Albian drilling ’ s and its hydropower potential in Algeria : Study and exploitation Albian

The Continental intercalary groundwater is highly sought for its water as resources hugely mobilized in Northern Sahara. A very high flow rate and output pressure characterizes this groundwater. It amounts from 50 to 400 l.s-1 for the flow, and from 5 to 40 bar for pressure. A survey of the Northern Sahara Aquifer System was essential to prove the existence of this potential. This energy appears into the artesian form, which remains very considerable for a very long time in most borehole. We have realized that this energy is immense, as well as the expanded volume of the groundwater, and the importance of its use in agriculture. Unfortunately, this potential remains untapped to this day and the energy of this water is completely neglected. Several turbo generator and/or inverted pump (PATs) integration tests were undergone. The new concept of reflection with respect to the environment and sustainable development has led us to structure our work towards the extension of this potential in order to extract the exploitable energy.


Introduction
Groundwater can be found in many forms.They may be in the form of free groundwater "aquifers", where the water level in the borehole corresponds to that of groundwater.Some groundwater are found confined deep down impermeable layers and thus contain under pressure of water.At the end of the 19th Century, the emergence of borehole in the Northern Sahara Aquifer System (NSAS) was intended to give new impetus to the development of the Sahara (PNUD- UNESCO, 1972).
Qualified in 1945 as "the greatest hydraulic system of the Sahara" by Savornin (1947) in Dubost (2002), and studied extensively in Dubost (2002).Covering an area of 600 000 km 2 and containing 50 000 billion m 3 of water in reserve (Hellal & Ourihane, 2004).It was presented in the sixties (Cornet, 1961) as the final solution to aridity and underdevelopment of the region (Figure 1).
Taking cue from the study by BURGEAP in 1963 (FUEL DIRECTION in France), a more quantified approach of hydraulic phenomena was reached.Other studies have been initiated by several authors on the use of geothermal energy of this water (Benhammou & Draoui, 2012;Hellel, Bellache, & Chenak, 2006;Salima Ouali et al., 2011;S Ouali, Khellaf, & Baddari, 2006;Saibi, 2009;Zouakh, Ferhane, & Bounouni, 2016), but no studies on the use of the hydraulic energy of the NSAS water has reached any results to this date.

ETSOURI, KACI, AND BOUAZIZ
The water that comes out of this source is too demanding of energy.It requires an engine running at a minimum of 30 Kilowatt to allow direct use.Yet the energy released from the gushing water borehole is not to be underestimated especially since we already lose it out at the start.
The collection of information on the Continental Intercalary, the study of the behavior of water at the outlet of borehole and quantification of the borehole water energy potential, are milestones data required for proper understanding of the situation.
Loss and unused energy from the water that came at a high pressure are the consequences of the use of water cooling tower.After the incorporation of a turbine engine in the circuit, the use of the smallest available energy has made the installation profitable (Pugliese, De Paola, Fontana, Giugni, & Marini, 2016).Source: Hellal and Ourihane (2004) The first application of geothermal energy from the Continental Intercalary groundwater was conducted in 1990 for heating greenhouses in southern Algeria (Saibi, 2009).
The exploitation of geothermal energy for greenhouses heating is too modest compared to the great potential geothermal resources in southern Algeria (Salima Ouali et al., 2011).
In Algeria, aquaculture is still in its beginning.Some projects of fish farming have been promising in South Algeria with use of the Continental Intercalary water (Zouakh et al., 2016).
The exploitation of the Continental Intercalary groundwater almost exclusively goes to agricultural use with nearly 1,95 billion cubic meters.The consumption of drinking water represents less than 10 % of the global exploitation according to (Khadraoui, 2006).
Continental Intercalary model as conducted by the PDGDRS's study has long established several simulations of various operating assumptions of the Continental Intercalary groundwater.We have recapped the report of the CDARS (1999b), to show the necessary elements, noticeably, the persistence of artesian flow for a longue time period in some areas of the Northern Sahara (up to year 2038).

State of the borehole
An inventory of all water points of the Northern Sahara and evaluation of the collected flows were completed by ANRH (National Agency of Hydraulic Resources).The results of this survey are presented in the Table 2.The Continental Intercalary groundwater The water quality of the Continental Intercalary, according to CDARS (1999a), varied between good (total mineralization <1,5 g.l -1 ) to very good (<0,5 g.l -1 ) on its outcrop zones, and was saltier near the sector of In Salah and relatively good in Ghardaia, Ouargla and El Oued (<2,5 g.l -1 ) (Table 1).This increased salinity is associated with increasing temperature, which exceeds 50°C for depths over 1500 m (Hellal & Ourihane, 2004;OSS, 2003).

Choice of borehole
The study of the Albian energy is focused on a newly constructed borehole, which showed no major problems affecting its production (Djamaa in El Oued Wilaya).The water of this borehole arrives to station head at a pressure of 18.10 5 Pa, a temperature of 50 °C and a flow of 100 l.s -1 .The borehole includes a water cooling tower by 16 meters high, including a hot air exhaust fan of 5 m diameter rotating by a motor of 30 kW.The electricity is routed to the borehole from conventional distribution network (Figure 2).The useful exploitable pressure is the one at the upstream output of the water cooling tower.This pressure will be calculated according to Equation (2) of Bernoulli, taking into account all existing load losses.We get a working pressure of 16.10 5 Pa (allowing, after calculation, a total pressure loss amounting to 2.10 5 Pa).
With ZA the reference level, ZE the Coast point "E" in relation to the reference, VA equals VE, PA is 18.10 5 Pa and DHA-E which is 1,4 m representing the total pressure loss between "A" and "E" (Figure 2 and Figure 3).
Flow rate entering the turbine is the amount of water arriving at the inlet of the turbine (the exit of water on upstream cooler).In our case, it is about 100 l.s -1 .The different cases we can encounter in the field are presented in Table 3.
A Hydraulic power amounting to 50 kW is obtained from a borehole of low potential, which is the power required to run a water cooling tower, to lower the temperature of the water from 70 to 35 °C.Whatever the characteristics of available borehole, they are able to provide a significant energy potential to be used for self-sufficiency neighboring farms.

Study of energy potential of borehole
The exploitable potential Pexp represents the hydraulic power available.The following formula is derived from the basic equation of power.
With Qt (m 3 .s - ) the flow rate entering the turbine, and Pr (Pa) the useful pressure.Source: Authors.

Energy transforming and device integration
Inverted pump (PATs) The excess head can be exploited for hydropower generation by using Pumps As Turbines (PATs) (Giugni et al., 2014).
PATs are pumps running in reverse mode, by inverting flow direction and using the electric motor as a generator (Chapallaz et al., 1992;Tamm et al., 2000).Only in recent years, the benefit of the use of PATs in water distribution networks was pointed out (De Marchis et al., 2014), and so recovering energy using micro hydropower turbines on the flow of wastewater by the use of multiple pump-as-turbines in parallel is studied by (Power et al., 2017).Jain and Patel (Jain & Patel 2014) provided a comprehensive review of the state-of-the-art of PATs, summarizing the main researches carried out (Pugliese et al., 2016).
The energy diagram shown by (Chapallaz et al., 1992) details the distribution of energy before and after the turbine.There is a good part of the total hydraulic energy that was absorbed by the turbine and which had to be transformed into electrical energy through the generator coupled directly to the shaft of the turbine.
The information necessary to calculate the power of the turbine inlet are obtained on the nameplate of motor -pump device.Hydraulic power is measured.
The generator output voltage is dependent on the number of rotations made by the turbine.The water gushes out of the turbine with an unused kinetic energy and discharged into the pool.The efficiency of the turbine is represented by the power supplied by the turbine divided by the power.
The PATs is subject to practically no effort since the latter is fed on water supplied by the tank, which pours it in the same tank.We obtained turbine efficiency of 22 %.
The groundwater level of the water tower is substantially fixed (level regulator); the electrical parameters of the PATs are invariable for a fixed output load.These require a constant hydraulic power at the input of the device.

Experimental turbine
The turbine dimensions are essentially derived from experimentation (Figure 4).After establishing some hypotheses (on the diameters to be chosen from the standard diameters), we obtained different dimensions.4. The number of rotations according to the flow moves in a linear regression with a slope of 3,83.Source : Authors The dimensions selected for the diameter of the turbine wheel as well as for the pipe are respectively 0,28 m and 0,10 m, allowing an important coupling.The energy line is used to determine the distribution of energy (potential and kinetic), pressures and losses, and energy gains along a hydraulic circuit (Figure 5).
to everyone (Mohammadabad & Riordan, 2000) might be used in the future.
Small hydropower is one of the most attractive and probably the Oldest environmental friendly energy technology (Ferreira et al., 2016).Small hydro potential is available on small rivers, canal heads, canal drops and Continental Intercalary borehole but only in the Northern Sahara.
However, we must consider that available hydraulic power gradually decrease over time due to aging borehole (CDARS, 1999a), as well as construction of other producing borehole and the growing interference of the fields of neighboring boreholes (M'ghaier, Djamaa and Touggourt) and therefore, the size of these groups must take account of these factors.

The micro hydropower in farms
Water cooling : The water arrives in the drill head at a pressure of 10.10 5 to 30.10 5 Pa and at a temperature of 40 to 80 °C (Hellal & Ourihane, 2004;S. Ouali et al., 2006).This water, although abundant, is inadequate for direct use in agriculture including irrigation because its temperature is very high and can create in the plant certain reticence (Seasholes & DeVoil, 1998).
The water seeps through holes inside the cooler.It is set at the temperature of 30 °C on the cooling tower by forced ventilation through the transfer of heat by evaporation (Declaye, Gendebien, & Lemort, 2016).
Cooling the water is achieved through the water burst into fine droplets on metal plates (Declaye et al., 2016;Oussedik, 2001).Atmospheric air, in contact with the water is heated and passes from the ambient humidity to a dampness close to saturation by evaporating a portion of the chilling water (Oussedik, 2001).The heat balance is shown in the Table 5.
Table 5.Heat balance of the cooling tower

Synthesis of the situation
The hydraulic power currently available within the borehole in exploitation is considerable; 250 kW and 150 kW at M'ghaier and Djama'a in Oued Souf (Table 3).Such hydraulic power can be usefully exploited for its transformation into electrical energy through turbine generators or inverted pumps (Ferreira, Camacho, Malagoli, & Júnior, 2016;Giugni, Fontana, & Ranucci, 2014).
Several type of turbine are used in micro hydropower (Branlard & Gaunaa, 2014;Kline, 1985;Simão & Ramos, 2010).It is difficult to settle for a turbine type, due to the nature of water energy.To simplify the matter, a trial with an experimental turbine to bring out this energy potential is to be undertaken.The integration of a turbo generator group is essential.An expert system named Small Hydropower Advisor (SHA), which was developed to make both the technical and legal issues behind a hydropower development accessible and understandable

ETSOURI, KACI, AND BOUAZIZ
The water-cooling tower is at a forced ventilation.The extraction of the hot and humid air is performed through an extractor of 5 m diameter, thus requiring a motor of 30 kW power.All this power is supplied from the national power grid.However, the existence of the Continental Intercalary hydropower, avoid to bring the external energy and waste that which is already available.The available energy from a single borehole may be more than enough for the extractor (Table 3).The rest of this energy can be used for other purposes in the neighboring farms.
Irrigation : Farms in the regions where the groundwater of Continental Intercalary is located, depends on Albian borehole.The location of the boreholes is very important to minimize the energy and financial expenses (Okot, 2013).
Farm's irrigation takes an important place in the invoice of expenses (Benmihoub & Bedrani, 2012).To make water reaches the last ramp of the pivot, a submersible pump of about 25 kW is recommended (Bruno Molle, Cyril Dejean, Daniel Colin, Jean-Marc Deumier, & Marsac, 2014) working for 18 hours non-stop.Peak hours cannot be avoided.
The fit out of a number of borehole with turbo-generator would supply the energy needs of the exploitation as well as surrounding ones.Indeed, it depends on the available water energy, the installed turbine and the irrigation system.At the end of the line, the integration of suitable turbine is possible, like the Schneider turbine that can generate power from relatively low-head hydroenergy sources such as rivers and irrigation canals (Morcos & Mikhail, 1986).
Amenities of neighboring farms : Farmers still need energy to develop cultivation, irrigation, farming, and personal comforts of their farms (Sourisseau, 2014;Weiland, 2013).
The need for light, ventilation, cooling water, packaging of milk and other products requires energy (Zahm et al., 2015).
The energy provided by borehole water can be enough to make up for a large part of these needs.Energy provided under thermal form may also be necessary during coldest times for heating greenhouses and surrounding installations (Dehina & Mokhtari, 2012).

Environment's turbine integration impact
Any hydroelectric development project has an impact on the environment and regional planning (Mottet & Lasserre, 2014;Perrin, 2015).They should always be within the sustainable development.But today, in most cases, technical solutions aid to limit the impact of these facilities on the local environment at quite acceptable level (Perrin, 2015).
The electrical set up includes the installation of electric poles, and the installation of voltage transformers.The integration of hydropower plants removes the previous installation and avoids hidden problems.Moreover, above all, because of its advantages and benefits, with low environmental impact, the small hydropower plants can be located closer to consumer centers.It is characterized by a small-occupied area and buildings with low environmental impact (Capik, Osman Yılmaz, & Cavusoglu, 2012;Nautiyal, Singal, Varun, & Sharma, 2011;Okot, 2013).

Conclusion
The quality of life and safeness of the present and future generations are strongly intertwined with the availability of energy sources and the sustainability of the energy infrastructure (Stambouli, Khiat, Flazi, & Kitamura, 2012).
Water's resources in Algeria are estimated at 18 billion m 3 , of which 10 billion m 3 of surface resources, 2,5 billion m 3 of groundwater resources in the North and 5,5 billion m 3 mainly underground in the South (MRE, 2014).Therefore, one of the fundamental priorities for a country such as Algeria is to use several renewable energies (RE) sources and environmentally friendly energy conversion technologies (Stambouli et al., 2012).
Undoubtedly, the Continental Intercalary is an asset for the economic development of the Algerian Sahara especially in areas where this source is shallow and gushing.
The Albian groundwater is a huge reservoir providing power without restraint.The lifetime of this energy is limited to maximum 40 years according to the simulations already made (OSS, 2003); subject to significant climate change.
The energy generated by a commonly used borehole is about a hundred kilowatts.The minimum estimate is 35 kilowatts in most artesian borehole.
The level of production of small hydroelectric power plants is insufficient, contributing very little to Algeria's energy balance.Production of hydraulic sector represents only 389,4 GWh of 28 950 GWh generated by the SPE power generation subsidiary company of Sonelgaz, while the bulk of electricity production (18 723 GWh), is provided by gas (Hamiche, Stambouli, & Flazi, 2015;MEM, 2014;Stambouli et al., 2012).
It seems crucial to make attention to these energies, not to develop mass production, but to save, control and orient the distribution of conventional energy; assuring that a sustainable development is respected.

Figure 3 .
Figure 3.Leading connection-seen from the back.Source: Authors

Figure 2 .
Figure 2. General diagram of the borehole.

Figure 4 .
Figure 4. Experimental turbine after machining and cleaning.In the left: Shell of the turbine, in the right: the wheel of the turbine.Source: Authors For each pair of data (DC [diameter of the pipe]; DT [Diameter of the impeller]), we have established the number of rotation N for various existing rates which are presented in Table4.The number of rotations according to the flow moves in a linear regression with a slope of 3,83.

Figure 5 .
Figure5.Energy diagram of a turbine in an installation, with "Z" reference height, "P" pressure "g" acceleration of gravity "r" the density and "v" the flow velocity.Source: Authors Figure6, shows a longitudinal section of the modelled turbine.This cut allows distinguishing the internal components.

Figure 6 .
Figure 6.Cross section of the experimental turbine.Source: Authors

Table 1 .
General data on the groundwater of the Continental Intercalary in Algeria

Table 2 .
Water use and state of the Continental Intercalary borehole

Table 3 .
Exploitable potential of Albian borehole in different cases

Table 4 .
Number of rotation for the different flow