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 twentyfour
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 Wp SHS provided much of the
development impact of the larger systems. For lighting-derived benefits, there was little
difference between the development impact of small and large systems. The larger systems
provided greater benefit for domestic tasks undertaken in kitchen buildings, since the small
and medium sized SHS did not provide lighting in these areas. For intrinsic benefits related to
health and convenience, the small systems provided much the same benefits as larger systems.
For financial benefits—considered by East Timorese SHS users to be the most important of the
intrinsic benefits—smaller systems were found to offer slightly positive benefits due to their
lower operating costs. Larger systems, however, were found to have a negative overall
financial impact.ii
The research suggests three significant implications for the design of SHS programs in East
Timor and comparable situations elsewhere: programs should focus on providing smaller
systems rather than larger ones; systems should be designed to provide a light in the kitchen
wherever possible to maximise the overall development impact; and SHS operating costs
should be carefully matched to the incomes of rural householders to ensure that operation of
the systems can be sustained by user households.