The document presents information from a presentation on biogas plants including different types of biogas plant designs, substrates used, factors that affect biogas production, and methods to calculate embodied energy and payback times. It discusses research that has been done on distributed renewable energy systems and embodied energy of building materials. Tables show data on embodied energy, net energy output, and payback times for different sized biogas plants. The conclusion is that embodied energy and payback times decrease with increasing plant size.

1. Presentation on biogas plant with some facts Presented by:- Shashank mathur 4-BT-42 Btech biotech IV SEM. JAIPUR NATIONAL UNIVERSITY

2. The contents are :- Introduction Objectives Researches Charts Tables References

3. Introduction :- Biogas plants may be classified in several ways depending upon the plant design and mode of working. In India are popularly known as the conventional type and Deenbandhu model. Digesters can also be vertical and horizontal displacement types depending on the orientation of digester. The horizontal plants are suited for high groundwater level or rocky areas. Deenbandhu is a low cost fixed dome biogas plant model. Substrates must be degradable. Substrates should have a nearly constant composition. Concentration of organic dry matter should be higher than 2 %. Substrates should be a liquid slurry. Digester volume should be more than about 100m3.

4. Objectives :- The waste disposal is a global environmental problem. Energy from waste as an alternative to fossil fuels provides an important contribution towards the reduction in landfill disposal and global warming. Energy recovery from waste provides a double environmental benefit. Firstly, the diversion of waste from landfill. secondly, the recovery of energy, displacing fossil fuel alternatives and reducing greenhouse gas emissions. To tackle climate change, there is an urgent need to reduce energy use by adopting more efficient technologies and to generate from sources that release much less or no carbon dioxide causing global warming.

6. Researches done by scientists :- Chandra (2007):Discussed distributed energy systems based on renewable energy resources like solar, wind, hydro and bio-waste and compared on the basis of energy pay back time. Chani et al(2003): Embodied energy of building materials in India had been presented.

7. VENKATARAMA REDDY (2004) :- He described a brief history of building materials, energy consumption in manufacture and transportation of some common and alternative building materials and the implication on environment. DAS AND KANDPAL (1997):- Comparative analysis were also carried out to gauge the energy efficiency of the walling elements and to identify the most suitable option.

8. Methodology :- Equations: Embodied energy= m e where, m =Quantity of materials used in constructing biogas plants in kg. e = energy density of the material in MJ/kg.

9. Table: Energy density of materials used in plants :- 11.83 ½” G.I. pipe 49.97 PVC pipe 32 Steel 29.06 Iron bar 0.08 Coarse sand 0.08 Sand 0.08 Stone chips 6.7 Cement 1.8 Brick Embododied energy Materials

10. Initial cost = Z C where, Z : Quantity of materials. C : unit cost of materials in Indian currency. Net energy output =HV.S.G. Where, HV= heating value of fuel, in MJ/m3 S= Capacity of biogas plant in m3 G = Gas production per day in m3 per biogas plant capacity.

11. Money pay back time in years (MPBT) = Input cost / running cost per unit time Energy pay back time (EPBT)= Embodied energy/Energy output

12. Embodied energy, net energy output and EPBT for different models and plants size EPBT (years) EPBT (years) Embodied Energy (MJ) Embodied energy (MJ) 1.330 74734.202 1.538 86585.8 154.22 14.02 4. 1.350 38374.094 1.599 45452.6 77.88 7.08 3. 1.824 31122.914 2.196 37471.1 46.75 4.25 2. 2.323 26412.914 2.809 31939.4 31.125 2.83 1. Vertical type Biogas plant Horizontal type Biogas plant Net energy (MJ/day) Plant size(m3) Serial no:

13. Input cost and MPBT for different models and plants size. 0.80 76998 0.91 86585.8 14.02 4. 0.99 48535 1.12 45452.6 7.08 3. 1.36 39655 1.55 37471.1 4.25 2. 1.54 29810 1.80 31939.4 2.83 1. MPBT (years) Input cost (rs.) MPBT (years) Input cost (rs.) Vertical type Biogas plant Horizontal type Biogas plant Plant size(m3) Serial no:

14. CONCLUSION :- EPBT decreases as the biogas plant size increases . MPBT also decreases in same manner with increase the plants size of the models.

15. Some snap shots of the area around a biogas plant

16. References :- Mathur J., 1998,Energy and Emission Analysis of Selected Energy Systems in India, Master of Technology Thesis, Centre for Energy Studies, Indian Institute of Technology, Delhi, India TERI, 1994, Biogas: A source of Rural Employment, Tata Energy Research Institute, New Delhi, 36.Tiwari, G.N., and Ghosal, M.K., 2005,Renewable Energy Resources: Basic Principles and Applications, Narosa TERI, 1982, Source: Punjab Agricultural University, Ludhiana, 38. Google searches…