Life-Cycle Analysis and Optimisation of Solar Home Systems
Contents
1. doubtless due to the small size of the systems which often cannot produce enough electricity to satisfy the demand of the household When the family tries to use more energy than the panel can supply it leaves the battery in a continuously low state of charge resulting in a damaged battery with a shorter life However according to ECN experience it is very unlikely that the size itself is the main reason for the lower performance A common practice in smaller systems is to leave out the battery charge regulator which saves on the first time investment costs but is detrimental for the quality of the system This discussion will remain unsettled before more monitoring data from data loggers become available Only by analysing the link between the user behaviour and performance of the system one can trace the real reasons for these high failure rates Swaziland ECN has conducted surveys in Swaziland as described in a report by Petra Lasschuit Survey results showed that 86 of the respondents were happy with their systems and 96 would recommend a PV system to others A much lower percentage than in Kenya 25 had problems with their systems However the lifetime of the batteries is shorter than the expected three years Of the people who had to replace their battery once or more 73 had to do so within 2 years and 42 even within one year Also in this case monitoring with data loggers will provide more insights into the determinants of2. electrification and to analyse the options to increase the rural connection rate in the most cost effective manner 18 ECN C 00 047 However the decentralised character of the population of rural areas and their small per capita commercial energy consumption has made these areas less attractive for grid extension The extension of the grid to rural areas is in many cases less cost effective as compared to urban areas Therefore the present emphasis in the energy policy with regard to supplying electricity to small and scattered loads is on decentralised generation of electricity The main options are minihydro photovoltaics wind biomass diesel Facing the social pressure to address the energy needs of the rural population governments in developing countries are increasingly considering off grid PV systems as an attractive means to address some of the energy problems in rural areas and to improve the quality of life A good example in this regard is Kenya with the highest penetration rate of household photovoltaic systems in the world To date more than 80 000 systems have been installed and current annual sales amount to approximately 20 000 systems Some 50 local and 15 international companies import assemble install and provide after sales in this market Although the example of Kenya clearly shows the potential role SHS systems can play in regional energy polices there is still a tremendous need for strengthening the local PV indust
3. 1 INTRODUCTION 1 1 Background Solar home systems for rural electrification in developing countries and grid connected PV systems in industrialised countries are the backbones of the global PV market and the corresponding renewable energy policy Grid connected solar PV systems are primarily sources of electricity while solar home systems can supply services for the two billion people which are not connected to an electricity grid Apart from appropriate financing mechanisms the price quality ratio is still a major barrier for large scale introduction Only with a substantial decrease in costs and improvement of quality one can expect that solar home systems will have a rapid breakthrough When solar home systems have to contribute to sustainable development it is essential to spend sufficient attention to socio economic and environmental aspects Because relevant and representative data about the use of solar home systems in households are very rare the pace with which solar home system components are being improved is slower than desirable There is a serious lack of knowledge world wide about the following topics e Reliability of solar home systems under field conditions Lifetime of PV system components in relation to their use Environmental effects of solar home systems over the complete product cycle Effects on the socio economic development of the areas where PV systems are introduced Preferences and wishes of potential end user
4. interfaces were working in parallel they are expected to display the same patterns This was not the case The main problems that were encountered are the following 1 A large discrepancy between voltage displayed and the actual voltage occurred with one sample 2 Large differences between displayed voltages of one or more days ago and actual voltages occurred twice 3 In one sample the display of the previous days did not shift every day 4 With symbols thumbs up and down the users are informed about the status of the system However three samples showed at the same time the two different symbols that users behaved well and not well AME the producer of the interface offered to add a software filter to reduce the first two problems and software modification for the fourth problem 50 interfaces were returned to AME and reprogrammed 14 ECN C 00 047 Second prototype ECN tested the interfaces with the adjusted software They were connected to a solar home system in two groups of 16 each In a period of three days the battery was discharged from 14 5 Volt to 11 Volt This resulted in the following findings e When the input voltage is within the range of 11 5 to 11 7 Volt the interfaces all displayed level 12 instead of level 2 Depending on the length of the measurement interval these values also show up in the history e Twice the voltage accidentally dropped to below 4 Volt No problems occurred due to the low input volt
5. the short battery lifetime ECN C 00 047 7 Indonesia Monitoring with surveys only provides a good overview of the technical and non technical problems occurring with the use of solar home systems However to be able to analyse these problems and identify solutions one needs to obtain more detailed information Part of this can be obtained by adding more specific questions to survey questionnaires But there is a limit to the extent to which one can gather information via surveys Ideally it should be complemented with on site measurements as was also concluded by Angele Reinders in an article regarding the experiences in Sukatani The combination of an analysis of monitoring data a field survey and interviews of SHS users show some contradictions For instance on the basis of monitoring data we could not conclude whether users had to adapt their electricity consumption in the rainy season In interviews however they told us that they did have to do this By comparing the number of installed lights with the lights actually used according to the villagers we noticed that their answers were influenced by the information given in the instruction sheet Due to deviations between real and narrated experiences we conclude that a field survey that comprises only interviews may not be sufficient to assess an SHS project 2 1 2 Complement survey information with in situ measurements Brazil Solar home systems have been installed in B
6. useof data lO CTS werner kee benee eee eenderde baan 9 2 2 FORMULATION OF SPECIFICATIONS FOR THE DATA LOGGER csceccececceccscececcscescscesescesescucesccecs 10 2 3 BUILDING AND TESTING OF THE FIRST PROTOTYPE sccsceccsceccececcsceccccecscscscscescscesescesescecescececs 11 24 SECOND PROTOTYPE OF THE DATA LOGGER ston nmr ee adenosis een eed 12 A CONCDESION Brevet tate ee tar PEP at ne UIE RN TN PR E OY A 13 3 ADVANCED USER INTERFACE siers onverdeeeonsneosenersensonsoodneenechennonvantendberseeneuussereanaohdanrnecden 14 4 PREPARATION FOR THE HOUSEHOLD SURVEY cccccccccccccccccccccccccccccceecs 16 5 SOCIO ECONOMIC AND INSTITUTIONAL ASPECTS OF INTRODUCTION OF SOLAR HOME SYSTEMS irslsentersrereerteelseorsberenvandeneersbeodoeeondendennudendeentoedaedseusseentuendedenerneeatindeeeeheedbeustecden 18 5 1 THE ROLE OF SHS IN NATIONAL AND REGIONAL ENERGY PLANNING ceccccececcecscecccececeeccceces 18 5 2 THE SOCIO ECONOMIC IMPACT OF THE INTRODUCTION OF SHS naan oenen een eenseneneenenn 19 5 35 FINANCING SOLAR HOME SYSTEMS rr soorittmboranetsaotonsneat sabbelen teens enn bmeberan es A AER 20 SA INSTITU TRIONALAARRANGEMEN a erna tenemen nn 22 6 PROPOSED ACTIVITIES FOR 2000 cecccccccccccccccccccccccccccccccccccccccccccccccscccscccccsccces 25 ANNEX 1 DRAFT SHS PERFORMANCE QUESTIONNAIRE 26 ANNEX 2 DATA LOGGER HARDW ARE 31 ANNEX 3 REFERENCES 34 ECN C 00 047 3
7. was seconded at ECN for a period of three months Mr Dlamini s research is reported in a separate document ECN I 99 005 In this chapter a number of main issues resulting from that study will be presented First the role of SHS in national and regional energy planning is outlined Next the socio economic impact of rural electrification in general and SHS in particular is explained and finally the financial and institutional aspects of the introduction of SHS is elaborated upon 5 1 The role of SHS in national and regional energy planning In developing countries urban households consume the largest part of residential electricity Although since 1970 approximately 800 million people in rural areas gained access to electricity the problem still remains that of the approximately 3 2 billion people living in rural areas of developing countries in 1990 1 8 billion are still without access to electricity This means that the development options of the vast majority of rural households are seriously hampered and production and service establishments in these areas are disadvantaged As a result the already existing social gap between urban and rural communities will further increase and will stimulate the migration to urban areas This situation is regarded by the national government as highly unsatisfactory and usually the energy policy formulated in developing countries is addressing this problem by initiating various activities to promote rural
8. 120 Wh per day in summer e There was not much difference in energy consumption between larger and smaller families e There was no energy cut off caused by a deep discharged battery FhG ISE usually applies data loggers that measure three currents and three voltages A reason given for having separate load and module voltage measurements 1s that it provides information about the low voltage and high voltage disconnect For example if the measured load current is zero but at the same time the load voltage is unequal to zero it shows that the user switched off the load and not the low voltage disconnect NREL Different groups at the National Renewable Energy Laboratory NREL have experience with data loggers for remote power systems Some of these can also be relevant for monitoring of solar home systems Despite years of efforts they are still looking for an ideal logger for remote power systems that is reliable and does not consume too much energy They usually apply Campbell Scientific data loggers that are of high quality However the own energy consumption of the Campbells is high which makes independent operation difficult Alternatives such as the weather loggers of NRG have lower own consumption but have fewer channels for the same costs A few years ago a proposal was formulated to develop a data logger especially for monitoring of small PV systems However no funding was obtained One of the problems that occurred in the field
9. 21 June 2000 ECN C 00 047 Life Cycle Analysis and Optimisation of Solar Home Systems Interim report over 1999 of ENGINE project 74513 J D Dogger J C Jansen M C C Lafleur P E Lasschuit N H van der Linden F D J Nieuwenhout M R Vervaart Abstract This report describes the activities and outcomes of the first six months of the three year ENGINE project Life Cycle Analysis and Optimisation of Solar Home Systems project number 74513 The whole project is divided into four main activities that cover different perspectives of the use of solar PV equipment by households monitoring of solar home systems conducting a household survey socio economic and institutional analysis and lifetime tests of PV equipment In this phase of the project we focussed on hardware development for a data acquisition system on preparation of a survey questionnaire and on general socio economic and institutional aspects of solar home system programmes An analysis was made of experiences with data loggers for solar home systems Furthermore a prototype was developed of a small data logger After testing the prototype it was concluded to postpone further development activities and rely for the near future on equipment that is readily available on the market Several versions of an advanced user interface were tested Improvements were discussed with the manufacturer AME Until now the modifications have not yet resulted in a version that can be teste
10. 4 Did you buy 1 a complete solar system at once 2 first bought a battery and at a later stage added a solar panel and other components 3 don t know 5 How was the system paid for L cash 2 credit from the solar supplier 3 loan from the bank indicate name of bank 4 loan from friends relatives 26 ECN C 00 047 5 other ANGICALe zranissennet wee ya kouenk Mave teduewianenueiedessenbeseeens 6 Who installed the solar system for you P installed by the supplier 2 installed by a technician other than the supplier 3 did the installation yourself 7 What are the solar panels mounted on roof grass thatched roof corrugated iron roof roof tiles pole next to the house outside wall of the house Use of a solar system 8 What do you use the solar system for 1 Lighting 2 Radio 3 B amp W TV 4 Colour TV 5 6 7 Be a a VCR Hifi Do you use a battery regulator L do not have a battery regulator go to question 11 2 use the regulator all the time 3 bypass the regulator every now and then 4 by passes the regulator all the time 5 don t know 10 Do you regularly look at the indicator lights of your regulator L don t have indicator lights De never look at the lights 3 frequently look at the lights 4 don t know 11 Are you happy with the performance of the solar system L 12 Are you planning to expand your system soon ECN C 00 047 27 13 Wha
11. age The interfaces were returned to AME for the second time According to the manufacturer a software error was traced and repaired Third prototype Testing of the latest version showed the following e When the voltage drops below a certain threshold all levels in history become equal to 1 After this happens the history can not be updated anymore not even by using the reset button Consequently when the voltage drops below a certain level which could not be determined precisely the interface becomes permanently destroyed In practice the interface will usually be connected directly to the battery There is a real chance that low input voltages would occur e The old problem with the voltage range of 11 5 to 11 7 volt still occurs Conclusions The problems that occur are too severe to have this third prototype of the user interface tested in the field Therefore we decided to test user reactions on the first prototype before further changes to the design will be made ECN C 00 047 15 4 PREPARATION FOR THE HOUSEHOLD SURVEY The technical monitoring process will be complemented with interviews among the end users The aim of the interviews is to get answers on questions that can not be derived from the technical monitoring process The information thus collected will include the following issues the quality of installations the maintenance of the systems use of appliances lifetime of components disposa
12. agencies e United Nations related bodies e g UNDP GEF Level 1 e Multinational banks e g World Bank regional development banks FIRST INTERM ED ARY Dn eve e National government SECOND INTERMED JARY e National development banks Level 3 e Commercial banks e Electricity utility THIRD INTERMED ARY e Rural cooperatives Level 4 e NGOs e Private companies e Other community based organisations END USER e Households e Small businesses Level 5 Figure 1 Typical finance delivery chain The next levels involve intermediaries whose goal is to see that the Level 1 funds end up with the consumer in Level 5 It s worth noting that the longer this intermediary chain the more the administrative overheads compile Often these intermediaries are necessary or at least perceived to be for successful PV market development They fulfil necessary services in the total market structure by creating economies of scale and hedging risk through the bundling of projects National governments often intercept the funds as is the case for GEF projects although this is not always necessary for example the Solar Development Corporation may skip level two directly into level 3 Actually there is also a possibility of a loop directly from Level one to four as is with the Solar Investment Fund Last in the chain is the consumer himself Although the literature contains diverse views on the exact details of how funds have to filter down to the co
13. al shunt Average battery current yes yes internal shunt external shunt Memory data retrievel methode Memory module Memory module RS 232 PCMCIA RS 232 Memory capacity registrations 86000 172000 256000 40000 Power supply via solar home system W 0 2 0 2 no no Battery life included battery no no 2 years 5 years Dimensions hxixd mm 40x100x60 40x100x60 40x150x80 25x104x56 As shown in the table there are functional differences between commercially available data loggers and our data loggers When we do not make the requirements regarding dimensions and memory too strict commercially available data loggers are suitable for our purposes In first instance option 2 Develop the current prototype to a production ready model and option 3 Develop an upgraded version of the current prototype are investigated to estimate the costs per unit Additional the costs from COTS commercial of the shelve components is under investigation option 1 The amount of money paid for the COTS components is set to HFL 1440 based on the quotations of CaTeC for 20 pieces of the Grant 401 It 1s very likely the price per COTS unit can be further reduced The cost breakdown for the current version and the upgraded version are listed in the table on the following page The figure cumulated costs for data loggers shows the different options in one picture based on rough cost estimates From the figure it s clear that a student is as exp
14. and not just remain a mere will On the other hand over enthusiasm on SHS can lead into ill planned projects yielding disastrous results The best role of public authorities seems to be one of market catalyst without excessive interventionism Public authorities can also play an important role in removing or reforming fiscal and policy regimes which are in disfavour of alternatives like SHS In the Senegal case authorities waived duties on solar energy equipment making systems more affordable and promoting the solar business Utilities The attitude of utilities towards alternative energy SHS for example is changing for the better Although not funding the project the utility is often responsible for quality assurance and standards issues which is a real achievement The South African Utility ESKOM has been involved with active research and implementation of alternative energies including solar since 22 ECN C 00 047 1991 It has also recently launched an ambitious electrification project in conjunction with the Renewables division of Shell which seeks to disseminate 50 000 system on a leasing basis The engineering background of utility engineers and technicians and the infrastructure utilities already possess could be extremely useful if available also for SHS programmes In fact utilities with a commitment to rural electrification should find SHS an attractive cost effective option in many instances The examples of utilitie
15. countered and solved e The sample time was not accurate enough Load and insolation pattern shifted in the order of one hour per week This was corrected by using a slightly different crystal oscillation frequency e A separation byte between the seven data bytes was accidentally overwritten due to a change from eight to seven data bytes 12 ECN C 00 047 Measurements of the Ah of the battery were wrong This was caused by a mistake in a counter The load current measurements were wrong This was solved Since early December 1999 the second prototype is being tested in the solar home system in Alkmaar However there are still a number of unsolved problems which require further research 2 9 There were problems with EMC The data logger module appears to be sensitive to all kinds of spikes Additional capacitors have been placed in the data logger but it is unlikely that all the EMC problems have been solved Measurements in the first hour show values that may be too low Causes are still unknown Voltage measurements are 0 1 to 0 2 Volt lower than the actual values Current measurements for battery and load current are not linear With a simple software correction some improvement have been achieved but measurements below 1A are still not accurate enough The data from the measurements in the solar home system have not yet been analysed It is therefore unclear what the influences of positive and negative switching are on this data
16. d in the field As preparation for the household survey which will take place parallel to the monitoring a first draft questionnaire has been formulated This needs to be expanded to include questions regarding lifecycle socio economic and institutional aspects Zimbabwe has been selected to conduct the household survey and the monitoring The socio economic impacts discussed in this study deal with improvement of the quality of life the stimulation of commercial activity and associated employment and getting acquainted with electricity In the first phase of this project the preparations have been made for the experimental work in the next phase We are ready to start survey and monitoring work soon 2 ECN C 00 047 CONTENTS l CIENERODUCTEION conan eetorne neen nadens 4 PE BACKGROUND oenen etende kat nit aber etheen tea Aat AEAN 4 2 OBIECTWESANDISCORPE OE WORK voer saremntbeentarmenntbein Hate saaotoxsau ances ausede EAR 4 13 PROIECTPROGRESSIN TOO ensen nee nnen tenten beten ennen Maere EA 5 2 DATA ACQUISITION IN A SOLAR HOME SYSTEM cccccsssssscccsssccccssscccsscsscccsssccccssscoees 7 2 1 EXPERIENCES OF OTHERS WITH MONITORING OF SOLAR HOME SYSTEMS aaan eneen eneenenennen 7 2 1 1 Monitoring of solar home systems with the help of SUrveys uuuunnnnseenn enen eer nennen 7 2 1 2 Complement survey information with in situ measurements unne verennenennnnnee eene nennnnnn 8 23 Experiences withthe
17. e following conclusions 1 For more accurate analyses and better insight into battery performance measurements are recommended by JRC or IEC of a power instead of current b power into the battery and from the battery and c non availability of power to the load 2 For determining the state of charge of the battery the recording interval needs to be decreased to less than one minute 3 Irradiance sensors and modules need to be cleaned once every two days 4 Use of a portable reference cell gave problems with correct orientation of the sensor and having simultaneous array current and voltage measurements Measurements of irradiance taken during site visits were therefore not used in the analysis 2 2 Formulation of specifications for the data logger In an early stage of the project a number of research questions were formulated regarding the use of solar home systems by households in developing countries which could possibly be handled by obtaining monitoring data Is there partial shadowing of the modules during the day What part of the electricity is used during the day and what part during the night What is the power consumption of the equipment used the load What is the state of charge of the battery at the beginning and at the end of the evening At what time of the day does low voltage disconnect occur What is the actual capacity of the battery What are the losses in the battery What are the different com
18. ected by far the cheapest however considering the factor time a student is not the best option The quickest way to obtain a ready to use data logger is to use COTS components instead A big advantage is the risk due to the make the prototype production ready does not exists for COTS components ECN C 00 047 31 For small numbers of sites to monitor COTS components will be the quickest and cheapest For larger quantities it is cheaper when our prototype monitor module is made production ready The break even point between COTS and home made units is considering HFL1440 for COTS approximately 70 units but negotiations are expected to bring the price down to HFL1000 to HFL1200 Figure Cost comparison of different options for producing or buying data loggers for cost assumptions see table on the next page Cumulated costs for data loggers 140000 120000 100000 2 Ke z 80000 Current version Upgraded version Be ee COTS 8 60000 Upgraded by student S o a 40000 20000 0 T T 10 20 30 40 50 60 70 80 90 100 Units Conclusion At this time the best way to obtain the required data loggers for monitoring of Solar Home Systems is to buy COTS components With COTS components the risks are minimised for both financial risk and delivery time risk If monitoring on larger scale is required e g more then 150 data loggers continuing development of the upgraded
19. ed from 1 1 2000 to 31 5 2001 For 2000 the following activities are planned 1 The draft survey questionnaire will be expanded with questions relevant to life cycle analysis and socio economic aspects 2 An updated version of the questionnaire will be tested in Swaziland and Indonesia in a few tens of households 3 Parallel to the pre survey data loggers will be installed in rural households in Swaziland and Indonesia 4 A household survey will be conducted in Swaziland in about 300 households 5 Analysis of socio economic impacts and institutional arrangements for SHS dissemination in South Africa Indonesia and possibly in Zimbabwe ECN C 00 047 25 ANNEX 1 DRAFT SHS PERFORMANCE QUESTIONNAIRE An lsOEA ON neen AoA A F Questionnaire no B Enumerator no G Date of interview C Name Household sela ca scevase a aE O E A D Interviewee 1 head 3 son D OMEk rnei 2 wife of head 4 daughter __ uussserresrseesseessssesssss E Number of occupied structures huts on the homestead exclude storage empty huts nos SUCES ona nvenanntiade Specifications Solar system 1 When was your solar system installed VEAL taan month 2 From whom did you buy the solar system N meSupplief minne edet CV OWD attent 3 What does your solar system consist of component no type brand name capacity 2 Battery Ah 3 Battery regulator nn 4 Battery box nn 5 Inverter DC DC
20. framework e Knowledge about how solar home systems are used over longer periods of time years e Information about preferences of users of solar home systems 4 ECN C 00 047 e A methodology for duration tests of solar home system components e Conclusions about the lifetime of a number of solar home system components e Insight into the effect of climate circumstances on performance of a solar home system The project is divided into four major activities 1 Monitoring In a representative group of households data loggers will be integrated into their solar home systems In some households in Indonesia a new user interface will be tested This user interface has been developed by ECN and the Indonesian company PT Cilengka A number of other households act as control group Outcomes will be used to formulate recommendations for modifying charge regulators and the user interface and for sizing of the different components 2 Survey Information from the monitoring activity will be linked to results from a household survey A number of households will be visited a few times over a number of years With the help of a survey questionnaire the following issues will be assessed among others failure rates of the different components maintenance and waste disposal 3 Socio economic and institutional analysis An analysis will be made of the social and economic circumstances of the users in relation to the solar home system and conclusions t
21. ghlights the importance of establishing a critical mass of demand in the service territory to improve economic viability this requirement is also echoed by Kalumlana et al and Aguilera et al Co operatives and Associations Experience in many countries shows that using existing co operatives and associations with a good reputation is more effective than trying to establish new structures These groups have more on the ground experience are in better contact with the people and so know the socio economic situation of their areas quite well However care should be taken to assess the capabilities of their officers and provide training where necessary In a successful project in Honduras Enersol worked with an existing coffee co operative COMARCA after the former had conducted training This approach can lead to prejudice though towards communities with strong organisation leaving out potential customers or deserving recipients in other communities In cases where using existing associations is not possible new organisations can be set up In the Pacific Islands the Tuvalu Solar Electric Co operative Society was established after failed attempts to involve the utility Similarly NGOs may be very effective in programmes since they are normally familiar with the communities they serve on more than just a monetary basis NGOs have the further advantage of having established extension networks which could be used for train
22. hat can be drawn regarding productive applications Furthermore we will assess how solar home systems fit into regional and national energy and environmental planning 4 Duration tests Lifetime tests will be conducted for a number of components charge regulators batteries and lights Based on the monitoring outcomes a selection of components for the duration test will be made 1 3 Project progress in 1999 Start In July we received formal permission to start work on the first phase of this project However some preparatory activities were conducted already earlier in 1999 We were explicitly asked to take the following three remarks into account 1 Beware for an overly high tech approach especially focussing on demands of the user and owner 2 What is new with respect to monitoring in Swaziland 3 This project focuses only on Indonesia and that makes the project vulnerable Spread the risks See if it can be applied in other countries for example Swaziland or Botswana The first remark will be taken care of through the survey questionnaire As can be seen in Annex 1 a number of questions explicitly enquire about user experiences especially questions 8 13 Also indirectly via the monitoring results we intend to learn more about household demands ECN was involved in evaluation of solar homes systems in Swaziland with a survey as the major instrument to obtain the required information In this Engine project additional t
23. ing and evaluation of solar home systems It aims to assess world wide experiences with solar home systems solar lanterns and battery charging stations Final results of the Novem study which is due May 2000 will provide more detailed insights into the actual requirements for field monitoring However in the framework of this ENGINE study some preliminary findings are outlined in this section 2 1 By conducting literature research that was supplemented with contacts with a number of institutes involved in monitoring the following picture emerges of existing world wide monitoring experiences Three modes of data gathering can be distinguished surveys with only questionnaires surveys supplemented with one time measurements and the use of data loggers which regularly measure a number of relevant system parameters 2 1 1 Monitoring of solar home systems with the help of surveys Kenya Most of the publicly available information on the performance of solar home systems comes from surveys One of the most useful publications is by Acker and Kammen describing a survey conducted in Kenya in about 40 households One of their findings was that 40 of the smaller solar home systems lt 25Wp is only partly operational and 13 is inoperational Large systems fare somewhat better 25 are partial operational and only 8 are inoperational Amorphous silicon modules mainly power small systems According to the authors the higher failure rate is
24. ing and information services Stone et al reports another institutional possibility religious missions The US Renewable Energy Laboratory NREL co financed a project with the Indian government in West Bengal The Ramakrishna Mission reliably managed the project that is now completed So reports Stone about the Mission as a project partner The Ramakrishna Mission has been perfect in this respect ECN C 00 047 23 Conclusion Experiences differ from country to country but some conclusions can be drawn for the conditions for successful project design The best role of public authorities seems to be one of market catalyst without excessive interventionism Experience in many countries shows that using existing co operatives and associations with a good reputation is more effective than trying to establish new structures 24 ECN C 00 047 6 PROPOSED ACTIVITIES FOR 2000 In general we propose to continue with the activities as described in the proposal formulated medio 1999 and accepted on July Sth 1999 In this proposal four activities were stated 1 monitoring with data loggers 2 Field survey with questionnaire 3 Socio economic and institutional analysis and 4 Laboratory tests in relation to lifetime aspects of solar home system equipment The fourth activity will be postponed to 2001 to benefit from the Novem project Ontwikkelen en uitvoeren van levensduurtesten van Solar Home Systemen which will be conduct
25. is no suitable data logger available in the market place that is small cheap and reliable has a large memory and a low own consumption Therefore we decided to develop a customised data logger for monitoring solar home systems The first design ideas for the data logger were based on a charge controller with an Ampere hour balance for the battery which was developed earlier by Mark Vervaart For the Ampere hour balance data acquisition and storage is required We expected that this could be expanded to a data logger measuring the specifications under a to e above Data are stored in an EEPROM which can be taken from the data logger and can be read via a special computer interface module In a relatively short time the prototype of the data logger and the computer interface were built Tests were conducted on this prototype in a small solar home system located in Alkmaar This solar home system is meant for test purposes and consists of a 19 Wp multi crystalline PV module an old 76 Ah battery two fluorescent lights Suntec of 7 Watt and PT LEN of 5 Watt and a timer for switching the lights on and off Some minor problems were detected in the tests The data of the first few hours were stored in one single location and only after an unknown number of hours the actual data logging started This problem was solved Results for a three day period in June 1999 are presented in figure 1 which shows hourly averages of system voltage the current fr
26. l Print ontwerp Produktie kosten per print 50 gulden Volgens offerte eerste prototype Componenten 35 gulden Schatting Mark F35 00 per print Behuizing 20 gulden TOTAAL KOSTEN ONDERDELEN PER PRINT 105 gulden Totaal kosten vervolg huidig ontwerp Ontwerp produktie integratie pcb onderdelen calibratie Totaal Machinale produktie Vaste kosten 23760 7500 5000 36260 Variabele kosten per print 25 300 105 180 430 Handmatige produktie Vaste kosten 23760 1500 5000 30260 Variabele kosten per print 720 300 105 180 1125 Totaal kosten vervolg upgraded ontwerp Ontwerp produktie integratie pcb onderdelen calibratie Machinale produktie Vaste kosten 59760 ECN C 00 047 7500 72260 33 ANNEX 3 REFERENCES R H Acker and D M Kammen The quiet energy revolution Analysing the dissemination of photovoltaic power systems in Kenya Energy Policy vol 24 NO 1 PP 81 111 Op Cit Page 99 gt P E Lasschuit Review of the PV market in Swaziland Evaluation of Government PV Demonstration Project Report ECN CX 98 018 January 1999 A Reinders et al Sukatani revisited on the performance of nine year old solar home systems and street lighting systems in Indonesia Renewable and Sustainable Energy Reviews 3 1999 1 47 5 C M Ribiero et al Performance evaluation of about 800 PV systems in the Northeast of Brazil after one year of operation paper presented at the 13th European Photovoltaic Solar Energy Conference Nice F
27. l of redundant system components impact of PV system on social and economic development user satisfaction The survey will consist of one comprehensive interview and biannual follow up visit Trained enumerators will accompany the technicians installing the data loggers and conduct the initial interviews using a standard questionnaire see draft questionnaire annex 1 After the first comprehensive interview a shorter questionnaire will be prepared to update the collected data especially on the technical issues Follow up interviews will be combined with the data readings data loggers and carried out by the technicians for 2 times a year viz once in summer once in winter The country selection has long been debated Initially one country viz Indonesia was selected as a study case for this project From a representative point of view the selection of a second country on another continent has been envisaged With most of ECN s PV implementation activities being carried out in Africa the choice for this continent seems obvious Below the pro s and con s of three potential countries are presented Swaziland ECN IDE carried out several energy surveys in Swaziland and through its long presence in the country has established a substantial network making the organisation of the survey rather easy In addition ECN IDE together with its local partner Swazitronix has installed about 500 solar homes system and has access to another 500
28. logger Conclusion The problems with designing a data logger module do not seem insurmountable However they probably require substantial changes in the current design Given the uncertainty in time requirements for these modifications it was decided to postpone the development of an ECN data logger and rely instead on data acquisition equipment that is readily available on the market When there is more experience at ECN with the use of data loggers in solar home systems we are better suited to formulate the right specifications ECN C 00 047 13 3 ADVANCED USER INTERFACE First prototype Users of solar home systems have limited information available about the state of charge of the battery Sometimes only two or three LEDs show if the battery is empty or full For users it can be helpful to be informed beforehand that they are depleting their battery too fast To assist users in determining if their demand is line with supply an advanced user interface has been designed The user interface shows in the form of histograms the highest and lowest voltage reached by the battery in the past week With the help of the trends shown by the display the user can adjust its electricity consumption A first prototype for a user interface for solar home systems was developed in an earlier project ENGINE project Autonomous Systems 74433 This is one of the solar home system components that will be included in the process of design and modification by
29. nalysis of the SHS market That analysis will be further explored in this chapter Its objective is to analyse social and economic circumstances of the users in relation to the solar home system and to draw conclusions regarding productive applications Furthermore it will be assessed how solar home systems fit into regional and national energy and environmental planning Unfortunately the implementation of this analysis was delayed by a number of factors that affected also the overall implementation of the project First the late date of approval of the project diminished the availability of persons to implement the project Secondly the approval resulted in a reduced budget available for the whole project which led to redefining of priorities and subsequently a re division of activities to be implemented for the socio economic and institutional analysis Thirdly and foremost the selected target area suffered from severe political and violence problems during the course of the year Therefore no field work could be undertaken to actually conduct the survey and identify and evaluate the main socio economic and institutional aspects relevant for the introduction of solar home systems Therefore the analysis presented in this chapter is of a more general nature and provides a framework for the actual analysis which is envisaged in the second phase of this project The analysis presented in this chapter draws heavily on work done by S Dlamini who
30. nsumer there are also remarkable similarities These exact details of flow of funds will be called financial mechanisms in this paper Example of the interactions between the levels is given in the section dealing with institutional arrangements Several financial schemes have been developed and applied to overcome the barrier of high initial investment namely e Revolving Loan Fund RLF the concept of RLF is simple Initially a fund is made available to finance the SHS programme The costs of the SHS are paid back in monthly ECN C 00 047 21 instalments that flow back in to the fund This money can be used again to finance new SHS programmes e Credit Financing in this financing scheme the consumer deposits a down payment and then pays the balance in regular payments e Leasing schemes this scheme draws similarities to the system of how grid electricity consumers pay for electricity The SHS is leased to the consumer for a monthly fee the utility or Energy Service Company will provide O amp M services and hand over the system after a number of years 5 4 Institutional Arrangements Institutional arrangements are usually meant to facilitate the processes of the financial mechanism s the product delivery mechanism s training and the after sales services For this reason it is difficult to disentangle finance issues and those that are institutional The following key players can be identified in this respect e the public a
31. o the surveys is the data gathering via data loggers which provide detailed information about the actual use of the PV system This information is limited in scope and quantity but can be much more reliable than behaviour distilled from survey questions By the parallel use of the tools of data loggers and surveys we intend to obtain a more complete picture of household demands than we have at the moment ECN C 00 047 5 The third remark is very well taken For the activities in 2000 we propose to apply the research both in Indonesia and in Zimbabwe The background for the selection of Zimbabwe is discussed in chapter 4 Monitoring module Due to the circumstances where the monitoring takes place an ideal solar home system data logger is small reliable has a large data storage capacity a low electricity consumption and has a low cost There is no data logger available in the market that is really suitable and meets all these requirements simultaneously Therefore a large effort was made to develop our own data logger for this specific purpose of monitoring solar home systems At the moment we have a version which is currently being tested but which still has a number of flaws For the second phase of this project in 2000 we propose to postpone development of our own data logger and use off the shelve products We propose to continue development of a data logger only after the use of existing data loggers have demonstrated that they are less
32. om the module and the current to the load The first day was acompletely clear day The low module currents before noon are due to shading Direct sunlight only reaches the module after about 13 00 hours MEST Especially during the second day the energy consumption of the load was larger than the energy generated by the module resulting in a decrease of the system voltage due to a lower state of charge of the battery Figure 1 Monitoring results for three days in the summer hourly averages of system voltage and currents from module and to the load Monitoring results SHS Alkmaar 3 days in June 1999 Module current X 100 mA Load current X100 mA Voltage V w gt oO pe le D e e gt Hours after start ECN C 00 047 11 Figure 2 Monitoring results for the same days as in figure 1 peak system voltage hourly average load current and peak load current Monitoring results peak system voltage average load current and peak load current 15 Peak power of load Watt Voltage or current N Peak voltage Volt Load current X100 mA 10 5 i 0 St N oO lap o o gt N LO oo ye St N c isp oO o gt N LO oo bami St oo ap hand y y N N N ca sp sp st st St St LO LO LO de de N N oO Hours from start 2 4 Second prototype of the data logger With the successful tests of the first prototype it was ill
33. ponents of the system losses due to a non optimal position and orientation of the module and b losses in cables charge regulator and battery 9 Does it happen that the battery is also charged in a battery charging station NS a cae T Based on these monitoring demands the following parameters were chosen for data logging in brackets the number of the questions in the above list a System voltage stored as minimum voltage and maximum voltage per hour 4 6 9 b Module current stored as average module current per hour 1 c Load current stored as average load current per hour 2 3 d Battery charging current stored per hour as Ampere hours in and Ampere hours out 4 6 7 e Flags per hour for low voltage disconnect and high voltage disconnect 5 Answering question 8 about the different system losses can not easily be achieved just with a data logger alone This requires additional on site measurements Furthermore it requires measurement of irradiation that is not planned by us due to the fact that it requires additional equipment and extra wires thereby increasing the expected chances of malfunctioning of the data logger In this stage only the parameters that need to be measured were formulated No other specifications were formulated such as environmental conditions level of accuracy and cost limits 10 ECN C 00 047 2 3 Building and testing of the first prototype As far as we knew at the start of this project there
34. rance 23 27 October 1995 pp 1081 1084 K Preiser P Schweizer and O Parodi Balde de Leyes the integrated way to electric light 13th European Photovoltaic Solar Energy Conference 23 27 October 1995 Nice pp 1787 1790 A Reinders et al op cit 8 UNESCO World Solar Programme 1996 2005 September 1997 See web page of Shell 1998 10 Smith P RETSs for Rural Electrification Some reflections Renewable Energy for Development Vol 11 No 1 April 1998 ll Kalumiana A Arvidson Establishing Photovoltaic Energy Service Companies in Rural Areas Renewable Energy for Development Vol 11 No 2 November 1998 J Aguilera E Lorenzo Rural Photovoltaic Electrification Programme in the Bolivian High Plateau Progress in Photovoltaics Vol 4 pp 77 84 1996 B CADDET webpage http www caddet re org html techpv htm 4 A Cabraal M Cosgrove Davies L Schaeffer Best Practices for Photovoltaic Household Electrification Programs The World Bank Technical Paper No 324 1996 S J Stone H S Ullal The Ramakrishna Mission PV project published on PV resources website 34 ECN C 00 047
35. razil by a number of utilities One of these CEPEL has developed a performance evaluation methodology that can be easily applied by the utilities technicians using only simple instrumentation Periodically or after a fault has been reported a performance evaluation form 1s filled out In situ measurements are made with a digital multimeter a current probe a portable solar radiation meter and a temperature probe The following measurements are made Battery voltage and current during charge and discharge Battery open circuit voltage PV panel short circuit current Solar radiation at measuring interval Ambient temperature No PV panel open circuit voltage measurements have been made because of reliability and cost reasons according to the authors FhG ISE Fraunhofer ISE developed a Solar Home System Tester a cheap easy to use hand held device which can assist in checking the performance of a solar home system in a short time The tester can measure all the parameters as measured by CEPEL in Brazil plus the module open circuit voltage For these measurements the tester is connected between the charge regulator on the one hand and the module battery and load on the other hand This requires some time and effort and a short measurement is only possible if the solar home system is already adapted for the use of the tester January 2000 one of the developers of the tester J Kuhmann of Fraunhofer ISE stated that the tester i
36. ry in many developing countries through studying the credit arrangements and standardisation of equipment 5 2 The socio economic impact of the introduction of SHS The socio economic impact of the introduction of SHS is related to the improvement of the quality of life the stimulation of commercial activity and associated employment and getting acquainted with electricity Improvement of the quality of life of rural population is brought about by the fact that electric lighting enables people to undertake a range of additional activities in the evening hours at home and in public facilities such as schools clinics and community buildings Outdoor lighting may also bestow a perception of improved security Electricity for radio and TV gives people access to mass media for entertainment but also for extension services and distance education Electric pumps powered by PV may facilitate access to safe drinking water Electricity for small local health facilities enable conservation of medicines and emergency distance communications Stimulation of commercial and agro industrial activity and associated productive employment is brought about by the establishment of a PV market consisting of dealers assemblers and after sales providers of the PV systems In addition improved lighting is an inherent benefit for shop owners stimulating their trade Electrification by means of PV can be seen as an interim measure to provide electricity services until
37. s November 1999 ECN and University of Utrecht started a Novem project that complements this ENGINE study The project Monitoring and Evaluation of Solar Home Systems is intended to target these issues by conducting a large literature survey into experiences with solar PV for households in developing countries Lessons learned from projects documented in the grey literature will be summarised and analysed May 2000 is the deadline for the Novem project Its outcomes will be useful in focussing the scope of the ENGINE project to those issues where the lack of information is most serious 1 2 Objectives and Scope of Work The main objective is to improve the price quality ratio of solar home systems Quality is defined here as the extent to which users are satisfied with the services provided by the system in a sustainable way The project has to contribute to increased knowledge of how solar home systems are used by households in developing countries Manufacturers can use these insights to design more appropriate components and systems and to improve system sizing Intended results are the following e Information about the causes of failures of PV systems and their components e Insight in the influence of the feed back of user information on actual use of SHS e Overview of the life cycle of SHS which will lead to recommendations for new products and product improvements e Insight into the strengths and weaknesses of the institutional
38. s in many countries that are already active in SHS should serve as a reassurance that it is possible to integrate SHS in electrification programmes An interesting example is CRE perhaps the largest electric co operative in the world which has the electrical concession for the state of Santa Cruz in Bolivia CRE has set up a solar electric utility within the co operative structure CRE has developed a tariff collection and maintenance system and has over 1000 customers Another distribution utility in Bolivia ELFEC considered setting up a similar electrification unit to CRE but later rejected it based on financial analysis Private sector initiatives Another venue is the entering of private sector in the provision of electricity services Such companies are usually referred to as Energy Service Companies ESCOs and work as a Solar Electric Utility which basically acts like grid electricity utilities This type of company sells electricity and retains ownership of the SHS The SEC in Kiribati is one example The principle advantage of utility based service is that it can provide electricity at low cost to the consumer It also transfers the maintenance responsibility from the user to trained technicians thus guaranteeing proper care of systems It however requires a capable technical and administration infrastructure in the area to be served and often needs access to long term credit at modest rates The Kiribati experience also hi
39. s not yet commercially available Conclusions From the monitoring results in Brazil it can be concluded that the extra on site measurements provide useful quantitative information about the performance of the systems This can be very helpful for maintenance purposes which is one of the main objectives of the utilities in Brazil However with this type of monitoring one still lacks information on time development of performance e g degradation of the battery What is even more important one still does not know how the systems are actually used by households during what part of the day the energy is consumed how often is the battery empty and what is the extent of shading of the module etcetera To obtain this type of information one has to use data loggers 8 ECN C 00 047 2 1 3 Experiences with the use of data loggers FhG ISE Fraunhofer Institut fur Solare Energiesysteme has experience in using data loggers in solar home systems in a number of developing countries In Balde de Leyes in Argentina data loggers were installed in two solar home systems Information that was obtained from the data loggers was e 95 of the electricity consumption occurs during the night e energy demand over the year is proportional to the lenght of the nights Where the seasonal irradiation varies between 3 kWh m day in winter and 8 kWh m day in summer the average energy consumption per household was only between 200 Wh per day in winter and
40. solar systems identified in a previous survey Despite the relative easy of organisation Swaziland is a rather small country and has a higher per capita income than most other countries in Africa Kenya Kenya has a substantially developed PV market probably the largest among the developing countries From this perspective Kenya would be an interesting and representative case study Discussions with local Kenyan organisation took place early December and suitable partners have been identified for the organisation of the survey A disadvantage of Kenya as a case study is that ECN has no ongoing activities in Kenya in the field of PV As such the organisation of the organisation of the survey will be more time consuming and costly Zimbabwe Zimbabwe is a country that overcomes both problems It has the second most developed PV market on the continent and ECN IDE has been actively involved in the country ECN has established a large network in the PV sector and will have permanent ECN staff in the country for the next 2 years 16 ECN C 00 047 Through one of our local partners viz PV supplier ECN will get easy access to a large customer data base and can make use of a team of qualified technician for the installation and readings of the data loggers ECN C 00 047 17 5 SOCIO ECONOMIC AND INSTITUTIONAL ASPECTS OF INTRODUCTION OF SOLAR HOME SYSTEMS As set out in Chapter 1 the study will also entail a socio economic and institutional a
41. suitable for monitoring solar home systems User interface A prototype of an advanced user interface was produced by AME based on a concept developed by PT Cilengka in Indonesia in cooperation with ECN Via a small LCD screen the user receives information about the use of their solar home system in the last week This prototype was tested by ECN and a number of problems were found Suggestions for improvements were formulated and these were implemented by AME Additional tests have been conducted which show that the user interface still needs further improvements For field tests in Indonesia we intend to use an older version of the user interface Preparation of the survey Some first preparations were made for the survey that will be conducted parallel to the field monitoring An inventory of important issues has been made and a first draft questionnaire has been formulated Socio economic and institutional aspects of introduction of Solar Home Systems A global review was conducted regarding the role of solar home systems in regional and national energy planning Furthermore we looked into socio economic impacts of the introduction of solar electricity the financing mechanisms and the different institutional arrangements 6 ECN C 00 047 2 DATA ACQUISITION IN A SOLAR HOME SYSTEM 2 1 Experiences of others with monitoring of solar home systems Parallel to this ENGINE project a study is being conducted for Novem called Monitor
42. t of finance when financing involves loans raising and servicing the financial arrangements comes with a cost e perceived risks all projects are exposed to risks which are often considered high when the project involves relatively new technologies Avoiding reducing and sharing risks amongst key players is essential for success Three finance related concerns can be identified that stand out as being critical if the SHS industry is to grow successfully namely e consumers need to obtain credit from banks or distributors e suppliers and retailers must be able to secure working capital if they are to be able to provide in turn credit to their customers e investors need credible financing opportunities to sway capital towards the solar industry Close inspection of literature reveals three main categories in the finance process arranged in a fixed vertical structure viz international financiers several institutional intermediaries who handle the funds and the end user of the funds In practice one can see a pattern which further breaks down these categories into five levels of actors again vertically integrated These are illustrated by figure 1 The level 1 actors are involved in supplying of capital usually as a grant subsidies and or loans with strings attached These may be organisations like aid agencies UN related bodies or multinational banks 20 ECN C 00 047 INTERNATDNAL FINANCER e Grants and subsidies from aid
43. t would you do if grid electricity would become available in your area L apply for a grid connection and re sell the SHS 2A apply for a grid connection and keep the SHS use both of them 3 not apply for a grid connection and keep on using the SHS 4 OUT ela NE ey Oe ee one RRC Battery Performance 14 Do you often have a flat battery 1 almost daily 2 once or twice a week 3 once or twice a month 4 a few times per year 5 never go to question 18 15 If it is flat how long does it take the battery on average to get charged by the solar panel i charged the following day De TONG SE TNC AC ens apicersersi sty e roeien N 16 Have you ever charged your solar battery other than with the solar panel L yes at a charging station l VER OUNCE osa O 3 no go to 18 17 How often do you charge the battery other than with the solar panel l once or more per week 2 once or twice per month 3 a few times per year 4 once every one to two years 18 Was the battery ever topped up with water iP yes topped up by you or somebody else in the family 2 yes topped up by a technician 3 no go to 20 19 If yes what kind of water was used L water from the tap 2 boiled water 3 distilled water 4 don t know 20 Did you ever replace the battery li yes 2 no go to 24 21 If yes after how much time did you have to replace the battery L less than 6 month 2 within one year 3 within two years 4 within three years 3 within four
44. taking into account life cycle aspects Before field testing can start the prototype was tested in the laboratory to see if it meets the specifications and if it can operate under developing country conditions Within the current preparatory phase of this ENGINE project only the laboratory tests were conducted Field testing has to start in the second phase of this project The user interface shows the actual voltage of the battery in the range of about 11 5 to 13 5 volt in steps of 0 2 Volt Displayed is a histogram with bars consisting of a number of small blocks of 0 2 Volt each It displays minimum and maximum battery voltage for the past 6 days This provides the users with information about how their electricity use is related to daily electricity supply Laboratory tests A number of laboratory tests have been conducted to test accuracy and reproducibility of voltage indications and to determine if the values are shifted correctly from day to day The first laboratory test was to check if the value of the voltage as shown by the user interface differs from the actual voltage as measured with a separate voltage meter The average difference found was 0 1 volt which is equivalent to half a block The maximum difference was 0 4 Volt occurring in 7 of the 42 measurements Furthermore tests were conducted in a small solar home system 14 user interfaces were connected parallel in groups of 2 or 4 for periods of a few weeks each Because the
45. the national grid will have reached the area However PV acquaints the consumer with the use of modern electricity usage This means that when a household eventually gets connected to the grid it is used to electric devices such as the radio and the TV and consequently electricity consumption after grid connection will be higher compared to the situation whereby electricity is introduced for the first time Higher consumption of course contributes positively to the financial performance of the rural electrification programme ECN C 00 047 19 5 3 Financing Solar Home Systems Two main potential consumer groups can be identified for SHS The first group comprises of potential consumers that do not have access to grid electricity The second group involves households connected to the grid but because of the frequent power interruptions uses the SHS as a backup device Most SHS however are meant for rural households which are not connected to the grid These households usually belong to the low income group of households which cannot afford the high initial investment that is required for the purchase of a SHS This raises the important question of how to finance a SHS programme In general the following constraints and impediments in financing frequently encountered in SHS programmes can be distinguished e access to finance this is claimed to be a cardinal pre requisite for SHS projects and renewable energy projects in general e cos
46. u receive a user manual from your supplier yes no go to question 35 Do you consider the manual useful yes AO WHY NOl deme Did the installer explain the use of the solar system to you L 2 yes no Would you recommend a solar system to other people Have other people shown an interest in your solar system 1 PA yes no 30 END OF QUESTIONNAIRE ECN C 00 047 ANNEX 2 DATA LOGGER HARDWARE At this time there are three options to obtain the required data logger for Solar Home Systems The possibilities are listed below 1 Buy a complete unit commercial of the shelf COTS 2 Develop the current prototype to a production ready model 3 Develop an upgraded version of the current prototype While developing the prototype of the data logger we realised the need for further improvements such as the use of more than four channels At the same time an answer is formed to the question if data loggers available on the market are applicable to suit our needs In the table Comparison table data logger functions below the functions per data logger are listed Comparison table data logger features quirrel of Grant Current version of Upgraded version of ECN logger Sample interval 0 1 seconds 0 1 seconds Storage interval 0 1 sec 24 hour 0 1 sec 24 hour Average battery voltage yes yes Average module current yes yes internal shunt external shunt Average load current yes yes internal shunt extern
47. ustrated that in principle the data logger can operate well However being integrated in a charge controller that is not commercially available is a barrier for normal use of the data logger Ideally you want to be able to use the data logger in all different types of solar home systems Therefore the next logical step is to develop a version that can operate independent from the charge regulator Given the relative ease with which the first prototype was developed it was assumed that modifying the design to make it independent would be a simple straightforward job which should be easy to accomplish In reality it turned out to be a long and tedious process A disadvantage of having the data logger separate from the charge regulator is that the information about the status of the charge regulator e g a disconnected load due to low voltage disconnect is no longer easily available This limits the parameters which can be measured to four system voltage PV module current battery current and load current A new circuit diagram was drawn for the second prototype In the summer a student was asked to draw a diagram for a PCB Inadvertently a number of errors were introduced in the PCB design This resulted in serious delays because the errors had to be repaired manually Laboratory tests of the second prototype showed problems with the data It took a considerable amount of time before some of the causes were traced The following problems were en
48. uthorities e the utilities and e the co operatives and associations Public authorities The conventional attitude of public authorities that SHS doesn t work its too expensive is on its own an institutional constraint This situation is encouragingly changing though and many developing country governments have already included RE technologies including SHS in energy policy objectives The Solar Summit Process in Harare 1996 gave a much required impetus to the change of attitude of public authorities resulting in their commitment to join in the development and implementation of the World Solar Programme 1996 2005 The declaration made during this summit includes inter alia three grave commitments in favour of renewable energies in general and solar energy in particular Here commitment two is quoted which reads We commit ourselves to work towards policies and effective mechanisms that will speed up and facilitate the use of solar energy avoiding duplication and administrative delays and the encouragement of international co operation including participation in regional and international bodies scientific and technical organisations The other two commitments are of similar seriousness Much work is ongoing and has already been done towards the fulfilling these commitments However there is still a great scope for improvements and this remains a challenge of authorities to ensure that commitments made are effected
49. version might be an interesting consideration taking into account the lessons learned from a smaller project with COTS components 32 ECN C 00 047 Kosten raming monitor module vervolg Ontwerp prototyping Prijs per uur gulden Componenten invoeren cad Current version Upgraded version 180 gulden uur Opmerkingen 16 uur Ontwikkelen aanpassen ontwerp 64 uur Schema tekenen 24 uur Review schema 4 uur Ontwikkelen aanpassen software 160 uur Pcb preplacement 16 uur Aanmaken shapes 8 uur Bestukken prototypen 16 uur Testen protypen 16 uur Aanmaken bedradings schema s 8 uur Totaal uren 132 332 uur TOTAAL KOSTEN MANUREN ONTWIKKELING 23760 59760 gulden Eventueel stagiair laten uitontwikkel en print ontwerp laten maken Calibreren en testen per print 1 1 Uur per unit KOSTEN CALIBRATIE PER PRINT 180 180 gulden Produktie kosten Uitbesteden bestukken EXTERNE PRODUKTIE AANLOOP KOSTEN 7500 gulden Golf solderen KOSTEN EXTERNE PRODUKTIE PER PRINT 25 gulden Bestukken print intern Per print 4 uur AANLOOP KOSTEN INTERNE PRODUKTIE 1500 gulden KOSTEN INTERN BESTUKKEN PER PRINT 720 gulden Integratie printen in behuizing Prijs per uur gulden Montage print in kast 100 gulden uur 3 uur MTSer extern In elkaar zetten kast aansluitkabel drie per print aan de ruime kant KOSTEN MONTAGE per print 300 gulden Onderdelen kosten Prijs PCB 5 weken lead time AANLOOP KOSTEN PCB PRODUKTIE 5000 gulden inc
50. was that tampering with the battery bank resulted in damaging the data logger Furthermore incorrect installation and accidental disconnection of wires have resulted in loss of data Lessons learned from a workshop with FhG ISE and Sandia held at NREL on October 19th 1999 were the following e It costs time to check and process data e Collecting data can be difficult e Take time for installation and checking e Include redundancy in measurements even when a parameter can be calculated from others still measure it Total Watt hour input and output to the batteries is required e The Data Acquisition System DAS needs its own power supply the interesting things happen when the system is dying e Data cards are the most practical method to gather data e Review of accurate log books is essential e Simple is best Utrecht University Angele Reinders formulates the most detailed description of monitoring of solar home systems with data loggers in an article In Sukatani Indonesia four channel data loggers were used of the Squirrel type manufactured by Grant Measurements were made of battery voltage current from the array current to the load and irradiance in the plane of the array or temperature in the ECN C 00 047 9 battery box Sample interval was 18 seconds and data were stored in half hourly averaged values Based on an extensive analysis of the monitoring data over the period 1988 1993 Reinders arrived at th
51. years 6 within five years ve after more than five years 22 From whom did you buy the new battery L from the supplier you bought the solar systems from 2 from another battery supplier 3 DL TEN 28 ECN C 00 047 25 What did you do with the old battery L returned it to the supplier 2e threw it away 3 OET renee Appliances Performance Check question 8 whether lights are being used if no go to question 28 24 How many lights are powered by your solar system no 25 Did you ever replace one or more tubes bulbs of you solar lamps L yes no of lights replaced 2 no go to 27 26 From where did you obtain the replacement tubes bulbs L spare tubes bulbs were provided by the supplier of the solar system 2 bought it from the supplier of the solar system 3 bought it somewhere else 27 Are you satisfied with the brightness of the lamps 1 yes 2 no not bright enough 3 no too bright Repair and Maintenance 28 Did you every had a problem with your solar system l yes no 29 If yes please indicate what kind of problem s system struck by lighting 30 31 How often did you call in a technician to check repair your system in the past 12 months DO OE AMES err asana 32 Did you ever clean the solar panel 1 yes did that once 2 yes do that regularly 3 no never cleaned it before ECN C 00 047 29 6 1 1 1 Information 33 34 35 36 37 N me N e Did yo
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