The hybrid system
on Mfangano island.
Source: juwi
 
23 September 2013 – It is a situation many villages in rural Africa know too well: If there is electricity at all, the costs for operating the diesel generator continuously increase. At best, this leads to power shortages, more often, it leads to total blackouts. To significantly reduce costs for diesel operated grids, juwi’s Off-Grid division developed the Solar-Fuel-Saver, an intelligent system for integrating solar systems into existing, or even new diesel generator grids.

What makes this concept unique is that it is the first hybrid system that doesn’t need batteries, making it up to 60% cheaper than battery-operated off-grid systems. On Mfangano Island in the eastern part of Lake Victoria, juwi installed such a system with local partners and this resulted in lower operating costs.

The solar plant on Mfangano Island is coupled with the existing diesel generator and is directly injecting its power into the mini-grid. This reduces the power demand on the generator. Fabian Jochem, Head of juwi’s Off-Grid division, says, “The idea behind our concept is to reduce the generators’ fuel consumption during daytime hours by injecting as much electricity as possible from the solar plant into the grid without harming the diesel generator. The power output of the photovoltaic plant is therefore controlled by an intelligent controller, the Solar Fuel Saver.”

Together with local partners, Dreampower and KPLC, the general concept was elaborated and then implemented on the island. Thanks to the solar park’s layout, it can take up to 25% of the average load during midday which is currently 40 kilowatts. In case the load is decreasing, the solar plant’s power output will be adjusted automatically to avoid the diesel generator operating under minimal part load conditions.

juwi sees great potential for so called Solar Fuel Saver plants in Africa, as the generation costs with diesel powers plants will constantly rise. “Electricity production with solar plants already represents an economical viable solution. The production costs of solar power in Kenya is approx. 0,15 KES/kWh and lays therefore about 60% lower than the production costs with diesel generator grids which have generation costs of higher than 40 KES/kWh,” Wiebke Krueger, project manager at juwi’s Off-Grid division, says.