Optimal Planning of Central Biogas Plants and

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işlenmesine ilişkin modelin planlama seçeneğinde; dört köyde 400 tongün-1 ...... Ü züm ler. 19.48. 19.48. Kırtepe. 22.00. 22.00. Doyranlı. 17.33. 17.33. Alaylı.
Ekoloji 20, 79, 21-28 (2011) doi: 10.5053/ekoloji.2011.793

O ptim al P lan n in g o f C en tral B io gas P lan ts and E valuation o f T h eir Environm ental Im pacts: A C ase Study from Tire, Izm ir, Turkey H alil B ak i U N A L 1* , H alil Ibrahim Y IL M A Z I, Bulent M IR A N 2 1Ege University, Agricultural Faculty, Department of Farm Structures and Irrigation, 35100 Izmir-TURKEY 2Ege University Agricultural Faculty, Department of Agricultural Economics, 35100 Izmir­

TURKEY *Corresponding author: [email protected] A bstract Recently, the practice, reclaiming the manure resulting from animal wastes, has been gaining ground with biomass energy systems in large-capacity central biogas plants. These plants enable the use o f a renewable source o f energy in an efficient way and make a significant contribution to the sustainability in the environment. This study was performed on a total o f 929 dairy farms which were members o f a cooperative in 43 villages in Tire, in the Izmir province, in Turkey. The aim o f the study was to estimate the methane emissions through manure management applications, to plan the optimum capacity and location for plants to produce biogas from the manure, and to evaluate the environmental effects o f biogas production. An emission factor o f 2.05 kg head-1 year-1, and methane gas emission value o f 0.036 Gg year-1, were estimated for local conditions. An optimization model was developed to minimize plant investment and manure transport costs for optimum biogas production. The model was chosen to include the approximate total o f 1600 tonnes day-1 produced in the area. A 400-tonne day-1 capacity biogas plant was planned for each o f the 4 villages and it was determined that 35.106 m3 year-1 o f biogas could be produced. It was calculated that total plant investment would be $9.497.680 and manure transport costs would be $432.525 per year. This biomass-energy conversion would also provide socio-economic benefits to the area, and help to form a clean environment by preventing methane gas emissions from animal production. Keywords: Biogas, dairy cattle, manure, methane, optimization model. M erkezi B iyogaz Tesislerinin O p tim al Planlam ası ve Ç evresel Etkilerinin D eğerlendirilm esi: İzm ir-Tire Y öresi Ö rneği Ö zet Günümüzde, hayvansal atık olarak ortaya çıkan gübrenin, biyokütle-enerji sistemleriyle büyük kapasiteli merkezi biyogaz tesislerinde geri kazanılması yaygınlaşmıştır. Bu tesisler, yenilenebilir enerji kaynaklarının etkin şekilde kullanımını sağlayarak sürdürülebilir çevre yönünden önemli katkılar sağlamaktadır. Bu çalışma, kooperatife üye toplam 929 adet süt sığırcılığı işletmesinin bulunduğu İzmir-Tire yöresine ait 43 köyde yürütülmüştür. Çalışmada, gübre yönetiminden kaynaklanan metan gazı salınımının tahminlenmesi, elde edilen gübreyi biyogaza dönüştürecek merkezi biyogaz tesislerinin kapasite ve konumlarının optimum planlanması ve biyogaz üretiminin çevresel etkilerinin değerlendirilmesi amaçlanmıştır. Yöre koşulları için emisyon faktörü 2,05 kgbaş-1yıl-1, metan gazı emisyon değeri ise 0,036 Gg yıl-1 olarak tahminlenmiştir. Optimum biyogaz üretimi için, tesis yatırımını ve gübre taşıma masraflarını minimize edecek bir optimizasyon modeli geliştirilmiştir. Yörede üretilen yaklaşık 1600 ton gün-1 gübrenin tamamının işlenmesine ilişkin modelin planlama seçeneğinde; dört köyde 400 tongün-1 kapasiteli birer biyogaz tesisi kurulması öngörülmüş ve buna bağlı olarak yaklaşık 35.106 m3yıl-1 biyogaz üretilebileceği belirlenmiştir. Bu üretim için toplam tesis yatırım masrafı 9.497.680 $ iken, gübre taşıma masrafı ise 432.525 $ yıl-1 olarak hesaplanmıştır. Bu biyokütle-enerji dönüşümü sayesinde, yörede sağlanacak sosyo-ekonomik faydaların yanısıra, hayvansal üretimde metan gazı salınımı önlenerek temiz bir çevre oluşturulacaktır. A nahtar K elim eler: Biyogaz, gübre, metan, optimizasyon modeli, süt sığırı. Unal HB, Yilmaz HI, Miran B (2011) Optimal Planning o f Central Biogas Plants and Evaluation o f Their Environmental Impacts: a Case Study from Tire, Izmir, Turkey. Ekoloji 20 (79): 21-28.

IN T R O D U C T IO N Global output o f human-derived greenhouse gases increased by 70% between 1970 and 2004. By examining greenhouse gas emissions for 2004 by source, it can be seen that energy production took

first place with 26% o f emissions, while agriculture provided 14%. In agriculture, unsound manure management practices in particular contributed to greenhouse emissions. In Turkey, total methane gas emission from manure management has been Received: 29.04.2010 / Accepted: 22.08.2010

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21

Ekoloji increasing, and reached 52.55 Gg year-1 in 2006. O f this output, 78% comes from cattle manure (Anonymous 2007, Anonymous 2009). In the present day, the practice o f reclamation from manure produced from animal waste on large modern farms by means o f biomass-energy systems has become more widespread. In Asian countries such as China and India small-scale biogas plants at farm level are used, whereas in countries such as Germany, the U K , the Netherlands and Denmark large-capacity plants are more widespread. These kinds o f plants are either set up on large farms or are constructed centrally in areas where there is a high concentration o f livestock farming (Anonymous 2010a). In countries o f the E U , the number o f cattle per dairy farm in 2004 was lowest in Lithuania at 2.3, and highest in Denmark at 75. The equivalent number for Turkey was 5.2 (Akman 2005). In Turkey there is no effective environmental control because the small-scale dairy farms with non­ standard buildings do not practice sound waste management (Unal and Yilmaz 2007). Akman (2005) stated that one o f the changes in sensitivity to the environment in animal production expected in the future in relation to Turkey's accession to the E U would be in the organization o f waste management. M anure is widely used as biomass in the production o f biogas. Biogas is a mixture o f gases, generally 60-70% methane (C H 4) and 30-40% carbon dioxide (C O 2), produced from wastes such as manure in an oxygen-free environment. Biogas produced in a biogas plant and burnt in a gas engine can produce electric energy and heat. Recently, large-capacity biogas plants have been set up on large farms or in areas where there is a large concentration o f animal-rearing. Such plants could have great importance for Turkey in terms o f a sustainable environment and the efficient use o f a renewable energy source, and it has been indicated that investment and research and development activities must be given priority (Tolay et al. 2008, Anonymous 2010a). Principal among the considerations in designing biogas plants are determining the amount o f suitable raw material and plant capacity, and choosing the location o f the plant. In studies on optimizing the use o f biomass, mathematical models have been used to determine optimally suitable biomass collection centres, the number o f biogas plants to be 22

Unal et al.

set up at these centres, and their capacity and location. For example, mathematical models were used to optimize biomass use in Sardinia, Italy by Celli et al. (2008), in Austria by Leduc et al. (2008), and by Yuttitham et al. (2003) in Nakhonpathom, Thailand. The world trend towards renewable energy sources such as biogas makes necessary an effective review o f Turkey's current potential. This must be given priority especially in provinces such as Izmir in the Aegean region, where cattle farming is widely practiced (Ozturk 2009). Thus, studies are needed on evaluating the environmental effects o f manure in areas where animals are reared, and determining the requirements o f biogas production plants when using manure as biomass. So far, adequate studies have not been carried out on this subject. In the present study, the emission values o f methane gas from manure management in dairy cattle farms organized as a cooperative in the areas o f Tire in the Izmir province were estimated, a model was developed to optimize the necessary investment in the conversion to energy o f the manure produced in the area and in transport costs, and alternative locations were presented for central biogas plants o f various capacities. It is intended that this model can be an example for other similar regions so that it can provide an optimum solution for those regions with the application o f basic local data. In addition, an evaluation was carried out o f other environmental benefits to be derived in the region along with biogas production. M A T E R IA L A N D M E T H O D S R esearch A rea Included in this study were all 929 farms which in 2008 were members o f the Tire Dairy Cattle Breeders' Association. These farms keep dairy cattle in 43 villages o f Tire district in the Izmir province in Turkey. The distribution o f these dairy farms is given in Table 1. C a lc u la tio n o f M eth an e G a s E m issio n s A risin g fro m M an u re M an agem en t Estimates o f methane gas emission values by the Turkish Statistics Institution are based on the first method in the IP C C (Intergovernmental Panel on Climate Change) guide (Anonymous 2006). In this method, evaluation is based on values for three climate regimes (hot, temperate and cold) in the Asian area, which includes Turkey, and the assumption that manure is mostly burnt for fuel. No: 79, 2011

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Optimal Planning o f Central Biogas Plants and Evaluation...

In the second method presented in the guide, the various manure management practices o f each different area are taken into account. In this study, methane emission values arising from manure management o f the farms in the research area were estimated according to both methods (Anonymous 1996). Equation 1 was used to calculate annual total emission values (ATEI) (Gg/year), according to data on regional location, local climate, and dairy cattle population. YTE = EF. P. 10-6 (1) In Equation 1, the emission factor EF (kg head-1year-1) was obtained from the relevant table in the IP C C guide, and P the dairy cattle population, was 17,426 in the research area according to data from 2008 (Anonymous 2010b). Annual total emission values according to the second method (ATEII) (Gg year-1) were calculated by means o f Equation 1 using the specific emission factor for the research area (EF;), which was found by means o f Equation 2 EF; = VS; 365 B o; 0.67 X M C F jk M S ijk

G in n = E Y jX jC j + x (0.13)(365)TkjX j A k

(3)

(2)

(jk)

where index i indicates the animal type category, index j represents the waste management system category, and index k is the climatic system category. Thus, EFi is the annual emission factor for the type and population o f animals in the research area (kg), VSi is the daily amount o f volatile solid matter for the type o f animals in the research area (kg head-1 day-1), Boi is the maximum methane production capacity for manure per animal in the research area (m3kg-1 VS), MCFjk is the methane conversion factor for the various waste management systems in the climatic systems o f the research area (%), and M S ^ is the animal fraction in the waste management systems in the climatic system o f the research area (%). The parameters VS, Bo, and M S were determined according to the average live weights o f the dairy cattle in the research area, and M C F values were determined according to manure management practices and climatic conditions by use o f the relevant tables in the IPC C guide. In 78% o f the farms in the research area the manure was stacked in piles in the open. The burning o f manure as fuel expected for Asia in the Guide was seen in only 2% o f the farms in the research area (Ozturk 2009).

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C re a tin g an O p tim al P lan n in g M od el for C en tral B io g as P lan ts In order to exploit the manure produced in the research area as biogas in an optimal way, an optimization model was developed to determine what the capacities o f the biogas plants should be and in which villages or biogas production centres they should be set up, and to establish which villages should supply the manure for processing in each plant. This model was created based on mixed programming including linear programming and 0-1 programming (Miran 2005, Taylor 1999). The objective function o f the model, predicted constraints, and values used are defined below. O bjective fu n ctio n (Z min) : This was set up so as to minimize investment costs for the biogas plants and the transport costs incurred in carrying the manure to these plants (Equation 3). O f the decision variables in the objective function, manure processing plants were expressed as a 0-1 variable, and manure transport cost as a continuous variable.

In the equation, Yi is the investment cost o f any type o f biogas plant (i= 1 ,2 ,3 ), Xj is the villages or centres where the biogas plants are to be located (j= 1,..., 10), C t is the alternatives for different types o f biogas plants to be set up with the capacity to process all the manure in the research area (t= 1 , . , 28), Tkj is the distance from the biogas plants to be set up to the villages in the research area (k = 1 , . , 43; j = 1 , . , 10), and Akis the amounts o f manure to be transported from the villages in the research area to the biogas plants to be set up (k = 1, ..., 43). The values 0.13 and 365 are used to determine the annual cost o f manure transport based on the average unit cost o f manure transport. Constraints: The constraints used in the model are defined below. - It was projected that biogas plants o f a capacity and number to process all the manure produced in the study area would be set up in the first 10 villages in order o f amount o f manure produced. The total manure production o f these villages was about 78% o f the total production o f the research area. - It was projected that 3 industrial-scale biogas plants o f different types and with the highest capacity would be set up from the producing firm's catalogue in order to exploit the manure produced in the research area. The capacity o f the manure 23

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processing plants to exploit the whole o f the manure obtained in the area (the first alternative) should not be less than the 1600 tonnes determined as the amount o f manure produced in the research area (Equation 4): E K j X j C t S i 600

(4 )

In the equation, Ki is the daily processing capacities o f the different types o f biogas plants (i = 1, 2, 3), Xj is the villages or centres where the biogas plants are to be set up (j= 1, ..., 10), and C t is the alternatives for the different biogas plants with the capacity to process all the manure produced in the research area (t= 1, ..., 28). -The maximum distance to transport the manure in the research area was based on a distance o f 40 km which is recommended and should not be exceeded in economically transporting manure with a m inimum dry matter content o f at least 70% (Anonymous 2007) (Equation 5):

Tkj < 40

(5 )

In the equation, Tkj is the distances from the villages to the biogas plants that are to be set up (k = 1 , . , 43, and j = 1 , . , 10). -It was projected that rather than having more than one plant at the centres, a single plant should be established with the purpose o f creating more employment in the research area and spreading the economic advantages over a larger area. In this way, because the centres would be close to the villages (an average distance o f 20.91 km, minimum 2.25 km and maximum 47.2 km), investment would be possible in more than one village without greatly affecting transport costs. The application o f this constraint rule to centres by the model is expressed in Equation 6

EX jCt = l j

(6)

where Xj is the centres where biogas plants are to be set up (j= 1 , . , 10) and C t is the alternatives o f the different types o f biogas plants with the capacity to process all the manure produced in the research area (t= 1 , . , 28). Variables: Variables used in the model are explained below. - Amounts o f manure produced: The amounts o f manure produced per day on each o f the farms in the villages in the study area was determined on the basis o f manure production values for the cattle on 24

the farms according to age and sex (Table 1) (Anonymous 2004, Anonymous 2005, Beaulieu 2004). - Capacities and investment costs o f various types o f biogas plants: Table 2 shows the investment costs o f biogas plants o f three different capacities operated on a continuous feed basis with the purpose o f processing the manure in the research area. - Manure transport distances and transport costs: the manure transport distances between the projected centres where biogas plants are to be set up and the other villages were determined on the basis o f communication by road (Table 3). In choosing a location for buildings and facilities to be used for keeping cattle, it is specified that these must be at least 1 km away from inhabited areas (Anonymous 1988). For this reason, the distance for the transport o f manure produced in a village to a biogas plant to be established outside the inhabited area o f the same village was taken as 1 km. The costs o f transporting the manure from the village to the biogas production centres were determined according to the average unit cost for the transport o f manure and transport distances. The average unit cost for the transport o f manure was calculated as $0.13 km-1 ton-1 according to the transport coefficient set each year by the Current Price Commission o f the Ministry o f Public Works and Settlement. The transport coefficient was expressed as the equivalent o f pay for an eight-hour day, whatever the type or tonnage o f the vehicle used (Anonymous 2009b). R E S U L T S A N D D IS C U S S IO N M eth an e G a s E m issio n s A risin g fro m M anu re Emission factor values calculated by the two different methods in relation to manure management practices on the dairy cattle farms in the research area were E F I= 16 kg head-1 year-1 and E F II= 2.05 kg head-1 year-1 and methane gas emission values were estimated as ATEI= 0.279 Gg year-1 and ATEII= 0.036 Gg year-1 (Table 4). Even though the climatic and population data used in the two methods were the same, ATEI was found to be larger than ATEII. This arises from the fact that the specific emission factor calculated according to the actual manure management practices in the research area (EFII) was smaller than the emission factor calculated according to the No: 79, 2011

Optimal Planning o f Central Biogas Plants and Evaluation... Table 1. Distribution o f dairy cattle farms and daily manure production amounts in the research area. N u m b er o f Farm s

Location T ire T ow n Gökçen

1 2

3 Kızılcahavlu 4 Işıklı 5 Derebaşı 6 Yeğenli 7 A kkoyunlu 8 Peşrefli 9 Karateke 10 Çiniyeri 11 Kireli 12 K ürdüllü 13 Boynuyoğun 14 Yeni Çiftlik 15 Çayırlı 16 Ü zü m ler 17 Kırtepe 18 Doyranlı 19 Alaylı 20 Yenioba 21 Büyükkale 22 M ahm utlar Total

177 106

M an ure production (tonnes day'1) 275.66 240.54 156.58 95.28 90.81 75.12

53 61 58 56 28 41 37 44 34 22 19 15 12 7 8 14 13 6 11 14

74.47 66.25 64.21 60.74 40.04 34.33 29.43 26.13 25.25 19.48 19.32 17.33 11.90 11.76 11.33 11.13

N u m b er o f Farm s

Location

M anure production (tonnes day"1)

23 H asançavuşlar 24 K ursak

5 6

11.12 8.87

25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

8 9 8 8

8.02 7.55 6.12 5.91

7 6 5 5 4 2 3 2 2 2 2 3 3 1 2

5.19 4.67 4.31 4.21 2.62 2.45 2.36 2.25 2.07 2.00 1.71 1.69

929

1 544.67

D ereli Sanlar Akçaşehir Saruhanh Ayaklıkırı O sm ancık Küçükkale M ehm etler T u rgu tlu Göldere Başköy Eskioba Işıklar Alacak Büyükkem erdere Ç obanköy Akyurt Küçükkem erdere Eğridere

1.66 1.44 1.36

Table 2. Investment costs for projected biogas plants (Anonymous, 2009a). Type of Plant

M anure Processing Capacity (tonnes day"1)

A B C

100 200 400

Plant Investment C osts Project Docum entation

Supervision

Equipm ent

Construction

($) 121 974 149 079 176 184

($) 23 039 23 039 23 039

(» 487 895 704 737 1 2 3 3 289

($) 365 921 528 553 941 908

Total (S) 998 829 1 4 0 5 408 2 374 420

Table 3. Transport distances between villages and biogas production centres in the research area. T ra n sp o rt D istan ces (km )

Karateke Ç iniyeri Kireli K ü rd üllü B o y nu y oğu n Y eni Ç iftlik Ç ayırlı Ü z ü m le r K ırtepe D oyran lı Alaylı Y en ioba Büyükkale M ah m u tlar H asan çavu şlar K u rsak D ereli S an lar A kçaşehir Saruh anh Ayaklıkın O sm an cık K üçükkale M eh m etler T u rg u tlu G öld ere B aşk öy E sk io b a Işıklar Alacak B ü y ükkem erdere Ç o b an k öy A kyurt K ü çü kk em erdere E ğridere

No: 79, 2011

10.55 12.20 8.55 7.45 8.95 9.85 5.15 23.65 7.40 22.25 14.95 22.80 14.80 18.90

23.25 3.60

Kızılcahavlu

10.55 23.25 28.35

12.20 3.60 8.70

13.40 16.60 7.35 28.35

1.00 24.85 13.40

24.85 1.00 21.70

16.25 24.60 28.35

7.80

14.25

20.20 8.70

22.60 26.35

16.25 7.80

2 4.60 2 0.20 22.60 24.65

13.40 21.70 1.00 28.35

3.00

8.70 26.35 13.15

22.75 3.00 18.00

22.75 1.00 20.75 7.55

3.05 24.65 13.15 18.00

20.75 1.00 16.00

7.55 16.00 1.00

10.30 13.65 14.55 41.30

19.50 20.40

4.7 0 8.05

17.50 18.40

15.70 14.40

8.95 35.85 19.60 34.45 5.85 14.75 2 7.00

13.70 16.10 15.95

430 5.20 4.20 31.10 14.85

Işıklı

17.80 5.10 7.35

1.00

5.20 8.55 9.45 36.35

10.30 13.65 14.55 38.90

4.5 5 5.45 2.45 29.35

20.10 34.95

25.20 40.05 4.50 11.15

13.10 27.95 10.55 19.45

43.10 18.85 8.15

2 5.20 40.05 4.15 16.25

17.95 21.80 25.50 26.55

32.60 36.70 36.00 30.30 38.55 34.80

20.50 2 4.60 23.90 18.20

35.65 32.95 39.05 26.55

3 2.60 36.70 36.00 30.30

17.75 3.25

26.45 22.70 10.75 13.60

41.60 37.85 24.00 21.90

38.55 34.80

19.60 12.70 30.25 15.30 28.45

34.75 21.00

31.70 8.20

45.40 23.60

42.35 10.80

43.60 43.95 26.40 19.50 44.65

2.25 11.15 27.50 31.60

20.75 17.00 10.75 18.00

33.45 29.70 7.40

15.10 26.35 18.10

20.85 16.60 16.60

21.25 8.05

30.90 25.20

22.75 23.10 12.35 15.60 23.80

5.70 8.30 13.40

8.70 26.35 13.15

18.20 12.50

13.90 17.10 2 4.55 19.70

17.80 5.10 1.00

5.30 26.60 4.40 37.25 7.00 35.45 35.80 25.05 2.90 36.50 27.80 39.05 30.80

15.00 16.35 16.60 16.50

27.70 3.65 29.30 29.20

20.35

7.65

12.50 7.55 3 1.70 8.55 42.35 11.15 40.55

14.25 3.05

40.90 30.15 8.00

28.80 18.05 11.20

41.60 32.90 44.15 35.90 32.80 7.80

29.50 20.80

34.40 34.30 11.80

22.30 22.20 15.95

32.05 23.80 20.70 11.95

21.80 25.15 26.05 37.70 28.25

16.45 9.65

18.75 12.55 21.30 28.55

I £

Ç iniyeri

5.70 20.85 17.80

5.10 8.30 16.60 5.10

i

Karateke

Işıklı D erebaşı Y eğenli A kkoyunlu Peşrefli

12.70 1.00

A kkoyunlu

1.00 12.70 17.80

Yeğenli

T ire T o w n G ökçen Kızılcahavlu

G ök çen

L ocation

T ire T o w n

B io gas P rod uction C entres

8.55 21.25 26.35

7.45 8.05 13.15

3 1 .1 0 30.40 24.70 32.95 29.20

23.50 23.50 24.55 18.15 11.35 19.45 4.95 20.45

22.45 2635 25.65 19.95 28.20

6.90 8.90

19.30 26.55

24.45 6.10 13.35

20.45 27.65 14.95 30.25

2 6 .1 0 8.00

22.15 25.65 16.65 28.25

2135 12.45 32.00 15.05

40.55 40.90 30.15 8.00

22.30 22.65 3.10 26.15

24.00 24.35 4.80 24.15

30.20 30.55 19.80 10.95

29.15 47.20 32.15 35.85

4 1.60 32.90 44.15 35.90 32.80

30.70 5.85 13.15 8.85

34.95 35.30 24.55 6.50 36.00

32.40 7.55 14.85 10.55

31.25 22.55 33.80 25.55

20.25 37.45 37.35

7.45 34.40 34.30

25.55 26.90 23.15 27.05

27.20 7.25 28.80 28.70

23.55 24.90

22.45 11.70 24.05 23.95

24.25

11.45

30.90

11.25

12.50 7.20

36.75 10.60

27.30 38.55 30.30

14.25

29.70 1030 19.20

24.85 25.05 28.90

15.70

Ekoloji values recommended in the IPC C guide (EFI). In the same way, Gonzalez and Ruis (2001) working in Mexico and Gupta et al. (2007) working in India, reported that the emission factor value estimated for cattle according to the values recommended in the IP C C guide were much higher than the specific emission factor value determined for the research areas. This was stated to arise from the fact that the values projected by the first method were determined according to manure management practices which had been generalized for much greater areas. At the same time, the fact that the emission factors determined according to the actual manure management practices in the research area were small doesn't mean that waste management practices in the research area were good, or that they did not damage the environment. Ozturk (2009) found that in the Tire region the buildings housing cattle on many farms were close to dwellings and that the manure from these cattle was generally piled up in the open thus constituting a significant threat to human and animal health and to the environment. O p tim u m C a p a c ity an d L o c a tio n fo r B io g as P lan ts Table 5 gives 13 different optimal planning choices obtained by the model to minimize investment and manure transport cost for biogas plants which would process all (100%) or part (