Feasibility Study on Electricity Generation from Poultry Litter Based Biogas in Bangladesh

ASM Mominul Hasan1 Md. Fayyaz Khan2 Raqibul Mostafa3 and Azizul Kaium4 1Centre for Energy Research, 2&3 Department of EEE, 4 SEBA Limited, 1-3United International University (UIU)

1-4Dhaka, Bangladesh 1mominul.hasan@hotmail.com

2fyk@eee.uiu.ac.bd 2rmostafa@eee.uiu.ac.bd

Abstract— Renewable Energy (RE) technology holds great potentials as alternatives to conventional energy generation to reduce the large deficit in electricity supply that currently exists in Bangladesh. Biogas plants are being considered as a promising RE source to supply electricity in a localized area. Traditional biogas plants have been based on cow manure from dairy farms. Recently biogas plants are being deployed based on poultry waste since the calorific value of poultry waste is higher than that of cow manure and also due to the existence of large number of moderate to big size poultry farms in this country. This paper presents studies on the amount of available electrical energy and also the economic feasibility of biogas plants deployed in poultry farms. The results presented in this paper shows that 60 kWh of electrical energy can be generated daily from a farm size of 6000 birds and the cost of investment can be recovered within a period of approximately 4 to 6 years. Keywords—RE technology, biogas, bio-slurry, poultry farms and economic feasibility

I. INTRODUCTION Bangladesh, as a developing nation has been struggling to

keep up with the energy demand for its large population. The country is producing annually about 4700 MW against the demand of about 5500 MW. Meeting such demands have traditionally relied on fossil fuel based generating plants. However, against the backdrop of rising fuel price and decreasing fuel resources, focus has shifted to renewable energy resources. Of the available renewable resources, solar based energy generation is being researched for potential application in contributing to the energy supply for the nation. In addition to solar based energy generation, biogas holds as a great potential resource for energy generation. Historically, the first biogas plant used in Bangladesh dates back to 1972 when Dr M. A. Karim constructed the first biogas plant at Bangladesh Agricultural University. Major construction of such plants started around 1976 when BCSIR constructed 23,000 biogas plants during the period of 1976-2004. EPCD constructed 250 such plants during 1982-1984. Other contributor in this era is LGED that constructed 5,000 biogas plants. After 2005, Grameen Shakti (GS) constructed 26,000 biogas plants while IDCOL, a government owned investment company constructed 25,524 such plants till 2012. [1] [2].

Traditional biogas plants rely on animal waste, specifically cow manure. However, poultry waste has been gaining

attention for being used as a biogas resource. This paper presents the current scenario regarding the poultry industry in Bangladesh and addresses the energy generation aspects of this industry as a potential biogas plant. Economic feasibility has also been investigated for using poultry waste based biogas plant. The outline of the paper is as follows. Section II presents some statistics on the current status of the poultry industry. Section III presents calculation of energy available from poultry waste along with the economic feasibility of such biogas plants. Section IV discusses the construction details of a biogas plant. Section VI provides an overall conclusion on the research presented in this paper.

II. STATISTICS ON POULTRY FARMS IN BANGLADESH Bangladesh holds as a promising place for poultry industry

as the number of poultry farms have steadily increased over the past years. The main target of the poultry industry was to contribute to the food supply against the backdrop of an ever growing demand from a highly dense population. Poultry industry has become successful as a home grown economy that is providing employment to a large number of people in terms of poultry feed supply, production and marketing and creating poultry related products. The approximate number of farms and the distribution among different farms size according to data presented in a Brac Bank study [3] is shown in Table 1.

Table 1: Distribution of Poultry Industry in Bangladesh. [3].

Poultry Farm Size (No of birds)

Approximate # farms

100-249 15000 250-499 35000 500-999 45000 1000-4999 12000 5000-9999 8000 10,000-50,000 1200 More than 50,000 50 Total 1,16,520

Table 1 shows that there is a significant number of poultry industries that host 1000+ birds. The poultry industry relies on a diverse eco-system that includes the poultry feed supply, main poultry farm and marketing entities. Each Upazilla in Bangladesh has at least a Poultry and Dairy Farm association that looks after the welfare of this industry. In addition to the

main supply of poultry meat and eggs, there is also the by-product of large amount of poultry waste. Waste removal from large amount of poultry can be turned into an economically feasible biogas based energy generation resources. SEBA Ltd, a Bangladesh based organization has conducted a survey among the poultry industry to assess the feasibility of such energy generation from processing poultry waste [4]. The survey was made in poultry sector (mainly Layer poultry) under the project of Implementation of Agribusiness Interventions for Waste Management Component of the Poultry Sector in 14 clusters ( Gazipur, Savar, Manikgonj, Comilla & B'Baria, Chittagong & Cox's Bazar, Feni & Noakhali, Moymensing & Kishorgonj, Rajshai,Nator &Pabna, Bogra & Joypurhat , Sylhet & Moulvibazar, Faridpur & Rajbari, Jessore &Khulna, Barishal in Bangladesh. The organization reports surveying 241 poultry farms and selected 170 farms having more than 6000 birds. Based on the responses of the survey, 72 poultry farms were selected for further assessment as potential clients. The study found that out of total 170 enterprises, 56 farms have their biogas plant in respective premises. . It is expected that at least 50 farms out of this 72 enterprises will set up biogas power generation plant in their premises. Out of the 170 industries surveyed, 124 had farm size of 6000-9999 birds, 23 had 10,000-14,999 birds and the remaining 23 had size of 15,000+ birds. A large number of the owners of the farms expressed their willingness to add biogas generator plant in their facilities.

III. ENERGY CALCULATION AND ECONOMIC FEASIBILITY A. Output Energy Calculation

The following parameters present the basis for calculating the energy output from a poultry waste based biogas plant. For poultry, the average values for these parameters are [5]:

Amount of daily waste/bird = 100 gram Amount of biogas per 1 kg poultry drops = 2.5 cft or

0.071 m3 (from 10 birds) For 6000 birds amount of gas produced= 42.6 m3. Amount of gas required per kWh electricity= 0.71 m3.

(Considering 35% machine efficiency and30% carbon content)

General rule of thumb: 1 KWh power plant capacity per 100 poultry birds or 10Wh per bird

Based on the average values of the numbers related to poultry waste to kWh of electricity conversion, Figure 1 shows the graph for energy generation in kWh as a function of number of farm size

Figure 2: Slurry output as a function of farm size.

The constituents of the biogas formed from biogas generated from animal waste (cow, poultry or human) include H2, N2, CO2 methane among other gases. Table 2 presents a comparison of the percentage of constituents of these gases between natural gas and biogas [6].

Table 2: Biogas constituents and their relative contents

Products Percentage Natural Gas Bio-Gas

Methane (CH4) 95 − 98 60 − 70 Carbon dioxide (CO2) 0.1 − 0.2 30 − 40 Hydrogen (H2) − 2 − 2.5 Nitrogen (N2) 0.4 1 − 1.5 Oxygen (O2) 0.1 0.3 − 0.4 Hydrogen Sulphide (H2S) − 0.1 − 0.2

It is worthwhile to analyse the electricity from biogas plants

based on cow manure from dairy farms. For dairy based biogas plants, the relevant parameters and their values are as follow:

Amount of daily manure/cow= 10 -20 kg depending on its origin i.e. local, cross breed or imported

Amount of biogas per 1 kg cow dung = 1.3 cft gas Total amount of gas produced from a single cow per

day= 13 or 26 cft. For midsized dairy farms (30+ cows), total gas

produced per day= 39 or 78 cft. Total amount electricity available per day

(considering 25 cft /kWh) = 1.56 to 3.12 kWh. Thus, compared to a midsized dairy farm, a midsized

poultry farm has the potential to produce greater electricity output from a biogas plant. B. Economic Feasibility

This section presents a cost analysis to investigate the economic feasibility and investment return period for a poultry based biogas plant. The set of parameters used in this analysis are as follow: Requirement Biogas digester for 2500cft. Or 71 m3 gas. Biogas generator: 15kVA. Key parameter for cost calculation Sponsor equity: 100% Interest rate on equity: 12% Lifetime of the project: 25 years Lifetime of standby generator: 25 years Operation and Maintenance cost: 10% of total depreciation and interest rate on equity cost per year Days of operation: 350/year Average grid electricity price: BDT: 9/kWh (commercial) Total investment cost to meet above specification is about BDT 1,710,000. Figure 3 shows breakdown of the total cost in pie chart format.

0

50

100

150

200

6000 8000 10,000 12,000 15,000Elec

trict

y ou

tput

, kW

h

Farm Size (Number of Birds)

Electricity Output for Different Farm Size

Figure 3: Biogas based power plant cost breakdown.

Based on the above key parameters, financial analysis determines the cost of energy is BDT 8.1 per kilowatt-hour. Additionally, the amount of total biogas slurry at outlet of the bio-digester is the 90% of total input at digester inlet, which is 90kg per day. In rural area slurry can be sold by BDT:5/kg as organic fertilizer. Electrical energy yield per year from the biogas plant is 35000kWh and worth of this energy is BDT: 2,83,500 (@ Tk.8.1/unit). In contrast, the financial value of the same amount of grid electricity is BDT: 315000 (@Tk.9/unit). Therefore, the biogas power plant is capable to save BDT: 31500 yearly. Figure 4 shows the break even curve of the plant. The first intersection can be observed in the fourth year of the project which is the in terms of the value of energy and by-product sales. However, the point can be shifted to 6th year if by-product is excluded from the revenue.

Figure 4: Break even curve of the plant

IV. POULTRY WASTE BASED BIOGAS PLANT CONSTRUCTION The main components of a biogas plant based from poultry

waste are shown in Figure 5. The waste materials are collected in receiving tank and subsequently supplied to the digester. The waste product is added with water for fermentation which in turn generates the desired biogas. The biogas is then collected in a separate chamber and can be utilized for electricity production near the process site. The fermented

biomass product can be removed from the digester and used as compost material for fertilizer materials.

Figure 5: Layout of biogas plant [7]

The digester has to maintain a temperature of 250c -350c to produce biogas. It has been observed that the local cow dung, poultry litter and human waste needs about 45 days to produce biogas in significant amount. The Ph level of the mixtures in the digester is an important factor for the production of biogas and a PH level of 6-7 is generally considered satisfactory in this case. The ratio of waste material and water is about 1:1 for Cow dung and 1:2 for poultry litter [6].

The construction of the biogas plant starts with a large excavation near the poultry farm and building the digester in that excavated area. Figure below shows the construction of the digester where the construction workers are putting the shutters Figure 6(a) and laying the concrete around the shutters Figure 6(b).

Figure 6: Construction of biogas plant (a) Placement of the shutters of the digester, (b) Concrete work around the shutters.

V. FINANCING OPTIONS FOR SUPPORTING BIOGAS PLANTS FROM POULTRY WASTE

Energy output calculation along with cost analysis and investment return rate presented in Section III points to the economic feasibility of operating a biogas plant from poultry waste. However, financing may be needed by many poultry farm owners to support the initial investment of setting up the plant. Several operating entities need to be involved in providing the required financing:

58%

38%

4%

Plant Setup Cost

Generator Cost

Other (H2S filtre and Accessories)

0

1000

2000

3000

4000

5000

1 3 5 7 9

BD

T (i

nTho

usan

ds)

Year

Revenue (Energy+Slurry)Asset+CostRevenue (Energy)

The associations for poultry farms in a particular locality can provide the required logistic support in securing loans from banks

Technical and financial support can be solicited from institutions like GIZ and IDCOL, respectively. SEBA Ltd can work as the implementing agency for IFC to do the necessary field work and promote awareness in this regard.

The feed suppliers for poultry industry can also join in the biogas plant projects as guarantors. Similar support can also be provided by the Generator and machineries suppliers.

Investment in Biogas plants from poultry waste is expected

to face low operating risk factors. Risk factors include exposure of the birds to avian or bird flu and occurrences of such diseases is not common. Risks from natural disasters can be countered by constructing the farm and plant accordingly. The short return period along with low risk factors is an attractive feature that should encourage financing agencies to come forward and support such projects.

VI. CONCLUSION The paper has discussed the prospect of setting up biogas

plants from poultry waste and has presented an analysis on the available energy output along with analysis on the economic feasibility. It has been shown that for medium sized poultry industries (i.e., number of birds = 6000+), significant electricity output can be generated that increased linearly with the size of the poultry farms. The analysis further reveals that the generated electricity and the by-product of slurries can be sold to recover the investment costs within about 4 to 6 years depending upon whether energy alone or energy sale along with slurry utilization is considered. Such industries pose low operational risks and are environment friendly.

REFERENCES [1] Source: M A Gofran Chairman, BBDF &Poultry consultant,

Grameen Sakti and Md Jalal Uddin, Biogas Engineer, Grameen Sakti.

[2] Source: The Daily Star (22.11.2010) [3] Islam, Khairul “Prospect of Biogas Power generation in Poultry

sector of Bangladesh”, December 7, 2010. [4] Seba Ltd., “Poultry Update Report – 24.11.10”, November 24, 2010. [5] Dr. Engr. Khurusheed-Ul-Islam, GiZ. [6] Model of Biogas plant by IDCOL. [7] http://www.krishisewa.com