Biogas plants in Animal Husbandry (GTZ, 1989, 153 p.) 2. A planning guide 2.1 Introduction 2.3 Checklist for building a biogas plant

Biogas plants in Animal Husbandry (GTZ, 1989, 153 p.)

2. A planning guide

2.1 Introduction

This guide to planning is intended to serve agricultural extension officers as a comprehensive tool for arriving at decisions concerning the suitability of locations for family-size biogas plants. The essential siting con-ditions capable of influencing the decision for or against a biogas plant are covered (cf. figure 2.1 for a summary survey). The detailed planning outline (table 2.1) has a ´'data" column for entering the pertinent information and a "rating" column for noting the results of evaluation.

Evaluation criteria

+ Siting condition favorable
o Siting condition unfavorable, but
a) compensable by project activities,
b) not serious enough to cause ultimate failure,
- Siting condition not satisfied / not satisfiable

Information on how to obtain and evaluate the individual data can be found in the corresponding chapters of this manual by following the pointers provided in the "reference" column. .

Despite its detailed nature, this planning guide is, as intended, nothing more than a framework within which the extension officer should proceed to conduct a careful investigation and give due consideration, however subjectively, to the individual conditions in order to arrive at a locally practical solution. By no means is this planning guide intended to relieve the agricultural extension officer of his responsibility to thoroughly familiarize himself with the on the-spot situation and to judge the overall value of a given location on the basis of the knowledge thus gained.


Fig. 2.1: Biogas planning modules (Source: OEKOTOP)

2.2 Detailed Planning Guide

Table 2.1: Detailed planning guide for biogas plants

Item	Reference	Data	Rating
0. Initial situation
Addresses/project characterization
Plant acronym:		.......
Address of operator/customer:		.......
Place/region/counky:		.......
Indigenous proj. org./executing org.:		.......
Extension officer/advisor:		.......
General user data
Household structure and no. of persons:		.......
User's economic situation:		.......
Animals: kind, quantity, housing:		.......
Crops: types, areas, manner of cultivation:		.......
Non-agricultural activity:		.......
Household/farmincome:		.......
Cultural and social characteristics of user:		.......
Problems leading to the "biogas" approach
Energy-supply bottlenecks:		.......
Workload for prior source of energy:		.......
Poor soil structure/yields:		.......
Erosion/deforestation:		.......
Poor hygiene . . ., other factors:		.......
Objectives of the measure "biogas plant"
User interests:		.......
Project interests:		.......
Other interests:		.......
1. Natural / Agricultural conditions
Natural conditions	Chapter 3.1
Mean annual temperature:		.......
Seasonal fluctuations:		.......
Diurnal variation:		.......
Rating:		.......	+ o -
Subsoil	Chapter 3.1
Type of soil:		.......
Groundwater table, potable water catchment area:		.......
Rating:			+ o -
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied / not satisfable
Water conditions	Chapter 3.1
Climate zone:	Table 3.1	.......
Annual precipitation:		.......
Dry season (months):		.......
Distance to source of water:		.......
Rating:			+ o -
Livestock inventory, useful for biogas	Chapter 3.2/3.3
production		.......
Animals: kind and quantity:		.......
Type and purpose of housing:		.......
Use of dung:		.......
Persons responsible for animals:		.......
Rating:
Vegetable waste, useful for biogas production	Chapter 3.2/3.3
Types and quantities:		.......
Prior use:		.......
Rating:			+ o -
Fertilization	Chapter 3.4
Customary types and quantities of fertilizer/areas fertilized:		.......
Organic fertilizer familiar/in use:		.......
Rating:			+ o -
Potential sites for biogas plant	Chapter 3.3
Combined stabling/biogas plant possible:		.......
Distance between biogas plant and livestock housing:		.......
Distance between biogas plant and place of gas consumption:		.......
Rating:			+ o -
Overall rating 4			+ o -
2. Balancing the energy demand with the biogas production	Chapter 4
Prior energy supply	Chapter 4
Uses, source of energy, consumption:		.......
Anticipated biogas demand (kWh/day or l/d)	Chapter 5.5.3
for cooking:	Table 5.17	.......
for lighting:	Table 5.20	.......
for cooling:	Table 5.22	.......
for engines:	Chapter 5.5.4	.......
Total gas demand	Chapter 4.1
a) percentage that must be provided by the biogas plant:		.......
b) desired demand coverage:		.......
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied / not satisfiable
Available biomass (kg/d) and potential gas production (l/d)	Chapter 3/4
from animal husbandry	Table 3.2	.......
...pigs:	Table 3.5	.......
...poultry:	Table 4.3	.......
...cattle:	Figure 5.2	.......
Night soil	Table 3.2	.......
Vegetable waste (quantities and potential gas yield)	Table 3.3
1...............................	Table 3.5	.......
2...............................
Totals: biomass and potential gas production	Chapter 4.2
a) easy to procure:		.......
b) less easy to procure:		.......
Balancing	Chapter 4.4
Gas production clearly greater than gas demand = positive rating (+)		.......
Gas demand larger than gas production
= negative rating (-); but review of results in order regarding:		.......
a) possible reduction of gas demand by the following measures		.......
b) possible increase in biogas production by the following measures		.......
If the measures take hold:		.......
= qualified positive rating for the plant location (o)
If the measures do not take hold:		.......
= site rating remains negative (-)
Overall rating 2			+ o -
3. Plant Design and Construction	Chapter 5
Selection of plant design	Chapter 5.3
Locally customary type of plant:		.......
Arguments in favor of floating-drum plant:	Chapter 5.3.1	.......
Arguments in favor of fixed-dome plant:	Chapter 5.3.2	.......
Arguments in favor of other plant(s):	Chapter 5.3.3	.......
Type of plant chosen:		.......
Selection of site		.......
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied / not satisfiable
Availability of building materials
Bricks/blocks/stone:		.......
Cement:		.......
Metal:		.......
Sand:		.......
Piping/fittings:		.......
Miscellaneous:		.......
Availability of gas appliances
Cookers:		.......
Lamps:		.......
...........................................		.......
...........................................		.......
Overall rating 3			+ o -
4. Plant operation / maintenance / repair	Chapter 7
Assessment of plant operation	Chapter 7.1
Incidental work:	Chapter 7.2	.......
Work expenditure in h:		.......
Persons responsible:		.......
Rating with regard to anticipated implementation:			+ o -
Plant maintenance	Chapter 7.3
Maintenance-intensive components:		.......
Maintenance work by user:	Table 7.2	.......
Maintenance work by external assistance:		.......
Rating with regard to anticipated implementation:			+ o -
Plant repair	Chapter 7.4
Components liable to need repair:		.......
Repairs that can be made by the user:		.......
Repairs requiring external assistance:		.......
Requisite materials and spare parts:
Rating with regard to expected
repair services:			+ o -
Overall rating 4			+ o -
5. Economic analysis	Chapter 8
Time-expenditure accounting	Chapter 8.2
Time saved with biogas plant	Table 8.1	.......
Time lost due to biogas plant		.......
Rating:
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied / not satisfiable
Microeconomic analysis	Chapter 8.3
Initial investment:	Table 8.2	.......
Cost of operation/maintenance/repair:		.......
Return on investment:energy, fertilizer, otherwise:		.......
Payback time (static):	Table 8.3	.......
Productiveness (static):		.......
Rating:			+ o -
Quality factors, useful socioeconomic effects and costs	Chapter 8.5
Useful effects: hygiene, autonomous energy, better
lighting, better working conditions, prestige:		.......
Drawbacks: need to handle night soil, negative social impact:		.......
Rating:			+ o -
Overall rating 5			+ o -
6. Social acceptance and potential for dissemination	Chapter 9
Anticipated acceptance	Chapter 9.1
Participation in planning and construction:		.......
Integration into agricultural setting:		.......
Integration into household: .		.......
Sociocultural acceptance:		.......
Rating:		.......
Establishing a dessemination strategy	Chapter 9.2
Conditions for and chances of the professional craftsman approach:		.......	+ o -
Conditions for and chances of the self-help oriented approach:		.......	+ o -
General conditions for dissemination
Project-executing organization and its staffing:	Chapter 9.3	.......
Organizational structure:		.......
interest and prior experience in biogas technology:		.......
Regional infrastructure for transportation and communication:		.......
material procurement:		.......
Craftsman involvement, i.e.	Chapter 9.4
which activities:		.......
minimum qualifications:		.......
tools and machines:		.......
Training for engineers, craftsman and users:	Chapter 9.5	.......
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied/not satisfiable
Proprietary capital, subsidy/credit requirement
on the part of	Chapter 9.6
user:		.......
craftsmen:		.......
Rating:		.......	+ o -
Overall rating 6		.......	+ o -
7. Summarization
Siting conditions		No.	Rating
Natural/agricultural conditions		1	+ o -
Balancing the energy demand and the biogas production		2	+ o -
Plant design and construction		3	+ o -
Plant operation/maintenance/repair		4	+ o -
Economic analysis		5	+ o -
Social acceptance and potential for dissemination		6	+ o -
Overall rating of siting conditions			+ o -
Ratings: + Siting condition favorable
o Siting condition unfavorable but compensable and/or not too serious
- Siting condition not satisfied / not satisfiable

Following assessment as in table 2.1, the biogas-plant site in question can only be regarded as suitable, if most of the siting factors have a favorable (+) rating. This applies in particularly to item 2, the positive energy balance, meaning that the potential biogas production must cover the gas demand.

If the favorable and unfavorable ratings are fairly well balanced, the more decisive factors should be re-evaluated to determine the extent to which supplementary measures could provide the missing conditions for building and operating a biogas plant despite some reservations but without injustifiable effort. Then, if the overall evaluation does not swing toward the positive side, the plant should not be built. If the site is given a favorable rating, further planning hints can be taken from the following checklist.

2.3 Checklist for building a biogas plant

1. Finishing the planning, i.e. site evaluation, determination of energy demand and biomass supply/biogas yield, plant sizing, selection of plant design, how and where to use the biogas, etc., ail in accordance with the above planning guide.

2. Stipulate the plant's location and elaborate a site plan, including all buildings, gas pipes, gas appliances and fields to be fertilized with digested slurry.

3. Draft a technical drawing showing all plant components, i.e. mixing pit, connection to stabling, inlet/outlet, digester, gasholder, gas pipes, slurry storage.

4. Preparation of material/personnel requirements list and procurement of materials needed for the chosen plant:

- bricks/stones/blocks for walls and foundation
- sand, gravel
- cement/lime
- inlet/outlet pipes
- metal parts (sheet metal, angle irons, etc.)
- gas pipes and fittings
- paint and sealants
- gas appliances
- tools
- mason and helper
- unskilled labor
- workshops for metal (gasholder) and pipe installation.

5. Material/personnel assignment planning, i.e. procedural planning and execution of:

- excavation
- foundation slab
- digester masonry
- gasholder
- rendering and sealing the masonry
- mixing pit
- slurry storage pit
- drying out the plant
- installing the gas pipe
- acceptance inspection.

6. Regular building supervision.

7. Commissioning
- functional inspection of the biogas plant and its components - starting the plant

8. Filling the plant.

9. Training the user.