Impact of renewableenergies – environmental

and economic aspects“Case of an Algerian company”

Lilia Abdelhamid and Lylia BahmedLaboratory of Research in Industrial Prevention (LRPI),

Industrial Health and Safety Institute, University Hadj Lakhdar of Batna,Batna, Algeria, and

Azzeddine BenoudjitLaboratory of Electrical Traction Systems,

Department of Electrical Engineering, University Hadj Lakhdar of Batna,Batna, Algeria

Abstract

Purpose – The purpose of this paper is to provide an immediate image about the reality of therenewable energies as experienced by an Algerian company.Design/methodology/approach – The adopted approach focused on assessment of renewableenergies’ impact (especially the thermal solar power) on the environment and on the economic aspectof an Algerian company.Findings – The perception of environmental dimension is highlighted by means of an evaluationstudy supported by the calculation of quantities of CO2 emitted by two power stations (the new hybridpower station of Hassi R’mel (SPPI) and a conventional one (Sonelgaz)).Research limitations/implications – This research has limitations that the authors plan to studyin perspective: assessing the impact of wind systems on the environmental and economic aspects.Practical implications – The analysis of obtained results shows and puts emphasis on theimportance of renewable energies, especially thermal solar power, by identifying and evaluating theenvironmental and economic aspects of the new hybrid power station of Hassi R’mel (SPPI) and aconventional one (Sonelgaz) and by comparing the importance of their atmospheric emissions.Originality/value – The paper shows that this new technology represents in theory a solution forenvironmental problems and could also be economically competitive with conventional energies ifwisely exploited.

Keywords Algeria, Electric power generation, Renewable energy, Atmospheric emissions (CO2),Environmental protection, Solar energy, Environmental aspects, Economic aspects

Paper type Case study

1. IntroductionDecision makers, social groups and scientists have at various moments in time expressedtheir interest in renewable energy sources such as power from wind, sun and biomass-derived fuels. Recently, this interest has been on the rise again. Several reasons arementioned for this: the risk of energy supply insecurity and the corresponding needfor resource diversification, the prospect of depletion and hence cost increases ofconventional oil and gas occurrences and the adverse impacts of climate change andlocal air pollution as a result of fossil-fuel burning related emissions (Bert et al., 2005).

The renewable energies cannot replace all the conventional energies in the nearfuture, but they can enrich the range of the energies exploited at the present time(Abdelhamid et al., 2010).

The current issue and full text archive of this journal is available atwww.emeraldinsight.com/1477-7835.htm

Received 1 March 2011Revised 2 June 2011Accepted 3 July 2011

Management of EnvironmentalQuality: An International JournalVol. 23 No. 1, 2012pp. 6-22r Emerald Group Publishing Limited1477-7835DOI 10.1108/14777831211191566

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The world’s energy consumption grows unceasingly, raising important questionsabout the problem of global warming due to greenhouse gases (GHG), on the one hand,and to the exhaustion of the fossil resources, on the other one. Given this awareness, aneconomic development that abides by the environmental requirements is absolutelynecessary (ACCRA, 2008).

Environmental protection has been raised recently due to the concerns regardingglobal weather and air pollution warming. A number of international agreementsin favor of forcing global emission reductions are currently applied and haveparticular impact on the electricity and power industry, such as the Kyoto Protocol(ACCRA, 2008), and the Large Combustion Plant Directive (Directive EC, 2001).

As the major solar field in Algeria is located in hydrocarbon regions endowed withnatural gas (NG), the Algerian strategic goal is to create a mixed solar-gas synergy,taking advantage of our abundant NG and solar resources. Coupled with renewableenergies the NG is an energy resource of choice for the development of Algeria andoffers the type itself of structuring vector for our integration to the world economy(Ainouch, 2006).

A first gas-solar hybrid project, of large capacity, is under development. The projectwill enhance the solar energy share in the global energy balance, increased renewableelectricity connected to the national distribution grid (Penik and Lonk, 1998).

The development of solar energy could save significant quantities of hydrocarbonsand particularly of NG. The positive implications are double: first, the reduction ofburned fossil fuels will reduce the GHG emissions, while contributing to improve theenergy supply of our partners (Harouadi et al., 2007; Brakmann et al., 2005).

2. Scope and diversity of renewable energy sourcesThere is a multiplicity of energy resources and energy forms. This multiplicityembraces: hydropower, wind, solar, biomass and geothermal for resources and in theenergy forms, light, heat, electricity, hydrogen and fuel. The transition from resourcesto forms of energy and the appropriate kind of mix depend on many factors such aslocation and resources availability (Abdelhamid et al., 2007; Abdelhamid, 2008).

Renewable energy sources and technologies are extremely versatile. The term“renewables” includes several families of resources (biogenic, geological, direct orindirect solar, magnetism) from which energy carriers including electricity, heat, andsolid or liquid fuels can be produced and used for any kind of energy service needed(traction process, heat, lighting, heating, cooling and others) (Singh et al., 2005; Goleaet al., 2006; Benlamoudi, 1996). From a technical perception, there is no energyapplication for which renewable energy technologies would not be suited.

3. Types of renewable energiesThese types include solar energy, wind power, geothermal power, biomass, wavepower and hydroelectricity (Wikipedia, 2011).

3.1 Solar energySolar energy is any kind of energy radiated from the sun but is usually associated withsolar energy technology, which converts it into electricity or thermal energy (heat).Solar energy is also essential for plants for the process of photosynthesis andconsequently the existence of life on earth, which we know today. Solar energy is also arenewable energy and pollution free which makes it highly attractive source of energyfor the future.

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Impact ofrenewable

energies

3.2 Wind powerWind power is the conversion of wind energy into a useful form of energy, such asusing wind turbines to make electricity, wind mills for mechanical power, wind pumpsfor pumping water or drainage or sails to propel ships.

At the end of 2008, worldwide nameplate capacity of wind-powered generators was121.2 GW, which is about 1.5 percent of worldwide electricity usage; and is growingrapidly, having doubled in the three years between 2005 and 2008. Several countrieshave achieved relatively high levels of wind power penetration, such as 19 percent ofstationary electricity production in Denmark, 11 percent in Spain and Portugal, and7 percent in Germany and the Republic of Ireland in 2008. As of May 2009, 80 countriesaround the world are using wind power on a commercial basis.

Large-scale wind farms are connected to the electric power transmission network;smaller facilities are used to provide electricity to isolated locations. Wind energy as apower source is attractive as an alternative to fossil fuels, because it is plentiful,renewable, widely distributed, clean and produces no GHG emissions. However, theconstruction of wind farms is not universally welcomed because of their visual impactand other effects on the environment.

3.3 Geothermal powerGeothermal power (from the Greek roots geo, meaning earth, and thermos, meaningheat) is power extracted from heat stored in the earth. This geothermal energyoriginates from the original formation of the planet, from radioactive decay of minerals,and from solar energy absorbed at the surface. It has been used for bathing sincePaleolithic times and for space heating since ancient Roman times, but is now betterknown for generating plants have the capacity to generate about 10 GW of electricity asof 2007, and in practice supply 0.3 percent of global electricity demand. An additional28 GW of direct geothermal heating capacity is installed for district heating, spaceheating, industrial processes, desalination and agricultural applications.

The earth’s geothermal resources are theoretically more than adequate to supplyhumanity’s energy needs, but only a very small fraction of it may be profitablyexploited. Drilling and exploration for deep resources costs tens of millions of dollars,and success is not guaranteed.

3.4 BiomassThe biomass designates the whole living matter of plant or animal origin of theterrestrial surface and the energy of the biomass designates the energy capable to beextracted directly, or indirectly, of these biologic materials.

We can distinguish three types of biomass. The first used source is wood whoseenergetic valorization represents actually three quarters of the primary production ofthe forest. The wastes are the second source of bioenergy; these wastes includedomestic, urban and industrial wastes, also the animal dejections. The third categoryin terms of energy production quantity concerns the liquid fuels, coming fromdedicated materials (oil, starch, sugar beet).

Globally we can use the biomass in three different ways: by burning it, rotting it or bytransforming it chemically to produce heat, electricity and liquid combustibles for transport.

3.5 Wave powerWave power is the transport of energy by ocean surface waves, and the capture of thatenergy to do useful work, for example for electricity generation, water desalination or

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water pumping (into reservoirs). Wave power generation is not currently a widelyemployed commercial technology although there have been attempts at using it sinceat least 1890. The world’s first commercial wave farm is based in Portugal, at theAgucadoura Wave Park.

3.6 HydroelectricityHydroelectricity is electricity generated by hydropower, i.e., the production of electricalpower through the use of the gravitational force of falling or flowing water. It is themost widely used form of renewable energy. Once a hydroelectric complex isconstructed, the project produces no direct waste, and has a considerably lower outputlevel of the gas carbon (CO2) than fossil fuel powered energy plants. Worldwide, aninstalled capacity of 777 GW supplied 2,998 MWh of hydroelectricity in 2006. This wasapproximately 20 percent of the world’s electricity, and accounted for about 88 percentof electricity from renewable sources.

4. Advantages and disadvantages of renewable energies4.1 AdvantagesThe reduction of the emissions by increasing in the renewable energies share is asignificant action, which will lead to an improvement of the quality of the air and publichealth. Renewable energies offer a considerable potential and could, in theory, provide asupply almost unlimited in energy of relatively clean and most of the time local one.

The renewable sources of energy are converted into useful energy while (Ainouch,2006):

. contributing to the reduction of the GHG emissions;

. providing opportunities for poverty eradication and for satisfying the energyneeds of the poor, particularly in rural and remote regions;

. limiting the risks and the pollution of air, water, ground and biosphere by theenergy production;

. decreasing our energy dependence while not depriving of access to energy thepresent and future generations;

. enhancing energy security;

. preserving the natural resources reserves;

. contributing to reduce the international tensions and allowing solidaritybetween people;

. reinforcing the local economy by the development of small- and medium-sizedcompanies; and

. creating export opportunities of electricity.

Renewable energy could be an alternative to the expensive extensions of the networkto the rural areas in the developing countries whose electricity offer is unsuited, whereit could contribute to a mixed energy, using smart gird network, to satisfy theelectricity demand in the growing urban zones.

4.2 DisadvantageIt is easy to recognize the environmental advantages of using the alternative andrenewable forms of energy but we must also be aware of their disadvantages.

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Impact ofrenewable

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One disadvantage of the renewable energy is that it cannot generate the equivalentquantities of electricity to those produced by fossil fuels. This lead us to think aboutreducing the amount of energy consumed or simply build more energy facilities. It alsodesignates that the appropriate solution to our energy problems may be to have abalance of many different power sources.

Another disadvantage of renewable energy sources is the reliability of supply.Renewable energy often relies on the weather for its source of power. Hydro generatorsneed rain to fill dams to supply flowing water. Wind turbines need wind to turn theblades, and solar collectors need clear skies and sunshine to collect heat and makeelectricity. When these resources are unavailable so is the capacity to make energyfrom them. This can be unpredictable and inconsistent. The current cost of renewableenergy technology is also far in excess of traditional fossil fuel generation. Thisis because it is a new technology and as such has extremely large capital cost(Solarschoolar, 2011).

In addition to these disadvantages each type of renewable energy has its own:

(1) Solar energy:

. Solar radiation is depending on geographical location.

. Solar radiation is depending on the cycle day/night.

. Capture of solar radiation is requiring a large amount of necessarymaterials.

(2) Wind energy:

. Wind turbines are noisy and can become dangerous for wild birds.

(3) Hydroelectric energy:

. Affects ecology by the process of vegetation decaying, which is releasingmethane, which is also responsible with the greenhouse effects.

. Flooding is another problem caused by the dam releasing.

(4) Geothermal energy:

. Geothermal wells drilling are costly.

. Together with the heat, poisonous gasses could be released.

5. Renewable energies in AlgeriaBeyond its hydrocarbon resources, Algeria has a high potential of renewable energy,which it has the ambition to develop with foreign partners. The development of thesepotentials, in particular huge reserves of solar energy would have several positiveconsequences for Algeria, its partners and the world community in general. Thepromotion of the electricity produced starting from the renewable energy sources is inthe forefront of the priorities of Algeria for reasons of energy supply diversification, forreasons of environmental protection and for reasons related to economic and socialcohesion (Figures 1 and 2).

Besides the solar and the wind resources, Algeria has great potentials in the othertypes of renewable energies such as hydropower, biomass and geothermal resources.

Hydropower energy can be well developed than the other two types; Algeria hadbuilt many dams all over the country of different capacities.

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38.0

36.0

Ténés Alger Béjaia Annaba

MaghressBiskra

H.Messaoud

Djanet

Tamanrasset

El KheiterAin Sefra

Bechar

Timimoun

In SalahAdrarTindouf

In Amenas

Djelfa

Tiaret

Ghardaia

oran

34.0

32.0

30.0

28.0

26.0

24.0

22.0

20.0

18.0–8.0 –6.0 –4.0 –2.0 0.0 2.0 4.0 6.0 8.0 10.0

1.5

3.0

4.0

5.0

6.0

6.5

7.0

Source: Ainouch (2006)

Figure 1.Estimation of the wind

resources in Algeria

Source: Francisco and Derriche (2007)

Figure 2.General view of the SPPI

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Impact ofrenewable

energies

The geothermal and biomass energies are still under experiment in forms of smallstudy projects in universities that lack experience and financial funding.

Algeria is rich not only by its petroleum and NG reserves but also itsrenewable energy resources that if rationally exploited will contribute certainly in thedevelopment and the promotion of the Algerian economy and also by improving itsenvironment.

6. Case study: the comparative study between two electrical stations:(solar power plant project I (SPPI), Tilghemt, Algeria)6.1 Presentation of the SPPIThe production of electricity from the hybrid solar-gas power plant has the capacity ofabout 150 MW: the combined cycle (CC) is 120 MW; the solar cycle is 30 MW. Theproject SPPI will include a solar field and a CC using the NG and the solar irradiationof Hassi R’mel. The solar field consists of parabolic-trough mirrors and otherequipment required to the production of heat by solar irradiation. The CC consists oftwo gas turbines, two heat-recovery steam generators (HRSG), one steam turbine, oneair-cooled condenser and other equipment required for electricity production usingNG and solar heat (Figure 2).

In a thermo-solar power station with integrated combined cycle (ISCC), the solarenergy coming from the parabolic-trough collectors is integrated in a power stationwith CC in order to increase the production of electricity without increasing theconsumption of fuel fossil. The thermal energy of the solar field is used to produceadditional steam and the capacity of the steam turbine is increased comparing to theone of the CC central (Figure 3).

To transform a power station with CC in a thermo-solar power station to ISCC, weadd a solar field and a second heat exchanger (solar heat exchanger).

This solar heat exchanger will partially be in parallel with the of HRSG; it isbrowsed by a coolant fluid instead of the exhaust gases of the gas turbine.

6.2 Presentation of Tilghemt stationThe electrical power station “Tilghemt,” of a global net power of 220 (2 � 110 MW)MW consists of two groups turbo alternator. It entered in recent conception

Parabolictrough collectors

393°C

Exhaust100°C Steam

540°C.100 bar

Source: Francisco and Derriche (2007)

293°CExhaust600°C

383°C

220°C

HRSG

Steamturbine

45°C

G ~

G ~

Electricityto the grid

Condenser

Gas turbine

Solar heatexchanger

Figure 3.A simplified diagram ofthe thermo-solar powerstation with integratedcombined cycle (ISCC)

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production; the extensively automated control of the groups permits a big autonomy ofworking. In particular, it assures a march in all security in the cases of unfavorableincidence of ambient factors, of transient system of the electric network or accidentswhile preserving the maximum availability of the electricity production. The powerstation is isolated on a mound to 27 km to the east of Hassi R’mel. It occupies a surfaceof 206,495 m2. The thermal group gas turbine MS900I1 is constituted by a gas turbineto only one shaft, in simple cycle, driving an alternator. The gas turbine includes adevice of starting with motor of launching, auxiliaries, a compressor, a system ofcombustion and a turbine of three floors.

At the beginning the shaft line is put in movement by the motor of launchingthrough a couple converters and the auxiliaries reducer that drives a certain number ofauxiliaries. The atmospheric air is aspirated, filtered and controlled through the shaftsof admission toward the entry of the compressor of floors. During the starting, theantidumping floodgates downstream the 17th floor are in open position, and the vanesin variable orientation situated at the entry of the compressor in closed position. To theexit of the compressor, the air penetrates in an annular space surrounding the 14 roomswith combustion; the injectors introduce the fuel in each of the rooms where it is mixedwith air. The mixture is put on fire by two candles of ignition; the flame propagates inthe other rooms through the tubes of interconnections. The hot gases coming from thecombustion rooms propagate through the 14 pieces of transition to cross the threeturbine’s floors. After their passage in the three turbine’s floors, the exhaust gasescross the exhaust setting and the distributor. They arrive then to the exhaust caissonwhere they are evacuated to the atmosphere. The work provided to the rotor of theturbine, in part used for the driving of the compressor and auxiliaries of the turbine,serves to turn the alternator (Figure 4).

6.3 Calculation of the quantities of CO2 emitted by the two power stationsThe technology of the hybrid power station of Hassi R’mel consists in a contribution ofheat near 20 percent coming from the solar field. Since the hybrid power stationproduces a theoretical power of 150 MWh, the power of the solar field will be of theorder of 30 MWh.

To appreciate the benefits of the realization of this power station from anenvironmental viewpoint, we intended to calculate the quantities of carbon dioxide(CO2) emitted by this power station in order to compare them with those freed by aconventional power plant.

Compressor Turbine Alternator

Combustionchamber

Exhaust gases(a) (b)

Figure 4.A simplified diagram of

the gas turbine group

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Impact ofrenewable

energies

We took the CO2 as example of the atmospheric pollution since this gas is responsiblefor a big part of the greenhouse effect phenomenon (Sooyoung et al., 2010).

6.3.1 Evaluation of the quantities of CO2 emitted by the hybrid power station (SSPI).For the hybrid power station that generates a net power of 150 MWh and whose solarcontribution is of 20 percent, we considered two cases: one corresponding to what wecalled a “day march” (when the hybrid cycle is fully put in march), and the other to a“night march” (CC calling on the gas and steam turbines but not to the solar field)(Blum et al., 2010).

(A) For the“day march”: in this first case, the solar contribution being of 20 percent,the ovens burners of the boilers are off, what means a much least fuel consumption.

The foreseen consumption of NG is of 9,072 kg/h:

DNG ¼ 9;072 kg=h ¼ 9;072=MNG ¼ 9;072=18:47 ¼ 491:24 kmol=h ð1Þ

Knowing that the molar mass of the NG is equal to:

MNG ¼X

Mi ¼ 18:47 kg=kmol

We gathered in the Table I the molar compositions and the partial molar debitsof the NG constituents necessary to the determination of the quantities of CO2 emittedby the combustion of each of these hydrocarbons.

For the estimation of the quantities of CO2 produced by combustion of the differentconstituents of the NG we supposed a complete combustion, i.e. it only generates theCO2 gas.

The different combustion reactions of the NG constituents are:

. For the methane (CH4):

CH4 þ 2O2 ! CO2 þ 2H2O ð2Þ

1 mol 1 mol449.27 kmol 449.27 kmolThus: DCO2

¼ 449.27 kmol/h

ConstituentsMolar mass(kg/kmol)

Molarfraction, yi

(molar %)

Partial molarmass, Mi

(kg/kmol)

Partial molardebits, Di

(kmol/h)QCO2

(kmol/h)

CH4 16 85.3 13.65 449.27 449.27C2H6 30 7.29 2.19 38.40 76.79C3H8 44 1.73 0.76 9.11 27.34C4H10 58 0.66 0.38 3.48 13.90C5þ 72 0.19 0.14 1.00 5.00

He 2 0.15 0.00 0.79 0.00CO2 44 0.24 0.11 1.26 1.26N2 28 4.44 1.24 21.81 0.00Total – 100.00 18.47 491.24 534.96

Table I.Composition and partialmolar debits of the NGconstituents consumed in“day march” by the hybridpower station andestimation of thequantities of CO2 clearedby combustion

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. For the ethane (C2H6):

C2H6 þ 7=2O2 ! 2CO2 þ 3H2O ð3Þ

1 mol 2 mol38.4 kmol 2 � 38.4 kmolThus: DCO2

¼ 76.79 kmol/h

. For the propane (C3H8):

C3H8 þ 5O2 ! 3CO2 þ 4H2O ð4Þ

1 mol 3 mol9.11 kmol 3 � 9.11 kmolThus: DCO2

¼ 27.34 kmol/h

. For the butane (C4H10):

C4H10 þ 13=2O2 ! 4CO2 þ 5H2O ð5Þ

1 mol 4 mol3.48 kmol 4 � 3.48 kmolThus: DCO2

¼ 13.9 kmol/h

. For the pentane (C5H12):

C5H12 þ 8O2 ! 5CO2 þ 6H2O ð6Þ

1 mol 5 mol1 kmol 5 � 1 kmolThus: DCO2

¼ 5 kmol/h

When adding the set of these quantities of CO2 emitted by the combustion of each of thehydrocarbons constituting the NG, we can estimate the global quantity of CO2 generatedby the hybrid power station at the day march (Table I): DCO2

¼ 534.96 kmol/h.This quantity of CO2 corresponds to a mass of: MCO2ðdmÞ ¼DCO2

� 44¼23,538.24 kg/h (dm: day march).

The established detailed climate data on one year by the ONM indicates a dailymedium length of sunshine of 9.5 hours. That means the daily contribution to the freeCO2 mass in day march by the hybrid power station is:

MCO2ðdmÞ ¼ 23;538:24� 9:5 ¼ 223;613:28 kg=day ð7Þ

So, we have annually:

MCO2ðdmÞ ¼ 223;613:28� 365 ¼ 81;618; 847 kg=year ð8Þ

(B) For the “night march”: In this case, there is no solar contribution, and therefore theovens’ burners of the boilers must be put in work, what means a superior consumptionof fuel comparing to that of the day march.

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Impact ofrenewable

energies

The foreseen consumption of NG is of 14.490 kg/h, so:

DGN ¼ 14:490 kg=h ¼ 14:490=MGN ¼ 784:51 kmol=h ð9Þ

Knowing that the molar mass of the NG equals: 18.47 kg/kmol.We gathered in the Table II the molar compositions and the partial molar debits of

the NG constituents necessary to the determination of the quantities of CO2 emitted bythe combustion of each of these hydrocarbons.

While proceeding in the same way as previously, we estimated these partialquantities of CO2 and therefore the total quantity of CO2 that would be cleared at the“night march” (Table II) is: DCO2

¼ 849.27 kmol/h.This quantity of CO2 corresponds to a mass of:

MCO2¼ DCO2

� 44 ¼ 37;367:88 kg=h

On the basis retained previously, 9.5 h/day of sunshine, means that the length of the“night march” would be of 14.5 h/day, thus a daily contribution of CO2 is:

MCO2¼ 37;367:88� 14:5 ¼ 541;834:26 kg of CO2=night ð10Þ

So, annually the mass of CO2 would be:

MCO2ðnmÞ ¼ 541;834:26� 365 ¼ 197;769; 505 kg=year ðnm : nightmarchÞ ð11Þ

(C) Global balance (24 hours): the global quantity of CO2 emitted by the hybrid powerstation will be equal to the sum of the contributions of the marches “day” and “night”that is during the 24 hours:

MCO2ðtotalÞ ¼ MCO2ðdÞ þMCO2ðnÞ ¼ 223;613:28þ 541;834:28

¼ 765;447:54 kg=24 hð12Þ

QCO2ðtotalÞ ¼ 534:96 þ 849:27 ¼ 1;384:23 kmol of CO2=h ð13Þ

ConstituentsMolar mass(kg/kmol)

Molarfraction, yi

(molar %)

Partial molarmass, Mi

(kg/kmol)Partial molar

debit, Di (kmol/h)QCO2

(kmol/h)

CH4 16 85.3 13.65 669.18 669.28C2H6 30 7.29 2.19 57.19 114.40C3H8 44 1.73 0.76 13.57 40.72C4H10 58 0.66 0.38 5.17 15.54C5þ 72 0.19 0.14 1.49 7.45

He 2 0.15 0.00 1.17 0.00CO2 44 0.24 0.11 1.88 1.88N2 28 4.44 1.24 34.83 0.00Total – 100 18.47 784.51 849.27

Table II.Composition and partialmolar debits of the NGconstituents consumed innight march by the hybridpower station andestimation of thequantities of CO2 clearedby combustion

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Knowing that the power station produces 150 MWh, the quantity of free CO2 by MWwould be therefore equal to: MCO2ðtotalÞ ¼ 5,102.98 kg of CO2/MW produced.

6.3.2 Evaluation of the quantities of CO2 emitted by Tilghemt station. Once again, toreally put in evidence the benefits of the realization of the hybrid power station, wecompared its performances with those of the conventional power station “Tilghemt” ofan appreciably similar capacity of 220 MW:

. Calculation of the quantity of CO2

Although this power station is proportioned to produce 220 MW, it does not have infact turned during the year 2009 only with a hourly average of 110.5 MW.

The numbers collected by Sonelgaz indicate that the monthly medium consumptionof NG by this power station during this year 2009 was of DNG¼ 25,996,562 m3/month(Tilghemt Sonelgaz, 2011).

Meaning an average of: DNG¼ 36,106,34 m3/hEquivalent to: DNG¼ 1,612 kmol/hTherefore, as following the same gait used in the previous part we calculated the

quantity of CO2 emitted during a march of 24 hours.The results are indicated in the Table III:

QCO2¼ 1;744:71 kmol=h

QCO2¼ 41;873:04 kmol=24 h

QCO2¼ 1;744:71� 44 ¼ 76;767:24 kg=h

QCO2¼ 1;842; 413:8 kg=24 h

QCO2¼ 672;481:032 kg=year

ð14Þ

Knowing that we took like basis of calculation the data of the year 2009 and thatduring this period, the power station produced only 110.5 MWh, the quantity of CO2

cleared by MW of electricity produced would be therefore equal to:

QCO2¼ 16;673:42 kg of CO2=MWproduced

ConstituentsMolar mass(kg/kmol)

Molarfraction, yi

(molar %)

Partial molarmass, Mi

(kg/kmol)Partial molar

debit, Di (kmol/h)QCO2

(kmol/h)

CH4 16 85.3 13.65 1,374.94 1,374.94C2H6 30 7.29 2.19 117.51 235.01C3H8 44 1.73 0.76 27.89 83.66C4H10 58 0.66 0.38 10.64 31.92C5þ 72 0.19 0.14 3.06 15.31

He 2 0.15 0.00 2.42 0.00CO2 44 0.24 0.11 3.87 3.87N2 28 4.44 1.24 71.57 0.00Total – 100.00 18.47 1,611.89 1,744.71

Table III.Composition and partial

molar debits of theconstituent of the NG

consumed by the powerstation conventional and

evaluation of thequantities of CO2 cleared

by combustion

17

Impact ofrenewable

energies

. Calculation of the gaps

To be able to compare the performances of the two power stations, we brought back thequantity of CO2 emitted by them by MW produced, since they do not produce in factthe same power. We regrouped in the Table IV below the quantities of CO2 emitted bythe two power stations. These quantities are expressed in different units (Figure 5).

The results show that the quantities of CO2 emitted by the conventional powerstations are higher than that emitted by the hybrid power station which is moreenvironmentally friendly (Table V).

6.4 The technical-economic assessment6.4.1 Evaluation of the saved quantity of the NG. The quantity of the NG capable to besaved thanks to this new technology that is the hybrid will be therefore the differencebetween these two values:

M ðNG savedÞ � 714; 567:36� 296; 289 ¼ 418; 278:36 kg=day ð15Þ

M ðNG savedÞ � 260; 817; 086� 108; 145; 485 ¼ 152; 671; 610 kg=year ð16Þ

V ðNG savedÞ � 866; 552:16� 359; 344:72 ¼ 507; 207:44m3=day ð17Þ

V ðNG savedÞ � 311; 958; 744� 131; 160; 823 ¼ 180; 797; 921m3=year ð18Þ

Hybrid (SPPI) Tilghemt Gaps (%)

Produced power (MW) 150 110.5 –QCO2

(kg/24 h) 765,447.54 1,842,413.8 58.45QCO2

(kg/MW) 5,102.98 16,673.42 69.39

Table IV.Comparative tablebetween the quantities ofCO2 emitted by the twopower stations

2,000,000Tilghemt power station

Hybrid power station1,800,000

1,600,000

1,400,000

1,200,000

1,000,000

800,000

600,000

400,000

200,000

0Comparative graphic between the

quantities of CO2 emitted by the power station

Figure 5.Comparative graphicbetween the quantities ofCO2 emitted by the twopower stations

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According to the results gotten in the technical economic assessment found above, wenote that the hybrid power station will have remarkable economical benefits by thereduction of the quantity of NG (Figure 6).

This new technology can in theory represent a solution for the environmentalproblems and also be economically competitive with conventional energies if wiselyexploited.

6.4.2 Evaluation of the cost of the NG saved. Since the price of one normal m3 isabout 12 DA, therefore the cost of the NG saved thanks to the use of the CC (gas/solar)will be:

. The cost of NG used in the hybrid station is:

CNG � 359; 344:72� 12 ¼ 4; 312; 136:6DA=day ð19Þ

CNG � 131; 160; 823� 12 ¼ 1; 573; 929:876DA=year ð20Þ

. The cost of NG used in the conventional station is:

CNG � 866; 552:16� 12 ¼ 10; 398; 625:92DA=day ð21Þ

CNG � 311; 958:744� 12 ¼ 3; 743; 504:928DA=year ð22Þ

Comparative graphic between the quantityof natural gas used by the two power stations

350,000,000Hybrid power station

Conventional powerstation

300,000,000

250,000,000

200,000,000

150,000,000

100,000,000

50,000,000

0

Figure 6.Comparative graphic

between the quantities ofnatural gas used by the

two power stations

MNG (kg/day) MNG (kg/year) VNG (m3/day) VNG (m3/year)

Hybrid power station 296,289 108,145,485 359,344.72 131,160,823Conventional power station 714,567.36 260,817,086 866,552.16 311,958,744

Table V.Comparative table

between the quantities ofnatural gas used by the

two power stations

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Impact ofrenewable

energies

The saved amount of money would be:

CðNG savedÞ ¼ 10; 398; 625:92� 4; 312; 136:6 ¼ 6; 086; 489:32DA=day ð23Þ

CðNG savedÞ ¼ 3; 743; 504:928� 1; 573; 929:876 ¼ 2; 169; 575:052DA=year ð24Þ

The results of this evaluation show that the hybrid station is more economical thanconvention alone because the quantity of NG used by the conventional power station isvery important compared to that used by the hybrid station. Thus, the operating costof the conventional station is higher than the hybrid station.

7. Discussion and conclusionBy observing the results obtained above, we note that the quantity of CO2

emitted by the conventional power station (Tilghemt), expressed in kg by 1 MW,represent 69.39 percent more than the one emitted by the hybrid power stationand for the quantity of CO2 expressed in kg per day emitted by the hybrid powerstation is 58.45 percent lower than that emitted by the conventional power station ofTilghemt.

Although the capacity of Tilghemt conventional station (110.5 MW) is lowerthan the one of the SPPI (150 MW) it is still generating much higher amountsof CO2. The results of our calculations showed that the amounts of CO2 emittedby the hybrid power plant are 2.4 times lower than the one of the conventional powerstation.

According to the results gotten in the technical economic assessment found abovewe note that the hybrid power station will have remarkable economical benefits afterthe end of its realization. These benefits will include the reduction of the quantity of NGused in the electricity production consequently saving money.

The objective of this study has been reached by an evaluation of the impacts of thetwo stations (a conventional power station and the hybrid power station of HassiR’mel) on the environment. Then, the calculation tools facilitated the comparisonbetween them. The results obtained by the calculation of the quantities of the CO2 gasemitted in the different phases of the stations functioning showed the benefits of therealization of the hybrid station from the environmental point of view.

Also, in the economical side the calculations showed the profits gained from thisnew technology in Algeria.

References

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Abdelhamid, L., Abdessemed, R., Amimeur, H. and Merabet, E. (2007), “Etude des Performancesdes Generatrices Utilisees dans les Systemes Eoliens”, International Conference onRenewable Energy ICRE’07, University of Bejaia, November 25-27, pp. 1-6 (CDROM).

Abdelhamid, L., Amimeur, H. and Bahmed, L. (2010), “Analysis and simulation of the variousgenerators used in wind systems”, JEE, Vol. 10 No. 10, pp. 1-2.

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ACCRA (2008), “Kyoto protocol to the united nations framework convention on climate change;Accra climate change talks”, available at: http://unfccc.int/meetings/intersessional/accra/items/4437.php

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Further reading

Poitiers, F. (2003), “Etude et Commande de Generatrices Asynchrones pour l’Utilisation del’Energie Eolienne”, Doctoral thesis, University of Nantes, Nantes.

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About the authors

Lilia Abdelhamid is a PhD candidate in the Electrical Engineering Department, University HadjLakhdar of Batna, where she is completing work centred on renewable energies.

Lylia Bahmed is a Lecturer in the Institute of Industrial Health and Safety, University HadjLakhdar of Batna, Algeria. She is an active member of the Laboratory of Research in IndustrialPrevention (LRPI) where she guides a research project agreed by the Algerian Minister of HigherEducation. Her privileged research field is the one of environmental management. Lylia Bahmedis the corresponding author and can be contacted at: bahmed_lylia@yahoo.fr

Azzeddine Benoudjit is a Professor in the Electrical Engineering Department, UniversityHadj Lakhdar of Batna, Algeria. He received the degree of Engineer from ENP (Ecole NationalePolytechnique Algiers), the Mphil from Birmingham University, UK, and the PhD from BatnaUniversity.

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