Deposited with permission of the author © 2009 Dr. Matthew Robert Peter Bond ; East Timor is rebuilding its stock of infrastructure after decades of underdevelopment and a wave of violent destruction in 1999. As part of this process the Government of East Timor aims to improve access to electricity from less than five percent of the population today to eighty percent by 2020. An important strategy to meeting this aim will be the use of solar home systems (SHS) in remote rural locations. To develop its policy for the deployment of SHS, the Government of East Timor must decide what size of SHS is optimal. This research investigates whether there is a relationship between SHS size and development. The research adapts an evaluation approach developed by World Bank/UNDP Energy Sector Management Assistance Program. This approach uses a combination of participatory and quantitative tools tailored to the East Timorese context through consultations with rural households about electrification and their use of SHS. Three SHS projects in East Timor were selected for evaluation, each of which had adopted a different sized SHS for their program. The smallest systems installed were 10 Wp single-lamp systems. The largest system was rated at 80 Wp and was supplied with four or six lamps. The third type of system was 40 Wp and provided three lamps To assess the development impact of these different sizes of SHS, a set of Participatory Evaluation exercises were conducted with seventy-seven small groups of SHS users in twenty four rural communities. These exercises were supplemented with a Socio-economic Household Survey of 195 SHS users. The combined results of these evaluation processes enabled the three sizes of SHS to be compared for two types of benefits—assistance with carrying out important household tasks (i.e. ‘lighting-derived’ benefits) and attributes of SHS which were advantageous in comparison to use of non-electric lighting sources (i.e. ‘intrinsic’ benefits). Analysis of the research results showed that the small 10 ...