One possibility to avoid high storage costs is to use the solar electricity only during daytime, with a small battery system for peak demands. At night or during rainy days the electricity is generated by the Diesel generator.
Experiences in Senegal
► Experience from EnDev.
In Senegal EnDev disseminates PV-diesel hybrid mini-grids for the electrification of villages with up to 500 inhabitants or 40 households.
The systems consist of (approximate total cost including installation in brackets):
- a PV array with a capacity of 5.1 kWpconsisting of 30 polycrystalline PV modules with a capacity of 170 Wpeach (15,000 €)
- a battery bank consisting of 24 elements of 2 V of lead-acid tubular plate batteries; element capacity is 800 Ah C10 leading to a bank capacity of 38,4 kWh (15,000 €)
- a monophase generator of 10 kVA linked to the PV system (7000 €)
- a 5000 VA inverter (4,000 €)
- 220 Volts low voltage three phase AC distribution through a mini-grid (10,000 € per km; 2-3 km per village)
- system housing (6,000 €).
The total costs of installing a system is between about 70,000 € and 80,000 €.
The 16 systems have a total PV capacity of 81.6 kWp and can generate 106.9 MWh per year. Electricity generation by the diesel generator is not included in this calculation.
Experiences in Kenya
► Experience from Prosolar
In Kenya, the GIZ project Promotion of Solar-Hybrid Mini-Grids (GIZ ProSolar) aims at promoting mini-grid electrification of remote areas in Kenya with the participation of private sector. The vision is to increase levels of cost-effective, affordable and sustainable rural electrification through private sector leadership.
- The Talek Power mini-grid is a pilot project set up in Talek in close cooperation with the Narok County Government and the German Agro Action. The mini-grid consists of a solar-hybrid generation power plant (40kWp solar), combining a storage system of 3.200 Ah, and a 12 kVA diesel generator. Commissioned in June 2015, the power plant delivers solar power to a rural business center and the community through a 3 km low voltage network. The community purchases electricity through a pay-as-you-go mobile money enabled metering technology. The project’s CAPEX (generation, distribution and metering system) cost was ca. 250.000 €. The pilot tests the social and economic viability of mini-grids and serves as a learning scheme for stakeholders. The mini-grid has improved the lives of the people of Talek, fostering economic development, education and improved health.
- Furthermore, an advanced training course has been developed for solar technicians, qualifying them to install hybrid solar systems in villages. The technicians receive their hands-on training at a 10kW solar-hybrid demonstration system, which was installed at Strathmore University. The demonstration training system was installed using the same technology as the one applied in Talek mini-grid, only in a smaller scale.