In any village the general household used energy for only two purposes. For cooking and for the heating of water. In the village we took a sample of eight households and collected data from them regarding their daily use of energy. From this data we calculated the total energy requirements of the village. There were a total of four hundred and thirty two households in the village. After finding the total amount of energy required, we calculated the total volume of gas equivalent required to satisfy the energy demand.

The total population of the village is 2000 (974 adults and 1026 children). For the purpose of calculation of energy requirements we have equated three children to two adults. Thus the total equivalent population come about to 1658 adults.

In our sample of eight households 19 children and 32 adult which was equivalent to 45 adults. They used 2,730 kgs of wood and 26 litters of kerosene per month. The calorific value of wood is 19.7 MJ/Kg and for Kerosene oil it is 46.5 MJ/L.

Wood 2730 x 19.7 MJ/Kg = 53871 x efficiency = 53872 x 0.15 = 8067.15 MJ

K.Oil 26 x 46.5.MJ/Kg = 1209 x efficiency = 1209 x 0.50 = 604.5 MJ

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Total Energy 8671.65 MJ

Thus the per capita energy consumption per month comes out to be

8671.65 / 45 = 192.7033 MJ

The per annum consumption is 2312.44 MJ

Extrapolating for the total population of 1658 adults the annual energy consumption comes out to 3834 GJ .

The stoves running on gas from either bio-gas or producer gas have an efficiency of around 60 per cent. Taking that into account, for the use of 3834 GJ of energy we have to generate 6390 GJ of energy per annum. The calorific value of bio-gas is 19.72 MJ/m³.

6390 x 10³/19.72 = 324036 m³

If we supply the whole energy demand by producing bio-gas only then we have to produce 324036 m³.

The daily requirements is

324036/365 = 888 m³ of bio-gas

To produce one m³ bio-gas we need 28.57 kgs of dung is required. Therefore for the production of 888 m³ of gas per day we need

28.57 x 888 = 25370.16 kg

And if the total requirements were met by producer gas then the volume of gas required per annum would be

6390 x 10³ / 4.184 = 1527246 m³,

the daily requirement would be 1527246 / 365 = 4142 m³

To meet this requirement the woody bio-mass needed would be

4142 / 3.54 = 1167.12 kg of wood per day. ( 1 kg of wood is equivalent to 3.54 m³ of producer gas)

Per annum requirement of wood will be

1167.12 x 365 = 426000 kgs = 426 metric tonnes of wood.

We have three options in front of us. Either we use an all gasifier system or an all bio-gas system or a system, which uses a combination of these two. We decided to go for a combination of the two systems

Because:

1. For an all bio-gas system the amount of dung required per day is enormous. Our total cattle population is less than one hundred . Even if we take the maximum possible dung output that comes to somewhere around 600 kgs per day. This is miniscule compared to our requirements. We have to source for 25 tonnes of dung everyday. This is next to impossible in an area like Sadanapura. So we decided to put the major load on the bio-mass gasifier and to use the bio-gas plant only for a small part of the requirements.

2. To meet our energy requirements we will have to use a lot of bio-gas plants if we use only the bio-gas plants. The govt. policies do not allow subsidy to bio-gas plants of capacity above 50 m³ per day. So for 888 m³ per day we shall require 18 bio-gas plants, each of 50 m³ per day, which is infeasible for logistical reasons and problems of coordination.

3. We are not going for a total dependence on biomass gasifiers only because we want to ensure optimum utilisation of available natural resources. We also don’t want to over exploit the available natural resources. So, the biogas plants will act to reduce pressure from the trees.

So, we have decided to go for two large bimass gasifiers of 500 kW rating and eight biogas plants of 20 m³ each .

The raw material requirement for this plan is as follows:

Gasifier of 500 kW rating needs 120 kg of woody biomass for every hour of operation.

So, to run two gasifiers for four hours every day we need 120 x 4 x 2 kg = 960 kg of wood per day.

Our total annual need of wood = 960 x 365 kg = 350400 kg or around 350 tonnes.

For a biogas plant of 20 m³ capacity we need to feed around 560 kg of dung every day in the plant.

So, total daily fresh dung requirement is 560 x 8 kg = 4480 kg (or approximately 4.5 MT/day)

Operation of biogas plants would also require use of 4.5 kiloliters of everyday.

The slurry output of these biogas plants will be around ( 4480*0.65 = 2912 kg) three MT/day.