Journal of Energy

Journal of Energy / 2016 / Article

Research Article | Open Access

Volume 2016 |Article ID 5082678 | 14 pages | https://doi.org/10.1155/2016/5082678

Modelling of Sudan’s Energy Supply, Transformation, and Demand

Academic Editor: Ciro Aprea
Received27 Mar 2016
Accepted12 Jun 2016
Published16 Aug 2016

Abstract

The study aimed to develop energy flow diagram (Sankey diagram) of Sudan for the base year 2014. The developed Sankey diagram is the first of its kind in Sudan. The available energy balance for the base year 2012 is a simple line draw and did not count the energy supply by private and mixed sectors such as sugar and oil industries and marine and civil aviation. The private and mixed sectors account for about 7% of the national grid electric power. Four energy modules are developed: resources, transformation, demand, and export and import modules. The data are obtained from relevant Sudanese ministries and directorates and Sudan Central Bank. “e!Sankey 4 pro” software is used to develop the Sankey diagram. The main primary types of energy in Sudan are oil, hydro, biomass, and renewable energy. Sudan has a surplus of gasoline, petroleum coke, and biomass and deficit in electric power, gasoil, jet oil, and LPG. The surplus of gasoline is exported; however, the petroleum coke is kept as reserve. The deficit is covered by import. The overall useful energy is 76% and the loss is 24%. The useful energy is distributed among residential (38%), transportation (33%), industry (12%), services (16%), and agriculture (1%) sectors.

1. Introduction

Figure 1 shows the energy Sankey diagram of USA as an example. The Sankey diagram is an important tool to visualize the energy balance for a system or a country or a region. The Sankey diagram depicts the energy flows from supply to demand taking into account transformation. Sankey diagram was developed over 100 years ago by the Irish engineer Riall Sankey to analyze the thermal efficiency of steam engines. Since then, it has been widely used. Besides visualization, Sankey diagram is a vital tool to identify sources of inefficiency and potential saving in the energy system.

For the preparation of Sankey diagram for a country, four modules are needed. The first is the demand module, which contains the details of the demand for end-use energy (both primary and secondary fuel) for the residential, services, industrial, agricultural, and transportation sectors [1]. The demand for each sector from primary and secondary energy is defined. For example, the demand of residential sector is electricity, oil products, and biomass for lighting, cooking, and HVAC. The second module is the transformation module. It consists of all energy transformation processes, such as electricity generation, oil refining, and charcoal conversion. In these modules, the energy is divided into useful energy and lost energy. The useful energy is then distributed to demand sectors. The third module deals with the available resources. The main energy sources are coal, crude oil, natural gas, hydroelectricity, biomass, nuclear energy, and renewable energy such as solar, wind, and geothermal energy. The fourth module deals with energy import and export. There exist a number of models used to develop the energy supply and demand modules. Prominent energy models include MARKAL, LEAP, ENERGY 2020, MAPLE C, NEMS, and MAED. Details on these models and their implementation can be found in a number of published studies [24].

This study is aimed at providing Sankey diagram for Sudan for base year 2014. What is available now in Sudan is energy balance for 2012 [7] (cf. Table 1). However, the available energy balance data did count only the energy produced by public sectors. The energy produced by private and mixed sectors is not counted. These include the electric energy produced by oil refineries and sugar factories which constitute a significant share of Sudan energy mix. It also did not count for bagasse and bioethanol. Likewise, it does not count the petroleum associated gas (AG) and renewable energy, in particular photovoltaic energy. The most difficult part of this work is the data quality check. There exist a number of reports on Sudan’s energy status. These reports include conflicting data, double counts, and inconsistent units. The authors have extensively verified the data from their original sources. Data on renewable energy status in Sudan is scarce as well. Extensive search including field survey was made to collect data on this area. Data on the demand side is not well documented as well and hence enormous effort was exerted to collect the data from their original sources. The main contribution of this work is to make proper documentation of Sudan energy data on both supply and demand side. The other contribution is to produce Sudan’s energy flow diagram for the first time.


Demand sectorsPowerOilBiomassTotal
ktoe%ktoe%ktoe%ktoe%

Residential40154.32987.9308862.2391140.0
Transportation299479.2307331.4
Services18124.5431.1130326.2157916.1
Industry12016.340010.657511.6113311.6
Agriculture364.9431.1850.9

Total738100377810049661009781100

Share of energy supply7.538.650.8100.0

2. Methodology

2.1. Data Collection

The energy supply, demand, and transformation data are obtained from the following reports:(1)Annual report of Sudan Central Bank.(2)Annual reports from the Ministry of Oil and Gas [6, 7].(3)Annual report from the Directorate of Agriculture and Forestry [8].(4)Annual report from Sudanese thermal power generation corporation [9].

The collected data is further subjected to quality check for completeness, avoiding double counting and uncertainty assessment.

2.1.1. Completeness

The available reports on electric power generation in Sudan account only for power produced by the public sector. The power generation of private and mixed sectors is not counted by the published reports. For example, the power generation of petroleum refineries and sugar factory, as mixed sectors, is not accounted for in Sudan energy balance for 2012 [6]. This data gap is filled using field survey. There also exists no inventory of standby generators countrywide.

2.1.2. Avoiding Double Counting

Some data duplicate is found in the available literature. For example, ORC produced Naphtha which is used as feedstock to KRC to produce gasoline and other products; hence, it is double counted in Sudan energy balance for 2012 and the reports of Central Bank and the Ministry of Oil and Gas. The reports of ORC and KRC refineries are considered rather than Sudan Central Bank’s reports.

2.1.3. Uncertainty Assessment

There is a lack of proper documentation of bagasse, animal waste, and agriculture waste. However, there are data of production of sugar, cereals, crops, cotton, and count of animals. The waste is estimated from production data. For example, bagasse is estimated from sugar production. The sugar recovery is taken as 9% of the crushed sugar cane and the bagasse is taken as 39.5% of the crushed sugar cane. The estimated bagasse is cross-checked by field survey of the sugar plants and it is found that the assumptions are accurate within 5% for all sugar factories. Similarly, the animal dung is estimated from animal count. The dung production is taken as 10.95, 1.83, 1.83, and 5.48 tons/animal/head for cows, sheep, goats, and camels, respectively [10]. The dung that is potential for energy use is taken as 10%. The agricultural waste is estimated using harvest index (HI) [11]. The harvest index for cereals, oil crops, and cotton is taken as 0.4, 0.52, and 0.16, respectively. The residue is calculated as amount of products multiplied by . The other challenge is that the portion of agriculture residue used as fuel is unknown as the residue is shared by many applications such as animal feed, building material, and pulp and paper industry. This is on the one hand. On the other hand, the residue is mostly left in the farm as a fertilizer or burned during land preparation. Under this circumstance, the ratio of agriculture waste accepted by Sudan energy balance 2012 was considered.

2.2. Energy Modelling

Although there exist a number of energy modelling software programs such Long Range Energy Alternative Planning Systems (LEAP), in this work, a simple Excel worksheet is used for energy modelling. The energy framework for development of Sankey diagram consists of four modules [1].(1)Energy resource module: this module takes account of all the primary fuel such as petroleum, coal, natural gas, uranium, biomass, and renewable energy (cf. Figure 2).(2)Transformation module: the transformation module handles data on the conversion of primary fuel into secondary fuel such as power generation and conversion of crude oil in the refinery to secondary fuels.(3)Demand module: the demand module contains the details regarding the end-use energy demand for both primary and secondary fuel. The consumption sectors include agriculture, industry, services, residential, and transportation sectors (cf. Figure 3).(4)Import and export module: this module deals with energy import and export. The energy import and export are normally in the end-use form such as electricity and secondary fuel oil.

The data generated by the four modules for the base year 2014 is used to develop the energy Sankey diagram for Sudan. The software “e!Sankey 4 pro” was used. e!Sankey is widely used software for the development of Sankey diagrams for a country or a region.

3. Results and Discussion

The main sources of primary energy in Sudan are oil, hydroelectricity, biomass, and renewable energy. Coal, natural gas, and uranium are nonexistent in Sudan. The main transformation and conversion processes are electric power generation, oil refinery, and wood-to-charcoal conversion.

3.1. Electric Energy Supply and Demand
3.1.1. Hydroelectric Power

Table 2 shows the hydroelectric power generation plants in Sudan. The installed capacity, nominal capacity (MW), expected GWh, and year of establishment are given. The planned and under-construction hydroelectric power plants are also given. The total installed and potential hydroelectric power in Sudan is 4176 MW; the installed capacity is 1585 MW (38%).


NumberNameYearCapacity
InstalledNominalProduction
MWMWGWh

Operational plant
1Merowe Dam2009125012405580
2Roseires Dam19662802701050
5Sennar Dam1962151249
3Jebel Aulia Dam2003301955
4Khasm El Girba Dam1964101015

Subtotal A158515516749

Under-construction plant
5Upper Atbra and Sitat2015323320834
6Sennar upgrading20151113.766

Planned plant
7Shereik4202103
8Kajbar3601799
9Sabaloka205866
10Dal Low6482185
11Dagash3121349
12Mograt3121214

Subtotal B22579515

Total (A + B)38416264

Available power%3839

3.1.2. Thermal Electric Power Generation

Table 3 shows the installed, under-construction, and planned thermal power plants. The installed power is 1400 MW and the under-construction and planned power are 405 MW and 600 MW, respectively. The installed thermal power generation is about 46% of the total installed public power generation (hydro + thermal). One important point in thermal generation is its diversity in prime movers and fuels sources. The prime movers in thermal generation include steam turbine (ST), gas turbine (GT), combined cycle of gas turbine (CCGT), and internal combustion (IC) engines. IC engines are used in remote areas that are not covered by the national grid. The fuels used include gasoil (GO), diesel (blend of gasoil and gasoline), heavy fuel oil (HFO) also called furnace and number 6 fuel oil, heavy coker gasoil (HCGO), crude oil, petroleum coke, and liquefied petroleum gas (LPG). Diversity is a merit; however, the use of gasoil in steam turbine is the weak point of thermal generation sector in Sudan. Gasoil is competitive oil as it is used by transportation and agriculture sectors, in addition to its high cost relative to heavy fuel oil and petroleum coke. But it seems that the use of gasoil in ST and GT generation is an issue of “energy security” rather than economic factors; otherwise, the use of gasoil is not a common practice in ST and GT power generation. Table 4 shows the electric power generation in Sudan in the period from 2002 to 2014. The hydroelectric power share increased from 42% in 2002 to more than 75% in 2014. This is mainly due to the inception of Merowe Dam in 2009. The imported electric power from Ethiopia increased to 469 GWh (4%) in 2014.


NumberThermal power plantYearPrime moverFuelCapacity
InstalledNominalAvailable
MWMWGWh

Operational thermal power plants
1Shahid Mahmoud Sharief 1 + 2 ST1984STHCGO6028212
2Shahid Mahmoud Sharief 3 + 4 ST1994STHFO + HCGO120110840
3Shahid Mahmoud Sharief 5 + 6 ST2011STHFO2001901408
4Shahid Mahmoud Sharief 1 + 2 GT1992GTGO5034265
5Garri1: CCGT2003CCGTGO + LPG1801701346
6Garri2: CCGT2003CCGTGO + LPG1801701346
7Garri4: ST2010STPet coke110100675
8Kusti2013STCrude oil5004703590
9Diesel generationICDiesel

Available thermal power A140012729682

Under-construction and planned thermal power plant
9Al Fula2016STAG/NG4053812908
10Red Sea2016STCoal6005344079

Planned thermal power cycle B10059156987

Total (A + B)2405218716669

ST: steam turbine.
HCGO: heavy coker gas oil (heavy gasoil).
HFO: heavy fuel oil (equivalent to number 6 fuel oil).
GT: gas turbine.
GO: gasoil.
CCGT: combined cycle gas turbine.
AG: petroleum associated gas; NA: natural gas.

YearHydroSteam turbineGas turbineDieselCombinedImportProductionHydro%Import%

201489141400020286446911848754
201383171205018358232010607783
20126619148451821145749509701
201164521631116121008455760
201061994731419262007499830
2009323688794309184706372510
200814661106152442234005506270
200714571057371140199705021290
200613681108501353119204521300
200512391047319385113504125300
2004110710371256349003749300
200311631168210328003354350
20021287116381310003094420

3.2. Private and Mixed Sectors Power Generation

There exist a number of private and mixed industries that produce their own power consumption. The major industries are as follows:(1)Oil refineries.(2)Oil fields production facilities.(3)Sugar industry.(4)Cement industry.(5)Sea port and civil aviation.(6)Others.

The power production by these sectors is not accounted for in Sudan energy balance 2012.

3.2.1. Oil Refinery

Table 5 shows the installed power of oil refinery and oil fields. The total installed power by oil industry is about 38 MW. A large portion of KRC refinery power generation is from waste heat and low grade fuel such as vent gas and oil slope (slurry). The electric power produced by oil industry is about 1% of the national grid electric power (the hydro and thermal power generation).


NumberOil industry power plantYearPrime moverFuelkW

1KRC (2 12 MW)1999STFG + bunker24000
2KRC (2 12 MW)2006GTFG + bunker12000
3ORC 50 Hz1999ICDiesel250
4ORC 60 Hz1999ICDiesel500
5Heglig oil field 1naICDiesel25.5
6Heglig oil field 2naICDiesel11.5
7Neem oil fieldnaICDiesel11.2
8Canar oil fieldnaICDiesel0.8
9Diffra oil fieldnaICDiesel3.9
10Other (mainly the power for the oil pipeline)naICDiesel1000

Total37803

FG: fuel gas mainly CH4.
Since 2014, it has become standby generator as the refinery is connected to national grid of 50 Hz.
3.2.2. Sugar Industry

Sudan ranks high in sugar production among African countries. Sugar industry produces its own power consumption from bagasse, a byproduct of sugar cane. The installed sugar capacity is about 1.0 Mt of sugar/year. Table 6 shows the installed capacity of electric power plants in sugar factory. The installed capacity is about 190 MW, which is about 6% of the national grid electric power. However, the available capacity is 96 MW as the White Nile sugar factory is working at low capacity. Bagasse is sufficient to produce electric power for 210 days/year including cane crushing season of 180 days/year. Besides electric power, the factories also produce their own process heat for sugar cane mills, heating, and evaporation and crystallization process. The potential for high power generation in sugar plant is feasible. If cogeneration is installed, the process heat load will be reduced as the sugar mills and shredders will be electric driven rather than steam driven which in turn saves steam for power generation.


Number FactorySugar capacityBagassePower plant
YearInstalledCurrent
ktonktonktonktoeMWD/YGWh

1Kenana1981300307.6135058020210326
2Sennar19767073.13211386.521033
3Assalaya19807065.42871236.521033
4Guneid19627073.13211386.021030
5New Halfa19667059.52611126.021030
6White Nile201245073.4322138(104) 6.021033

Total980652.128621230(190) 96485

Bagasse sugar ratio: 4.4.
The design capacity of power plant is 104 MW.
Personnel contact.
3.2.3. Standby Power Generation

All public utility services such as hospitals, universities, municipals, city water, and commercial buildings have their own standby IC electric power generators. However, there is lack of inventory data on standby generators countrywide. In this work, a field survey was made and about 100 standby IC generators with name plate capacity of about 1.2 kW with diesel as fuel source have been established. However, due to lack of information on the operation hours of the standby power generation, it is excluded in the present study. Besides services, air aviation and sea port also rely heavily on off-grid generation.

3.2.4. Photovoltaic

Table 7 shows the solar radiation in a number of Sudanese cities. The average sunshine duration is about 9 h. Most of the solar installation in Sudan is photovoltaic cell. The total installed capacity is about 2 MW. About 50% of the installed capacity is by telecommunication industry. All remote off-grid antennas and satellites are solar driven.


StationMean temperatureSunshine durationSolar radiation
ChMJ/m2/day

Port Sudan28.49.020.87
Shambat29.79.922.82
Wadi Medani28.49.822.84
ElFashir25.89.622.80
Abu Na’ama28.88.821.90
Ghazala Gawazat27.29.321.72
Dongala27.210.524.06
Toker28.87.317.60
Zalingi24.58.822.98
Babanusa28.28.921.30
Kadugli27.58.521.30

3.2.5. Summary of Power Supply and Demand

Table 8 shows the power supply by various power producers and consumption by various sectors. The hydropower represents the biggest share of about 70% despite the fact that the installed capacity is about 54% of the total installed power capacity. This is due to the high outage associated with thermal power generation. The power demand by various sectors is also given. The residential sector has the biggest share of demand followed by the service sector.


Power supply (ktoe)Power demand by sectors (ktoe)Total
HydroThermalICImportPVResidentialIndustrialAgricultureServiceTrans.

Public sector767677174005341515228301019
Oil industry540002900029
Sugar industry610006100061
Renewable000.40000.400

Total767285174005342405228301109

%69.1125.651.573.630.0348.1221.684.6725.530.00100.00

PV: photovoltaic.
3.3. Oil Supply and Demand

Table 9 shows Sudan’s oil production in the last 3 years, after the separation of South Sudan. The portion of export is given as well. Besides oil production, a significant amount of associated gas (AG) is also produced. However, the AG is not utilized; it is flared. The historical and projected daily flared amount is about 15–17 MMSCFD from 2006 up to 2030 [14]. For this work, the minimum is considered (15 MMSCFD). Sudan has four oil refineries with a total installed capacity of 143.7 thousand BPD (cf. Tables 9 and 10). However, three of these refineries are out of service representing about 20% of the total installed refinery capacity.


YearOil productionExport
MMBPD(000 tonnes) BPD

201442.411,093
201345.115,837
201237.47,210


NumberRefineryCapacity (000 tonnes) BPD
InstalledAvailable

1Khartoum Refinery Corporation (KRC)100100
2Port Sudan Refinery Corporation (PRC)21.70
3Obeid Refinery Corporation (ORC)1515
4Concorp Refinery100
5Abu Gabra Refinery20

Total capacity143.7115

Tables 1117 show the fuel oil of ORC, KRC, import, total supply, total demand and supply and demand balance, and thermal power generation oil consumption, respectively. The main products include fuel oil, gasoil, kerosene, gasoline (Mogas), LPG, jet fuel, and petroleum coke. The surplus of benzene is for export. Sudan has surplus in some fuel oil and deficit in others. It has surplus in crude oil, gasoline, and pet coke. The surplus of crude and gasoline is for export while the surplus of pet coke is kept as reserve. The deficit of gasoil, LPG, and aviation is met from import. One of the causes of deficit in gasoil is its competitiveness. Gasoil is used by power generation, transportation, and agriculture sectors. As energy conservation measure fuel shift of gasoil is recommended for power generation and agriculture sector and gasoil is to be limited to transportation sector, heavy fuel oil is recommended for thermal power generation and total electrification of agricultural sector via using electric water pump for irrigation system rather than IC motors.


YearFuel oilGasoilKeroseneNaphthaTotal
ktoe

2010361641.00134446.0038011.0026981.00405
2011385330.00141606.0040405.0027299.00414
2012385352.00140899.0041439.0024245.00148
2013307604.00114010.0030937.0019070.00328
2014339663.00126600.0032510.0024547.36312


Year CrudeFuel oilGasoilKeroseneBenzeneLPGJet fuelHCGOPet cokeTotal
ktoe

2010426512801860390012419093274131336163797683220324379
2011385438101651867011502163118401338823214132851633964
2012373819101655445010998003196901179242772302681023850
201334032390151556401009741289363794382536122555213501
2014340511301379208010679143214531070742933682360963573


YearGasoilLPGAviationTotal
Tonktoe

201033786437760136538540
201165366192282150459945
2012628063114013109110899
2013898842195335826741244
20141159119132903665931427


Year Fuel oilGasoilKeroseneBenzeneLPGAVPet cokeDieselTotal

201055529023801753018824232398347235344340858261314763395
201153199123583663497838924231382289474211637223844487655
201234806325444503119901671374968223797265292198874681247
201333780024758634270918269357588190060189236310884504174
201429069626162313744895420397251144718245672279134621645


YearFuel oilGasoilKeroseneBenzeneLPGNaphthaAVH. coker GOPet cokeDiesel

2010
2011
2012
2013
2014


FuelFuel oilBenzeneH. coker GOPet cokeDieselTotal

tonne2228442409811625811489933916425
ktoe2142581561138677


Itemktoe%Share%

Crude oil production606779.89
Associated gas1001.32
Gasoil 120615.88
Aviation710.93
LPG1501.98

Subtotal A7594100.00

Flared AG1005.931.32
Crude export158794.0720.90

Subtotal B: export + loss1687

Subtotal C = A − B5907

Refinery conversion + distribution + emission303.19
Benzene export16517.82
Power production67773.13
KRC + ORC (internal consumption for power generation)545.85

Subtotal D = C − oil used in power generation926100.0012.19

Residential3988.00
Transportation393579.00
Service501.00
Industry54811.00
Agric.501.00
Fuel for consumption by sectors498165.59

Total by sectors5907100.00100.00

Service includes public buildings, school, universities, hospitals, municipals, and so forth.

Table 17 shows summary of the oil supply and demand. The total supply is 7594 ktoe (7.594 Mtoe). This oil mix consists of crude oil, AG, and imported oil (gasoil, aviation, and LPG) as shown in Table 17. The imported oils represent about 19% of the total oil mix. 9.6% of the total supply is for thermal power generation including the electric power generated by KRC and ORC. The total energy mix is distributed as follows: 65.6% demand, 20.9% export, 12.9% energy conversion loss, and 1.32% flared gas. The demand is distributed to the following sectors: industry (11%), residential (8%), service (1%), transportation (79%), and agriculture (1%).

3.4. Biomass

The types of biomass used for energy in Sudan include(1)firewood,(2)charcoal,(3)agriculture residue,(4)bagasse,(5)bioethanol,(6)animal waste.

3.4.1. Bagasse and Ethanol

Table 18 shows the sugar produced by 6 Sudanese sugar factories. Bagasse is estimated from the produced sugar. It is taken as 39.5% of crushed sugar cane and the sugar recovery is taken as 9% of the sugar cane. Hence, the bagasse sugar ratio is 4.4-ton bagasse/ton sugar. Table 18 also shows the bioethanol production. Bioethanol is produced from molasses. All bioethanol produced is from Kenana sugar company. It should be remembered that all bioethanol is for export.


YearCapacity (000 tonnes/year)BagasseBioethanol
KenanaNew HalfaGuniedSennarAssalyaW NileTotalMtonktoe(000 m3)

20023768594786469730591315
20033988387857672932001376
20044288887797475533141425
20053937387728871331271344
20064008581818172831951373
20074058387939075833261430
20084028185869174532681405
20093828488879873932411393
20102765788777557425181082
2011356759871946933040130740
20123506692779066802985128355
201347156777690738433698159067
201430860737365736522862123070

All bioethanol is produced from Kenana sugar factory.
3.4.2. Firewood and Charcoal

Tables 19 and 20 show the firewood and charcoal, respectively, obtained from the annual report of the Directorate of Agriculture and Forestry of Sudan. It is clear that there is large data missing/gap. When these data are compared with data in the open literature, a large variation is found. Hence, these data are not considered and literature data is rather considered.


YearNorthKhartoumCentralEasternKordofanDarfurTotal

200542670520873122812932410311227217
2006354703763216038577803138903773922
20075379070113711162379229079199479
20085153770838083373427840164868466733
20093000039828153600058188
2010118550756212914012708933056276761
2011653834072992343079982845955259960
201234105004949097539311072464
2013315005207984006515070144
20142000237579627138375236399784


YearNorthKhartoumCentralEasternKordofanDarfurTotal

200589502978815615525472052272
200691201047985513201221927665
200715680172395070167620990
20081012158160164247911820101572501
2009003102995003305
20108556010004305455570261512607643
2011192760192198399412410970082345606
201200320098750013075
20130035005930009430
2014001302155001457

Table 21 shows firewood and charcoal production obtained from the open literature for some years as a cross-check. The data of Sudan energy balance of 2012 is adopted in this work as it is close to that given by other references.


SourceFirewoodCharcoalTotal as firewood
ktoektoektoe

[7]3146878 (2926)6072
[16]2410795 (2650)5060
[17]39441328 (4427)8371

Data in brackets is firewood converted into charcoal with conversion efficiency of 33%.
The original data is given as consumption per capita.
3.4.3. Agriculture Residues

Table 22 shows the cereals, oil crops, and cotton production. The agricultural waste is estimated using harvest index (HI). The harvest index for cereals, oil crops, and cotton is taken as 0.4, 0.52, and 0.16, respectively. The agriculture waste is calculated as the amount of crop multiplied by [11]. The portion of agriculture residue used as fuel is very small as the majority is used as animal feed and building material and in pulp and paper industry, among others. On the other hand, the agriculture waste is mostly burned during land preparation for the next season. The data is cross-checked against Sudan energy balance of 2012 and is found to be consistent.


YearSorghumMilletWheatGroundnutSesameSun flowerCottonTotal residue
HI [11]
0.40.40.40.520.520.520.16
kton/yearMtonktoe

20024.3945782479902744722.792105
20032.82558133055012218862.461852
20044.697693987903997663.212418
200526628036452027712862.561932
2006432767541655540044759.447117
20074.99979666956424273613.342516
20083.869721587716350100243.172389
20094.197637641942318247313.482620
20102.6347140354924846122.161624
20114.6056342921.185363124141.921445
20121.8833783241.03218792551.601208
20134.5241.092651.76756286251.14857
20142.24935919396320556312.121600

3.4.4. Animal Waste

Sudan is rich with cows, sheep, goats, and camels, besides donkeys, horses, and chickens. Table 23 shows the animal counts. The animal dung is estimated from average dung production per head. The dung is generally used for biogas production. The dung available for biogas production is estimated by many researchers as 10% [16]. Currently, there are no reports for biogas production in Sudan. There is some biogas production in the 1980s; however, with the inception of crude oil production, biogas production was abandoned nationwide. Hence, the animal waste is not considered in the energy balance for the base year 2014 as there was no information or rates of use in the energy sector. Table 24 shows summary of biomass supply and demand.


YearCowsSheepGoatsCamelsDung
Dung production (tons/year/head) [10]
10.951.831.835.48Mtonktoe
Million head

200239.47948.13641.4853.3436125690
200339.66748.4442.033.5036225878
200439.7648.9142.1793.5196225971
200540.46849.79742.5263.9086326479
200640.99450.3942.7564.0786426821
200741.13850.65142.9384.2386426958
200841.42651.06743.1044.466527185
200941.56351.55543.274.566527321
201041.76152.07943.4414.6236627479
201129.61839.29630.6494.7154819986
201229.8439.48330.8374.7514820124
201330.0139.56830.9844.7734820225
201430.19139.84631.0294.7924920337


Supplyktoe%Demandktoe%

Firewood 314628.68Residential355332.39
Charcoal2925 (965)26.66Services149613.64
Agricultural residue160014.58Industry6626.03
Bagasse123011.21Transport00.00
Bioethanol360.33Agriculture00.00
Animal waste203418.54Electric power123011.21
Charcoal conversion loss196017.87
Export360.33
Not utilized203418.54

Total1097110010971100.00

Data in brackets is firewood converted into charcoal with conversion efficiency of 33%.
Animal waste is not considered as there is no record for animal waste utilization in the base year 2014.
All bioethanol is exported.
Animal waste is not utilized.
3.5. Sankey Diagram

Sudan Sankey diagram has been developed using the energy supply, transformation, and demand data obtained for the base year 2014 (cf. Figure 4). The Sankey diagram gives a detailed flow pattern indicating the proportional consumption of primary and secondary energy in different energy demand sectors. It also shows the energy loss during transformation and conversion. The main features of the Sankey diagram are as follows:(1)Primary energy: Sudan’s primary energy consists of oil (39%), biomass (56%), hydroelectricity (5%), and a very small portion of solar energy (photovoltaic). Besides primary energy, Sudan imports 1427 ktoe of fuel oils (gasoil + aviation + LPG) and 40 ktoe of electricity from the neighbouring country of Ethiopia. The import is about 7% of Sudan’s energy mix. However, natural gas, coal, nuclear energy, and other renewable energy sources are nonexistent in the country’s primary energy mix, despite the huge potential of solar, wind, and geothermal energy. The high proportion of biomass is due to the large population located in rural areas (70% rural population). They have no access to national grid electricity, fuel gas, and kerosene and therefore are absolutely biomass dependent in meeting their demand for cooking, heating, and lighting.(2)Transformation and conversion: the transformation processes in Sudan’s energy balance are power generation (hydro, oil, and bagasse), refinery of crude oil to secondary fuels, and conversion of wood to charcoal. The transformation and conversion and other losses are about 25% of the end-use energy. These losses are thermodynamic loss and energy management loss. It is worth highlighting two examples of energy management loss:(a)Lack of cogeneration in sugar industry: the potential electric power generation in sugar industry is double the present level if cogeneration in the sugar industry is introduced [12]. Cogeneration is the standard practice in sugar industry worldwide. Lack of cogeneration made the sugar industry in Sudan burn bagasse inefficiently; otherwise bagasse poses serious hazard to factory safety.(b)Flaring of AG: about 15 MMSCFD or 100 ktoe (1.7% of the oil supply) is attributed to flaring of AG. In the oil fields, a significant amount of AG is produced. AG produced is, however, not utilized; it is rather flared. The study conducted by [14] indicated that AG is useful primary energy and if utilized in power generation it can drive steam turbine power plant of 80 MW or can be utilized to produce LPG of annual value of $40 M/year.(3)Demand: 74% of the total energy demand is useful energy and 26% is loss. 49% of the total loss is due to low efficiency of conversion from wood to charcoal (charcoal conversion efficiency is 33%). The useful energy is distributed among the various demand sectors: agriculture (1%), service (16%), industry (12%), residential (39%), and transportation (32%) sectors.

The developed Sankey diagram is the first of its type in Sudan. The main differences between the present and previous energy balance are the following:(1)The previous energy balance is presented in simple line draw diagram rather than a professional Sankey diagram as all lines representing different flows are of the same size.(2)The energy balance accounts only for power produced by public sectors. For example, the electric power produced by the refinery and sugar factory is not accounted for in the overall balance. Likewise, renewable energy though small is not accounted for as well.

4. Conclusion

The study provides important information on Sudan’s energy sector covering supply and demand sides as well as conversion, distribution, and transmission. For the supply detailed data on electric power generation, oil production and conversion, biomass sources and conversion, and renewable energy was given. Energy import and export were also reported. On the demand side, detailed data of different sectors is reported. The work provided energy flow diagram (Sankey diagram) for the first time. Sankey diagram is an important piece of information for decision-makers. It can be used to develop strategies and identify potential saving, opportunities, and mitigation measures. The weak point of Sudan’s energy status is solar energy despite the high intensity of solar radiation and long sunshine hours across the country.

Competing Interests

The authors declare that there are no competing interests regarding the publication of this paper.

Acknowledgments

The authors acknowledge the research grant by the Ministry of Higher Education and Scientific Research of Sudan.

References

  1. A. Kumar, Subramanyam, and V. R. Kabir, Development of Energy, Emission and Water Flow Sankey Diagrams for the Province of Alberta Through Modeling. University of Alberta, Department of Mechanical Engineering, Department of Energy, Government of Alberta, Alberta, Canada, 2011.
  2. IRG, “Energy Planning and Development of Carbon Mitigation Strategies-Using the MARKAL Family of Models,” International Resource Group, Washington, DC, USA, 2010. View at: Google Scholar
  3. M. A. Jaccard, Estimating the Effect of the Canadian Government's 2006-2007 Greenhouse Gas Policies, C. D. Howe Institute, Toronto, Canada, 2007.
  4. O. Bahn, L. Barreto, B. Büeler, and S. Kypreos, “A multi-regional MARKAL-MACRO model to study an international market of CO2 emission permits: a detailed analysis of a burden sharing strategy among the Netherlands, Sweden and Switzerland,” PSI Technical Paper, Paul Scherrer Institut (PSI), Villigen, Switzerland, 1998. View at: Google Scholar
  5. Quadrennial Technology Review, An Assessment of Energy Technologies and Research Opportunity, Department of Energy, Washington, DC, USA, 2015, http://energy.gov/sites/prod/files/2015/09/f26/Quadrennial-Technology-Review-2015_0.pdf.
  6. MOF, Study of Causes of Demand Increase on Oil Product and Options and Strategy of Subsidy Removal, Ministry of Finance, Khartoum, Sudan, 2014.
  7. AEC, “Sudan energy status,” in Proceedings of the 10th Arab Energy Conference, Energy and Arab Corporation, Abudabi, UAE, 2014. View at: Google Scholar
  8. Directorate of Agriculture and Forestry (DAF), Annual Report, Directorate of Agriculture and Forestry (DAF), Khartoum, Sudan, 2014.
  9. NEC, Executive Summary for Year 2014, National Thermal Electricity Corporation, Khartoum, Sudan, 2014.
  10. M. Niamir, Report on Animal Husbandry among the Ngok Dinka of the Sudan-Integrated Rural, Sudan and Harvard Institute for International Elation, Khartoum, Sudan, 1982.
  11. V. Smil, “Crop residues: agriculture's largest harvest,” BioScience, vol. 49, no. 4, pp. 299–308, 1999. View at: Publisher Site | Google Scholar
  12. A. A. Rabah, “Future of sugar industry in Sudan,” Sudanese Engineering Journal, vol. 5, no. 3, pp. 60–64, 2013. View at: Google Scholar
  13. A. M. Omer, “Energy, environment, and sustainable development in Sudan,” IIOAB Journal, vol. 2, no. 1, pp. 31–44, 2011. View at: Google Scholar
  14. W. Abdelhamid, Flared gas uilization [M.S. thesis], Chemical Engineering, University of Khartoum, Khartoum, Sudan, 2013.
  15. M. Bashir, B. M. Elhassan, and A. A. Rabah, “Assessment of standby evaporator as an energy conservation measure: case of sudanese sugar industry,” Sugar Tech, vol. 13, no. 3, pp. 179–184, 2011. View at: Publisher Site | Google Scholar
  16. A. M. Omer, “The environmental and economical advantages of agricultural wastes for sustainability development in Sudan,” Journal of Brewing and Distilling, vol. 1, no. 1, pp. 1–10, 2010. View at: Google Scholar
  17. G. E. Ali, Studies on Consumption of Forest Products in the Sudan—Woodfuel Consumption in the Household Sector, Energy Research Institute, Khartoum, Sudan, 1994.

Copyright © 2016 Ali A. Rabah et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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