Overview and feasibility study for the 300 MW Ifahsa
pumped-storage project in Morocco
P.Baztán, F.J.Baztán, G.Rodríguez
GNF ingeniería y desarrollo de generación (GNFidg)
Acanto, 11
28045 Madrid
Spain
1. Introduction
The Ifahsa pumped storage power station (PSPS) is planned as a reversible hydro electric plant located in
the Oued Laou basin.
The Ifahsa PSPS site is situated approximately 10 km to the north-east of the Talembot dam. It is close to
the confluence of the Es Sarem and the Laou wadis. The Talembot wadi passes approximately 3 km to the
south west of the project and flows into the Laou wadi. The layout of the development is indicated in the
figure below:
Figure 1. Location of the Ifahsa PSPS project.
The Ifahsa PSPS site is close to the P4105 road, 15 km east of the national highway (N2) linking the
towns of Chefchaouene and Tétouan.
The P4105 road linking the towns of Oued Laou and Chefchaouene permits access to the lower sector of
the works but access to the upper sector is difficult as the roads are steep and unsurfaced (see Fig. 2):
↑ Oued Laou
N2 P4105
Site du projet
Chefchaouene
Figure 2. Access: P4105 road between the towns of Oued Laou and Chefchaouene and project site.
1.1. Description of the site
The wadi Laou basin is located in Northwest Morocco in the provinces of Tetouan and Chefchaouen. It is
in the central part of the Rif Mountains also known as the High Rif. It is bordered by the peaks of Jbel
Kelti (1928 m) with Soukna to the west (1800 m) and Tissouka (2180 m) to the south east, Tazoute
(1800 m) is in the north east and the Mediterranean sea is to the north.
The Laou wadi´s basin is small with a surface area not exceeding 930 km² (its maximum east-west width
is 28 km and it is 47 km long north-south) and its main water course, the Laou wadi, has a total length of
70 km.
The upper course of the Laou wadi follows a south-north direction in the region of Chefchaouen. It is
bordered to the east by the aligned peaks of the limestone range and to the west by high numidian peaks.
The medium and lower water courses are situated on the North-Rif slopes and flow in a SW-NE direction.
Despite the relatively low altitudes in this area, (varying between 300 m and 900 m) with the exception of
the coastal plain, it is an extremely rugged area with steep slopes and considerable inclines.
The landscape in this area is characterised by the enclosure of the hydrographic network between narrow
ridges with extremely steep slopes, which at times are like cliff edges and which are extremely steep.
1.2. General presentation of the project
The Ifahsa PSPS project concerns the construction of a Pumped Storage Power Station (PSPS) or pump
turbine plant in a cavern between two reservoirs to be built in the vicinity of the villages of Ibouharane
and Tifiraouine.
The plant has been designed to produce power during peak consumption times, through the flow of water
from the upper to the lower reservoir by means of a turbine. The water will be repumped back into the
upper reservoir when the energy needs are reduced.
The hydraulic system and the machinery cavern are the main components of the project. It consists of the
following elements (see figs 4 and 5):
1. Upper reservoir, on the Talaaf Adrhousse mountain which is an artificial lake covered
with a geomembrane, the peak has an altitude of 934.5 m
2. Upper reservoir water intake
3. Upper hydraulic pipeline with a design flow of Q = 44 m3/s, and 3.0 m diameter
comprising the following elements: supply pipe installed in a trench (length 1.386 m),
vertical pressure shaft (height 311 m), and a section of penstock (33 m)
4. Underground power house comprising two caverns, the machinery cavern and the
transformer cavern
5. A tailrace tunnel designed for a flow of Q = 44 m3/s, 3 m in diameter and a 417 m length
6. Surge chimney in shaft: 118 m high and 5.0 m in diameter
7. Lower reservoir water intake
8. An artificial lower reservoir which is close to the natural flow of the Es Sarem wadi (a
tributary of the Laou wadi) covered with a geomembrane, height of the ridge 175.0 m
2. Background
The companies PROJEMA, ISL and EQUITER carried out a preliminary feasibility study of the Ifahsa
PSPS in December 2002.
In July 2009 GAS NATURAL FENOSA Engineering (GNFe) was awarded the tender for drafting a
study of the Preliminary Project Design (hereinafter the PPD study) and a Feasibility study for the Ifahsa
Pumped Storage Transfer station, pursuant to the call for tenders nº SP0694MP8 issued by the National
Electricity and Drinking Water Office (ONEE).
The studies were compiled in accordance with the following principal phases:
1. Award of the tender to GNF Engineering: July 2009
2. Signature of a contract between ONEE and GNF Engineering: July 2009
3. Previous preliminary studies for the project - review of the preliminary feasibility report
and reference data: July 2009 to September 2009
4. First visit to the site and compilation of new data: July 2009
5. Geology: study of bibliography, aerial photography and visit to site: November 2009
6. Analysis of data and results of preliminary studies: December 2009
7. Definition by GNF Engineering of surveying work schedule leading to feasibility
studies for the option chosen: January 2009
8. Surveying works: January 2009 to November 2010
9. Technical feasibility studies, studies of the different possible variants of the project and
definition of the preliminary equipment outline: December 2011
10. Definition by the Consultant of geological survey schedule required to carry out the
feasibility studies for the option chosen: May 2012
11. Geological and topographical surveys: June 2012 to October 2013
12. Visit to the site following the geological investigation: October 2013
13. Definition of the final solution: November 2013
14. PPD and Feasibility studies: February 2014
3. Summary of the various options
Following to the definition of the original project outline (IFAHSA PSPS pref), a number of site visits
and new geological studies, several variants were put forward for comparison, in order to select the best
option.
The options considered were located in an area between the towns of Tifiraouine, Tinisse, Ibouharane,
Tamtile, Amellil, Ifahsa, and the J.S. Salah hill.
Three possible sites for the lower reservoir were considered from a geological perspective during the visit
to the site, as well as a new site for the upper reservoir.
The waters of the Laou Wadi river were used in addition to two tributaries from the areas of Ifahsa (Oued
Abïyati), and Tamrabète and Tinisse (Es Sarem) as a result of installing upper reservoirs on the hills of
J.S. Salah and the Talaaf Adrhousse mountain with altitudes of 900 m NGM and 960 m NGM
respectively.
Seven alternatives were studied as possible options, as follows:
1. Alternative A1. It is an improved version of the outline of the preliminary feasibility
study with a dam on the hills of J.S. Salah as the upper reservoir and the IFAHSA dam
(which was included in the complementary layout for the existing hydroelectric set up of
the Laou wadi reservoir considered in the pre feasibility study) as the lower reservoir.
2. Alternative A2. It comprises the same reservoir on the J.S. Salah hills as in the A1 option,
as the upper reservoir, and a dam on the Es Sarem tributary as the lower reservoir. The
pipeline in the tunnel under the Laou wadi passes through it.
3. Alternative A3. It comprises the same reservoir on the J.S. Salah hills as in alternatives 1
and 2, as the upper reservoir, and a dam on the IFAHSA tributary as the lower reservoir.
4. Alternative A4. It comprises the same reservoir on the J.S. Salah hills as in alternatives 1,
2 and 3, as the upper reservoir, and a dam on the IFAHSA tributary as the lower
reservoir, slightly downstream of the dam in alternative A3.
5. Alternative A5. It comprises an artificial reservoir on the Talaaf Adrhousse mountain as
the upper reservoir, and the same dam on the Es Sarem tributary as in Alternative A2 as
the lower reservoir. The pipeline is completely underground.
6. Alternative A5.1. This one has the same layout as alternative A5 but with a pipeline
partially on the surface.
7. Alternative A5.2. This one has the same layout as alternative A5.1 but replacing the dam
on the Es Sarem Tributary with an artificial reservoir close to that same natural water
course.
The following figure shows the location of the seven different possible options:
Oued Laou
Tamtile
Amellil
4 Ibouharane Tamrabete
3
Ifahsa
5
5.1 Tinisse
2 5.2
1 Tifiraouine
Tajiniarte
Usine Laou - Talembote
Oued Talembote
Figure 3. Location of the alternatives analysed and the original scheme
Alternative A5.2 was considered to be the best from a technical and cost-related perspective, and
was chosen with a view to further development during the Feasibility Study phase.
Having selected this option, the geological-geotechnical study was carried out.
Finally, in order to perfect the chosen option, a further visit to the project site was organised in October
2013. During the visit, the following changes were added to the A5.2 option in order to finally define
the ideal solution:
Having analysed the topographical and geological data available, it was decided that the site proposed
for the lower reservoir had some disadvantages. As a result it was decided to select a more
advantageous location. A site close to the original location was finally chosen, on a small plateau:
The original location of the A5.2 option had a considerable effect on the natural flow of an
important stream which it would have interrupted, and diverting the waters would have
been difficult, not to mention a definite risk for the reservoir in the event of unexpected
surges.
The new set up will make it possible to divert a less significant stream and as a result it will
be easier to manage.
From a geological perspective, the conditions of the A5.2 option were not as favourable as
those initially planned, and as a result the slopes of the excavation embankments had to be
less pronounced than those established in the aforementioned study of alternative options,
which means that the height of the clearances were more significant.
The conditions of the terrain are more favourable to the new layout as it will allow more
vertical excavation embankments and will reduce the total clearance elevations and the
resulting visual impact.
4. Description of the main characteristics of the solution adopted
The plan for installing the IFAHSA PSPS comprises the following works (Fig..4&5):
Upper reservoir, on the Talaaf Adrhousse mountain forming an artificial lake covered
with a geomembrane and with an altitude of 934.5 NGM, and a useful volume of 793,000
m3.
Upper reservoir water intake
Upper hydraulic circuit designed for a control flow of t Q = 44 m3/s, with a diameter of
3.0 m comprising the following:
An air inlet pipeline installed in a trench (1,700 m length)
A vertical well (205 m high)
A section of penstock (33m)
Underground power house comprising two caverns, the machinery cavern (turbine hall)
and the electrical equipment cavern
Cable outlet shaft 204 m high with external transformer post platform 225 kV with a
surface area of 1,900 m2
A lower hydraulic circuit comprising the tailrace tunnel designed for a flow of Q = 44
m3/s, 3.0 m in diameter and 161.5 m long
A surge chimney in a vertical shaft: 137 m total high and a diameter varying from 3.0 m
to 5,0 m
Lower reservoir water intake
An artificial lower reservoir, on the right bank of the natural flow of the Es Sarem wadi
(a tributary of the Laou wadi) covered with a geomembrane, height of the ridge 175.0 m
NGM, with a volume of 793,000 m3
Pumping station for the first fill of water of the lower reservoir, and refilling of PSPS
evaporation losses with water from the Laou wadi.
Access to the works namely:
An access tunnel to the underground power house with a length of 615 m and 7.5 m high.
The access routes to the works (upper and lower reservoirs, transformer post and surge
chimney).
Features of the IFAHSA PSPS
Number of groups 2
Net average turbine head 753.45 m
Maximum turbine flow 2 x 22 m3/s
Maximum pumping flow 2 x 18.5 m3/s
Turbine power 2 x 150 MW
Pumping power 2 x 150 MW
Synchronous speed 750 rev/min
Table 1. Features of the IFAHSA PSPS
Figure 4. Ifahsa PSPS. General layout of the works. Plant view
Figure 5. Ifahsa PSPS. General layout of the works. Profile
5. PSPS energy performance
The IFAHSA PSPS project will function on the basis of a daily cycle. Every week, the daily cycle will
generate approximately 1500 MWh over 5 hours with peaks in the morning and in the afternoon. The
pumping operates for periods of approximately 6.5 hours during which all the water passing through the
turbines during the day will be pumped to the upstream reservoir.
During this slow period, the PSPS regulates the system and acts as a spinning reserve.
5.1. Volumes and levels of the upper and lower reservoirs in the PSPS
As indicated previously, the characteristic operating heights of the reservoirs will be as follows:
Minimum operating
Normal hold height
Ifahsa PSPS height
[m]
[m]
Upper reservoir 933.70 914.50
Lower reservoir 174.10 155.00
Table 2. Operating levels of the IFAHSA PSPS
The maximum gross head will occur at normal holding levels in the upper reservoir and the minimum
operating level will occur in the lower reservoir. It reaches a value of 778.70 m.
Conversely, the minimum gross head will occur at minimum holding level in the upper reservoir and the
normal holding height in the lower reservoir. It reaches a value of 740.40 m.
5.2. Design flow for pumping and turbines
The maximum turbine power will be 150.0 MW for each unit (300.0 MW total). This power is obtained
for the 2 units in operation at a maximum flow and gross head of (44,0 m3/s - 778,70 m).
The maximum pumping power will be 150.0 MW for each unit, the same value as for the turbine. The
maximum flow will vary according to the gross head at any given time between 32 m3/s (maximum head)
and 3.7 m3/s (minimum head).
The details of the operation of the equipment may be consulted in the sub dossier 2/3. Set up concept.
5.3. Energy produced
The pumping-turbine cycle of the PSPS lasts 24 hours. This is indicated in the following table:
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Hour
1.
2.
3.
4.
5.
6.
7.
8.
9.
Operation P P P P P P P T T T T T
With turbines operating, the PSPS power is 300 MW which will allow a production of 1.5 GWh per day
(hypothetical operation of 5 hours daily)
The 5 hour turbine cycle will complete the 793,000 m3 of useful volume of the reservoirs. With the
variable pumping flow between 32 and 37m3/s, this volume will be repumped in approximately 6.5 hours.
The Authors
P. Baztán M. Sc. in Civil Engineering (Branch Hydraulics and Energy) and Master degree in Business
Administration (MBA) by IESE. He works as International Project Manager in the Hydraulic Engineering Unit. With
more than 25 years of experience, he has led or participated in the design of numerous hydropower plants, both
internally for GNF group and external clients, in Spain and abroad (in more than 12 different countries), from early
stages of potential site identification, prefeasibility and feasibility studies to construction and commissioning.
F. J. Baztán M. Sc. in Civil Engineering (Branch Hydraulics and Energy). He is the Director of the Hydraulic
Engineering Department in GNFidg, belonging to the Hydropower Engineering and Construction Unit. With more
than 23 years of experience, he has managed or been involved in the design, bidding and construction of numerous
hydropower plants, both internally for GNF group and external clients, in Spain and abroad.
G. Rodríguez M. Sc. in Civil Engineering (Hydraulics and Energy Branch), and Master degree in Business
Administration (MBA by ESADE. She works as Project manager in the Hydraulic Power Plants Division. With 13
years of experience, Gemma has led and participated in hydroelectric power plants feasibility studies, preliminary and
detailed hydraulic design and power plants construction management and engineering supervision, for GNF and
external clients.
