1. A pre-feasibility study evaluated building a 1000 MW pumped storage hydroelectric plant in Saudi Arabia to help meet peak electricity demands. Three potential sites were identified - two using seawater at a coastal "Magna" site, and one using an existing freshwater reservoir at the Baysh dam site. 2. Capital costs were estimated to be $1.45 billion for the Magna site using corrosion protection on seawater components, $1.35 billion using desalination instead of corrosion protection, and $1.41 billion for the Baysh dam site. Social and environmental impacts were expected to be minimal due to the remote locations. The study concluded any of the three options could provide the needed

1. 1
Pre-Feasibility Study of a 1000 MW Pumped Storage Plant in Saudi Arabia
Willy Kotiuga, Souren Hadjian, Michael King
SNC-Lavalin Inc., Hydro Division, Canada
Luai Al-Hadhrami, Mohamed Arif, Khaled Yousef Al-Soufi
King Fahd University of Petroleum and Minerals, Saudi Arabia
Abstract
Electricity demand has grown in the Kingdom of Saudi Arabia at a very fast pace and
there are large differences between the summer and winter peak loads as well as
between morning and evening peak loads. Thus, the predicament facing the Saudi
Arabia power sector is how to reduce the requirement and investment for new thermal
peak plants in order to meet the rapidly increasing short-term peak demands.
To ensure a reliable power supply, the system needs expensive peaking units to
operate just for a few hours during the whole year. To reduce the peak thermal
generation, the possibility of building pumped storage hydroelectric power plants is
being considered. During the off peak generating hours, when surplus generation is
available, the pumped storage plant will pump water to an upper reservoir, and then use
this stored water for hydro generation during peak load hours.
The scoping study started in April 2012 showed that a 1,000 MW pumped storage plant,
that could generate power for eight hours, would eliminate the need for 1,000 MW
thermal plant burning heavy fuel oil. It also identified a number of potential sites that will
be ranked using Multi-Criteria Analysis (MCA) to combine criteria such as: geological
conditions; environmental and social impacts, capital cost and economic viability; as
well as access to the transmission grid. The major challenge is the limited experience in
using seawater for pumped storage. Mitigation of corrosion effects from seawater is a
major issue and may become a significant cost factor. Saudi Arabia’s extensive sea-
water corrosion mitigation experience and world-wide experience from tidal water power
projects will be integrated in the solutions proposed for the first large scale sea-water
pumped storage plant.
This paper presents the results of the prefeasibility study which includes: impact on
meeting the peak demand, site selection criteria, integration to the existing network and
pumped storage plant configuration.

2. 2
STUDY OBJECTIVES AND APPROACH
Objectives
The study’s purpose was to address the developing problem in Saudi Arabia of the
varying demand load shape, on both hourly and seasonal basis, which is compounded
by the rapidly increasing electricity demand in the Kingdom’s power system. Since the
power supply is entirely thermal, the economics of generation can be significantly
improved if there is a mechanism for levelizing the demand being met by the thermal
plant generation.
The study examined possibilities for pumped storage hydroelectric generation to at least
partially levelize the demand on the thermal system, whereby water is stored at an
upper reservoir during off peak hours, and then used for generation during peak load
hours. This reduces the demand on the thermal system during peak hours and utilizes
relatively low cost thermal plant during the off peak pumping hours. The cost of this off
peak pumping to storage is primarily the fuel cost for thermal plants operation during off
peak hours.
The three main objectives of the study included:
• Analysis of the load curve characteristics to develop a relationship between load
factor modification and installed capacity and storage from pumped storage to
determine ‘optimal’ sizing
• Identification and evaluation of potential sites, including the redevelopment of
existing water storage projects
• Provide an preliminary environmental and economic assessment of these
potential sites
The study evaluated both new sites, originally expected to be using seawater, pumped
to adjacent high ground as well as the possible redevelopment of existing freshwater
storage dams with the addition of upper reservoirs and pumping/generation facilities.
Overall Study Components
The three main components of this project were: (i) a scoping study, (ii) project
identification, and (iii) environmental and economic assessment.
The Scoping study included:
• Review of international practices as part of the process to develop project
criteria, especially as related to seawater use.
• Analysis of load characteristics, hourly and seasonal, as well as future
projections
• Study of installed capacity ranges, in order to relate project size to thermal
demand modification
• Development of siting criteria to provide the basis for project site identification

3. 3
Project identification is closely related to the scoping study, it included:
• New site investigations to identify sites meet the siting criteria (physical
parameters, related to storage and cost efficiency)
• Assessment of pumped storage options for existing storage dams
• Ranking and selection of candidate sites for environmental and economic
assessment
The environmental and economic assessment followed the project identification
phase and was applied to only the selected possible sites, including:
• Preliminary environmental and social impact assessment to determine if there
are any major risks associated with the selected sites
• Economic evaluation to determine the costs and benefits associated with each of
the selected candidate sites
• Development of overall implementation schedules for the selected projects
The conclusions developed in the study are presented in the following subsections.
RESULTS
International Practice
The purpose of this review was to define current maximum size applications, which
provide a sound indication of economic and design limits, and to investigate experience
in saltwater applications.
Conventional (Freshwater) Plants
A review of conventional international pumped storage development showed that most
experience has been developed by USA, Japan, Ukraine, Germany and France, with
USA and Japan providing about 40% of the total pumped storage installed capacity.
Project data shows that single stage reversible pumped storage units are now being
designed for up to about 800 m head, and in the next decade this limit may increase to
about 900 m. Higher heads may be developed using multiple stage arrangements,
however for the purpose of this study a practical limit of about 800 m head and single
stage units were assumed.
The largest power stations in the world are in the 2000 to 3000 MW range. However
plants sizes in the 1000 MW to 1500 MW range are more common and, typically in
these larger stations, the units sizes are in the 300 to 400 MW range.
The analysis of the load shape for the system and sizing of existing thermal united
showed that an installed capacity of 1000 MW with ability to supply full capacity for eight
hours would be required. Thus, for the purpose of evaluating alternative sizes a typical
station configuration, such as 4 x 250 MW units with a maximum head of 800 meters
was taken into account.

4. 4
The other parameter of interest was the relation between head (elevation difference
between upper and lower reservoirs), and the distance between reservoirs
(approximately the overall water conduit or tunnel distance). Clearly, the shorter the
distance in relation to the head the more cost effective the layout is. Comparison of this
parameter (L/H) showed that plants being developed were almost always with a ratio of
less than 10. Thus, for a maximum head of 800 m, the maximum distance between the
upper and lower reservoirs should be less than 8 km.
Seawater Plants
Experience of pumped storage using seawater is limited to a single project in Japan, the
30 MW Okinawa project with a head of 136 m, operating since 1999. Its small size
allowed very expensive corrosion protection to be applied, and plant performance has
been successful. A much larger plant, with about the same head, is at the conceptual
study stage in Ireland.
No direct information was found on the cost of erosion protection needed for a seawater
plant, or the overall reliability and life of such protection. However, this protection would
have to include extensive epoxy painting, cathodic protection and prevention of
saltwater leakage from the system.
Load Shape Modification
The analyses considered the growth in the demand for the central, eastern, western and
southern operating systems separately for the period up to 2028 and then, based on
planned internal interconnections, analyzed the effect on construction of a 1,000 MW
pumped storage on the system thermal requirements. The analyses used hourly load
patterns for 2011.
The analyses showed that the plant would operate between May and October, with a
typical operating pattern of 8 hours during the peak period and 12 hours of pumping
during the off-peak period.
The major deciding factor for the pumping/generation rate is the Load Marginal Cost
(LMC) in each of the four operating areas. The pumping would be done in off-peak
hours and powered by the marginal thermal unit in the system where the LMC at off-
peak is the lowest – interconnection capacity allowing. Then the pumped storage plant
(PSP) would generate power to replace thermal power during peak hours in the areas
where the LMC during peak hours is the highest – interconnection capacity allowing.
Analyses showed that the LMC in off peak hours was lowest in the western operating
area providing the pumping energy. The maximum benefit would result from supplying
peak generation to the southern area. However interconnection capacity could limit this,
so the analysis of benefits assumed peak supply to the western, central and eastern
areas.
An analysis was done to evaluate the relation between net benefits and plant sizes, and
it demonstrated that benefits increased with plant size. However, if expressed as a

5. 5
function of plant size (and thus investments), benefits decrease rapidly for plant sizes
above 1,000 MW. This provided the basis for selecting 1,000 MW as a nominal
maximum plant size for this study.
Search for Saltwater Sites along the Western Coastline
To identify candidate saltwater sites,
topographic studies were made of the
whole coastline from Aqaba to the
Yemen border, approximately 1800
km. The screening of potential sites
was made using the head limit of 800
m, and L/H of less than 20. The figure
to the right represents the plan view
and profile 20 km parallel to the coast
line.
A total of 27 specific cross sections,
or profiles from the sea, were
identified, and compared for
maximum heads of 500 and 800 m. Three alignments in the Gulf of Aqaba were
identified that met the basic criteria. This provided the initial conclusion that the Gulf of
Aqaba offered the most potential for economic pumped storage development.
The next phase was the identification and comparison of ten potential sites along the
Gulf of Aqaba. The procedure was to identify suitable upper reservoir locations and
then, by inspection, a tunnel alignment linking each of them to the sea.
Three sites, approximately 90 kms south of Aqaba,
provided significantly better cost indicators. In terms
of construction access, the preferred site of these
three, referred to as the Magna site (XS-1), was
selected on the basis of better topography in the
powerhouse / tailrace areas.
The Magna site would provide the following project
parameters:
Installed capacity 1000 MW
Units 4 x 250 MW
Head 755 m
L/H 4.64
Turbine discharge 165 m3
/s
Upper reservoir storage 5 h2
m (total)
Reservoir dam 80 m high x 350 m crest length

6. 6
Existing Dams
The evaluation of existing water storage dams
included seven projects: Rabigh, Murwani, Therad,
King Fahd, Hali and Baysh. Review of adjacent
topography at each site confirmed that in all cases,
the existing reservoirs would have to be the lower
reservoir. Thus, the study sought to locate upper
reservoir options for each, whereby between 300
and 800 m of head could be developed with a L/H
ratio of less than 10-12, and where the upper
reservoir topography was adequate for the required
reservoir size.
Three possible sites were identified for each
existing dam. These upper reservoir sites were
ranked for each project and only Baysh could offer
qualifying upper reservoir site locations. Thus, this
option was retained for more detailed study,
because Baysh would meet the reservoir size
requirement to provide 360 m of head, with a cost
indicator L/H of 11. The existing reservoir and the
proposed new upper reservoir are shown in the
figure to the right.
Selected Sites and Capital Costs
The more detailed studies consisted preparing of preliminary layouts and cost
estimates. The economic assessment concentrated on the best of the coastal saltwater
sites, Magna, and the redevelopment of the existing Baysh dam.
The Magna site was evaluated with two options:
• Use of saltwater taken directly from the sea, with the addition of corrosion
protection, and associated increased capital and maintenance costs (Magna A)
• Use of freshwater from a desalination plant at the tailwater discharge, requiring
the desalination plant and a lower reservoir at sea level, however without
additional costs for corrosion protection (Magna B).
The rational for the desalination option at Magna was twofold:
• The uncertainly in predicting increased costs for erosion protection and the
effectiveness of these measures
• The probability that cost of a desalination plant would be significantly lower than
the cost for erosion protection.

7. 7
Table 1 Summary of Project Options
Item Magna A Magna B Baysh
Installed capacity MW 1000 1000 1000
No units 4 4 4
Head m 755 755 330
Upper reservoir dam height m 80 80 112
Upper reservoir dam crest length m 350 350 400
Plant max discharge m3
/s 165 165 375
Headrace tunnel length m 786 786 832
Headrace tunnel diameter m 5 5 7.8
Powerhouse dimensions m 72Lx21x20H 72Lx21x20H 87Lx5Wx59H
Tailrace tunnel length m 3200 3200 2536
Tailrace tunnel H x W m 6.8x5.6 6.8x5.6 14x14
Desalination plant No Yes No
Transmission interconnection Tabuk Tabuk Jizam
Transmission distance kms 205 205 70
Voltage kV 330 DC 330 DC 330 DC
Project preparation time (years) 7.5 7.5 7.5
Construction time (years) 5 5 5
Capital cost $US (million)
Civil works - direct 279 366 426
Electro-mechanical - direct 485 485 523
Camps/construction power 28 37 43
Transmission 104 104 42
Total direct cost 897 992 1,034
Indirect costs 301 327 353
Total project cost 1,198 1,319 1,387
Environment / social mitigation 14 18 21
Desalination plant (5000m3
/d) 0 15 0
Corrosion protection 239 0 0
Total budget ($US million) 1,451 1,352 1,408
Cost/kW ($/kW) 1,451 1,352 1,408
These costs are essentially the same at the accuracy level of this study. However it
should be noted that the operation and maintenance (O&M) costs for both Magna
alternatives will be higher that for Baysh. Magna A will have higher maintenance and
equipment replacement costs due to corrosion effects. Whereas, Magna B will include
higher operation costs associated with the desalination plant, primarily for power supply
and O&M for the desalination plant itself.
Social / Environmental Impacts
A preliminary social and environmental impact study was included in this study.
Essentially, due to the remote or low population environments for each site, social and
environmental impacts are expected to be minimal.

8. 8
Given that both projects are essentially underground, primary biological environment
impacts will be associated with the reservoirs, and with the construction process.
Mitigation actions will mainly consist of strictly observing the Wildlife Regulations of
Saudi Arabia and ensuring an adequate clean up and restoration of the work sites after
project completion.
However, there will be significant social impacts during construction due to the influx of
construction workers, although these will primarily be housed in camps. Impacts will
essentially occur in the towns of Magna and Baysh, and transport infrastructure will also
be affected
There will be social and environmental benefits that will accrue from the construction
and long-term operation of either project. These are outlined below.
Socioeconomic Advantages:
• Direct or induced generation of local employment.
• Increased economic well-being and spill-over effects in the area
• Availability of back up renewable power generation to the community with an
emission-free source.
• Improved social values due to cross-cultural exchange of communities
• Increased overall social welfare of the energy market, both on the supply and
demand sides.
Environmental Advantages:
• The project will produce electricity without burning fossil fuel. Hence it will
ultimately help in reducing the carbon emission by Saudi Arabia
• The freshwater dam will help increase the groundwater table within the project
area which will benefit the terrestrial environment.
• Preliminary study of terrestrial biological environment indicates that there is no
protected area in or to immediate vicinity of either site.
Economic Assessment
The economic assessment compares and evaluates two options for the seawater
Magna site and one for the redevelopment of the Baysh dam.
• Magna A - Use of saltwater taken directly from the sea, with the addition of
corrosion protection, and associated increased capital and maintenance costs
• Magna B - Use of freshwater from a desalination plant at the tailwater discharge,
requiring the desalination plant and a lower reservoir at sea level, however
without additional costs for corrosion protection.
• Baysh - Addition of a pumped storage plant to the Baysh water storage dam,
using the existing Baysh reservoir as the lower reservoir
Each alternative would provide 1000 MW of peak generation

9. 9
For Magna A, the lower reservoir is not required, hence its capital cost is reduced by the
cost of lower reservoir (M$86 USD). However, an allowance of a 20% increase in costs
was used to take into account the measures required to mitigate the corrosion affects
on the plant, in terms of erosion protection and waterproofing to prevent salt water
leakage.
For Magna B, the capital and O&M costs of the desalination plant have been included in
the economic analysis. Based on the data obtained from various sources on
desalination plant costs, the desalination plant capital and O&M costs were assumed to
be USD 2,900/m3
/day and USD 0.50/m3
respectively. The desalination plant capacity is
assumed to be equivalent to the make-up water requirements, meaning 5,000 m3
/day.
For both alternatives, Magna (Gulf of Aqaba) and Baysh, an allowance for
environmental mitigation costs of 5% of the civil work costs was assumed for the
economic analysis.
The basic comparative parameter used was the benefit cost ratio (B/C). The results for
each of the selected options are provided below:
Magna A – Pumped storage plant with seawater: B/C = 1.31
Magna B – Pumped storage using desalinated water: B/C = 1.49
Baysh pumped storage: B/C = 1.43
A sensitivity analysis was carried out for each alternative, and the B/C ratios were
determined for the following: range of capital cost (+/- 20%), range of purchase price of
electricity for pumping (+/- 20%), range of electricity selling price (+/- 20%), as well as
alternative discount rates of 3% and 7% versus the base case of 5% discount rate.
Payback periods were also determined for each case.
Essentially, positive B/C ratios were obtained for each case, confirming that the results
are robust and not sensitive to assumptions regarding costs and electricity prices. Also,
the ranking between alternatives remained unchanged for each sensitivity case.
CONCLUSIONS
The study’s objective was to provide a high level assessment of whether, and to what
extent, pumped storage could be used as a cost effective and technically viable
approach to reduce future thermal generation costs, and thus overall costs for meeting
the electricity demand in Saudi Arabia.
Based on the study results, which are summarized in the previous subsections, the
following conclusions may be drawn.
Technical Feasibility
Conventional pumped storage using freshwater is in widespread use worldwide. Recent
experience seems to favor plants in the 1,000 to 1,500 MW range. At an initial stage of

10. 10
assessment, the most probable economic plant configuration would be about 1,000 MW
for a head under 800 m.
There is no technical impediment for a conventional pumped storage development, and
there is widespread experience in design, construction and equipment manufacture in
this field.
Experience on pumped storage plants using saltwater is limited to a small research
plant in Japan. Thus, there is no direct experience on which to base technical feasibility
or additional costs for corrosion protection for plants in the 1,000 MW with 800 m head
range.
However, there is significant experience on low head saltwater hydroelectric plants for
tidal power, as well as for corrosion protection in maritime seawater environments.
In conclusion, if a pumped storage plant using with sea water is to be promoted, the
next step would be a mid-size project in the 250 MW with 300 m head range, in order to
allow further development of designs for corrosion protection.
This study considered the option of providing desalinated makeup water for coastal
plants, which would be technically and economically a viable option for the development
of coastal pumped storage.
Load Shape Modification
System simulations showed that the addition of peak hourly capacity from pumped
storage with an associated energy loss for pumping would have a significant effect on
reducing thermal generation requirements and would be economic.
It was also determined that an optimum addition would be of about 1,000 MW, as
benefits as related to plant size and cost would proportionally decrease for higher
installations. Thus further, investigations should target this size range.
Coastal Pumped Storage Sites
Based on topographic studies of the complete Saudi Arabia western coastline, that is
from Aqaba to the Yemen border, it was determined that the most favorable topography
for a cost effective pumped storage development would be in the Gulf of Aqaba.
Based on the screening of ten sites in the Gulf, the most potentially cost effective site
would be near Magna, allowing the construction of a plant of 1,000 MW under a head of
755 m.
The alternatives for the Magna site would be seawater use with corrosion protection
(feasibility not confirmed at this stage) or desalinated water use.

11. 11
Redevelopment of Existing Storage Dams
A study of seven existing water storage dams concluded that the most promising site for
adding pumped storage generation would be the Baysh dam, where the existing
reservoir would serve as the lower reservoir. Topography would limit the plant to 330 m,
however it could be developed with a 1,000 MW installed capacity.
Environment
No social or environmental issues would severely mitigate against pumped storage at
either of the two sites, Magna and Baysh, were identified.
Economics
Based on the three selected alternatives of 1,000 MW, that is Magna with and without
desalination as well as Baysh, costs were similar at $1,350/kW to $1,450/kW, with the
differences being well within the margin of accuracy at this preliminary stage. Estimated
costs included all indirect costs, but without interest during construction and they are
consistent with those from other similar planning studies.
The economic studies showed attractive results for all three options, with the Magna
alternative with desalination being the preferred alternative. Base case B/C ratios were
in the order of 1.3 to 1.5, with payback periods of 11 to 12 years.
Way Forward
In order to reduce future thermal requirements, the study has shown that either coastal
development (with desalination) or redevelopment of Baysh would be viable solutions.
Any decision to undertake further studies should include a non-cost evaluation of the
coastal versus redevelopment concept for the selection of the next project.
The conventional project implementation process could involve at least 5 years for
project preparation, including studies, design and contracting, followed by about 5 years
of construction. The next step would be a detailed pre-feasibility study, involving some
field investigations at the selected site which would take at least one year, followed by a
final feasibility study and environmental assessment.

12. 12
Author Biographies
Dr. Willy Kotiuga is Senior Director, Strategic Studies with SNC-Lavalin Global Power
with over 30 years of experience advising utilities, governments and funding institutions
as well as the private sector on power sector issues. He has been the principal
investigator in the preparation of regional and national power sector plans where he
played a key role in the development of methodologies for forecasting load demand,
assessment of power market opportunities, optimization of generation resources and
economic evaluation of options. He obtained his PhD from the University of Walterloo in
Canada
Dr. Luai Al-Hadhrami is Director of the Center for Engineering Research and Associate
Professor of Mechanical Engineering with the, King Fahd University of Petroleum and
Minerals (KFUPM), Saudi Arabia. He has over 10 years experience in teaching and
applied research in energy conservation and thermo fluids. He has published several
technical papers in refereed technical journals and conference proceedings. Dr. Al-
Hadhrami obtained his PhD from Texas A&M University and MS and BS degree from
KFUPM, Saudi Arabia.
Mr. Mohammed Arif is a Research Engineer with the Research Institute, King Fahd
University of Petroleum and Minerals (KFUPM), Saudi Arabia. He has 30 years of
experience in field of power system planning and power quality studies. He has
published several technical papers in refereed technical journals and conference
proceedings. Mr. Arif obtained his MS in Electrical Engineering from KFUPM in 1985
and BS from Nagpur University, India, in 1980.
Mr. Khaled Al-Soufi is a Research Engineer with the Center for Engineering Research,
KFUPM, Saudi Arabia with over 25 years of experience in applied research in the areas
of high voltage and power systems. He supervises the High Voltage Laboratory and has
managed many research projects including: establishing an electrical equipment testing
laboratory, determining environmental effects on polymer insulators properties,
performance of high voltage insulators, captive power generation policy, and effects of
underground high voltage cables on water trees.
Mr. Michael King graduated from McGill University, Canada, in civil engineering in
1961. He worked for Shawinigan Engineering up to its take-over in 1982 by Lavalin, and
its subsequent fusion with SNC to form SNC-Lavalin in 1991. He has extensive
experience in generation planning and in the planning and design of hydroelectric
projects in Canada, Pakistan, Malaysia, East Africa, Southern Africa, Nigeria, Honduras,
Panama, Bolivia, Argentina and Guyana. He has been involved in the Saudi Arabia
pumped storage study throughout its execution.
Mr. Souren Hadjian is a Senior Engineer with SNC-Lavalin with over 30 years of
experience in the design of the civil works of power plants around the world. He
graduated from Concordia University in Montreal Canada in civil engineering and is a
registered professional Engineer.