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The proliferation of off-grid photovoltaic (PV) systems is rapidly increasing in the least developed countries. The sizing of system componentsprimarily PV panels and batteries-is critically influenced by the expected daily load. However, accurately estimating incipient electrical load of rural consumers is fraught with challenges. Load estimation error is propagated through the design phase, potentially resulting in a system that is unduly expensive or fails to meet reliability targets. This article investigates the effects of daily load estimation error on system design, cost and reliability. Load and insolation data from seven off-grid systems in Malawi were collected. The systems were redesigned using three different intuitive design approaches considering different levels of load estimation error, ranging from ± 90% of the actual measured load. The cost of each design is estimated from in-country prices. The reliability of each design is determined from an hourly simulation using the measured data. The results show that PV array and battery sizing scale proportionately with load estimation error and that the cost of load over-estimation is approximately US$1.92 to US$6.02 per watthour, whereas underestimation can precipitously degrade reliability. A cost-versus-reliability analysis shows that for the Malawi systems, on average 46% of the PV and battery costs are used to improve the simulated hourly

Background: A novel project sustainability framework is used to evaluate 65 off-grid solar photovoltaic (PV) energy system projects in Malawi. This study addresses PV projects serving rural public facilities, a solution known to have had historical issues with poor sustainability. A recent countrywide program targeting such facilities was evaluated against existing projects to determine whether this latest iteration offered better results. Method: Sustainability is defined at the project-level with metrics justified under the main themes of technical, economic, social, and organizational. Data captured for each project is based on a custom survey and interview of key stakeholders. Projects are grouped according to age, project implementer, income level, and PV system size to compare relative results. Results: The sustainability outlook for each project is evaluated. We find sustainability for most projects to be low. Social sustainability was weak with many projects due to low local community stakeholder engagement in terms of numbers of stakeholders, meeting frequency, and community contributions. Organizational challenges included a lack of key management positions in place and extremely limited training provisions. Furthermore, the evaluation highlights the economic health of the system to be key to sustainability, with the "healthiest" projects affording only 37% of expected operations and maintenance costs. Relative to expected demand, systems were found to be undersized for both panels (53% of required) and batteries (57%). Users reported achieving only 60% of their desired consumption. Poor sizing standards related to the lack of load profiles for first-time electricity users as well as poor quality components reduced the overall technical sustainability. Conclusion: Rural public facilities with solar PV in Malawi are not well served by isolated community management. Improved sustainability requires the establishment of a robust financial framework prior to project development that includes formal local government support. This paper discusses ideal management frameworks and their ultimate implications for project developers, policy makers, and the research community.

The sustainability challenges of off-grid community energy projects using solar photovoltaics in Malawi have been widely acknowledged. However, little evidence has been produced regarding the factors that affect the sustainability of these projects. This paper presents the results of a nationwide study of community solar PV project sustainability in Malawi. The concept of sustainability as a holistic measure is defined and captured through field survey at 43 projects. A multi-factor scoring technique provides a relative ranking of the surveyed projects. The majority of projects have serious shortcomings undermining their ability to produce a positive impact as intended. The results provide useful insights to the design of solar PV projects for community energy practitioners and indicate that the underlying challenges are both internal and systematic, from a poor technical design approach to limitations in the skills required to effectively manage such projects

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