Case Study: Uganda

Standardized Power Purchase Agreement (SPPA)

Uganda has in place the Renewable Energy Policy 2007 of which the over-arching objective is “to increase the use of modern renewable energy from the current 4% to 61% of the total energy consumption by the year 2017." The country has  established a Standardized Power Purchase Agreement and Feed-in Tariffs (FiTs) for renewable energy projects, although these are not yet applicable to the Kiziizi mini-grid.

Private model

The mini-grid provides reliable electricity, primarily to the hospital, but also to the greater residential and business community.  The mini-grid is operated as a private company, Kisiizi Hospital Power Ltd., and because the facility operates below 500 kW the company can set its own tariffs and raise revenue from the sale of electricity.

Mini-hydro plant

The Kisiizi mini-grid is composed of a 294 kVA Ossberger crossflow turbine, a 60 kVA Giikes turgo hydro turbine that generates power just enough for the local hospital, and an 80 kVA standby generator utilised as back up during the dry season when there is reduced flow from the river.  The system is AC coupled.

 

A sluice gate controls the flow of water into an 80m long channel, which carries water to two penstocks.  An arrangement of sluice gates permits different combinations of turbine operations to be achieved, with a wider channel supplying water to the larger turbine.

 

Power is generated independently from the two turbines, with the Ossberger turbine as the main source serving both the hospital and the broader town, while in times of lower river flow, the Giikes turbine acts as a backup sufficient for the hospital alone.  There is currently no provision for synchronizing their two outputs, however the Ossberger is equipped to synchronize with the Uganda national grid in future.

 

Power is distributed 8km towards Nyarushanje and 2km to Upper Kisiizi.  There is a 315 kVA step-up transformer at the turbine house which takes the voltage to 11,000 volts.  Power then passes through an auto-recloser which disconnects the 11kv lines in the event of a fault. 

 

Power to the hospital, which is situated close to the turbine house, is distributed at 415 v by underground cable.  Eight 50 kVA and two 25 kVA transformers step the voltage down for local distribution to customers.