*3.1. Systematic, Integrated Literature Review*

The aim of the integrated literature review [49] is to identify the general availability of case studies and in-depth data including on OPEX—and CAPEX of RE MGs as well as identified specific challenges for the operation of these systems in rural, developmental contexts. The analysis is based on a number of categories such as the type of study and data presented and indications with regard to the system sustainability in relation to the overall research questions and are presented in Table A1.

In total, 26 studies published over the last decade have been evaluated. The studies have been selected on the basis of the technology (RE) and energy system-type (MG) presented, the regional focus (developing country) and the search was based on the keywords "sustainability", "financial sustainability", "technical optimisation" and "consumer

perspective". The search was mainly focused on studies published between 2017 to 2021 to capture the most recent findings. The review included academic papers as well as acknowledged reports and academic theses of either specific MG case studies or feasibility studies of RE off-grid systems including solar PV and mini-hydro in a rural developing context mainly in Africa and Asia. The review was focused on the sustainability parameters applied in the studies, identified challenges of the systems, operational data and applied tariff schemes. It was also analysed whether the wider community context has been taken into account in the studies evaluated. The aim of the analysis is to detect MG data gaps and sustainability trends from a cross-regional perspective.

### *3.2. Empirical Data: Community Surveys, Stakeholder Interviews, Focus Group Discussions*

The results from the literature review data inform the evaluation of empirical survey data from Zambia which will be mirrored with survey data from Uganda. This data has been generated through a mixed-method approach of qualitative interviews, focus group discussions, rural household surveys and on-site data collection to gain a comprehensive understanding of rural household energy needs [50] and their socio-economic conditions as essential attributes of the community ecosystem and to account for the specific importance of local end-user perspectives for the sustainability of rural energy solutions [51].

The household surveys were rolled out in two stages. The first round of surveys (N = 1016) was deployed in rural communities in Uganda and Zambia focused on the general socio-economic situation, energy needs and demands which were captured through 106 questions. Based on the findings gathered in this round, the surveys in round two (N = 50) were focused on gaining a deeper understanding of the potential value chain opportunities for the productive use of energy and were rolled out in two rural communities in the Southern Province of Zambia. For the evaluation, the survey data presented in this study has been clustered into various energy-consumer subgroups which are presented in Table 2.



The data of MG users has been collected within the communities of the 30 kWp Sinda solar PV MG in Zambia which is presented as a detailed case study in this analysis and for Ugandan MG users of the 1.6 MWp solar-thermal hybrid MG in Kalangala [52].

The survey rounds were complemented by site-visits and focus group discussions with representatives of different community groups such as members of cooperatives and parent-teacher associations (PTAs), local women self-help groups (SHGs), local businesses as well as public representatives such as councillors, health workers and school staff in five rural communities in the Southern Province of Zambia.

The physical data was collected through the lens of a potential RE project development in cooperation with a local energy project developer to gain a better understanding of site selection strategies [53] and included existing local infrastructure, population density, present social or economic groups and environmental conditions including soil erosion and deforestation. The evaluation also included a review of findings from 45 qualitative interviews with off-grid energy companies and public sector stakeholders to embed the community-level perspective into the wider energy policy-making and governance context to derive strategic implications based on previously identified current energy governance structures in Uganda and Zambia [54].

### *3.3. Mini-Grid Case Studies: Context and Selection*

Based on identified data gaps through the integrated literature review, the study incorporates detailed technical, financial and operational data from two existing solar MGs in Zambia located in Mpanta and Sinda. This embedment of in-depth MG case studies aims to support the closing of existing data and knowledge gaps with regard to MG operation and the generation of important strategic learning lessons for rural electrification processes [55]. The MG data has been collected through a number of site visits performed by researchers of the University of Zambia resulting in a technical and financial assessment [56], stakeholder interviews and desk-based research. The technical and financial evaluation of the Mpanta MG complements previous local studies on community-level engagemen<sup>t</sup> and energy transition [41,57].

### *3.4. Country Context: Energy Access and Governance in Zambia*

Zambia shares central features in terms of energy access and the socioeconomic structure of rural communities with a number of SSA countries. This includes a low density of the main electrical grid which leaves the majority of rural Zambia unelectrified with offgrid RE systems being the preferred solution to enhance energy access in these areas [58]. The rural electrification rate in Zambia is significantly below ten per cent. Although specific energy access data is currently lacking according to the Rural Electrification Authority' (REA), this rate is well below the average rural electrification rate in SSA, which is estimated at around 22.59% [59,60].

Following the establishment of REA Zambia in 2003, which is mandated to enhance access to electricity in rural areas to 51% by 2030, planning and policy approaches to increase energy access in Zambia have originally been dominated by grid-expansion projects mainly in peri-urban areas and in cooperation with the parastatal national utility ZESCO Ltd. The 'Rural Electrification Masterplan' (REMP) which has been developed with significant support from the Japan International Cooperation Agency (JICA) and which was adopted in 2008 identified 1217 Regional Growth Centres that were clustered in 180 project packages to be electrified by 2030 [61]. According to the 'REMP', a total investment of around \$1.1 bn would have been required for the realization of all project packages which amounts to a required annual investment of roughly \$50 million per year between 2008 and 2030 to achieve the electrification target [62]. However, due to the slow progress of project implementation, national budget constraints, the high costs of grid extension projects and the emergence of more cost optimised solutions [63], REA began to review the electrification strategy laid out by the REMP [64] and explored a potential shift towards emphasizing decentralized energy solutions like solar PV MGs. Consequently, these off-grid energy solutions have been gaining more and more interest in Zambia since 2011/2012, a process that was increasingly pushed by foreign donor organisations who started to develop and implement off-grid procurement programs, some of these programs in cooperation with REA and other institutional partners in Zambia.

This resulted in the implementation of off-grid electrification projects now being largely 'outsourced' to the private sector and foreign donor organisations [43]. In the course of this strategic shift, RE MGs have become an emerging technology for rural electrification alongside SHS in the country. Over the last seven years, more than 20 MGs have been implemented through partnerships between private sector companies and foreign donor organisations with dozens of more projects in the pipeline of being deployed for example through the EU-funded Increased Access to Electricity and Renewable Energy Production (IAEREP) Project.

According to REA, as of February 2021, around 29 solar PV MGs with installed capacities between ten and 50 kWp and two mini-hydro MGs with an installed capacity of 640 kWp and 750 kWp have been operational in Zambia with two additional PV MGs currently under construction. These MGs have largely been implemented through tenderbased procurement processes with CAPEX grant-funding levels of around 70 to 80% supported through various foreign initiatives including the Beyond the Grid Fund for

Zambia (BGFZ), the Mohammed bin Rashid Initiative for Global Prosperity and U.S. African Development Foundation (USADF)/Power Africa.

Most of the Zambian MGs are applying mixed tariff schemes but shifting from subsidised towards 'Individualised Cost-Based Tariff' schemes in alignment with the regulatory framework for MGs introduced in 2018 by the Energy Regulation Board Zambia (ERB). The framework defined certain technical, financial and operational requirements for MGs including the requirement of cost-reflective tariffs while energy tariffs in the on-grid sector remain subsidised in Zambia [65].

Although the challenges of enhancing rural electrification have been acknowledged by leading national and foreign stakeholders, recent research has evidenced that the energy policy framework ye<sup>t</sup> lacks a clear integrated strategy for on- and off-grid electrification and energy access governance structures are still highly top-down oriented and largely lack the inclusion of community-level representatives [54].
