*4.3. Mini-Grid Case Studies Zambia*

The literature review presented earlier revealed substantial gaps with regard to the available technical and financial data in MG studies and limited inclusion of community context data while the previous section illustrated end-user perceptions and socio-economic conditions that heavily impact mini-grid operation. Consequently, in the third analytical step of this study, the implementation and operation of two Zambian solar PV MGs located in Mpanta and Sinda are evaluated in more detail to complement and mirror the analysis of community—and consumer perceptions. The goal is to analyse the interdependencies of the technical- financial and socio-economic sustainability components in more detail and illustrate how the community ecosystem impacts MG operation.

### 4.3.1. Community and System Context: Socioeconomics and Geography

The solar MG in Mpanta developed and commissioned in 2013 by the REA Zambia was the first solar PV MG in Zambia. With an installed capacity of 60 kWp, it was initially designed to provide street lighting in the village as well as basic electricity services to about 450 private households to power small appliances such as radios, lights, TV sets or mobile phone charging, to schools, a rural health centre, small businesses, harbour facilities and churches. The original design of the MG was comprised of 300 × 200 Wp monocrystalline solar PV modules, 720 × 650 A/2 V deep cycle batteries, 4 × 15 kVA inverters and 4 × 100 A/240 V DC charge regulators. The whole system operates at 240 V DC to AC and electricity is distributed through two 0.4 kV lines within a distance of 1 km. A re-wiring of the whole system, the exchange of all inverters and charge controllers was necessary in 2015 after lightning hit the system a few times causing high voltage surges which led to the failure of the components. During the reconfiguration, the string size has been increased from 10 to 14 panels per string to optimize the voltage requirement of the controllers. The number of panels was reduced from 300 to 224 which resulted in a reduction of energy output by 15.2 kW or 25.3% compared to the former configuration leading to an average energy output of around 209 kWh per day. Accordingly, the number of charge controllers and inverters was also reduced from four to two providing a 45 kVA instead of a 60 kVA power output which was sufficient due to the low energy demand. With the downsizing of the system, the daily power supply is rationed and power is now available only at certain times and for 14 h a day. The estimated annual energy output is 76,500 kWh based on a projected local energy yield of around 1700 kWh per kWp installed [71] excluding

transmission and distribution losses per year. The battery system, which is the largest cost position in an off-grid solar system is currently sized at 720 batteries each 2 V and 650 Ah capacity, i.e., total energy storing capacity of 720 × 2 V × 650 Ah = 936 kWh in Mpanta. This configuration if fully operational, would allow two days of battery autonomy so that the users can enjoy uninterrupted power during cloudy days.

The 30 kWp mini-grid in Sinda village, commissioned in 2017, was developed as a pilot project to enhance private sector investment in the RE sector in Zambia and has been developed and owned by the Zambian developer Muhanya Solar Ltd. It is the first MG in Zambia that has been established as a public-private partnership project and is operated by a private company in cooperation with the community. The system is comprised of a 30 kWp solar PV generator, one 20 kW inverter and 140 kWh of battery storage capacity which is connected to four 100 A charge controllers. The 2.5 km overhead distribution network with a voltage of 230 V currently connects around 60 households and 5 businesses.

The implementation of Mpanta in 2013 was part of a wider \$4.78 million energy access programme rolled out by REA and funded by the United Nations Industrial Development Organization (UNIDO) with an investment volume for Mpanta MG estimated at around \$1.3 m which was 100% grant-funded [72,73]. The CAPEX for the Sinda MG stands at approximately \$350,000 based on approximately 70% gran<sup>t</sup> funding from Power Africa Off-Grid Energy Challenge and Musika Development Initiatives which was complemented by 30% equity provided by Muhanya Solar Ltd. [74]. Hence both MGs were implemented with significant gran<sup>t</sup> investment with CAPEX per kWp installed being almost twice as high for Mpanta compared to Sinda. Table 3 presents an overview of the technical specifications of both MGs.


**Table 3.** Overview technical and financial specifications for Mpanta and Sinda Mini-Grids.

\* See Table 5; [74]. \*\* See Appendices A and B.
