ECONOMICAL IMPACT OF USING WIND/PV HYBRID SYSTEMS ON ENERGY SECTOR IN JORDAN

Mohammad AL Zubi, Trilochan Singh, Hesham AL Salem Mechanical Engineering Department, Wayne State University, Detroit, Michigan,USA

ABSTRACT

Despite being in the oil-rich region, Jordan is completely dependent on the imported oil from neighboring countries. This significantly affects the country’s economy and people’s lives. Therefore, the search for alternative sources of energy was one of the serious responsibilities of the decision makers in Jordan. One of the feasible solutions was to adopt the r e n e w a b l e e n e r g y a p p r o a c h . These s o u r c e s have become a competit ive alternative to conventional sources in many countries. Economically, the price of energy generated by renewable decreases day after day compared with a continuous increase in crude oil prices. In the present work, the focus will be on the economical impact of wind/PV (photovoltaic) hybrid system in rural areas. Unlike the previous projects, which were either in pilot or experimental form, the present study considers a commercial type project. An actual site of the applied study will be assessed in terms of electricity consumption, wind and solar energy availability, equipment cost and energy saving. This implies an accurate evaluation of the complete and partial replacement of the existing electricity sources used for water pumping and electrification in the examined site. Different scenarios will be investigated to illustrate various economical options of the capital cost and payback periods. Finally, the impact of this project on spreading this idea to many sites of similar conditions will be discussed.

INTRODUCTION

In Jordan, the feeling of renewable energy importance was prevailing for decades. Royal Jordanian Air Force (RJAF)is one of the most vital military foundations in Jordan which is a land-locked country in the middle east ,RJAF defends the kingdom against any air threat and supports the land forces as well as supporting security forces, on the other hand RJAF provides air lift operations, search and rescue, medical evacuations, and relief operations. Despite the limited size and number of executed renewable energy projects, their role and potential were significant. Tables 1 and 2 illustrate few samples of these projects, which have been installed in 1980s and 1990s to satisfy various needs for remote customers as specified in [1, 2]. The sharp growth in electrical demand at the beginning of 1990’s was going in parallel with a decrease in the oil prices in that period.

Table 1: wind energy installations Site/project location capacity year Mudawara water pumping

Southern part

3.2m3/h 1983

Jurf El-Daraw-sh Water pumping

Southern part

5m3/h 1987

Kharana W ater pumping

South east

4m3/h 1992

Grid connected wind turbines

Different locations

15kW 1986- 1992

Table 2: PV installations

Site/project Location capacity year Umari PV pumping system

Southern part

40m3/day 1985

Rahmeh PVP system

Southern part

2.225kW 1986

Ma'mora clinic decent-lized PV

South east

1100W p 1990

Remote schools and police stations-PV

Different locations

0.1kW 1kW 1986- 1992

In parallel to these projects, several testing facilities were established to serve the existing and future renewable plants. These facilities include solar collector testing station, solar simulator, solar heating systems, and wind pump test facility. Despite the size of work done in the renewable energy field, the country was not able to make big steps or large projects in this area. The decision makers of energy plans in Jordan did not give a big weight for developing renewable sources to secure the energy future. This paper will focus on the economical side of renewable energy projects taking a case study of a wind farm as an example.

OVERVIEW OF THE STUDIED CASE The considered project belongs to the Royal Jordanian Air Force (RJAF). The latter is one of the most important official establishments in Jordan. It depends totally on diesel generators and national grid to feed its remote sites with electricity. These sites do not only consume large quantities of

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electricity, but operate in continuous mode. This is attributed to the presence of vital loads of military equipment such as radars, communication equipment and security units. In parallel to this equipment, each site has several camps, which need electricity for lighting and water pumping. On the other hand, the existing diesel generators have become inefficient which incurred additional cost for maintenance and spare parts [3]. This problem is aggravated because of the harsh operating conditions of these generators. Therefore, the management of RAF has strongly appreciated the initial study done in this field to clarify the feasibility of such projects. The candidate site was selected for its high wind and solar potentials, which are reflected on the annual energy yield. This compensates the high cost of electricity purchased from the national grid by the RJAF.

The selected site is called “Attl Alasfer” and it lies in the eastern region of Jordan, as shown in Figure 1, its altitude is 1090 m above sea level, and this contributes in the good wind speed in the site, from the map, it is obvious how important Jordan’s location is especially with all that is occurring in the area (Syria, Iraq, Egypt, Israel), so it is of national security to maintain the presence and readiness of RJAF and this project will help to do that .

Figure 1: The location of the considered project

The h o u r l y a v e r a g e a n n u a l w i n d s p e e d o f t h e selected site is more than 8 m/s. The wind speed site measurements were correlated with the records of the Jordanian Meteorological Department (JMD). To show the potential of wind/PV (photovoltaic) hybrid system, the electrical l o a d s in the site were thoroughly studied. These loads are fed from the national grid, with a net meter installed in the site to record the monthly kW h consumption. The loads in winter are more than those in summer. This is attributed to the heating systems in the site which are operated continuously from October to March. The average load in the site is about 60kW , while the maximum load reaches 70kW.

The cost of kW h generated by diesel generator is higher by 16% than that purchased from the grid.

RJAF is a bulk consumer and purchases the kW h for

0.075JD. Therefore, the annual cost of electricity for this site is more than 40000JD. The generators used in the site are of Cummins type, with a rated power of 100kVA. An automatic switch gear and change over switch are used to feed the load from either the grid or the generators. Table 3 illustrates the electricity consumption of the considered site.

Table 3: Electricity consumption of Attl Alasfar

Month

Consumption

(kWh)

Cost (JD)

Av. hourly consumption

(kWh) Jan 50400 3780 70

Feb 48000 3600 66.6

Mar 46100 3457.5 64.02

Apr 43250 3243.75 60.06

May 41150 3086.25 57.1

June 39900 2992.5 55.4

July 38500 2887.5 53.5

Aug 37900 2842.5 52.6

Sep 41200 3090 57.2

Oct 44350 3326.25 61.6

Nov 45420 3406.5 63.1

Dec 48850 3663.75 67.8

Annual. consumption

525020

Annual cost

39376.5

60.76

For the water pumping system in the site, there is a

well with a submersible pump and a 40m3

storage tank, with a total head of 50m. The power consumption calculations of the pump are based on manufacturer's specifications, current, voltage and power factor. The pump consumes 5.65 kW h to

pump 1m3of water. This means that pumping a 1m

3

of water costs 0.42JD. Therefore, the pumping load forms 10% of the site total load. Table 4 below, illustrates these findings. Table 4: Water consumption costs

Month Average

consumption 3

( m )

Pumping load (kWh)

Monthly cost(JD)

Jan 540 3051 228.8

Feb 560 3164 237.3

March 625 3531.25 264.8

April 830 4689.5 351.7

May 880 4972 372.9

June 900 5085 381.4

July 1100 6215 466.1

Aug 1137 6424.05 481.8

Sep 850 4802.5 360.2

Oct 695 3926.75 294.5

Nov 600 3390 254.2

Dec 580 3277 245.7

Annual consumption

9297

Annual load 52528.05

3939.6

APPLICATION OF WIND ENERGY FOR THE CONSIDERED SITE

Depending on the percentage of load to be covered, wind generation can be used for partial or complete

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Wind turbine rating (kW)

Annual estimated

energy (kWh)

Annual value of energy yield (JD)

Rotor area

2 (m )

Turbine

price (JD)

10 37066 2780 23 15500

20 89708 6728 78.5 31000

30 151990 11400 133 46500

60 244115 18308 177 67000

100 477198 35790 346 103000

operation

hours

Annual energy required, cost and number of

turbines achieving this load

Annual energy(kWh)

Cost(JD) #of turbines to achieve 70kW load

#of turbines to achieve 60kW load

24 613205/

525600

45990 39420

1*100kW

+1*30kW

1*100kW

+1*20kW

18 459900/

394200

34492 29565

1*100 kW 1*30kW+

1*60kW

12 306600/

262800

22995 19710

1*60kW+

2*10kW

1*60kW+

1*10kW

8 204400/

175200

15331 31400

1*60kW 1*30kW+

1*10kW

supply of the load. Therefore, according to the sensitivity of these loads, the cost of replacement, and available investment resources, different scenarios are proposed to compute the required energy at the site. Since the cost of the PV- generated power is much higher than that generated

The above values can be converted into energy measured in kilo-watt hours( kW hs), using the wind power equation[8] with the estimated hours from the above figure and a cut-in speed of 4m/s [5,9].

from the wind and the space it occupies is significantly larger, PV panels will be used for limited purposes to partially feed the pumping system and

P = 0.5ρAV3 Cp

W here:

(2)

some lighting loads.

As the average wind speed in the site is known, Weibull distribution [4] can be used to model this speed to get the frequency curve of the wind speed at the site. This statistical tool tells us how often winds of different speeds will be seen at a location with a certain average (mean) wind speed. Knowing this helps us to choose a wind turbine with the optimal cut-in speed (the wind speed at which the turbine starts to generate usable power), and the cut- out speed (the speed at which the turbine hits the limit of its alternator and can no longer put out increased power output with further increases in wind speed)[5]. The probability density function is given by [6, 7]:

P: is the power in the wind(Watts)

ρ: is the density of air(=1.225

kg/m3)

A: is the swept area perpendicular to the wind flow

(m2).

V: is the wind speed in m/s. Cp: is the power coefficient of the rotor (=0.4).

Several wind turbines were considered to ease the selection of one or more wind turbines according to RAF’s budget. Each turbine has its own rotor swept area taken from the manufacturer catalogues as shown in Table 5 below [10]. The annual energy for different turbines is estimated as follows.

Table 5: Total estimated energy yield for several turbine ratings

f (v) = ( k

)( v

) k −1

exp[−( v

) k

] (1)

Where:

c c c

f(v): is the probability of observing wind speed v. c: is the W eibull scale parameter, which has a reference value in the units of wind speed(11.5m/s) k: is the dimensionless W eibull shape parameter (k=1.8).

v: observed wind speed range in the site(4-18m/s)

Figure 2 shows the estimated number of hours, which the wind speed will have.

The annual value of energy yield is calculated using a tariff of 0.075JD/kW h. Different scenarios were proposed to compute the required energy based on a price of 0.075JD/kW h as shown in Table 6.

Table 6: Operational periods and costs of the load at

Attl Alasfer.

Figure 2: Probability distribution function for the wind at examined site

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If the wind turbines are required to meet all loads at the site for the two scenarios (70, 60 kW s), the payback period will be as that shown in Table 7.

In this context, it is worth considering the savings, which might be achieved annually. This calculation can be done for each type of studied turbines and different operational hours in a day at 11.5m/s wind speed, and 0.075JD/kW h, as shown in Table 8.

An example of the results shown in table 8 is taken for the 10kW wind turbine , at 11.5m/s , the power extracted from it is 7500W depending upon equation(2), if it is operated for 4 hours a day, the annual power from it will be 10950kWh, which cost 821JD, the other calculations are done by the same way.

Table 7: Payback periods according to the cost estimation of load at Attl Alasfer Daily load(kW) Annual

energy

cost(JD)

Wind

turbines

required

Payback

period

(years)

70 45990 1*100+ 1*30

3.2

60 39420 1*100+ 1*20

3.4

The payback period was calculated by dividing the total cost of the wind turbines from table 5 by the annual energy cost of the daily loads.

The mentioned wind turbines were used in a current site in Jordan since 1986[9], the maintenance cost is not included in this study and can be considered a small amount of money.

Table 8: Annual estimated savings achieved from each turbine operating for different hours.

operational daily periods, as shown in figure 3

and table 9 ,respectively.

Figure 3: Operational periods of loads at the site Table 9: Operational costs and required turbines for loads at the site for different operational hours

The loads at the site can be divided into three main categories .the first category is the vital load(Radar),which has a power rating of 40kw. The second category of loads is the water pumping system with a total rating of 6kw. Finally, other loads are estimated to have 14kw. To feed these loads from wind energy, different

scenarios were suggested for several

As mentioned earlier, the use of PV to supply heavy loads is costly. To demonstrate t h i s fact, the pumping load (6kW) is suggested to be fed from PV power. Typically, commercial PV systems are installed at around $7 per watt (5 JD’s per watt). The

0

50000

100000

150000

200000

250000

300000

350000

400000

24 18 12 8 6 4

annu

al re

quire

d en

ergy

(kw

h)

daily operational period of load(hours)

Radar

water pumping

other loads

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pump consumes 5.65kW h to pump one cubic meter of water. With a daily average water

consumption of 26m3,which needs 147kWh to

pump this volume of water , the cost and area of PV panels needed are 615000 JD and

30m3

respectively. Therefore, covering this load by PV is costly and difficult to apply at the present time. These difficulties are attributed to the fact that the initial cost of producing 1kW from PV is 3 times the same power from wind energy. However, PV application for big loads could be possible at other RAF’s sites in the future as the price of this technology would decreasing with time due to advancement in technology and increased demand.

CONCLUSION A sample of existing renewable energy projects in Jordan was given. A remote windy site was selected to demonstrate the potential of wind/PV hybrid system as alternative source of energy. The load was calculated to size the required wind turbines. PV systems are not suitable for supplying big loads due to their high costs. The project was shown feasible and the payback period is short. The replacement of diesel generators for remote loads is necessary if adequate wind exists in the area. Recently, many sites with good wind speeds were studied to apply the idea of integrating wind turbines with the current power source to achieve reasonable savings in the electricity bill.

REFERENCES

[1] RSS Report about Renewable Energy Projects executed in Jordan in Cooperation with the German Organization GTZ. [2]. Z.J. Sabra, wind energy in Jordan-use and perspective. DEW I Magazine 1999;15. [3] Annual reports of electromechanical directorate in RAF headquarter (2004-2010). [4] W ind Energy Conversion Systems, L.L Freris, prentice hall, 1990. [5] Renewable energy in United Kingdom (www.reuk.co.uk). [6] W ind data analyzer, Ziad Halahet, March, 2006. [7] A statistical analysis of wind speed data used in installation of wind energy conversion systems E. Kavak Akpinar , S. Akpinar , Energy Conversion and Management 46 (2005) 515–532,2005. [8] W ind power systems,applications of computational intellegance, Lingfeng W ang, Chanan Singh, and Andrew Kusidk, Springer, 2010. [9] M.Abderrazzaq, “Tower height assessment for optimal wind energy exploitation”, International Journal of Renewable Energy Engineering. Vol 4, No 1 April 2002. [10] Wind energie catalogue, 2009.

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