**3. Materials and Methods**

The study aims to provide a better understanding of the specific interrelations between the financial, social and technical sustainability dimensions of decentralised energy systems based on empirical survey data and MG case studies. The novelty of the approach presented lies in its interdisciplinary by evaluating financial—technical—and consumer-based aspects of RE MG operation and revealing their interdependencies.

The country focus of the analysis is Zambia as it shares central features in terms of energy access and socio-economic challenges with other countries in the region and the data generated from Zambia will be contextualised with a regional perspective to discuss its validity for other countries in the region.

Consequently, the research aims to derive strategic implications to enhance the operational sustainability of MGs in a developmental context which are highly relevant for further scaling of MGs in developing countries. The study also aims to shed light on the question, whether substantial gran<sup>t</sup> financing of MG CAPEX in an environment of costreflective tariff requirements is the right option to implement MGs that operate sustainably and provide reliable and affordable energy to rural households in the specific context.

Based on the understanding of the functioning of rural infrastructure solutions determined by the community ecosystem, the study approaches these questions through a three-step approach: a comprehensive literature review of MG case studies in a developmental context, the evaluation of empirical data on the socio-economic conditions and energy demands of rural communities in Uganda and Zambia which is mirrored by an in-depth evaluation of OPEX and CAPEX data of two solar PV MGs in Zambia.

The methodological approach is limited by three factors. The first is, that the focus on Zambia as the country context establishes certain specifics, for example with regard to currency fluctuation, energy markets and—supply chain which has specific impacts on energy pricing and which might be different in other developing countries. Secondly, the overall number of respondents who are existing MG customers in Uganda and Zambia is relatively low which however also presents an opportunity for enhancing comparative empirical research on different types of energy consumer perspectives in developing countries. Finally, it has proven to be challenging to gather specific financial data on the MG operation in Zambia including detailed revenues and costs due to the absence of comprehensive and systematic recording of this data by the operators. Consequently, some of the financial calculations presented in this study are based on assumptions that are highlighted and discussed in the results section.
