s −11 −11 −10 −13 −5−12
2080s −16 −15 −12 −12 −15 −16
Total 2020s −11 −5−8−629
2050s −20 −24 −12 −19 −2−15
2080s −24 −26 −19 −29 −23 −20
(c)
(b)(a)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Generation (GWh)
Time equal or exceeded (%)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Generation (GWh)
Time equal or exceeded (%)
Historical CGCM-A1B CGCM-A2 CGCM-B1
HadCM-A1B HadCM-A2 HadCM-B1
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0% 20% 40% 60% 80% 100%
0% 20% 40% 60% 80% 100%
0% 20% 40% 60% 80% 100%
Generation (GWh)
Time equal or exceeded (%)
Fig. 5. Total hydropower generation duration curve for three horizons: (a) 2020s; (b) 2050s; (c) 2080s
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EO
i;t¼Pi;t×ðΔTt−ΔTP
i;tÞð3Þ
where ΔTt=total number of hours in period t.
Eqs. (1)–(3) are used to estimate the on-peak and off-peak
hydropower generation. In the original MODSIM formulation,
run-of-the-river projects are modeled as hydropower plants below
reservoirs with no storage capacity and constant ¯
Hi;t. However, this
may not be applicable to the Karkheh II powerplant, which has a
limited storage capacity and is used for regulation of the flow.
Therefore, the following equation is used to estimate the power out-
put of this powerplant:
ΔTKarkheh II;t¼MINK·Qt·¯
Ht·eKarkheh IIðQt;¯
HtÞ
Pt;max
;
×The number of hours per time periodð4Þ
where ΔTKarkheh II;t=number of hours Karkheh II powerplant runs
during period t; and Qt=upstream inflow (volume/time period).
This equation implies that the Karkheh II powerplant is operated at
any time when inflow is sufficient (operation is not limited to the
on-peak and spill times only).
Results and Discussion
The model was run for 18 different climate change scenarios
extracted from a previous climate change impact assessment study
in this basin (Jamali et al. 2012). Fig. 2shows the mean monthly
inflow exceedence probability curves for the six reservoirs of the
basin in different time horizons. These curves result from the op-
eration rules suggested by the Karkheh River Basin integrated
water resource planning study (IWPCO 2011) based on the histori-
cal climatic conditions. The first observation is that there is no
significant reduction in mean monthly inflow to all reservoirs in the
first time period. In fact, for some climate change scenarios, a slight
increase in high flows is expected during the first time period. In the
second and third time periods, a decrease of 25–80% in both high
and low flows is expected for most future climate scenarios. The
magnitude of flow reduction significantly increases in the 2070–
2090 period. Low flows will decrease at all reservoirs. The
projected inflow changes can affect the performance of the basin’s
hydropower systems, having important implications for reservoir
operations.
Fig. 3compares the average annual hydropower production
under the historical climatic conditions during the control period
with that under the optimistic and pessimistic climate change
scenarios during different future time horizons. Generally, optimis-
tic scenarios (from the hydrological standpoint) suggest lower
reductions of annual runoff or even minimal increase in the total
annual runoff. Here, HadCM-B1, HadCM-A2, and CGCM-B1 can
be considered as optimistic scenarios in the 2020s, 2050s, and
2080s, respectively. Pessimistic scenarios suggest higher levels
of decrease in the annual flows. Here, CGCM-A1B, HadCM-
A1B, and CGCM-A2 represent the pessimistic scenarios in the
2020s, 2050s, and 2080s, respectively. The results indicate that
the future average annual production in almost all scenarios will
decrease. The reduction in production in all periods is mainly attrib-
utable to decreasing reservoir inflows under the drier conditions
with climate change.
Fig. 4shows the estimated changes in the average annual hydro-
power production in the basin for different climate change scenar-
ios in different future time periods with respect to the control period
with historical climatic conditions. The expected generation losses
under all scenarios (expect for two climate change scenarios in the
2020s) suggest that the Karkheh River Basin hydropower plants
will not be able to meet the target hydropower generation level,
based on the design specifications, relying on historical climate
conditions. Although the average annual hydropower generation
reduction may not be considerable in the first time period (near
to 3.5%), the expected reduction is considerable in the second
and third periods (15 and 24%, respectively). Table 2shows ex-
pected average variations of hydroelectricity production of each hy-
dropower plant in the basin under future climatic conditions in
different time horizons with respect to historical climatic conditions
in the control period. This table suggests that generally, hydro-
power production is expected to decrease at all plants in the future
(except for two climate change scenarios in the first time horizon).
The greatest hydropower generation reduction is expected at the
Saymareh, Saz Bon, Garsha, and Koran Bozan hydropower plants
in the first time horizon (expect for two climate change scenarios).
Other hydropower plants will not experience serious electricity
production deficits during this period. Decrease in hydropower
production is more significant in the second and third horizons
for all hydropower plants. The Saz Bon, Saymareh, Garsha, and
10
0
20
0
30
0
40
0
50
0
60
0
70
0
80
0
90
0
Generation (GWh)
10
20
30
40
50
60
70
80
90
Generation (GWh)
10
20
30
40
50
60
70
80
90
Generation (GWh)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(a)
(b)
(c)
Fig. 6. Average monthly hydropower generation in the basin for 342
three horizons: (a) 2020s; (b) 2050s; (c) 2080s
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Koran Bozan hydropower plants can experience serious generation
reductions (up to 50%) in these time periods.
Fig. 5shows the total hydropower production exceedence
curves for different climate scenarios in the 2020s, 2050s, and
2070s. The expected hydropower generation reductions become
more significant in the 2050s and 2080s. The significant reduction
in hydropower generation is very important, given the fact that
these reservoirs are already in construction or will be constructed
based on the design plans, which completely ignore the climate
change effects. The inability of the system to meet the target hydro-
power generation reductions is attributable to plans that have been
developed and are in implementation without recognition of cli-
mate change impacts on the Karkheh River Basin.
Fig. 6indicates the average monthly hydropower generation in
the basin for different climate scenarios in the 2020s, 2050s, and
2080s. In the first period, reduction in annual generation is not sig-
nificant. Monthly generation variation in this period ranges from
þ10% in February to −11% in May and June. In the 2050s, gen-
eration losses will be more, and can be up to 31% in May and June.
During the last period, higher hydropower generation reductions
are expected (up to 40% in May and June). Moreover, deficit in
peak of electricity demand can be as high as 20% in this period.
Table 3provides an overview of the estimated average seasonal
and annual hydropower productions in different study periods.
Results suggest that the decrease in the total annual hydropower
generation is mainly attributable to the expected hydropower
generation reduction during spring. The spring’s hydropower re-
duction is expected to increase over time as a result of projected
drier conditions. In Iran, hydropower plays a key role in providing
electricity during warm months when the electricity demand is
higher for cooling. Therefore, the availability of hydroelectricity
is of considerable importance during hotter (summer) months.
The study results suggest that fortunately, hydropower generation
reduction is not significant during summer months.
Conclusions
Potential climate change impacts on hydropower systems of the
Karkheh River Basin were examined in this study. Results indicate
that the expected climate change impacts on hydrological variables
will substantially affect hydropower generation in the basin.
Because of insignificant streamflow reductions in the 2020s, hydro-
power production may not change considerably during this period.
However, serious hydropower generation deficit is expected in the
2050s and 2080s in the Karkheh River Basin. Results indicate that
in the first period, hydroelectricity reduction is less than 4%. In the
second and third periods, reduction may be more than 15 and 23%,
respectively. These significant expected reductions in hydropower
generation under future climatic conditions in the basin suggest
that operation rules and the suggested design specifications for
future hydropower projects in the basin may result in suboptimal
hydropower operations. The Garsha, Koran Bozan, Saz Bon, and
Saymareh hydropower plants are expected to experience serious
challenges in meeting the target generation levels under future
climatic conditions.
Given the limited availability of water resources in the region,
reconsideration of hydropower development plans is necessary to
avoid future failures in meeting the target hydropower production
levels. With timely consideration of future climatic conditions and
appropriate adaptive actions, future undesired conditions can be
avoided in the basin. Such appropriate actions may include revi-
sions of the suggested operations rules and omitting some reser-
voirs and/or hydropower plants from the system, which can be
the focus of future studies. It should be noted that although recon-
sideration of hydropower development plans might not necessarily
result in increased hydropower production, it can result in consid-
erable cost savings by preventing implementation of overdesigned
projects.
Acknowledgments
The authors are thankful to Eisa Bozorgzadeh, Ali Heidari, and
Mahmoud Talebbidokhti at IWPCO for providing valuable advice
and data.
References
Agrawala, S., Raksakulthai, V., Aalst, M. V., Larsen, P., Smith, J., and
Reynolds, J. (2003). Development and climate change in Nepal: Focus
on water resources and hydropower, Organization for Economic
Co-operation and Development (OECD), Paris.
Bergström, S., Carlsson, B., and Gardelin, M. (2001). “Climate change im-
pacts on runoff in Sweden—Assessments by global climate models,
dynamical downscaling and hydrological modeling.”Clim. Res., 16(2),
101–112.
Brown, C., Meeks, R., Ghile, Y., and Hunu, K. (2010). “An empirical analy-
sis of the effects of climate variables on national level economic
growth.”World Bank Policy Research Working Paper 5357, World
Bank, Washington, DC.
Brown, C., Meeks, R., Hunu, K., and Yu, W. (2011). “Hydro climatic risk
to economic growth in Sub-Saharan Africa.”Clim. Change, 106(4),
621–647.
Christensen, N. S., Wood, A. W., Voisin, N., Lettenmaier, R. N., and
Palmer, R. N. (2004). “The effects of climate change on the hydrology
and water resources of the Colorado River Basin.”Clim. Change,
62(1–3), 337–363.
Connell-Buck, C. R., Medellin-Azuara, J., Lund, J. R., and Madani, K.
(2011). “Adapting California’s water system to warm vs. dry climates.”
Clim. Change, 109(Suppl 1), S133–S149.
Garr, C., and Fitzharris, B. (1994). “Sensitivity of mountain runoff and
hydro-electricity to changing climate.”Mountain Environments in
Changing Climates, Beniston, M., ed., Routeledge, London, UK, 4.
Guégan, M., Madani, K., and Uvo, C. B. (2012a). “Climate change
effects on the high-elevation hydropower system with consideration
of warming impacts on electricity demand and pricing.”CEC-500-
2012-020, California Energy Commission, Sacramento, CA.
Guégan, M., Uvo, C. B., and Madani, K. (2012b). “Developing a module
for estimating climate warming effects on hydropower pricing in
California.”Energy Policy, 42, 261–271.
Harrison, G. P., and Whittington, H. W. (2001). “Impact of climatic change
on hydropower investment.”Hydropower in the New Millennium,
Proc., 4th Int. Conf. on Hydropower Development (Hydropower '01),
Bergen, Norway, 257–261.
Table 3. Average Hydropower Generation in GWh for Annual and Seasonal Periods
Decade Spring Summer Autumn Winter Annual
2020s 1,754 (−8%) 743 (−1%) 699 (−3%) 1,090 (4%) 4,284 (−3%)
2050s 1,402 (−27%) 671 (−10%) 641 (−11%) 972 (−7%) 3,678 (−15%)
2080s 1,219 (−36%) 656 (−12%) 633 (−12%) 940 (−10%) 3,456 (−24%)
Note: The number in parentheses indicates changes with reference to historical data.
JOURNAL OF ENERGY ENGINEERING © ASCE / SEPTEMBER 2013 / 159
J. Energy Eng. 2013.139:153-160.
Downloaded from ascelibrary.org by Syracuse University Library on 09/04/13. Copyright ASCE. For personal use only; all rights reserved.

Harrison, G. P., Whittington, H. W., and Wallace, A. R. (2003). “Climate
change impacts on financial risk in hydropower projects.”IEEE Trans.
Power Syst., 18(4), 1324–1330.
Intergovernmental Panel on Climate Change (IPCC). (2007). Summary for
policymakers. Climate change 2007: The physical science basis. Con-
tribution of the working group I to the fourth assessment report of the
intergovernmental panel on climate change, Cambridge University
Press, Cambridge, UK.
Iran Water, and Power Resources Development Company (IWPCO).
(2011). “Karkheh River Basin integrated water resources planning
study.”Technical Rep., Tehran, Iran (in Farsi).
Jamali, S., Abrishamchi, A., and Marino, M. (2012). “Climate change
impact assessment on hydrology of Karkheh Basin.”Water Manag.,
166(2), 93–104.
Labadie, J. (2010a). MODSIM: Decision support system for river basin
management, documentation and user mannual, Colorado State Univ.
and U.S. Bureau of Reclamation, Ft. Collins, CO.
Labadie, J. (2010b). MODSIM: Decision support system for river basin
management, technical appendices, Colorado State Univ. and U.S.
Bureau of Reclamation, Ft. Collins, CO.
Madani, K. (2011). “Hydropower licensing and climate change: Insights
from cooperative game theory.”Adv. Water Resour., 34(2), 174–183.
Madani, K., and Lund, J. R. (2009). “Modeling California’s high-elevation
hydropower systems in energy units.”Water Resour. Res., 45(9),
W09413.
Madani, K., and Lund, J. R. (2010). “Estimated impacts of climate warming
on California’s high-elevation hydropower.”Clim. Change, 102(3–4),
521–538.
Marjanizadeh, S. (2008). “Developing a ‘best case scenario’for Karkheh
River Basin management (2025 horizon): A case study from
Karkheh River Basin, Iran.”Ph.D. thesis, Univ. of Natural Resources
and Applied Life Sciences, Vienna, Austria.
Markoff, M. S., and Cullen, A. C. (2008). “Impact of climate change on
Pacific Northwest hydropower.”Clim. Change, 87(3–4), 451–469.
Medellin-Azuara, J., et al. (2009). “Adaptability and adaptations of
California's water supply system to dry climate warming.”Clim Chang.,
87, S75–S90.
Minville, M., Brissette, F., Krau, S., and Leconte, R. (2009). “Adaptation
to climate change in the management of a Canadian water-resources
system exploited for hydropower.”Water Resour. Manage., 23(14),
2965–2986.
Minville, M., Krau, S., Brissette, F., and Leconte, R. (2010). “Behaviour
and performance of a water resource system in Québec (Canada) under
adapted operating policies in a climate change context.”Water Resour.
Manage., 24(7), 1333–1352.
Muthuwatta, L. P., Ahmad, M., Bos, M. G., and Rientjes, T. H. M. (2010).
“Assessment of water availability and consumption in the Karkheh
River Basin, Iran using remote sensing and geo-statistics.”Water
Resour. Manage., 24(3), 459–484.
Payne, J. T., Wood, A. W., Hamlet, A. F., Palmer, R. N., and
Lettenmaier, R. N. (2004). “Mitigating the effects of climate change
on the water resources of the Columbia River Basin.”Clim. Change,
62(1–3), 233–256.
Robinson, P. J. (1997). “Climate change and hydropower generation.”Int.
J. Climatol., 17(9), 983–996.
Schaefli, B., Hingray, B., and Musy, A. (2005). “Climate change and
hydropower production in the Swiss Alps: Quantification of potential
impacts and related modeling uncertainties.”Hydrol. Earth Syst. Sci.,
9(1/2), 95–109.
Shafer, J., and Labadie, J. (1978). “Synthesis and calibration of a river basin
water management model.”Completion Rep. No. 89, Colorado Water
Resources Research Institute, Colorado State Univ., Fort Collins, CO.
Sowers, J., Vengosh, A., and Weinthal, E. (2011). “Climate change, water
resources, and the politics of adaptation in the Middle East and North
Africa.”Clim. Change, 104(3–4), 599–627.
Vicuna, S., Leonardson, R., Hanemann, M. W., Dale, L. L., and
Dracup, J. A. (2008). “Climate change impacts on high elevation hydro-
power generation in California’s Sierra Nevada: A case study in the
Upper American River.”Clim. Change, 87(Suppl. 1), S123–S137.
Viers, J. H. (2011). “Hydropower relicensing and climate change.”J. Am.
Water Resour. Assoc., 47(4), 655–661.
Westaway, R. (2000). “Modeling the potential effects of climate change
on the grande dixence hydro-electricity scheme, Switzerland.”Water
Environ. J., 14(3), 179–185.
Zereini, F., and Hotzl, H. (2008). Climate changes and water resources in
the Middle East and North Africa, Springer, Environmental Science and
Engineering, Berlin.
160 / JOURNAL OF ENERGY ENGINEERING © ASCE / SEPTEMBER 2013
J. Energy Eng. 2013.139:153-160.
Downloaded from ascelibrary.org by Syracuse University Library on 09/04/13. Copyright ASCE. For personal use only; all rights reserved.