Survey of Plastic Tube Digesters in Kenya: Field Assessment Survey of the Performance of Plastic...

Survey of Plastic Tube Digesters in Kenya A field assessment survey of the Performance of Plastic tube digestors in Kenya

STUDY REPORT

December, 2010

Francis Xavier Ochieng

Commissioned by:

ENERGIE KONSULT LTD.

Survey of Plastic Tube Digestors in Kenya Page 1 of 49

Published By: Deutsche Gesellshaft für Technische Zusammentarbeit (GTZ) GmbH

-German Technical Cooperation-

Survey of Plastic Tube Digesters in Kenya

Dag-Hammarskjöld-Weg 1-5 65760 Eschborn/German T +49 6196 79 2438 F +49 6196 79 802438 E [email protected] I www.gtz.de


Survey of Plastic Tube Digesters in Kenya

A field survey of the Performance of Plastic tube digestors in Kenya

Study Conducted by

GTZ – Regional Energy Advisory Platform (East Africa)

Nairobi, December, 2010

ENERGIE KONSULT LTD.


Consultancy Reference Number: INT/EK/04/2010/GTZ

Study undertaken

By

Francis Xavier Ochieng

Director,

Energie Konsult Ltd,

P. O. Box 7764 – 00200, Nairobi, Kenya

Tel: +254-714-693299 / +254-20-3203802

E-mail: [email protected] , [email protected] , [email protected]

www.energiekonsult.com

Prepared For:

Michael Franz

Regional Energy Advisory Platform (East Africa) - REAP (EA)

German Technical Cooperation (GTZ); Utumishi Cooperative House, 5th Floor

Mamlaka Road, off Nyerere Road,

P. O Box 41607-00100, GPO; Nairobi, Kenya

Email : [email protected]

History of Changes

Version Description of Amendment Date

01 Draft Report Issued 29/11/2010

02 Changes in data bases, PTD pricing, Integration of all questionnaire answers into report and finally provision of a video on PTD’s

07/12/2010

03 Addition of Subsidy analysis and referencing 17/12.2010

17TH December, 2010


Acknowledgements

The German Technical Cooperation (GTZ) is through the Energizing Development Programme (EnDev) funding the installation of 15,000 biogas digestors before December 2010 in Rwanda (Renwick et al (2007). In achieving this target, an optimal cost effective Biogas digester has to be adopted. It is within this framework that an assessment of Plastic Tube Digesters was undertaken. Essentially, the study sought to ascertain the truth of the performance of digester types in the field (i.e. practice) and also ground truth the claims of practitioners in terms of scope and applicability of the technology.

This output informs the basis on which decisions regarding the adoption, modification or non-adoption of the tubular biogas digesters could be made. More importantly it lays the truth regarding the industry practices and what can be done about it.

This research would not have been possible without Dedan N. Ndungu of Modeline Electrical and Mechanical engineers, who took the time to take me through the various sites, many of which I had no form of contact information like telephone numbers. It is also important to mention that Dedan also provided a video of some of the sites he has installed these PTD’s. The first part of the video gives not only the technical information about the digesters, its costs, sizes and installation, but also provides information on the end-users views on the use of the digester and the benefits they accrued. His contact information can be obtained from page 7

In addition we gratefully acknowledge the support of Oscar Onguru of GTZ-REAP and Gerard Hendriksen for their invaluable contribution in supporting and commenting on this work. Last but not least we thank Samuel Nene of Pioneer Technologies for providing that very invaluable initial contact list and availing the time to give the investigator more in depth understanding of the tubular digesters.

Lastly we do acknowledge that the views expressed in this report are entirely the responsibility of the Author and may not be the official views of GTZ or its affiliated partner agencies. Thus any comments, contributions and clarifications should be addressed to the Author. It is our hope that the work will enrich the ongoing discussions among practitioners, policy makers and academia and welcome any feedback and comments

Francis Xavier Ochieng,

C.E.O Energie Konsult Ltd,

P. O. Box 7764 – 00200, Nairobi, Kenya

www.energiekonsult.com


Table of Contents

ACKNOWLEDGEMENTS..................................................................................................................... 4 TABLE OF CONTENTS........................................................................................................................ 5 LIST OF TABLES ................................................................................................................................. 6 LIST OF FIGURES ............................................................................................................................... 6 ABSTRACT .......................................................................................................................................... 7 1. ABOUT THE FIELD ASSESSMENT ............................................................................................ 8

1.1 INTRODUCTION AND BACKGROUND TO THE FIELD STUDY ............................................................ 8 1.2 STUDY PROBLEM...................................................................................................................... 8 1.3 JUSTIFICATION / SIGNIFICANCE OF THE STUDY............................................................................ 9 1.4 AIM, SCOPE AND EXPECTED DELIVERABLES OF THE STUDY ......................................................... 9

1.4.1 Aim of the Study................................................................................................................. 9 1.4.2 Specific objectives ............................................................................................................. 9 1.4.3 Scope of the Study .......................................................................................................... 10 1.4.4 Expected deliverables o f the study................................................................................. 10

1.5 STRUCTURE AND METHODOLOGY OF THE STUDY...................................................................... 10 1.6 DETERMINATION OF THE SAMPLE SIZE AND DIGESTERS TO VISIT ................................................ 10

1.6.1 General overview............................................................................................................. 10 1.6.2 Statistical determination of the Sample Size ................................................................... 11 1.6.3 Digester sampling and Survey methodology ................................................................... 13

1.7 PTD STUDY REVISED WORK PLAN........................................................................................... 14 1.8 CHALLENGES AND LIMITATIONS OF THE FIELD SURVEY.............................................................. 15

2. RESULTS OF THE FIELD SURVEY.......................................................................................... 16 2.1 DIGESTER MATERIAL AND SIZE................................................................................................. 16

2.1.1 Digester material and size ............................................................................................... 16 2.2 PTD COSTS........................................................................................................................... 17

2.2.1 Costs from Pioneer .......................................................................................................... 17 2.2.2 Costs of PTD from the field/study.................................................................................... 17 2.2.3 Subsidy and cost comparisons of PTD with Fixed dome digester .................................. 18

2.3 FARM LAYOUT AND DIGESTER INLET FEEDING DESIGN CHARACTERISTICS .................................... 0 2.4 DIGESTER PERFORMANCE......................................................................................................... 0 2.5 BIOGAS APPLICATIONS .............................................................................................................. 2 2.6 PTD PAYBACK PERIOD.............................................................................................................. 3

2.6.1 Payback period based on Charcoal use............................................................................ 3 2.6.2 Payback period for PTD and Fixed Dome Digester based on other Biomass fuels.......... 3

2.7 BENEFITS OF DIGESTER SYSTEMS ............................................................................................. 5 2.8 EXTENSION SERVICES............................................................................................................... 5 2.9 PTD SUSTAINABILITY................................................................................................................ 5 2.10 PTD AND OWNERSHIP FINDINGS ................................................................................................ 6


2.11 SECOND HAND PTD.................................................................................................................. 6 3. LESSONS LEARNT AND CHALLENGES EXPERIENCED ......................................................... 7

3.1 LESSONS LEARNT ..................................................................................................................... 7 4. RECOMMENDATIONS.............................................................................................................. 10

4.1 FRAMEWORK FOR PTD INSTALLATION AND OPERATION MANUAL................................................ 10 4.2 RECOMMENDATIONS FOR THE PTD ADOPTION IN RWANDA ....................................................... 10 4.3 RECOMMENDATIONS FOR FURTHER SCIENTIFIC RESEARCH AND FIELD STUDIES .......................... 11 4.4 RECOMMENDATIONS FOR BETTER MARKET DELIVERY MODELS ................................................. 11 4.5 END-USER RECOMMENDATIONS............................................................................................... 12 4.6 RECOMMENDATIONS TO POLICY MAKERS.................................................................................. 12

5. APPENDICES............................................................................................................................ 13 5.1 TOOLS USED IN FIELD SURVEY ................................................................................................ 13

5.1.1 Institutional Questionnaire ............................................................................................... 13 5.1.2 End-User Questionnaire .................................................................................................. 17

5.2 INITIAL PTD’S LIST FROM PIONEER TECHNOLOGIES LIMITED ..................................................... 20 5.3 REFORMATTED AND UPDATED LIST OF CONTACTS .................................................................... 23 5.4 PTD DATA BASE..................................................................................................................... 28

6. REFERENCES........................................................................................................................... 32

List of Tables

Table 1: Sample size at 95% confidence level with a degree of variability P of 0.5 ............................. 12 Table 2: Selection of Digester sites based on pre-determined sample size ......................................... 13 Table 3: Selection of final sites to visit based on household location type ........................................... 14 Table 4: PTD performance study – Revised Work plan ........................................................................ 14 Table 5: Performance of Installed PTD in Sample and in total population............................................ 16 Table 6: Comparative assessment of costs and subsidies of PTD and Fixed dome digesters .............. 0 Table 7: Overall performance of PTDs.................................................................................................... 0 Table 8: Payback period of different digesters based on different Biomass fuels .................................. 4 Table 9: Assumptions for a household of 5 people ................................................................................. 4 Table 10: Current and potential Companies installing Plastic Tube digesters in Kenya......................... 7

List of Figures

Fig 1: Trend analysis of PTD’s prices and installations over the years................................................. 18 Fig 2: Biogas Cook stove, with the feed inlet pipe being shown ............................................................. 2


Abstract

This report documents the results of a field survey of Plastic tubular digestors (PTD) in Kenya. Using a precision level (e) of 17% of the total probable biogas digestors installed by a local company – Pioneer Technologies Limited, 34 biogas digestors were visited, Of these 28 were working, 3 were not working, two had been dismantled and replaced with masonary ones and the last one had been installed at Jomo Kenyatta University of Agriculture and Technology for experimental purposes, whose objects have since been achieved, and the PTD’s operations there stopped.

The implications of this is that of the expected countrywide installations of PTDs about 82.4% are working, while 8.8% are not working, 5.9% have been decommisioned and masonary ones installed in thier place and lastly 2.9% have been decommissioned/abandoned and nothing replaced in thier stead.

Findings indicate that most of the end-users, who are mostly farmers were quite satisfied with the PTD, however some did express dissapointment on the challenges they face. These included low gas pressure during the morning and evening cooking periods, low/insufficient gas production as energy needs increased and lastly insufficient farmer training on how to feed and maintain the Biogas digesters. These challenges are mainly a user management problem on what the digester if fed with and how frequently it is fed. Nevertheless, the issue of low gas production during morning and evening cooking period is more of how well the digester is insulated from the elements, which is a training issue. The use of UV treated double layer plastic did not seem to be a problem only in as far as the Platic tube was not pierced.

The opportunity cost of not collecting firewood, and the utilisation of animal waste for energy, seems to be the main motivator for the uptake of PTD’s. In essense, Household cooking and general sanitation of the farm were also, in many cases, the key motivating factor for wanting a biogas digester in Kenya. In order however to scale up and/or replicate this experience in other places, it is important that priority be given to extension services and maintenance.

Equally important is optimizing gas production by correct retention time, research into the effects of adding cattle urine, toilet waste, using other locally available material and recycling of slurry. Furthermore, the success of the biogas project is dependent on the farmers' payment of the digesters, which can be achieved by establishing an efficient credit system.


1. About the Field Assessment

1.1 Introduction and Background to the Field Study

The German Technical Cooperation (GTZ) is through the Energizing Development Programme (EnDev) funding the installation of 5,000 biogas digestors before December 2010 in Rwanda. This is undertaken within the framework of the National Domestic biogas programme (NDBP). The NDBP aims at installing 15, 000 Biogas units by December 2011 (Rwanda, 2009). , and targets rural households in Rwanda that have 2 -3 cows. The fixed Dome biogas digestor type with a capacity of between 6 – 10 m² is being considered by the NDBP as a technology of choice for promotion.

However, for many of the rural households the cost of installation of the digestor at about € 1,000 is too high despite a € 350 subsidy and a bank credit. Thus the November 2009 project review mission recommended assessment of cost reduction opportunities. Based on GTZ experience in some South American Countries, the possibility of an alternative biogas technology apart from the fixed dome is now being considered. (GTZ Terms of reference for the Survey of plastic tube digesters in Kenya)

The Plastic Tube Digestors (PTD’s) as experienced by GTZ in the aforementioned countries provides such an option. Within the Eastern Africa region institutional memory exist in form of Pioneer Technologies who claim that they have since the year 2006 installed about 300 PTD’s in Kenya. However, no independent surveys of these PTD’s to verify these claims have been undertaken

Initial studies to verify these claims have been undertaken by the consultant applying for this study under the auspices of the Institute of Energy and Environmental Technology (IEET) of Jomo Kenyatta University of Agriculture and Technology (JKUAT). The Consultant together with his team have tested the performance of the Pioneer Technologies PTD’s at IEET and done preliminary site/field visits of the Pioneer Technologies installed PTD’s.

Subsequently, the GTZ PTD’s study furthers the Scope of work done by the Institute and provides an even greater sample space to draw scientifically valid lessons which can be used to deal with the challenge facing NDBP of which this study seeks to solve.

1.2 Study Problem

NDBP is interested in assessing the potential of the PTD technology as another option for the farming households in Rwanda. While there are claims that a Pioneer Technologies has installed over 300 PTD’s in Kenya, no independent surveys have been done to verify these claims (apart from the single performance study and preliminary studies done by the applying consultant who is based in IEET – JKUAT).


Therefore a need exist to survey the PTD’s installed by Pioneer Technologies. More knowledge of Kenya’s experience with PTD is required to gauge if and how they can be used in Rwanda. This should then enable NDBP make a sound judgment on whether or not to pursue the introduction of PTD’s in Rwanda.

1.3 Justification / Significance of the study

The study will collect data and other relevant information to enable the NDBP make a sound judgement on whether or not to pursue the introduction of PTD’s in Rwanda. This is necessitated by the realisation that the installation of Fixed dome Digestors is out of reach of the rural households with 2 – 3 cows, despite the a € 350 subsidy and a special bank Credit.

In addition the study will verify the claims made by Pioneer Technologies that it has since the year 2006 installed about 300 PTD’s in Kenya of which about 90% are operational. The significance of a positive or negative verification of this claim will provide lessons on technology adoption, adaptation and fuel further research in the area of PTD’s.

Lastly the study will complement the initial studies that had been undertaken by the applying consultant on PTD’s at the institute of Energy and Environmental Technology of the Jomo Kenyatta University of Agriculture and Technology (JKUAT). It will enable the orientation of the further research in dealing with the design and performance issues noted in the initial studies, since only a small sample space was used.

1.4 Aim, Scope and expected deliverables of the study

1.4.1 Aim of the Study

The main aim / objective of the assignment is to assess the performance of the Plastic Tube Digestors (PTD’s) installed by Pioneer Technologies in Kenya to inform the Rwanda biogas program about possible introduction into the country.

1.4.2 Specific objectives

Specifically the study will seek to attain the following:

1. Compilation of a list of PTD’s installed by Pioneer Technologies in Kenya. The list will contain

the contact details and other pertinent information on the PTD like status, digestor

specifications and performance

2. Site visits of 30 randomly selected PTD’s from the aforementioned list above to assess their

performance and obtain their technical details.


3. Creation and Verification of a Data base of PTD’s installed in Kenya.

4. Provision of report indicating the status of PTD’s in Kenya and lessons learnt in the

experience. This report will be based on the findings of the above objectives

1.4.3 Scope of the Study

The study being limited in both time and depth of assessment will confine itself to the general assessment of the working condition of 30 randomly selected Plastic tube digestors. The aim is to give a general picture on the performance of these digestors.

1.4.4 Expected deliverables o f the study

Two main deliverables are provided by this study:

1. A report detailing the status of PTD’s in Kenya and lessons learnt in the experience. This report will be based on the findings of the aforementioned specific objectives

2. A verified data base of PTD’s installed in Kenya

1.5 Structure and Methodology of the study

The Study essentially utilised Stratified random sampling to identify about 26% of the total installed PTD’s. This translated to about 30 PTD’s sampled and visited.

From original list obtained from Pioneer Technologies ( 5.2), a corrected and reformatted list which included Counties as per the First Schedule, Article 6(1) of the Constitution of Kenya (AG, 2010) was developed. The need for including counties is based on the demands of the stratified random sampling wherein, in determining the sample size, the data is stratified / divided in accordance with administrative divisions i.e. Counties. Appendix 5.3 is the results of this correction and stratification.

1.6 Determination of the sample size and digesters to visit

1.6.1 General overview

Determination of the number of digesters to visit (sample size, n) out of the total number of digesters (expected population size, N) is a bit complex but nevertheless simplified using on a number of scientifically proven statistically techniques, and which unfortunately end up giving a slightly different n from the pre-determined sample size given in the Terms of Reference (ToRs).

In determining the size of the sample n a number of factors are considered including: purpose of the study, population size, risk of selecting a “bad” sample and the allowable sampling error. In studies


involving a lot of variables and/or high precision demands, then more stringent sample determination are utilised. In simple studies like this one, simple formulas can be applied.

It is however, the question of the population size that tends to seriously impact on the determination of the sample size. Various methods have evolved for determining N (Israel, u.d, Bartlett et. al. 2001). For our purpose an initial sample size of 300 was given.

In terms of reducing the risk of selecting a “bad” sample, where a bad sample in this case would refer to selecting only the working digesters or the ones that are not working. The constituents of the sample have to be selected randomly, both in time and space. The implications of this to our study being that the sites visits were done both during weekdays and weekends, morning, afternoons and evenings. It also meant that different geo-administrative locations were visited. Lastly it implied that the telephone contact numbers we had were called randomly and whoever agreed to meet us, irrespective of status of digesters, or even its existence/presence was visited. No preference was given to whether the digester was installed by the main study client (i.e. Pioneer Technologies Ltd) or not.

Lastly an acceptable/allowable margin of error, which is also known as the level of precision (e) has to be defined. This is the range at which the true value of the estimated population is estimated to be. Generally researchers increase this value when a higher margin of error is acceptable or decrease it when a higher degree of precision is needed. In our case, based on uncertainty in the true population (or number) of the PTDs’ in the field a higher e value than the normal one of ± 5% can be utilised. This is further discussed below.

1.6.2 Statistical determination of the Sample Size

This study is based on the realisation that the total population of PTDs’ installed countrywide in Kenya is unknown. Consequently, certain assumptions based on scientifically accepted statistical approaches have to be utilised. In the case of survey research, this normally means use of random samples that are generally assumed to cover the whole population. The determination of sample size based on scientific approaches cannot be underscored. This is mainly done to avoid to common errors in survey research (Bartlett et. al. 2001)

Subsequently, Yamane (Israel, u.d) provides such a formula for calculating the sample size (Eqn 1):

Eqn 1: Simplified formula for determining sample size

(Israel, u.d)


Based on Eqn 1 the following Table 1 was derived.

Table 1: Sample size at 95% confidence level with a degree of variability P of 0.5

Sample size (n) at a Desired Precision level (e) of Expected population (N) 30% 20% 17.0% 15.0% 12% 10% 8% 5% 3% 1% 30 8 14 16 18 21 23 25 28 29 30 40 9 15 19 21 25 29 32 36 39 40 50 9 17 20 24 29 33 38 44 48 50 60 9 18 22 26 32 38 43 52 57 60 70 10 18 23 27 35 41 48 60 66 70 80 10 19 24 29 37 44 53 67 75 79 90 10 20 25 30 39 47 57 73 83 89 100 10 20 26 31 41 50 61 80 92 99 116 10 21 27 32 43 54 67 90 105 115 118 10 21 27 32 44 54 67 91 107 117 120 10 21 27 32 44 55 68 92 108 119 121 10 21 27 33 44 55 68 93 109 120 130 10 21 27 33 45 57 71 98 116 128 150 10 21 28 34 47 60 77 109 132 148 180 10 22 29 36 50 64 84 124 155 177 210 11 22 30 37 52 68 90 138 177 206 240 11 23 30 38 54 71 95 150 197 234 270 11 23 31 38 55 73 99 161 217 263 300 11 23 31 39 56 75 103 171 236 291 330 11 23 31 39 57 77 106 181 254 319 500 11 24 32 41 61 83 119 222 345 476 600 11 24 33 41 62 86 124 240 390 566 700 11 24 33 42 63 88 128 255 429 654 800 11 24 33 42 64 89 131 267 465 741 900 11 24 33 42 64 90 133 277 497 826 1,000 11 24 33 43 65 91 135 286 526 909 2,000 11 25 34 43 67 95 145 333 714 1667 4,000 11 25 34 44 68 98 150 364 870 2857 5,000 11 25 34 44 68 98 152 370 909 3333 10,000 11 25 34 44 69 99 154 385 1000 5000 100,000 11 25 35 44 69 100 156 398 1099 9091 300,000 11 25 35 44 69 100 156 399 1107 9677 1,000,000 11 25 35 44 69 100 156 400 1110 9901

(Author)

From Table 1 it is noted that the higher the number of PTD expected to be actually installed (N), so will a higher sample size (n) be obtained. Subsequently based on the initially pre-determined sample size of 30, only two options are open to us in terms of the precision level (e): Either we assume e is 1% and hence N is 30 or we take a higher value of e and subsequently have a wider choice of N.

For this studies purpose an e value of 17% was chosen. This was based on a two point criteria: First, that we have an e that can cover as wide a range of known and unknown Population (N), and secondly to have a sample size (n) that is as near as possible to that given in the ToRs. A much bigger


sample space will mean more time and resources (money, transport etc) to undertake the survey than was initially agreed upon or allowed by the contract. Subsequently an e value of 17% allowed the study to be able to choose a sample size that covers not only the final list given to us by Pioneer Technologies of 116 installed PTDs but more importantly to also cover their initial claim of 300 installed PTD’s. In addition it allows us to have a sample size that can cover a possible potential of exceptionally high numbers of installed PTD’s – since no census of the number of installed PTD’s has been done or is known. .

It is thus for the above reasons that the initial suggested sample size of 30 PTD’s was increased to 34. This allowed us to be able to cover between an expected population of between 30 to 10,000 installed PTD’s.

1.6.3 Digester sampling and Survey methodology

The study was undertaken using a stratified sampling methodology, based on Geo-administrative units referred to as counties. Whereas other sample methods could have been used to determine the sample size (Bartlett et. al. 2001), the Terms of Reference (ToR’s) had already a pre-determined minimum sample size of 30 digesters which was increased to 34 based on statistical analysis (section 1.6.2). Thus the sampling of digesters in Appendix 5.3 resulted in the following selection of sites (Table 2) based on a stratified sampling approach.

Table 2: Selection of Digester sites based on pre-determined sample size

County Household location Type

Number of digesters

% of digesters in population

Sample size per county

Sample or sites visited

Embu Rural 3 3% 1 0 Kajiado Rural 2 2% 1 1 Kiambu Rural 67 58% 18 18 Kisumu Rural 6 5% 2 0 Machakos Rural 7 6% 2 1 Meru Rural 2 2% 1 0 Muranga Rural 5 4% 1 3 Nairobi City Urban/peri-urban 3 3% 1 8 Nakuru town Urban/peri-urban 12 10% 3 0 Nyeri Rural 3 3% 1 0 Taita Taveta Rural 2 2% 1 0 Uasin gishu Rural 4 3% 1 0

Total 116 100% 31 31 [Author]

Realizing that the household location types were similar in certain areas, sampling of the counties was done on the basis of whether they are in rural areas or Urban/peri-urban areas. Which allowed the research to concentrate only on certain parts of the country and not transverse the whole country. Results of this geo-administrative sampling based on Counties to be visited is shown (Table 3). It meant in principle that site visits would be made of Kajiado, Kaimbu, Machakos, Muranga and Nairobi


City counties, while ignoring the rest, since the location types of the ignored sites are similar to the ones visited.

Table 3: Selection of final sites to visit based on household location type

Household location Type

Number of digesters

% of digesters in population

Sample size per county

Sample or sites visited

Total Rural 101 87% 27 23 Total Urban/peri-urban 15 13% 4 8

Total 116 100% 31 31 [Author]

Based thus on the selected sites above, questionnaires were developed (appendices 5.1.1 and 5.1.2) and by use of Geographical position system, a former engineer from Pioneer technologies and the tools indicated in the appendices above, the sites were visited in accordance with the indicated work plan (Table 4).

1.7 PTD study Revised Work plan

In achieving the study, the following work plan (Table 4) was utilised. It will be noted that names of the localities to be visited are also correlated to the aforementioned counties (Table 2)

Table 4: PTD performance study – Revised Work plan

Localities to be visited

Tues, 23rd Nov

Wed, 24th Nov

Thur, 25th Nov

Frid, 26th Nov

Sat, 27th Nov

Sun, 28th Nov

Mon, 29th Nov

Tue, 30th Nov

Mon, 1ST Dec

Kajiado, Nairobi City

Kiambu, Machakos

Kiambu, Muranga

Site Visits

Nairobi City, Kiambu

Data analysis Draft report writing, data base creation

Receipt of comments

Submission of final report and cleaned data base


[Author]

1.8 Challenges and limitations of the Field survey

1. Distribution and accessing the digesters:- The biggest challenge in the study was in not only identifying the digestors but also in accessing them. As will be noted, the original list obtained from Pioneer technologies was pretty scarce on information, especially contact details. Subsequently use had to be made of someone who has been installing the PTD’s to personally take the Author to the sites. This was both expensive and difficult since there were areas where the vehicle could not access and one had to make the journey on foot. The distance between one site to the other was also huge, and meant transversing huge distances to reach only one site.

2. Things not covered in performance Assessment: - The performance assessment has not covered the more technical aspects of the gas composition nor the digestor temperature. But it is assumed that these are in within the acceptable ranges based on the fact that the gas is actually burning on the stove and is almost odourless. Other aspects not covered in the survey include size of the households, their incomes and even household energy expenditure before and after installation of the Biogas systems.

3. Time frame constraints: - The study was constrained by time not because of poor planning but mainly due to unexpected events. This has got to do with the delay in obtaining the initial contact list and even in having the first interview with Pioneer Technologies. It took almost 4.5 weeks before these could be accomplished, hence leaving only 1.5 weeks for going to the field.


2. Results of the Field Survey

2.1 Number of digesters installed

After initial analysis and data base verification we can now state that based on the studies undertaken

that the data base has a total of 147 installed PTD’s countrywide. Of these based on the statistical

analysis indicated in Table 7 that the following is the current situation of the installed digesters as per

the new data base.

Table 5: Performance of Installed PTD in Sample and in total population

PTD performance Units Sample

% Total

population Working 28 82.40% 121 Not working 3 8.80% 13 Upgraded to masonry type (Floating or fixed dome) 2 5.90% 9 Abandoned / decommissioned 1 2.90% 4

Total 34 100% 147 [Author]

The above presents a statistical analysis with a margin of error of 17.5% in both the upward and

downward direction. However, it does give an indication that quite a number of the Digesters are

working, though they may not be doing so satisfactory as indicated by the responses of the farmers

who felt that the digesters did not meet all their needs like lighting and during the morning and evening

periods gas pressure was quite low that cooking took a bit longer than expected.

2.2 Digester material and size

2.2.1 Digester material and size

Based on discussions with Pioneer Technologies, it was realized that the company has been selling Plastic Tube Digestors since 2006 on commercial basis; however, further discussions with Dedan Ndungu indicated that the Plastic Tube digester work actually began sometime in 2002 with the 1st generation of Plastic Tube digester which was essentially two layers of Polythene.

Various modifications led to the 2nd Generation PTD. This consisted mainly of an elastic /expandable tube like that of a bicycle inner tube. The 3RD generation was a modification of the 2nd Generation whilst the 4th Generation consisted mainly of a double layer UV treated Polythene material with Glass reinforced Fibre (GRF) again. The digester has thickness gauge of about 300 micron, making it quite long-lasting, with an estimated lifespan of about 5 - 15 years depending on the maintenances and feeding capacity and frequency.


The aforementioned changes from the 1ST generation to the current 4TH generation have had significant impacts on the quality and performance of the PTD. These include longevity (life span), UV protection of the digester, and the general aesthetics of the digester. A comparative analysis in terms of analytical performance was not undertaken.

2.3 PTD Costs

2.3.1 Costs from Pioneer

Thus, the current PTD in the Kenyan market is essentially a 4th generation tube, of which, as per Pioneer Technologies, comes in two sizes: Standard and large

1. Standard type (Length=10m, Diameter=1.5m, total volume=6m³), with a daily Gas production of =2.4m³/day and costing about KES 42, 000/- (ca. US$ 5251 /-)

2. Large type (Length =10m,Diameter=2.6m,Total Volume=16m³), with a daily Gas production of 3.2m³/d and costing about KES 65, 000/- (ca. US$ 812.50 /-)

The aforementioned costs generally include Transportation to most parts of Kenya, the stove, gas pipes, Biogas Digester bag and installation costs. It does not include the cost of digging the Trench where the digester will lie in.

2.3.2 Costs of PTD from the field/study

The results from the field however indicate a different cost from that given by Pioneer Technologies. From the study it was noted that the cost ranged between US$ 250 and US$ 562.50. Two main reasons are attributed to this discrepancy: first quite a number of the PTD’s in the sample were not installed by Pioneer as such, but by a one Dedan Ndungu before he joined Pioneer in 2006 and also by other Companies.

Secondly, a trend analysis over the years (Fig 1) shows a slow increase in the general prices of both PTD’s sizes, which maybe attributed to increased cost of raw materials. For Pioneer’s competitors it was found out based on 2009 – 2010 figures, that for the Standard type it costs about US$ 488, while the large sized costs about US$ 563, making them 7% and 31% cheaper than Pioneer’s respectively. Raising the question of sourcing of raw materials and allowable profit margins, which do impact on the final digester price.

1 Exchange rate being 1 USD = KES 80


Fig 1: Trend analysis of PTD’s prices and installations over the years.

Trends in PTD's prices and installations over the years

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10

Date of installation

Cost

of i

nsta

llatio

n in

KES

Large sized PTDSmall sized PTD

[Author] Analysis of Fig 1 shows that generally 65% of Digesters are of Standard size while 35% are the large

size type. It is postulated that the choice for more Standard sized Digesters is based on its

comparatively lower price. However, Fig 1 shows an increase in prices of both standard PTD’s

(35.7%) and large sized PTD’s (55.6%). The increase in digester prices can be attributed to the

general increase in input material costs, transport and labour charges. Nevertheless, as farmers come

to experience the advantages of bio-digesters and/or as the number of cows they keep increase, the

tendency of farmers to move from standard sized PTD, to large sized ones and/or masonry based

fixed or floating type bio digesters increased.

In fact during the site visits, 2 sites were found where initially PTD’s had been installed, but they were

no longer there. The Farmers had decommissioned them to the much bigger Fixed dome Biogas

digesters due to demand for more gas (especially for lighting) and also as a way of maintaining

sanitation and reducing bad odours from Cow dung due to the large numbers of zero-grazed cows.

The Standard type can work with 1 dairy cow, whilst the large type may require between 1 - 3 cows. In the event of local indigenous cows the number of the cows will range from 1 to 4 depending on the size of the cow, the quantity of dung it removes and the frequency of dung removal.

2.3.3 Subsidy and cost comparisons of PTD with Fixed dome digester

Renwick et. al. (2007) in a study of Biogas digesters in Africa provided the following costs for installation and maintenance of a fixed dome biogas digester which we compare with a PTD (Table 6). In determining the probable costs of a PTD in Rwanda, certain assumptions were made these included:

1. That the subsidy level being given for fixed dome digesters in Rwanda will be extended to


the plastic tube digesters

2. That the possibility of local manufacture of the PTD exists in Rwanda

3. That the in-kind contribution with respect to PTD’s is significantly less than that of fixed dome and mainly include labour for digging the trench and putting up a protective fence. In case a protective roof is put over the PTD the contribution will rise slightly.

4. The annual repair and maintenance basically deals with repair of the protective fence and roof. In case of Digester being pierced (which is assumed not to be a common occurrence) the costs will go up significantly

From the comparative analysis it is clear that a locally produced PTD with subsidy will cost far less than similar sized fixed dome ones. It should be pointed out that the production costs for locally produced PTD in Rwanda has been assumed to be similar to that of Kenya. In reality if this is a Government of Rwanda project, and efforts are made to establish a local manufacturing plant, then the cost of the net cost of the PTD to the end user may be far cheaper than the half net cost of the 6 m³ fixed dome i.e. below the US$ 236 mark.

Table 6: Comparative assessment of costs and subsidies of PTD and Fixed dome digesters

Country / Region Digester Type Average plant size

Total cost of plant (US$)

Proposed subsidy

(US$) Subsidy

(%) in-kind

contribution (US$)

Annual repair &

maintenance (US$)

Net cost of digester

(US$)

Uganda Fixed dome 8 m³ 770 200 26% 77 11.6 493.00 Rwanda Fixed dome 6 m³ 859 300 35% 86 12.9 473.00 Ethiopia Fixed dome 6 m³ 747 186 25% 75 11.2 486.00 Sub-Saharan Africa Fixed dome 6 m³ 750 200 27% 75 11.3 475.00

Kenya Plastic Tube Digester 6 m³ 563 0 0% 15 5 548.00

Rwanda (estimated) - locally made with subsidy

Plastic Tube Digester 6 m³ 563 196.62 35% 15 5 351.38

Rwanda (Estimated) - locally made with no subsidy - Assuming same production costs as Kenya

Plastic Tube Digester 6 m³ 563 0 0% 15 5 548.00

Rwanda (Estimated) - imported from Kenya with subsidy (additional charges include a 30% transport & taxes charge)

Plastic Tube Digester 6 m³ 731.9 255.61 35% 15 5 461.29

[Author, Renwick (2007)]

2.4 Farm layout and Digester inlet feeding design characteristics

The general farm layout with respect to the design characteristics and placement of the PTD’s was on

average similar. For most parts, 1 – 3 cows were kept in an enclosure with a cement floor (zero

grazing unit) and their dung by way of either cemented drainage canals or manual collection using

buckets, was brought to the digestor site. At the digestor site, two approaches were witnessed in terms

of feeding frequency:

1. Either a rectangular trench was dug, wherein the fresh dung was placed, such that whenever

the digester was to be fed, a bucket were used to collect the dung from this trench for feeding

into the digester

2. A second more advanced approach involved a masonry modification of the above. The inlet

pipe of the digester was enclosed within a 40 – 60 cm high square masonry tank. The inlet

pipe being at the bottom. A second masonry tank that feeds the aforementioned one is also

built. The two tanks share a inner wall, which has a gate that allows the contents of the latter

tank to flow into the former and into the digester. Both tanks are sized in such a manner as to

have a total volume of 160 litres (80 litres each). Fresh dung is thus poured into the latter tank,

after releasing its previous contents to the former tank with inlet pipe. This ensures proper

mixing of water and dung, and also proper volume feeding into the digester.

2.5 Digester performance

Results of the survey (Table 7) indicate the following status in terms of the sampled digesters:

Table 7: Overall performance of PTDs

PTD performance Units Sample % Working 28 82.4% Not working 3 8.8% Upgraded to masonry type (Floating or fixed dome) 2 5.9% Abandoned / decommissioned 1 2.9%

Total 34 100% [Author]

Table 7 is summarised from four main factors which in totality ascertain the performance of the PTDs.

These are:-

1. Digestion process: - 82.4% of the sample size indicated that their digestor was producing gas

regularly an indication of normal digestion process in the digester. Of this 82.4%, 5.9% (2

sites) had problems with the digester bag. In both cases the digester bag had developed


hole(s) due to piercing from Animals or children. For the Kiserian Site, the owner had repaired

it using a bicycle repair kit normally used to repair punctures in the elastic inner tube of the

bicycle tyre. For the other site in Ngome area, the owner had tried using Super Glue ™ but

gas leakage was still experienced. This however, did not adversely affect the gas production

nor the digestion process. Hence, the digester was still working till date. A key lesson was

thus learnt regarding the 4TH generation PTD – i.e it is possible for the digester bag to be

repaired using normal puncture repair kit for elastic tube – provided the hole or tear is not so

big.

2. State of the Digester bag (the PTD itself):- Of the Sampled digesters

8.8% were not working due to the digester bag having bursted /torn or thick scum forming

due to infrequent feeding or inappropriate feeding material. One case, the owner digester

was not being utilised, though the problem was simply that the connecting gas transfer

pipes from the digester to the kitchen had become detached at one point.

The remaining 82.4% had the digester bags still working, some since 2004. It was also

observed that 90% of the sample had the digester bag whose outside appearance was

clean and in most case shaded from direct sunlight.

3. State and performance of the cooking equipment: -

• For all those receiving gas from the digester, 100% had their cooking stove

working and producing sufficient heat for a long period to allow satisfactory

cooking.

• The data analysis revealed that the number of cooking hours ranged from 2 to

about 6, the average being about 5 hours. Based on the general eating habits of

rural and urban populance in Kenya, this meant 1 hour in the morning, 2 hours

during lunch time and 2 hours during the evening period. However for meals

requiring longer cooking hours like “Githeri” – a mixture of beans and maize,

which incidentally is very common among the rural populations in Central parts of

Kenya, the hours would probably change with 3 to 4 hours being utilised to cook it

during mid-day, when incidentally there was more Biogas production.

• There was however a concern that during the morning and late evening’s gas

production is a bit low, limiting the cooking duration and heat intensity. However

during mid-day on sunny days, the gas production is quite high. This is indicative

of a problem with temperature that allows the digestion bacteria to function. A

possible solution to this would be the availability of a gas storage bag, of which of

the 100% sampled none had a gas storage bag.

4. State and performance of gas transmission pipes and water traps: - 100% of the sample did

not have a water trap to capture the condensate coming out of the digester. Rather, the gas


transmission pipe had been made in such a manner as to slope from the Kitchen area back to

the digester, hence allowing the condensate to flow back to the digester. 100% of the gas

transmission pipes were quite in order. Choice was however being made between PVC low

density pipes and recommended flexible gas pipes.

Based on the above it was noted that apart from the singular incident of one person whose digester

bag had a leak all the other had PTD system that was function quite well. This leads us to the

conclusion that 82.4% of the Biogas digesters were operation quite well without any trouble.

2.6 Biogas applications

In all cases (100%) Biogas was being used for cooking using a cooking stove (Fig 2), and in some

cases even baking using a modified biogas baking oven.

Fig 2: Biogas Cook stove, with the feed inlet pipe being shown

[Author] Wherein some had expressed interest in the utilisation of biogas for lighting, it was noted that this was

not possible mainly because of gas pressure issues. Like in the cases of Uganda (Pandey et.al.,

2007:51), the low gas pressure normally meant that lighting is not feasible when using PTD nor is it

possible to have many biogas cook stoves connected to one PTD, since it had a corresponding

increase in the amount of time spent cooking due to decreased gas pressure. Consequently, none of

the sampled sites had biogas based lighting systems nor more than one Biogas cook stove. In two

cases the owners due to demand for more gas at higher pressure especially for lighting,

decommissioned the PTD and installed the Masonry types.

Nevertheless, many of the owners / end-users from the sampled were quite happy with the benefits

that system was giving especially in terms of savings in the use of charcoal and firewood, the

reduction of indoor air pollution (hence less expenditure on health) and the simple convenience and

Cleanliness of the gas.


A key application of the Biogas was the utilisation of the slurry. In all the sites visited where the biogas was in good working condition, the slurry obtained was mainly used as an organic fertilizer and soil conditioner. In addition farmers quoted the benefits of the digester as a sanitizer, since it decomposes the cow dung which when in huge quantities would lead to foul smelling air.

2.7 PTD payback period

2.7.1 Payback period based on Charcoal use

It is estimated that the biodigestors can pay for themselves between 15 to 43 months, depending on

the type of fuel the digester is replacing, its cost (or what one would pay for it, if bought) fuel use., and

based on the assumption that the Bio-digestors could be used instead of charcoal for 54% or more of

the household cooking.

The determination of the payback period for the PTD is calculated as:

Cost of investment / savings per month

Or Cost of investment / 2.31 times the price of a sack of charcoal per month

The calculation assumes that a household of about 5 people will use an equivalent of 15.1 Kg of

charcoal per week, which translates to about 0.54 of a sack of charcoal, leading to 64.7kg per month

(about 2.31 Sacks of charcoal). A sack of charcoal is about 28 Kg.

In our case based on the average digestor cost of KES 45, 040, the payback period based on the

current prices of a sack of charcoal going for KES 900. The payback period translates to about 16.25

months and is calculated as follows:

PTD payback period = Cost of investment / (2.31 * price of a sack of charcoal/month)

= KES 45, 040/ (2.31 * KES 1,200/month)

= KES 45, 040 / (KES 2,772 / month) = 16.25 Months ~ 17 months

It is however noted that the lower the price of charcoal the longer the payback. Realizing then, that the

price of charcoal is increasing due to a diminishing resource base (less trees being replanted and

increased desertification and denudation of forests), it is feasible that the prices will be on an upward

trend, leading to increased attractiveness of PTD digesters.

2.7.2 Payback period for PTD and Fixed Dome Digester based on other Biomass fuels

In Rwanda and many other rural East African Countries, use of fuelwood and biomass residues like

maize cobs is quite common. An comparative analysis was thus done on the payback period of not

only the PTD but also the Fixed dome “Chinese Design” Biogas digester based on different Biomass


fuels (Table 8). The assumptions underlying Table 8 is based partly on Table 9 and also on studies

done. For instance the Biogas (2008) provides a Rwandan cost for 6 m³ Fixed dome digester used in

the calculation since obtaining the cost in Kenya for such a small digester was not possible

Table 8: Payback period of different digesters based on different Biomass fuels

Masonry (Fixed dome) - "Chinese design" Plastic Tubular

Cost (KES) (installations, materials, accessories) 68,720.00 45,040.00

Cost (US$) (installations, materials, accessories)

859.00 (Source: Biogas, 2008) 563.00 (In Kenya)

Lifetime 20 years or more

When polythene is used Lifetime is less than 5 years, but when butyl

rubber is used lifetime is comparatively longer (greater than 10

years) Digester Size (M³) ~ 6 ~ 6

Biogas production (M³/day) ~ 3 ~ 3

Payback period with Charcoal (months) 24.79 16.25

Payback period with Firewood (bought) in Months 42.95 28.15

Payback period with Biomass residue (maize cobs etc) in

months 65.45 42.90

Exchange rate (1 US$ is equal to KES) 80

[Author, Fao (2001), ]

Table 9: Assumptions for a household of 5 people

Assumptions for a household of 5 people

Fuel type Unit costs (KES) Usage per

month / unit Fuel use per month (KES)

Fuel use per Month (US$)

Charcoal (2.31 times the price of a sack of charcoal) 1,200 2.31 2,772 34.65 Firewood (how much would be spent if bought) 400 4 1,600 20.00 Biomass residue (how much would be spent if bought) 150 7 1,050 13.13

[Author, Karanja & Kiruiro (2003), ]

Generally, from the PTD comparative analysis (Table 8), the PTD has a slightly shorter payback

period as compared to the fixed dome of similar size. The only challenge as has been identified from

the field is the temperature fluctuations hence subsequent gas production fluctuations. This is

attributed to the exposure of the PTD digester bag to the elements, while the fixed is normally fully

enclosed within the ground affording it constant temperature for microbial activity.


2.8 Benefits of Digester systems

The main benefits indicated by the farmers / end-users being accrued from the Biogas digesters were:

1. 90% of the respondents indicated that the PTD helped them in save in the use of paraffin,

charcoal and fuelwood, allowing the money so used to be channelled to other things like

Education, obtaining more cows etc

2. No respondent in the survey (0%) indicated the possible reduction of indoor air pollution

(hence less expenditure on health)

3. About 10% of the survey sample indicated the benefits obtained by the simple convenience

and Cleanliness of the gas.

4. Of the 28 working digesters visited, all of them indicated the benefits the obtain from using the

Slurry as an organic fertilizer and soil conditioner. However other uses like Hydroponics, use a

feeding supplement for pigs and fishes were not indicated.

2.9 Extension services

Of the sampled, 96.7% had experienced some form of contact with the PTD installer after its

installation. This took the form of Telephone support (38%) or site visits (62%). The frequency of the

extension occurred ever since the installation was done (29%), or whenever they have a problem

(61%) or between 0 to 3 months after installation and nothing since then (10%).

It was further noted in all cases (100%) the farmers were given either a face to face training or a

manual (user guide) or both training and manual that describes not only the workings of a Biogas

digestor, but that also explained how and when the digester should be fed. Most of the problems to

arising with the Biogas digester were noted to emanate mainly from the low pressure and low gas

production matrix.

2.10 PTD Sustainability

The sustainability of the PTD’s was noted to be significantly reduced due to poor end-user

management of the especially the gas tube. More specifically, infrequent feeding, over-feeding and

under-feeding were the causes of low pressure and/or low gas production. In a bid to deal with the

hardened scum formed due digester feeding issues, 3% of the users had attempted to agitate the tube

by stepping on it. The end result being that the tube burst.


It is thus realized that with proper maintenance, and end-user education including proper extension

services these PTD’s can last up to 15 years, making them the most sustainable of all cooking fuels

currently available.

2.11 PTD and ownership findings

It was noted that the 97% of the users who had bought the digesters with the own money, took better

care of their digestors as compared to those (3%) who had obtained their digesters either through

subsidy or through donations.

This led to the question of Ownership and financing mechanism of the digesters. From the field survey

it was noted that a process whereby the farmer actually spends his/her own money to obtain the

digester generally tended to take better care of the system than the ones who had received it wholly

through some charitable organisations.

In view of the Rwandan situation, a mix of farmer’s contribution and subsidy or a total loan programme

approach may be recommended to allow for ownership development. Additionally, ownership issues

are a sub-set of the how well the farmer has been trained to use the digester including the attendant

extension services. The well trained farmers who received regularly extension services (97%) of the

study tended to take better care of their digesters.

2.12 Second hand PTD

About 5.9% of the surveyed had switched from plastic tubular digesters to Masonry ones. The main

reasons for these is the increased energy demands in terms need for Biogas lighting and increased

biogas use due to increased cooking activities. In addition other reasons for the switch include the low

gas pressure during the early morning and late evening periods, leading to non-effective and rather

long cooking times.

In the case where the Farmers upgraded to Masonry digester, they normally gave out the PTD to one

of their relatives. However, it can be postulated that if they were to sell it after 3 years, a probable

costs would less than KES 24,772 (US$ 309.65) for the Large sized digester. This is based on a

straight line depreciation of 15%.


3. Lessons Learnt and challenges experienced

3.1 Lessons learnt

1. Companies installing PTD’s in Kenya:- It was noted that a number of companies exist (

2. Table 10), which are installing PTD’s in Kenya these include:

Table 10: Current and potential Companies installing Plastic Tube digesters in Kenya

1. Dedan N Ndungu Modeline Electrical and Mechanical Engineers P. O. Box Tel: +254-(0)723 389642 Email: [email protected]

2. Samuel N. Nene, Pioneer Technologies Limited P. O. Box 32910 – 00600, Nairobi, Kenya Tel: +254-(0)20 253442 Mobile: +254-(0)722 552505 Email:- [email protected]

3. E. K. Kahiga Biens Limited, P. O. Box 57859 Nairobi, Tel: +254-(0)778030 / +254-(0)737521242 Email: [email protected]

4. Samwel Kinoti Skylink innovators, P. O. Box 64459 - 00620 Nairobi, http://skylinkinnovators.blogspot.com

Email: [email protected]

[Author]

The 4th Company, Sky link Innovators is one of the top five East African energy SMEs in the Access to Clean Energy Challenge and a winner of the GVEP-I Ashden Award . Skylink also has received financial training and expect further funding in 2011 for piloting a plastic biogas digester from Mexico from the Access to clean Energy Challenge promoters.

However, it was noted that due to the rather cut-throat competition, none was willing to give information or even acknowledge the existence of the other competitor, thus the study was unable to get more contact details of other competitors.

3. Installation methodology: - Simple approaches have been devised to allow for proper feeding. This has taken the form of either a masonry tank or rectangular trench. In other cases, used 200 litres oil drums are used to store the fresh cow dung before it is transferred to the digestor.

4. After sale services and end-users training: It was realized that with this 4TH generation


Plastic tube digestor that proper end-user training in form of manuals and/or face to face training is key in dealing with the inherent problems of digester breakdown. This couple with a robust after-sale / extension service will definitely enable the PTD’s to last up to their expected lifetime of 15 years.

5. Failure of PTD’s:- The main cause of failure of the PTD’s is mainly related to end-user maintenance and utilisation of the tubular digestor on one hand and poor or inadequate extension service on the other contribute to the digestor failing or under-performing.

6. Multiplying and Upgrading / scaling up of digestors: - It was noted that those farmers / end-users who have managed to acquire the PTD and also been blessed with an increase of cows tend to install a bigger Biogas digestor. In most case this being the fixed dome or the floating dome.

7. Essentially the problems experienced with the PTD's in Kenya are a combination of either Management issues (managing / taking care of the digester by the end-user) or After-sale service from the installing company. The Technology itself (the current PTD being the 4th generation one) is sound.

8. Lessons learnt in terms of Performance of the digestors

Number of digesters installed: - based on the initial figures provided by Pioneer Technologies of having installed 116 Biogas digestors, and realizing that of the sampled PTD’s visited only about 20% were installed by pioneer, being indicative of the scale at which different players are installing PTD’s in Kenya. The installation however is from our study mainly in former Central province of Kenya with forays into Rift valley and parts of Western Kenya.

Ratio of Bio digesters working to those not working (statistical analysis): It was noted that only 8.8% of the Biogas sampled are not working as compared to the 82.4% working ones. The reasons for the 3% not working are based mainly on maintenance issues.

Savings w.r.t. to charcoal use: A savings of KES 2,772 (US$ 34.65) is made monthly in avoided cost of buying 2.31 sacks of charcoal. Savings are made in reduced deforestation due to acquisition of firewood. In addition savings in terms of avoided costs of buying the fuel source are made for fuelwood (US$ 20) and US$ 13.13 for Biomass residues like maize cobs.

Sustainability – Unlike the previous generation of PTD’s which were made of heavy gauge Polythene, the 4TH Generation PTD will probably last much longer than 5 years in contrast to what many literature indicate. The exact time span is however not clear, since they have only been around since 2003 (about 7 years as at the time of undertaking this study).


Though quite a number of the consumers were satisfied with the PTD, a number of them expressed disappointment that the digester could not meet all their needs like lighting and further that the fluctuation in gas production especially during morning and late evenings was very inconvenient. It was on this reason that about 5.9% of the sampled decommissioned their PTD digesters and moved to the Masonry type.


4. Recommendations

4.1 Framework for PTD installation and operation manual

It is recommended that 12 page, double sided A5 user guide or operational manual, in the event PTD’s are to be installed elsewhere, be developed. The manual will among other things cover the following issues:

1. The process occurring inside a biogas digestor – use of diagrams and photographs is highly recommended (about 2 pages)

2. A brief description including a measurement based schematic / cross-sectional diagram of the Plastic tubular digester ( about 1 page)

3. A brief description with diagrams of the layout and installation of the plastic tubular digestor (2 to 3 pages)

4. How to feed the Biogas digester, including feeding frequency and use of simplified formulas for retention time, daily feeding capacity and frequency, and expected gas amount ( about 1 page)

5. A diagrammatic how to section dealing with things like digestor feeding, digestor repair, digestor agitation in case of scum formation etc ( 4 pages)

6. Frequently asked questions (trouble shooting ) (2 pages)

7. Contact details of local installer, local extension officer and/or artisan who can repair the digestor (back cover)

4.2 Recommendations for the PTD adoption in Rwanda

Based on the above, it seems quite recommendable to suggest PTD for the Rwandan programme, but

certain things will need to be in place, to make up for the shortfalls experienced in the Kenyan

Programme. Such issues include:

1. Proper end-user support programmes and training

2. Developing of the local capacity to repair the digestor using modified Bicycle tube puncture repair kits.

3. Support of a local company to be able to produce Double layer UV resistant Plastic material, gauge 300 micron. For this butyl rubber or other relevant material can be used.


4. Exploring ways to ensure that end-user takes ownership of the digestor, i.e. the digester should not be a gift.

5. Exploring the need of whether to incorporate a gas bag in the whole setup.

4.3 Recommendations for further scientific research and field studies

It is also recommended that further scientific research and field studies be done with respect to:

1. Determination of the life span of the Plastic tube digester, including the best kinds of cost effective materials to be used in manufacture and repair of Tubular digesters. Of particular interest in such a research is the Ultra-Violet light protection mechanism of the tube, its thermal capacity (ability to retain or lose heat) and its thickness which is important in terms of light piercing of the digester

2. Efficiency Benchmarking:

• Determining the quality and quantity of gas produced by both a PTD and masonry type digester like Fixed dome and/or floating drum

• Determining on a comparative basis the performance of the digester (PTD, fixed dome and floating drum) based on time of day, feeding frequency, feeding quantity, feeding type, effect of temperature fluctuations on gas production etc

3. Investigating cost-effective, easily adaptable and locally available approaches to repairing a

• Torn / bursted plastic digester bag

• Pierced Plastic digester bag

4. Development and piloting of a PTD value chain and also of a sustainable PTD market delivery model. This will specifically target the problems experienced in terms of

• End-user support

• Extension services

4.4 Recommendations for Better Market delivery models

1. Supporting on a local scale in Rwanda, an industry or a number of Small and medium Enterprises (SME’s) to mass produce UV protected thick double layered PTD tubes

2. Support of local skills upgrading in Biogas installation and repair


3. Support industry in availing affordable PTD repair kits

4. Government support in extension services for small scale farmers owning PTD’s

5. Local industry support for biogas equipment and accessories. These would include gas valves and biogas stoves.

4.5 End-user recommendations

1. Development of a PTD end-user manual (section 4.1) and wide distribution to end-users in a language they can understand

2. Regular user support visits from Government extension officers and installers

3. Protection of the PTD against animals, children and other harm

4. Farmer training on type of feeding material and feeding frequency for digester

5. Development and dissemination of a video on PTD installation, operation (feeding, cleaning, troubleshooting etc), repair and gas use. An example of such a video is given for a short time period at this link: http://www.energiekonsult.com/consultancy/GTZ-REAP/

4.6 Recommendations to policy makers

1. Undertake study on effect of subsidies on end-user management of the PTD’s (See section 2.3.3 and Table 6)

2. Determination and piloting of best financing mechanism of PTD’s for poor households in the context of ownership creation and sustainability

3. Scaling up of the whole programme region-wide


5. Appendices

5.1 Tools used in Field survey

5.1.1 Institutional Questionnaire

Questionnaire with Pioneer Technologies:

Aim:

1. Understand the history of the company and its staffing level including branches and/or outposts

2. Distributors / retailers and suppliers of their products or manufacturing material

3. Understand their scope of activities (installation areas, costs / area, what they do (activities)

4. Understand the technology and its processes

5. Understand the challenges they are experiencing

6. Obtain a database of all their installed plants including names of clients, their contact details, location of installation, date of installation, frequency of monitoring & evaluation, Cost of installation at that time,

7. Their extension processes.

Interviewee _________________________________ Tel ____________________________

Contacts _____________________________________ Position ______________________

Main issue Sub-issues Responses

Company Contacts

Branches

Staffing levels

Branches /outputs

History (when it started,

people involved, growth

record)

Delivery network Distributors

Retailers

Suppliers of the materials /



material availability

Scope of

activities

Installation areas (provinces,

districts, locations)

Installation costs (stratified

per installation area)

Number of installed PTD’s &

area of installation (geo-

referencing?)

Any other activities they are

involved in

Technology Who manufactures it

How it works

Operation parameters (PH,

Temp, etc)

Feedstock type

Lifespan

Average gas production / day

Manufacturing costs and

energy

Challenges Production

Transportation

Installation



End-user operation &

Education

Extension (end-user) support

Policy

Others

Extension

processes

Who does extension?

What kind of extension?

(Education, O&M, marketing

etc)

Who pays for it?

Database

compilation

Location of installation

Geo-reference

Names of client

Contacts (postal, mobile, e-

mail)

Installation date

Cost of installation at that time

Frequency of M&E,



Repair works + costs

Performance of PTD (gas

production, feedstock

availability,

PTD

type

Size & cost Retention time & days before it

starts working, Temperature issues,

Gas volume


5.1.2 End-User Questionnaire

Plastic Tube Digester questionnaire with End users:

Preamble:

The Government of Rwanda is intending to install about 5,000 Biogas digesters for small households

having 1-3 cows. For this reason, they are assessing the performance of different types of Biogas

digesters within the region.

For this reason, they have obtained permission from Pioneer Technologies to undertake a quick

assessment of the digesters installed by them in order to obtain an understanding of how the digesters

are performing in real life. We thus kindly request a few minutes of your time in responding to this

questionnaire and if possible allowing our interviewer to access your digester, gas storage bag, gas

piping and gas cooking stove.

Questions Responses

1. Location of the digester (Geo-reference if possible)

Physical/administrative location ……………………………………………………………………………………………………………………………………………..

Latitude ……………………………………………… Longitude ……………………………………………….

2. Name owner and contact details

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

3. Date of installation ………………………………………………………………….. 4. Costs of installation ……………………………………………………………………. 5. Time to construct the digesters

………………………………………………………………………………………………………………………………………………

6. Time between construction date and the start of the gas production/use

…………………………………………………………………………………………………………………………………………………………………………………………………………………….

7. What is the feeding material?

……………………………………………………………………………………………………………………………………………………………………………………………………………………..

8. What is the gas used for?

Cooking Lighting Operating dual fuel engines (for water pumping, electricity generation and/or running agro-machinery)

Other uses: 9. Average hours of cooking and/or light per day

………………………………………………………………………………………………………………………………………………

10. Operating condition of the digester, Gas bag and cooking equipment

Digester condition & performance

Gas bag condition & performance

Cooking equipment condition & performance


Questions Responses

Gas pipes conditions & performance

Water trap condition & performance

Digestor Size

Feeding frequency Number of cows …………………….

11. Farmers’ opinion on the performance of the digester

………………………………………………………………………………………………………………………………………………

12. If out of order, what are the reasons

Digester busted along the seam – settings interfered with

No gas production – overfeeding, wrong feeding material

Low pressure

Stove not lighting – condensate, pressure, gas production issues

Protection of digesters from animals and children

Lack of interest from end-user – delegation of digester maintenance to farm helper etc,

Others: - ……………………………………………………………………………………………………………………………………………………………………………………………………………………..

13. After sales services provided

After sale service provided: Yes No

After sale service provider

After sale provider is Pioneer Other after sale provider (state name and contact details)

…………………………………………………………………………………………………………………………………………… In what form

Telephone support Site visits Others

…………………………………………………………………………………………………………………………………………… How frequent

0 – 3 months after installation

Whenever their is a problem

Ever since installation of digester

Other frequency ……………………………………………………………………..

14. How did the farmer hear about the PTD's?

Saw it from neighbours / friends


Questions Responses During trade fairs / agricultural shows

Training events

Internet, Audio-visual Media

Print media, publications

Word of mouth

Others ………………………………………………….

15. Did he see it from neighbours/ friends before purchasing the unit?

Yes No

16. Does he use the slurry? For what for what purpose? Benefits compared to dung?

Yes No

As organic fertilizer

Feeding fish

food supplement for pigs and chicken

In mushroom cultivation

Earthworm cultivation

In hydroponics (growing plants in a nutrient rich solution)

Others: …………………………………………………………………………………………………………………………………………………………………………………………………………………….

Any other comments / Observations / photos / maps etc

………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………

………………………………………………………………


5.2 Initial PTD’s list from Pioneer Technologies Limited

DATE CLIENT NAME CONTACT LOCATION 22.10.06 Shem Njiraini 733719001 Githunguri 23.10.06 Job Mwangi 722288907 Mwiki 19.09.06 Luka Kinyanjui 735499043 Kinoo 15.11.06 Mr Wanjehia 733528830 Mangu,Gatukuyu 21.10.06 Mama Leah 722513825 Ruai 15.11.06 Mrs Kimathi Thika sports club 10.11.065 Nehaemiah Kisumu 23.11.06 Mr karanja 722376389 Gikuni 13.11.06 Mrs Karanja 721717154 Kiserian 23.11.06 Anthony Mugwanja Thika sports club 14.11.06 Hinga Mangu,Gatukuyu 6.12.06 Land o lakes Mukurwini 06.12.06 Land o lakes Nakuru 20.11.06 Nehemiah int Kisumu 20.11.06 Mayor Kericho-Isaiah Rono Kericho 05.12.06 Mrs Matu Thika Delmonte 18.12.06 Mr Wanjohi Josephat 722623606 Ngong 20.12.06 Kiteto Joy 722958019 Voi 20.12.06 Elizabeth Mwhihaki 721339460 Kibiciku 20.12.06 Gichuhi Mwaniki Kimende 015.01.07 George Ngugi 722856040 Limuru 10.01.07 Jane Nganga Limuru 02.02.07 Joram Njenga 724596606 Kibiciku 05.02.07 Joyce 723480488 Ndeiya 02.02.07 Lilian Meru 07.02.07 Mirium Meru 10.02.07 Mr Kamau Wangige 13.02.07 Nahashon Kariuki Ruku 12.02.07 Nehemiah - oira O kIsumu 12.02.07 Nehaemiah - j.Omtata kIsumu 12.02.07 Nehemiah int Kisumu 12.02.07 Nehemiah int- GERORGE kIsumu

13.02.07 Land o lakes nakuru Kabarak Kabarak

27.02.07 Koigi MwANgi Chumga mali 13.02.07 Land o lakes Kericho 13.02.07 Land o lakes - Kiarii Githunguri 26.03.07 Land o lakes Rongai 26.03.07 Land o lakes Cura wangige 03.04.07 Mr mwaura Cura wangige 05.04.07 George Tharao Njugia Kimende 04.04.07 Mrs Nyaga Thome 24.04.07 Benote Nakuru 24.04.07 Kingshop Nakuru


DATE CLIENT NAME CONTACT LOCATION 24.04.07 Pokea Farm Nakuru 04.05.07 Cosmas Munyeke Machakos 30.04.07 Wakulima Dairy members Mrs Thairu Mukurweini mr karanja metal Mukurweini wahu muira Mukurweini Penina njeri Kago Mukurweini kim chair Mukurweini Best dairies Mukurweini kwamunga Mukurweini Githioro Mukurweini Njenga kim Mukurweini Mutho w Mukurweini Hosea mwangi Mukurweini Tiiri Mukurweini Peter maina Mukurweini macharia gaitho Mukurweini 26.04.07 Njoroge Nguru Kimende Nguru githiaka Kimende Wanjiklu kibe Kimende Mr koigi Kimende Wamai Bahati Baba Njenga Bahati Pastor wangonbe Bahati Cidar lodge Bahati 18.04.07 WANJEMA Nakuru 07.05.07 mRMuthui Nakuru 07.05.07 Mr muthui Nakuru 08.05.07 Mr kariuki Nakuru 11.06.07 Evans Karanja Gikuni wangige 12.06.07 Daniel kilonzo MULI Tala 13.06.07 Pastor Afwayi 733393528 Njiru 14.06.07 Peris kabaria Tinganga 20.06.07 Kariuki Ravine nkr

21.06.07 Naomi Wangari goko wendani kahawa

03.07.07 Job Mwangi mwiki 23.07.07 Bernad Ngige kahawa 16.07.07 Ann wachinga Kiambu 16.07.07 Paul kuria muranga mbiri

23.07.07 Isaac kogi muranga kangari

26.07.07 Nuthia mwathi Naivasha 20.08.07 Paul wachira 722722697 Limuru 10.07.07 Roy Ngure kahawa 19.09.07 Daniel mbugua 722263523 wangige

15.09.07 Endarasha school for orphans

Nyeri endarasha


DATE CLIENT NAME CONTACT LOCATION 20.11.07 James njenga kaguora limuru Gichagi 01.12.07 NYS TUMAINI OLO-KALAO 01.12.07 Ngugi mwaura 722868550 ndenderu 04.12.07 Alice kihara githiga 10.12.07 Joseph mwangi 722211874 Nazareth 04.12.07 Kigali teachers embu town 13.12.07 Ithururu dairy farmers nyerii 14.12.07 Drmwatu machakos 13.08.07 mbuguas githunguri 15.08.07 prof.kiriko Njunja JKUAT 16.08.07 jOYCE Muranga 31.08.07 Susan mbiti wamunyu 02.10.078 Nicholas muindi Machakos 19.09.07 Jikaze wiyumiririe 19.07.07 Daniuel ikoro Wangige 17.12.07 kamwende 722735026 embu 14.01.08 Boniface mwaniki embu kanja

14.012.07 David mbugua nduati Githunguri ngewa

21.01.08 John kiarii 722706820 Githunguri 19.02.08 Njuki munano karura 19.02.08 Land o lakes - grace makau Nyeri 19.02.08 Land o lakes - kamau Kimende 05.02.08 Land o lakes - mwororo Machakos 08.04.08 Land o lakes- mutukus Machakos

08.04.08 Land o lakes - samuel balazi Machakos

12.04.08 karanja jabini 13.04.08 Njoroge k jabini 13.04.08 P.MWAI GITHIGA 13.04.08 Baldo Ndaragwa


5.3 Reformatted and updated List of contacts

INDEX-No.

INSTALLATION DATE CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon

1 20.12.06 Elizabeth Mwhihaki 0721339460 Kibichiku Kiambu 1° 13' 60'' S 36° 43' 60'' E

2 13.11.06 Mrs Karanja 0721717154 Kiserian Kajiado 1° 25' 60'' S 36° 40' 60'' E

3 10.12.07 Joseph mwangi 0722211874 Nazareth Kiambu 1° 7' 60'' S 36° 43' 60'' E

4 19.09.07 Daniel mbugua 0722263523 wangige Nairobi City 1° 13' 0'' S 36° 43' 0'' E

5 23.10.06 Job Mwangi 0722288907 Mwiki Nairobi City

6 23.11.06 Mr karanja 0722376389 Gikuni Kiambu 1° 11' 60'' S 36° 42' 0'' E

7 21.10.06 Mama Leah 0722513825 Ruai Nairobi City

8 18.12.06 Mr Wanjohi Josephat 0722623606 Ngong Kajiado 1° 19' 0 S

36° 43' 60 E

9 21.01.08 John kiarii 0722706820 Githunguri Kiambu 0° -23' 60 N 37° 28' 60 E

10 20.08.07 Paul wachira 0722722697 Limuru Kiambu 1° 6' 0 S 36° 38' 60 E

11 17.12.07 kamwende 0722735026 embu Embu 0° -35' 0 N 37° 40' 0 E

12 15.01.07 George Ngugi 0722856040 Limuru Kiambu 1° 6' 0 S 36° 38' 60 E

13 01.12.07 Ngugi mwaura 0722868550 ndenderu Kiambu 1° 10' 60'' S 36° 45' 0'' E

14 20.12.06 Kiteto Joy 0722958019 Voi Taita Taveta 3° 21' 0 S 39° 40' 0 E 15 05.02.07 Joyce 0723480488 Ndeiya Kiambu 16 02.02.07 Joram Njenga 0724596606 Kibichiku Kiambu 17 15.08.07 Self 0726811416 Juja IEET-JKUAT Kiambu 18 13.06.07 Pastor Afwayi 0733393528 Njiru Kiambu 19 15.11.06 Mr Wanjehia 0733528830 Mangu,Gatukuyu Kiambu 20 22.10.06 Shem Njiraini 0733719001 Githunguri Kiambu


INDEX-No.


21 19.09.06 Luka Kinyanjui 0735499043 Kinoo Kiambu 22 14.01.08 Boniface mwaniki embu kanja Embu 23 04.12.07 Kigali teachers embu town Embu 24 19.09.07 Self wiyumiririe Jikaze Kiambu

25 26.03.07 Client Cura wangige Land O' Lakes Kiambu 26 13.02.07 Client Githunguri Land O' Lakes Kiambu 27 19.02.08 kamau Kimende Land O' Lakes Kiambu 28 6.12.06 Client Mukurwini Land O' Lakes Kiambu

29 30.04.07 Mrs Thairu Mukurweini Wakulima Dairy members Kiambu

30 30.04.07 mr karanja metal Mukurweini Wakulima Dairy members Kiambu

31 30.04.07 wahu muira Mukurweini Wakulima Dairy members Kiambu

32 30.04.07 Penina njeri Kago Mukurweini Wakulima Dairy members Kiambu

33 30.04.07 kim chair Mukurweini Wakulima Dairy members Kiambu

34 30.04.07 Best dairies Mukurweini Wakulima Dairy members Kiambu

35 30.04.07 kwamunga Mukurweini Wakulima Dairy members Kiambu

36 30.04.07 Githioro Mukurweini Wakulima Dairy members Kiambu

37 30.04.07 Njenga kim Mukurweini Wakulima Dairy members Kiambu

38 30.04.07 Mutho w Mukurweini Wakulima Dairy members Kiambu

39 30.04.07 Hosea mwangi Mukurweini Wakulima Dairy members Kiambu

40 30.04.07 Tiiri Mukurweini Wakulima Dairy members Kiambu

41 30.04.07 Peter maina Mukurweini Wakulima Dairy Kiambu


INDEX-No.


members

42 30.04.07 macharia gaitho Mukurweini Wakulima Dairy members Kiambu

43 26.04.07 Wamai Bahati Kiambu 44 26.04.07 Baba Njenga Bahati Kiambu 45 26.04.07 Pastor wangonbe Bahati Kiambu 46 03.04.07 Mr mwaura Cura wangige Kiambu 47 11.06.07 Evans Karanja Gikuni wangige Kiambu 48 04.12.07 Alice kihara githiga Kiambu 49 13.04.08 P.MWAI GITHIGA Kiambu 50 13.08.07 mbuguas' githunguri Kiambu

51 14.012.07 David mbugua nduati

Githunguri ngewa Kiambu

52 12.04.08 karanja Njabini Muranga 53 13.04.08 Njoroge k Njabini Muranga 54 10.07.07 Roy Ngure kahawa Kiambu 55 23.07.07 Bernad Ngige kahawa Kiambu 56 19.02.08 Njuki munano karura Kiambu 57 16.07.07 Ann wachinga Kiambu Kiambu

58 05.04.07 George Tharao Njugia Kimende Kiambu

59 20.12.06 Gichuhi Mwaniki Kimende Kiambu 60 26.04.07 Njoroge Nguru Kimende Kiambu 61 26.04.07 Nguru githiaka Kimende Kiambu 62 26.04.07 Wanjiklu kibe Kimende Kiambu 63 26.04.07 Mr koigi Kimende Kiambu 64 10.01.07 Jane Nganga Limuru Kiambu

65 20.11.07 James njenga kaguora limuru Gichagi Kiambu

66 13.04.08 Baldo Ndaragwa Kiambu 67 04.04.07 Mrs Nyaga Thome Kiambu 68 14.06.07 Peris kabaria Tinganga Kiambu


INDEX-No.


69 31.08.07 Susan mbiti wamunyu Kiambu 70 10.02.07 Mr Kamau Wangige Nairobi City 71 19.07.07 Daniuel ikoro Wangige Nairobi City 72 14.11.06 Hinga Mangu,Gatukuyu Kiambu 73 05.12.06 Mrs Matu Thika Delmonte Kiambu 74 15.11.06 Mrs Kimathi Thika sports club Kiambu 75 23.11.06 Anthony Mugwanja Thika sports club Kiambu

76 21.06.07 Naomi Wangari goko wendani kahawa Nairobi City

77 10.11.065 Client Kisumu Nehemiah int'l Kisumu 78 12.02.07 Oira O. Kisumu Nehemiah int'l Kisumu 79 12.02.07 Client Kisumu Nehemiah int'l Kisumu 80 12.02.07 George Kisumu Nehemiah int'l Kisumu 81 12.02.07 J. Omtata Kisumu Nehemiah int'l Kisumu 82 20.11.06 Client Kisumu Nehemiah int'l Kisumu 83 05.02.08 mwororo Machakos Land O' Lakes Machakos 84 08.04.08 mutukus Machakos Land O' Lakes Machakos 85 08.04.08 samuel balazi Machakos Land O' Lakes Machakos 86 02.10.078 Nicholas muindi Machakos Machakos 87 04.05.07 Cosmas Munyeke Machakos Machakos 88 14.12.07 Dr. mwatu machakos Machakos 89 12.06.07 Daniel kilonzo Muli Tala Machakos 90 02.02.07 Lilian Meru Meru 91 07.02.07 Mirium Meru Meru 92 16.08.07 Joyce Muranga Muranga 93 23.07.07 Isaac kogi muranga kangari Muranga 94 16.07.07 Paul kuria muranga mbiri Muranga 95 03.07.07 Job Mwangi mwiki Nairobi City 96 26.07.07 Nuthia mwathi Naivasha Nakuru 97 26.04.07 Cidar lodge Bahati Cidar Lodge Nakuru 98 06.12.06 Client Nakuru Land O' Lakes Nakuru 99 26.03.07 Client Rongai Land O' Lakes Nakuru


INDEX-No.


100 07.05.07 Mr. Muthui Nakuru Nakuru 101 07.05.07 Mr muthui Nakuru Nakuru 102 08.05.07 Mr kariuki Nakuru Nakuru 103 18.04.07 Wanjema Nakuru Nakuru 104 24.04.07 Benote Nakuru Nakuru 105 24.04.07 Kingshop Nakuru Nakuru 106 24.04.07 Pokea Farm Nakuru Nakuru 107 20.06.07 Kariuki Ravine nkr Nakuru 108 13.02.07 Nahashon Kariuki Ruku Kiambu

109 15.09.07 Self Nyeri endarasha Endarasha school for orphans Nyeri

110 13.12.07 Self Nyeri Ithururu dairy farmers Nyeri 111 19.02.08 grace makau Nyeri Land O' Lakes Nyeri 112 27.02.07 Koigi Mwangi Chumga mali Taita Taveta 113 13.02.07 Client Kabarak Land O' Lakes Uasin Gishu 114 13.02.07 Client Kericho Land O' Lakes Uasin Gishu

115 20.11.06 Isaiah Rono (Self) Kericho Mayor-Kericho Municipal council Uasin Gishu

116 01.12.07 Self OLO-KALAO National Youth Services-Tumaini Uasin Gishu


5.4 PTD Data base


6. References

1. AG (2010), The Constitution of Kenya. The National Council for Law reporting, Available at http://www.kenyalaw.org/Downloads/The%20Constitution%20of%20Kenya.pdf last accessed 28.11.2010

2. Bartlett, J. E., Kotrlik, J. W., and Higgins, C., C., (2001), Organizational Research: Determining appropriate sample size in Survey Research. Information Technology, Learning, and Performance Journal, Vol. 19, No. 1, Spring 2001. Available at http://www.osra.org/itlpj/bartlettkotrlikhiggins.pdf Last Accessed: 29.11.2010

3. Israel, Glenn D., (u.d.) Determining Sample Size. University of Florida. Available at http://edis.ifas.ufl.edu/pdffiles/PD/PD00600.pdf Last accessed: 12.12.2010

4. Republic of Rwanda (2009). Action plan 2009 – 2010. Ministry of Infrastructure, Kigali. Available at http://mininfra.gov.rw/index.php?option=com_docman&task=doc_download&gid=87&Itemid=319 last accessed 12.12.2010

5. PAndey, B., Subedi, P. S., Sengendo, M., Monroe, I., (2007). Biogas for Better Life: An African initiative. Report on the feasibility for a national household Biogas Commercialization Program in Uganda. Winrock International. Available at http://www.snvworld.org/en/Documents/Biogas_for_better_life_an_African_initiative_Feasibility_study_Uganda_2007.pdf Last accessed: 13.12.2010

6. Biogas (2008). South Africa household Biogas Feasibility Study. By Biogas for a Better Life Initiative. January 2008. Available at http://www.biogasafrica.org/index.php?option=com_docman&task=doc_download&gid=23 Last Accessed: 17.12.2010

7. Karanja, G.M., Kiruiro, E.M., Biogas Production, KARI Technical Note Series No. 10, January 2003. Available at http://www.kari.org/fileadmin/publications/tech_notes/tecNote10.pdf Last access 17.12.2010

8. Fao (2001), Mixed crop-livestock farming A review of traditional technologies based on literature and field experience. ISBN 92-5-104576-3 Available at http://www.fao.org/docrep/004/y0501e/y0501e07.htm last Accessed: 17.12.2010

9. Renwick M., Subedi P. S., Hutton, G., (2007). Biogas for Better Life: An African Initiative. A cost-benefit analysis of national and regional integrated Biogas and Sanitation programs in Sub-Saharan Africa. WinRock International. Available at http://www.winrock.org/clean_energy/files/biogas_for_better_life_an_african_initiative.pdf Last accessed: 17.12.2010

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