**4. Results**

### *4.1. The Sustainability of MG Documented in the Literature*

The literature review revealed three major types of scientific resources: single case studies, reviews of multiple case studies and feasibility studies including simulations for potential project locations. The analysis shows that, despite a substantial overall number of studies on MG sustainability, the presentation of specific financial data including OPEX, CAPEX, details on revenues and tariff models is ye<sup>t</sup> very limited, even in those studies which focused explicitly on the financial sustainability of MGs.

Secondly, 18 out of 21 case studies reported substantial financial sustainability challenges for all regions due to various combinations of low energy affordability, poor revenue collection and high operation and maintenance costs. The reported financial challenges in the case studies evaluated outweigh other issues such as consumer behaviour and acceptance (14), policy-related or legal challenges (11) or technical problems (8). With regard to MG revenues covering its OPEX, none of the case studies presented specific data for the operational sustainability of the MG. Only six case studies revealed some information regarding the tariff models of the MGs applied which indicates a data gap and evidence to perform a comparative analysis of the connection between cost-reflective vs. subsidised MG tariff models and operational sustainability.

The review also shows that although financial, technical and end-user focused sustainability dimensions have been included to some extent in most of the case studies, the focus on economic community-impact including the productive use of energy in the context of a comprehensive community eco-system approach which includes analysis and understanding of local income patterns and community value-chains is clearly underrepresented. None of the case studies reviewed correlate technical—financial—and community-based approaches or integrate these dimensions but focus mainly on technical and financial analyses instead with the availability of detailed data however being generally limited. The few studies that include the community—or end-user context either lack a specific technical or a financial evaluation.

The reviewed feasibility studies largely follow that pattern of selected modelling usually incorporating technical and financial calculations based on an LCOE approach. They generally demonstrate the tendency of an economic and technical advantage of RE MG systems over grid connections in the rural context and more clearly over fossil fuel alternatives [30,66,67]. The feasibility studies evaluated however usually do not account for potential community eco-system impact factors illustrated in Figure 1 on energy systems including fluctuating income, sensitivity to exogenic effects or existing socio-economic structures. Consequently, the optimised theoretical financial and operational projections of the feasibility studies reviewed are in stark contrast to the actual case studies.

The literature review evaluation a clear gap between theoretical modelling presented in feasibility studies and the operational reality of RE MG operation in a developmental context which substantiates the necessity of the inclusion of the community ecosystemssetting into MG planning and modelling processes. The evaluation also reveals specific MG data gaps and highlights the important links between financial sustainability, technical managemen<sup>t</sup> and end-user behaviour which informs the requirement of combined research approaches aiming for an understanding of the complex socio-economic community settings for the evaluation of the sustainability of RE MGs in the developing context from which strategic implications can be derived to improve their overall operational long-term sustainability.
