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

  • 3,526 views
Uploaded on

This report presents the findings of a field survey on Plastic tubular digestors (PTD) in Kenya. Using a precision level of 17% of the total probable biogas digestors installed by a local company (the …

This report presents the findings of a field survey on Plastic tubular digestors (PTD) in Kenya. Using a precision level of 17% of the total probable biogas digestors installed by a local company (the Pioneer Technologies Limited), 34 biogas digestors were visited. Functioning and challenges assessed and reported.

[ Originally posted on http://www.cop-ppld.net/cop_knowledge_base ]

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
3,526
On Slideshare
0
From Embeds
0
Number of Embeds
1

Actions

Shares
Downloads
8
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. 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:ENERGIEKONSULT LTD.
  • 2. 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 oscar.onguru@gtz.de I www.gtz.deSurvey of Plastic Tube Digestors in Kenya Page 1 of 49
  • 3. Survey of Plastic Tube Digesters in Kenya A field survey of the Performance of Plastic tube digestors in Kenya Study Conducted by ENERGIE KONSULT LTD. GTZ – Regional Energy Advisory Platform (East Africa) Nairobi, December, 2010Survey of Plastic Tube Digestors in Kenya Page 2 of 49
  • 4. Consultancy Reference Number: INT/EK/04/2010/GTZ Francis Xavier Ochieng Director, Study Energie Konsult Ltd, undertaken P. O. Box 7764 – 00200, Nairobi, Kenya By Tel: +254-714-693299 / +254-20-3203802 E-mail: xavierfo@yahoo.com , xavierf@gmx.de , director@energiekonsult.com www.energiekonsult.com Michael Franz Regional Energy Advisory Platform (East Africa) - REAP (EA) German Technical Cooperation (GTZ); Utumishi Cooperative House, 5th Floor Prepared For: Mamlaka Road, off Nyerere Road, P. O Box 41607-00100, GPO; Nairobi, Kenya Email : michael.franz@gtz.deHistory of ChangesVersion Description of Amendment Date 01 Draft Report Issued 29/11/2010 02 Changes in data bases, PTD pricing, Integration of all questionnaire 07/12/2010 answers into report and finally provision of a video on PTD’s 03 Addition of Subsidy analysis and referencing 17/12.2010 17TH December, 2010Survey of Plastic Tube Digestors in Kenya Page 3 of 49
  • 5. AcknowledgementsThe 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 beadopted. 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 thetechnology.This output informs the basis on which decisions regarding the adoption, modification or non-adoptionof the tubular biogas digesters could be made. More importantly it lays the truth regarding the industrypractices and what can be done about it.This research would not have been possible without Dedan N. Ndungu of Modeline Electrical andMechanical engineers, who took the time to take me through the various sites, many of which I had noform of contact information like telephone numbers. It is also important to mention that Dedan alsoprovided a video of some of the sites he has installed these PTD’s. The first part of the video gives notonly the technical information about the digesters, its costs, sizes and installation, but also providesinformation on the end-users views on the use of the digester and the benefits they accrued. Hiscontact information can be obtained from page 7In addition we gratefully acknowledge the support of Oscar Onguru of GTZ-REAP and GerardHendriksen for their invaluable contribution in supporting and commenting on this work. Last but notleast we thank Samuel Nene of Pioneer Technologies for providing that very invaluable initial contactlist 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 theAuthor 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 willenrich the ongoing discussions among practitioners, policy makers and academia and welcome anyfeedback and commentsFrancis Xavier Ochieng,C.E.O Energie Konsult Ltd,P. O. Box 7764 – 00200, Nairobi, Kenyawww.energiekonsult.comSurvey of Plastic Tube Digestors in Kenya Page 4 of 49
  • 6. Table of ContentsACKNOWLEDGEMENTS ..................................................................................................................... 4TABLE OF CONTENTS........................................................................................................................ 5LIST OF TABLES ................................................................................................................................. 6LIST OF FIGURES ............................................................................................................................... 6ABSTRACT .......................................................................................................................................... 71. 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 .............................................................. 152. 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 ................................................................................................ 6Survey of Plastic Tube Digestors in Kenya Page 5 of 49
  • 7. 2.11 SECOND HAND PTD.................................................................................................................. 63. LESSONS LEARNT AND CHALLENGES EXPERIENCED ......................................................... 7 3.1 LESSONS LEARNT ..................................................................................................................... 74. 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.................................................................................. 125. 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..................................................................................................................... 286. REFERENCES........................................................................................................................... 32 List of TablesTable 1: Sample size at 95% confidence level with a degree of variability P of 0.5 ............................. 12Table 2: Selection of Digester sites based on pre-determined sample size ......................................... 13Table 3: Selection of final sites to visit based on household location type ........................................... 14Table 4: PTD performance study – Revised Work plan ........................................................................ 14Table 5: Performance of Installed PTD in Sample and in total population............................................ 16Table 6: Comparative assessment of costs and subsidies of PTD and Fixed dome digesters .............. 0Table 7: Overall performance of PTDs.................................................................................................... 0Table 8: Payback period of different digesters based on different Biomass fuels .................................. 4Table 9: Assumptions for a household of 5 people ................................................................................. 4Table 10: Current and potential Companies installing Plastic Tube digesters in Kenya......................... 7 List of FiguresFig 1: Trend analysis of PTD’s prices and installations over the years................................................. 18Fig 2: Biogas Cook stove, with the feed inlet pipe being shown ............................................................. 2Survey of Plastic Tube Digestors in Kenya Page 6 of 49
  • 8. AbstractThis report documents the results of a field survey of Plastic tubular digestors (PTD) in Kenya. Using aprecision 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 notworking, two had been dismantled and replaced with masonary ones and the last one had beeninstalled at Jomo Kenyatta University of Agriculture and Technology for experimental purposes, whoseobjects 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% areworking, while 8.8% are not working, 5.9% have been decommisioned and masonary ones installed inthier place and lastly 2.9% have been decommissioned/abandoned and nothing replaced in thierstead.Findings indicate that most of the end-users, who are mostly farmers were quite satisfied with thePTD, however some did express dissapointment on the challenges they face. These included low gaspressure during the morning and evening cooking periods, low/insufficient gas production as energyneeds increased and lastly insufficient farmer training on how to feed and maintain the Biogasdigesters. These challenges are mainly a user management problem on what the digester if fed withand how frequently it is fed. Nevertheless, the issue of low gas production during morning and eveningcooking period is more of how well the digester is insulated from the elements, which is a trainingissue. The use of UV treated double layer plastic did not seem to be a problem only in as far as thePlatic tube was not pierced.The opportunity cost of not collecting firewood, and the utilisation of animal waste for energy, seems tobe the main motivator for the uptake of PTD’s. In essense, Household cooking and general sanitationof 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 prioritybe given to extension services and maintenance.Equally important is optimizing gas production by correct retention time, research into the effects ofadding 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.Survey of Plastic Tube Digestors in Kenya Page 7 of 49
  • 9. 1. About the Field Assessment1.1 Introduction and Background to the Field StudyThe 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 isundertaken within the framework of the National Domestic biogas programme (NDBP). The NDBPaims at installing 15, 000 Biogas units by December 2011 (Rwanda, 2009). , and targets ruralhouseholds in Rwanda that have 2 -3 cows. The fixed Dome biogas digestor type with a capacity ofbetween 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 istoo high despite a € 350 subsidy and a bank credit. Thus the November 2009 project review missionrecommended assessment of cost reduction opportunities. Based on GTZ experience in some SouthAmerican Countries, the possibility of an alternative biogas technology apart from the fixed dome isnow 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 providessuch an option. Within the Eastern Africa region institutional memory exist in form of PioneerTechnologies 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 undertakenInitial studies to verify these claims have been undertaken by the consultant applying for this studyunder the auspices of the Institute of Energy and Environmental Technology (IEET) of Jomo KenyattaUniversity of Agriculture and Technology (JKUAT). The Consultant together with his team have testedthe performance of the Pioneer Technologies PTD’s at IEET and done preliminary site/field visits ofthe Pioneer Technologies installed PTD’s.Subsequently, the GTZ PTD’s study furthers the Scope of work done by the Institute and provides aneven greater sample space to draw scientifically valid lessons which can be used to deal with thechallenge facing NDBP of which this study seeks to solve.1.2 Study ProblemNDBP is interested in assessing the potential of the PTD technology as another option for the farminghouseholds in Rwanda. While there are claims that a Pioneer Technologies has installed over 300PTD’s in Kenya, no independent surveys have been done to verify these claims (apart from the singleperformance study and preliminary studies done by the applying consultant who is based in IEET –JKUAT).Survey of Plastic Tube Digestors in Kenya Page 8 of 49
  • 10. Therefore a need exist to survey the PTD’s installed by Pioneer Technologies. More knowledge ofKenya’s experience with PTD is required to gauge if and how they can be used in Rwanda. Thisshould then enable NDBP make a sound judgment on whether or not to pursue the introduction ofPTD’s in Rwanda.1.3 Justification / Significance of the studyThe study will collect data and other relevant information to enable the NDBP make a soundjudgement on whether or not to pursue the introduction of PTD’s in Rwanda. This is necessitated bythe realisation that the installation of Fixed dome Digestors is out of reach of the rural households with2 – 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 year2006 installed about 300 PTD’s in Kenya of which about 90% are operational. The significance of apositive or negative verification of this claim will provide lessons on technology adoption, adaptationand fuel further research in the area of PTD’s.Lastly the study will complement the initial studies that had been undertaken by the applyingconsultant on PTD’s at the institute of Energy and Environmental Technology of the Jomo KenyattaUniversity of Agriculture and Technology (JKUAT). It will enable the orientation of the further researchin dealing with the design and performance issues noted in the initial studies, since only a smallsample space was used.1.4 Aim, Scope and expected deliverables of the study1.4.1 Aim of the StudyThe 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 aboutpossible introduction into the country.1.4.2 Specific objectivesSpecifically 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.Survey of Plastic Tube Digestors in Kenya Page 9 of 49
  • 11. 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 objectives1.4.3 Scope of the StudyThe study being limited in both time and depth of assessment will confine itself to the generalassessment of the working condition of 30 randomly selected Plastic tube digestors. The aim is to givea general picture on the performance of these digestors.1.4.4 Expected deliverables o f the studyTwo 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 Kenya1.5 Structure and Methodology of the studyThe Study essentially utilised Stratified random sampling to identify about 26% of the total installedPTD’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 whichincluded Counties as per the First Schedule, Article 6(1) of the Constitution of Kenya (AG, 2010) wasdeveloped. The need for including counties is based on the demands of the stratified random samplingwherein, in determining the sample size, the data is stratified / divided in accordance withadministrative 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 visit1.6.1 General overviewDetermination 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 ofscientifically proven statistically techniques, and which unfortunately end up giving a slightly different nfrom 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 thestudy, population size, risk of selecting a “bad” sample and the allowable sampling error. In studiesSurvey of Plastic Tube Digestors in Kenya Page 10 of 49
  • 12. involving a lot of variables and/or high precision demands, then more stringent sample determinationare 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 ofthe 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 referto selecting only the working digesters or the ones that are not working. The constituents of thesample have to be selected randomly, both in time and space. The implications of this to our studybeing that the sites visits were done both during weekdays and weekends, morning, afternoons andevenings. It also meant that different geo-administrative locations were visited. Lastly it implied that thetelephone contact numbers we had were called randomly and whoever agreed to meet us, irrespectiveof status of digesters, or even its existence/presence was visited. No preference was given to whetherthe 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 tobe 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 itwhen 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. Thisis further discussed below.1.6.2 Statistical determination of the Sample SizeThis study is based on the realisation that the total population of PTDs’ installed countrywide in Kenyais unknown. Consequently, certain assumptions based on scientifically accepted statistical approacheshave to be utilised. In the case of survey research, this normally means use of random samples thatare generally assumed to cover the whole population. The determination of sample size based onscientific approaches cannot be underscored. This is mainly done to avoid to common errors in surveyresearch (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)Survey of Plastic Tube Digestors in Kenya Page 11 of 49
  • 13. 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) ofExpected 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 willa higher sample size (n) be obtained. Subsequently based on the initially pre-determined sample sizeof 30, only two options are open to us in terms of the precision level (e): Either we assume e is 1% andhence 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), andsecondly to have a sample size (n) that is as near as possible to that given in the ToRs. A much biggerSurvey of Plastic Tube Digestors in Kenya Page 12 of 49
  • 14. sample space will mean more time and resources (money, transport etc) to undertake the survey thanwas initially agreed upon or allowed by the contract. Subsequently an e value of 17% allowed thestudy to be able to choose a sample size that covers not only the final list given to us by PioneerTechnologies of 116 installed PTDs but more importantly to also cover their initial claim of 300installed PTD’s. In addition it allows us to have a sample size that can cover a possible potential ofexceptionally high numbers of installed PTD’s – since no census of the number of installed PTD’s hasbeen 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 installedPTD’s.1.6.3 Digester sampling and Survey methodologyThe study was undertaken using a stratified sampling methodology, based on Geo-administrative unitsreferred to as counties. Whereas other sample methods could have been used to determine thesample size (Bartlett et. al. 2001), the Terms of Reference (ToR’s) had already a pre-determinedminimum sample size of 30 digesters which was increased to 34 based on statistical analysis (section1.6.2). 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 Household Number of % of digesters Sample size per Sample or sites County location Type digesters in population county 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 wasdone on the basis of whether they are in rural areas or Urban/peri-urban areas. Which allowed theresearch 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). Itmeant in principle that site visits would be made of Kajiado, Kaimbu, Machakos, Muranga and NairobiSurvey of Plastic Tube Digestors in Kenya Page 13 of 49
  • 15. City counties, while ignoring the rest, since the location types of the ignored sites are similar to theones visited. Table 3: Selection of final sites to visit based on household location type Household location Number of % of digesters Sample size per Sample or sites Type digesters in population county 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 thetools indicated in the appendices above, the sites were visited in accordance with the indicated workplan (Table 4).1.7 PTD study Revised Work planIn achieving the study, the following work plan (Table 4) was utilised. It will be noted that names of thelocalities to be visited are also correlated to the aforementioned counties (Table 2) Table 4: PTD performance study – Revised Work plan Tues,  Wed,  Thur,  Frid,  Sat,  Sun,  Mon,  Tue,   Localities to be  Mon,  23rd  24th  25th  26th  27th  28th  29th  30th  visited  1ST Dec    Nov  Nov  Nov  Nov  Nov  Nov  Nov  Nov  Kajiado,     Nairobi City                          Kiambu,     Site Visits  Machakos                          Kiambu,     Muranga                          Nairobi City,     Kiambu                          Data analysis                             Draft report  writing, data     base creation                          Receipt of        comments                          Submission of  final report     and cleaned  data base                         Survey of Plastic Tube Digestors in Kenya Page 14 of 49
  • 16. [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.Survey of Plastic Tube Digestors in Kenya Page 15 of 49
  • 17. 2. Results of the Field Survey2.1 Number of digesters installedAfter initial analysis and data base verification we can now state that based on the studies undertakenthat the data base has a total of 147 installed PTD’s countrywide. Of these based on the statisticalanalysis indicated in Table 7 that the following is the current situation of the installed digesters as perthe new data base. Table 5: Performance of Installed PTD in Sample and in total population Sample Total PTD performance Units % 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 anddownward direction. However, it does give an indication that quite a number of the Digesters areworking, though they may not be doing so satisfactory as indicated by the responses of the farmerswho felt that the digesters did not meet all their needs like lighting and during the morning and eveningperiods gas pressure was quite low that cooking took a bit longer than expected.2.2 Digester material and size2.2.1 Digester material and sizeBased on discussions with Pioneer Technologies, it was realized that the company has been sellingPlastic Tube Digestors since 2006 on commercial basis; however, further discussions with DedanNdungu indicated that the Plastic Tube digester work actually began sometime in 2002 with the 1stgeneration 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 /expandabletube like that of a bicycle inner tube. The 3RD generation was a modification of the 2nd Generationwhilst the 4th Generation consisted mainly of a double layer UV treated Polythene material with Glassreinforced Fibre (GRF) again. The digester has thickness gauge of about 300 micron, making it quitelong-lasting, with an estimated lifespan of about 5 - 15 years depending on the maintenances andfeeding capacity and frequency.Survey of Plastic Tube Digestors in Kenya Page 16 of 49
  • 18. The aforementioned changes from the 1ST generation to the current 4TH generation have hadsignificant impacts on the quality and performance of the PTD. These include longevity (life span), UVprotection of the digester, and the general aesthetics of the digester. A comparative analysis in termsof analytical performance was not undertaken.2.3 PTD Costs2.3.1 Costs from PioneerThus, the current PTD in the Kenyan market is essentially a 4th generation tube, of which, as perPioneer 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, gaspipes, Biogas Digester bag and installation costs. It does not include the cost of digging the Trenchwhere the digester will lie in.2.3.2 Costs of PTD from the field/studyThe 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 mainreasons are attributed to this discrepancy: first quite a number of the PTD’s in the sample were notinstalled by Pioneer as such, but by a one Dedan Ndungu before he joined Pioneer in 2006 and alsoby other Companies.Secondly, a trend analysis over the years (Fig 1) shows a slow increase in the general prices of bothPTD’s sizes, which maybe attributed to increased cost of raw materials. For Pioneer’s competitors itwas found out based on 2009 – 2010 figures, that for the Standard type it costs about US$ 488, whilethe 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 thefinal digester price.1 Exchange rate being 1 USD = KES 80Survey of Plastic Tube Digestors in Kenya Page 17 of 49
  • 19. Fig 1: Trend analysis of PTD’s prices and installations over the years. Large sized PTD Trends in PTDs prices and installations over the years Small sized PTD 600 500 Cost of installation in KES 400 300 200 100 0 05/11/2001 13/02/2002 24/05/2002 01/09/2002 10/12/2002 20/03/2003 28/06/2003 06/10/2003 14/01/2004 23/04/2004 01/08/2004 09/11/2004 17/02/2005 28/05/2005 05/09/2005 14/12/2005 24/03/2006 02/07/2006 10/10/2006 18/01/2007 28/04/2007 06/08/2007 14/11/2007 22/02/2008 01/06/2008 09/09/2008 18/12/2008 28/03/2009 06/07/2009 14/10/2009 22/01/2010 02/05/2010 10/08/2010 18/11/2010 Date of installation [Author]Analysis of Fig 1 shows that generally 65% of Digesters are of Standard size while 35% are the largesize type. It is postulated that the choice for more Standard sized Digesters is based on itscomparatively 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 thegeneral increase in input material costs, transport and labour charges. Nevertheless, as farmers cometo experience the advantages of bio-digesters and/or as the number of cows they keep increase, thetendency of farmers to move from standard sized PTD, to large sized ones and/or masonry basedfixed 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 wereno longer there. The Farmers had decommissioned them to the much bigger Fixed dome Biogasdigesters due to demand for more gas (especially for lighting) and also as a way of maintainingsanitation 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. Inthe event of local indigenous cows the number of the cows will range from 1 to 4 depending on thesize 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 digesterRenwick et. al. (2007) in a study of Biogas digesters in Africa provided the following costs forinstallation 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 theseincluded: 1. That the subsidy level being given for fixed dome digesters in Rwanda will be extended toSurvey of Plastic Tube Digestors in Kenya Page 18 of 49
  • 20. 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 significantlyFrom the comparative analysis it is clear that a locally produced PTD with subsidy will cost far lessthan similar sized fixed dome ones. It should be pointed out that the production costs for locallyproduced PTD in Rwanda has been assumed to be similar to that of Kenya. In reality if this is aGovernment of Rwanda project, and efforts are made to establish a local manufacturing plant, then thecost of the net cost of the PTD to the end user may be far cheaper than the half net cost of the 6 m³fixed dome i.e. below the US$ 236 mark.Survey of Plastic Tube Digestors in Kenya Page 19 of 49
  • 21. Table 6: Comparative assessment of costs and subsidies of PTD and Fixed dome digesters Annual Proposed in-kind Net cost of Average Total cost of Subsidy repair & Country / Region Digester Type subsidy contribution digester plant size plant (US$) (%) maintenance (US$) (US$) (US$) (US$)Uganda Fixed dome 8 m³ 770 200 26% 77 11.6 493.00Rwanda Fixed dome 6 m³ 859 300 35% 86 12.9 473.00Ethiopia Fixed dome 6 m³ 747 186 25% 75 11.2 486.00Sub-Saharan Africa Fixed dome 6 m³ 750 200 27% 75 11.3 475.00 Plastic TubeKenya Digester 6 m³ 563 0 0% 15 5 548.00Rwanda (estimated) - Plastic Tubelocally made with 6 m³ 563 196.62 35% 15 5 351.38 DigestersubsidyRwanda (Estimated) -locally made with no Plastic Tubesubsidy - Assuming 6 m³ 563 0 0% 15 5 548.00 Digestersame productioncosts as KenyaRwanda (Estimated) -imported from Kenyawith subsidy Plastic Tube(additional charges 6 m³ 731.9 255.61 35% 15 5 461.29 Digesterinclude a 30%transport & taxescharge) [Author, Renwick (2007)]
  • 22. 2.4 Farm layout and Digester inlet feeding design characteristicsThe general farm layout with respect to the design characteristics and placement of the PTD’s was onaverage similar. For most parts, 1 – 3 cows were kept in an enclosure with a cement floor (zerograzing unit) and their dung by way of either cemented drainage canals or manual collection usingbuckets, was brought to the digestor site. At the digestor site, two approaches were witnessed in termsof 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 performanceResults 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
  • 23. 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 gasSurvey of Plastic Tube Digestors in Kenya Page 1 of 49
  • 24. 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 digesterbag had a leak all the other had PTD system that was function quite well. This leads us to theconclusion that 82.4% of the Biogas digesters were operation quite well without any trouble.2.6 Biogas applicationsIn all cases (100%) Biogas was being used for cooking using a cooking stove (Fig 2), and in somecases 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 wasnot 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 itpossible to have many biogas cook stoves connected to one PTD, since it had a correspondingincrease in the amount of time spent cooking due to decreased gas pressure. Consequently, none ofthe sampled sites had biogas based lighting systems nor more than one Biogas cook stove. In twocases 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 benefitsthat system was giving especially in terms of savings in the use of charcoal and firewood, thereduction of indoor air pollution (hence less expenditure on health) and the simple convenience andCleanliness of the gas.Survey of Plastic Tube Digestors in Kenya Page 2 of 49
  • 25. A key application of the Biogas was the utilisation of the slurry. In all the sites visited where the biogaswas in good working condition, the slurry obtained was mainly used as an organic fertilizer and soilconditioner. In addition farmers quoted the benefits of the digester as a sanitizer, since it decomposesthe cow dung which when in huge quantities would lead to foul smelling air.2.7 PTD payback period2.7.1 Payback period based on Charcoal useIt is estimated that the biodigestors can pay for themselves between 15 to 43 months, depending onthe type of fuel the digester is replacing, its cost (or what one would pay for it, if bought) fuel use., andbased on the assumption that the Bio-digestors could be used instead of charcoal for 54% or more ofthe 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 monthThe calculation assumes that a household of about 5 people will use an equivalent of 15.1 Kg ofcharcoal 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 thecurrent prices of a sack of charcoal going for KES 900. The payback period translates to about 16.25months 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 monthsIt is however noted that the lower the price of charcoal the longer the payback. Realizing then, that theprice of charcoal is increasing due to a diminishing resource base (less trees being replanted andincreased desertification and denudation of forests), it is feasible that the prices will be on an upwardtrend, leading to increased attractiveness of PTD digesters.2.7.2 Payback period for PTD and Fixed Dome Digester based on other Biomass fuelsIn Rwanda and many other rural East African Countries, use of fuelwood and biomass residues likemaize cobs is quite common. An comparative analysis was thus done on the payback period of notonly the PTD but also the Fixed dome “Chinese Design” Biogas digester based on different BiomassSurvey of Plastic Tube Digestors in Kenya Page 3 of 49
  • 26. fuels (Table 8). The assumptions underlying Table 8 is based partly on Table 9 and also on studiesdone. For instance the Biogas (2008) provides a Rwandan cost for 6 m³ Fixed dome digester used inthe 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, 68,720.00 45,040.00 materials, accessories) Cost (US$) (installations, 859.00 (Source: Biogas, 563.00 (In Kenya) materials, accessories) 2008) When polythene is used Lifetime is less than 5 years, but when butyl Lifetime 20 years or more 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 24.79 16.25 (months) Payback period with Firewood 42.95 28.15 (bought) in Months Payback period with Biomass residue (maize cobs etc) in 65.45 42.90 months 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 Usage per Fuel use per Fuel use per Fuel type Unit costs (KES) month / unit month (KES) 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 paybackperiod as compared to the fixed dome of similar size. The only challenge as has been identified fromthe field is the temperature fluctuations hence subsequent gas production fluctuations. This isattributed to the exposure of the PTD digester bag to the elements, while the fixed is normally fullyenclosed within the ground affording it constant temperature for microbial activity.Survey of Plastic Tube Digestors in Kenya Page 4 of 49
  • 27. 2.8 Benefits of Digester systemsThe 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 servicesOf the sampled, 96.7% had experienced some form of contact with the PTD installer after itsinstallation. This took the form of Telephone support (38%) or site visits (62%). The frequency of theextension 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 amanual (user guide) or both training and manual that describes not only the workings of a Biogasdigestor, but that also explained how and when the digester should be fed. Most of the problems toarising with the Biogas digester were noted to emanate mainly from the low pressure and low gasproduction matrix.2.10 PTD SustainabilityThe sustainability of the PTD’s was noted to be significantly reduced due to poor end-usermanagement of the especially the gas tube. More specifically, infrequent feeding, over-feeding andunder-feeding were the causes of low pressure and/or low gas production. In a bid to deal with thehardened scum formed due digester feeding issues, 3% of the users had attempted to agitate the tubeby stepping on it. The end result being that the tube burst.Survey of Plastic Tube Digestors in Kenya Page 5 of 49
  • 28. It is thus realized that with proper maintenance, and end-user education including proper extensionservices these PTD’s can last up to 15 years, making them the most sustainable of all cooking fuelscurrently available.2.11 PTD and ownership findingsIt was noted that the 97% of the users who had bought the digesters with the own money, took bettercare of their digestors as compared to those (3%) who had obtained their digesters either throughsubsidy or through donations.This led to the question of Ownership and financing mechanism of the digesters. From the field surveyit was noted that a process whereby the farmer actually spends his/her own money to obtain thedigester generally tended to take better care of the system than the ones who had received it whollythrough some charitable organisations.In view of the Rwandan situation, a mix of farmer’s contribution and subsidy or a total loan programmeapproach may be recommended to allow for ownership development. Additionally, ownership issuesare a sub-set of the how well the farmer has been trained to use the digester including the attendantextension services. The well trained farmers who received regularly extension services (97%) of thestudy tended to take better care of their digesters.2.12 Second hand PTDAbout 5.9% of the surveyed had switched from plastic tubular digesters to Masonry ones. The mainreasons for these is the increased energy demands in terms need for Biogas lighting and increasedbiogas use due to increased cooking activities. In addition other reasons for the switch include the lowgas pressure during the early morning and late evening periods, leading to non-effective and ratherlong cooking times.In the case where the Farmers upgraded to Masonry digester, they normally gave out the PTD to oneof their relatives. However, it can be postulated that if they were to sell it after 3 years, a probablecosts would less than KES 24,772 (US$ 309.65) for the Large sized digester. This is based on astraight line depreciation of 15%.Survey of Plastic Tube Digestors in Kenya Page 6 of 49
  • 29. 3. Lessons Learnt and challenges experienced3.1 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 Kenya1. Dedan N Ndungu 2. Samuel N. Nene, Modeline Electrical and Mechanical Pioneer Technologies Limited Engineers P. O. Box 32910 – 00600, Nairobi, Kenya P. O. Box Tel: +254-(0)20 253442 Tel: +254-(0)723 389642 Mobile: +254-(0)722 552505 Email: modelinetechnologies@yahoo.com Email:- pioneerteknik@yahoo.co.uk3. E. K. Kahiga 4. Samwel Kinoti Biens Limited, Skylink innovators, P. O. Box 57859 Nairobi, P. O. Box 64459 - 00620 Nairobi, Tel: +254-(0)778030 / +254-(0)737521242 http://skylinkinnovators.blogspot.com Email: ekahiga@yahoo.com Email: skylinkinnovations@gmail.com [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 generationSurvey of Plastic Tube Digestors in Kenya Page 7 of 49
  • 30. 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 PTDs 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).Survey of Plastic Tube Digestors in Kenya Page 8 of 49
  • 31. 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.Survey of Plastic Tube Digestors in Kenya Page 9 of 49
  • 32. 4. Recommendations4.1 Framework for PTD installation and operation manualIt is recommended that 12 page, double sided A5 user guide or operational manual, in the eventPTD’s are to be installed elsewhere, be developed. The manual will among other things cover thefollowing 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 RwandaBased on the above, it seems quite recommendable to suggest PTD for the Rwandan programme, butcertain things will need to be in place, to make up for the shortfalls experienced in the KenyanProgramme. Such issues include:1. Proper end-user support programmes and training2. 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.Survey of Plastic Tube Digestors in Kenya Page 10 of 49
  • 33. 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 studiesIt 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 digester2. 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 etc3. Investigating cost-effective, easily adaptable and locally available approaches to repairing a • Torn / bursted plastic digester bag • Pierced Plastic digester bag4. 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 services4.4 Recommendations for Better Market delivery models1. 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 tubes2. Support of local skills upgrading in Biogas installation and repairSurvey of Plastic Tube Digestors in Kenya Page 11 of 49
  • 34. 3. Support industry in availing affordable PTD repair kits4. Government support in extension services for small scale farmers owning PTD’s5. Local industry support for biogas equipment and accessories. These would include gas valves and biogas stoves.4.5 End-user recommendations1. Development of a PTD end-user manual (section 4.1) and wide distribution to end-users in a language they can understand2. Regular user support visits from Government extension officers and installers3. Protection of the PTD against animals, children and other harm4. Farmer training on type of feeding material and feeding frequency for digester5. 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 makers1. 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 sustainability3. Scaling up of the whole programme region-wideSurvey of Plastic Tube Digestors in Kenya Page 12 of 49
  • 35. 5. Appendices5.1 Tools used in Field survey5.1.1 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 ResponsesCompany Contacts Branches Staffing levels Branches /outputs History (when it started, people involved, growth record)Delivery network Distributors Retailers Suppliers of the materials /Survey of Plastic Tube Digestors in Kenya Page 13 of 49
  • 36. Main issue Sub-issues Responses material availabilityScope of Installation areas (provinces,activities districts, locations) Installation costs (stratified per installation area) Number of installed PTD’s & area of installation (geo- referencing?) Any other activities they are involved inTechnology Who manufactures it How it works Operation parameters (PH, Temp, etc) Feedstock type Lifespan Average gas production / day Manufacturing costs and energyChallenges Production Transportation InstallationSurvey of Plastic Tube Digestors in Kenya Page 14 of 49
  • 37. Main issue Sub-issues Responses End-user operation & Education Extension (end-user) support Policy OthersExtension Who does extension?processes What kind of extension? (Education, O&M, marketing etc) Who pays for it?Database Location of installationcompilation Geo-reference Names of client Contacts (postal, mobile, e- mail) Installation date Cost of installation at that time Frequency of M&E,Survey of Plastic Tube Digestors in Kenya Page 15 of 49
  • 38. Main issue Sub-issues Responses Repair works + costs Performance of PTD (gas production, feedstock availability,PTD Size & cost Retention time & days before it Gas volumetype starts working, Temperature issues,Survey of Plastic Tube Digestors in Kenya Page 16 of 49
  • 39. 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 householdshaving 1-3 cows. For this reason, they are assessing the performance of different types of Biogasdigesters within the region.For this reason, they have obtained permission from Pioneer Technologies to undertake a quickassessment of the digesters installed by them in order to obtain an understanding of how the digestersare performing in real life. We thus kindly request a few minutes of your time in responding to thisquestionnaire and if possible allowing our interviewer to access your digester, gas storage bag, gaspiping and gas cooking stove. Questions Responses Physical/administrative location ……………………………………………………………………… 1. Location of the digester …………………………………………………………………….. (Geo-reference if possible) 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 ……………………………………………………………………… Digester condition & performance 10. Operating condition of the digester, Gas bag and cooking Gas bag condition & performance equipment Cooking equipment condition & performanceSurvey of Plastic Tube Digestors in Kenya Page 17 of 49
  • 40. 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 ……………………………………………………………………… 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 12. If out of order, what are the reasons Protection of digesters from animals and children Lack of interest from end-user – delegation of digester maintenance to farm helper etc, Others: - ……………………………………………………………………… ……………………………………………………………………… …………………………………………………………………….. 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 13. After sales services Others provided ……………………………………………………………………… …………………………………………………………………… 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 Saw it from neighbours / friends about the PTDs?Survey of Plastic Tube Digestors in Kenya Page 18 of 49
  • 41. 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 Yes No purchasing the unit? Yes No As organic fertilizer Feeding fish food supplement for pigs and chicken 16. Does he use the slurry? For what for what purpose? Benefits In mushroom cultivation compared to dung? Earthworm cultivation In hydroponics (growing plants in a nutrient rich solution) Others: ……………………………………………………………………… ……………………………………………………………………… …………………………………………………………………….Any other comments / Observations / photos / maps etc………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………Survey of Plastic Tube Digestors in Kenya Page 19 of 49
  • 42. 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 Land o lakes nakuru 13.02.07 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 NakuruSurvey of Plastic Tube Digestors in Kenya Page 20 of 49
  • 43. 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 wendani 21.06.07 Naomi Wangari goko 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 muranga 23.07.07 Isaac kogi 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 Endarasha school for Nyeri 15.09.07 orphans endarashaSurvey of Plastic Tube Digestors in Kenya Page 21 of 49
  • 44. 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 Githunguri 14.012.07 David mbugua nduati 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 Land o lakes - samuel 08.04.08 balazi Machakos 12.04.08 karanja jabini 13.04.08 Njoroge k jabini 13.04.08 P.MWAI GITHIGA 13.04.08 Baldo NdaragwaSurvey of Plastic Tube Digestors in Kenya Page 22 of 49
  • 45. 5.3 Reformatted and updated List of contacts INDEX- INSTALLATION CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon No. DATE 36° 43 60 1 20.12.06 Elizabeth Mwhihaki 0721339460 Kibichiku Kiambu 1° 13 60 S E 36° 40 60 2 13.11.06 Mrs Karanja 0721717154 Kiserian Kajiado 1° 25 60 S E 36° 43 60 3 10.12.07 Joseph mwangi 0722211874 Nazareth Kiambu 1° 7 60 S E 36° 43 0 4 19.09.07 Daniel mbugua 0722263523 wangige Nairobi City 1° 13 0 S E 5 23.10.06 Job Mwangi 0722288907 Mwiki Nairobi City 36° 42 0 6 23.11.06 Mr karanja 0722376389 Gikuni Kiambu 1° 11 60 S E 7 21.10.06 Mama Leah 0722513825 Ruai Nairobi City Mr Wanjohi 36° 43 60 8 18.12.06 Josephat 0722623606 Ngong Kajiado 1° 19 0 S E 37° 28 60 9 21.01.08 John kiarii 0722706820 Githunguri Kiambu 0° -23 60 N E 36° 38 60 10 20.08.07 Paul wachira 0722722697 Limuru Kiambu 1° 6 0 S E 11 17.12.07 kamwende 0722735026 embu Embu 0° -35 0 N 37° 40 0 E 36° 38 60 12 15.01.07 George Ngugi 0722856040 Limuru Kiambu 1° 6 0 S E 36° 45 0 13 01.12.07 Ngugi mwaura 0722868550 ndenderu Kiambu 1° 10 60 S 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 KiambuSurvey of Plastic Tube Digestors in Kenya Page 23 of 49
  • 46. INDEX- INSTALLATION CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon No. DATE 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 Wakulima Dairy 29 30.04.07 Mrs Thairu Mukurweini members Kiambu Wakulima Dairy 30 30.04.07 mr karanja metal Mukurweini members Kiambu Wakulima Dairy 31 30.04.07 wahu muira Mukurweini members Kiambu Wakulima Dairy 32 30.04.07 Penina njeri Kago Mukurweini members Kiambu Wakulima Dairy 33 30.04.07 kim chair Mukurweini members Kiambu Wakulima Dairy 34 30.04.07 Best dairies Mukurweini members Kiambu Wakulima Dairy 35 30.04.07 kwamunga Mukurweini members Kiambu Wakulima Dairy 36 30.04.07 Githioro Mukurweini members Kiambu Wakulima Dairy 37 30.04.07 Njenga kim Mukurweini members Kiambu Wakulima Dairy 38 30.04.07 Mutho w Mukurweini members Kiambu Wakulima Dairy 39 30.04.07 Hosea mwangi Mukurweini members Kiambu Wakulima Dairy 40 30.04.07 Tiiri Mukurweini members Kiambu 41 30.04.07 Peter maina Mukurweini Wakulima Dairy KiambuSurvey of Plastic Tube Digestors in Kenya Page 24 of 49
  • 47. INDEX- INSTALLATION CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon No. DATE members Wakulima Dairy 42 30.04.07 macharia gaitho Mukurweini 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 David mbugua Githunguri 51 14.012.07 nduati 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 George Tharao 58 05.04.07 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 James njenga 65 20.11.07 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 KiambuSurvey of Plastic Tube Digestors in Kenya Page 25 of 49
  • 48. INDEX- INSTALLATION CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon No. DATE 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 Naomi Wangari 76 21.06.07 goko wendani kahawa Nairobi City 77 10.11.065 Client Kisumu Nehemiah intl Kisumu 78 12.02.07 Oira O. Kisumu Nehemiah intl Kisumu 79 12.02.07 Client Kisumu Nehemiah intl Kisumu 80 12.02.07 George Kisumu Nehemiah intl Kisumu 81 12.02.07 J. Omtata Kisumu Nehemiah intl Kisumu 82 20.11.06 Client Kisumu Nehemiah intl 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 NakuruSurvey of Plastic Tube Digestors in Kenya Page 26 of 49
  • 49. INDEX- INSTALLATION CLIENT NAME CONTACT LOCATION ORGANISATION County Lat Lon No. DATE 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 Endarasha school for 109 15.09.07 Self Nyeri endarasha 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 Mayor-Kericho 115 20.11.06 Isaiah Rono (Self) Kericho Municipal council Uasin Gishu National Youth 116 01.12.07 Self OLO-KALAO Services-Tumaini Uasin GishuSurvey of Plastic Tube Digestors in Kenya Page 27 of 49
  • 50. 5.4 PTD Data baseSurvey of Plastic Tube Digestors in Kenya Page 28 of 49
  • 51. Survey of Plastic Tube Digestors in Kenya Page 29 of 49
  • 52. Survey of Plastic Tube Digestors in Kenya Page 30 of 49
  • 53. Survey of Plastic Tube Digestors in Kenya Page 31 of 49
  • 54. 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=3 19 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: 17.12.2010Survey of Plastic Tube Digestors in Kenya Page 32 of 49