electric water pumps for potable water, the daily energy requirement is known and
a system designer can calculate the size of solar panel required.
Figure 2: Typical system components of a SHS: World Bank12
Solar home systems (SHS) are a package designed for households and cottage
industries, and typically comprise of a small solar panel and mounting,
rechargeable batteries for energy storage and battery charge controller. The retail
price of a SHS ranges from about US$100 to US$500 for 10 W to 50 W systems,
respectively.13 The installed cost of electricity from solar PV ranges from US$1.5 –
3.5 per kWh.3 A list of solar suppliers in Africa can be found in Annex 3. Special
training is required for the caretaker of the system. A SHS with a 50W solar panel
in an area with a good solar resource can power four energy efficient lights for up
to five hours a night.
There are a wide range of battery types available, with varying usages,
performance, maintenance requirements and cost.14 There is no such thing as a
universal battery; a single type of battery cannot cover all applications. Batteries
should be well matched to the application to ensure good performance. Some
batteries require regular maintenance to ensure good performance and long life.
Batteries have a life span significantly less than that of solar panels and can be
expensive to replace. The owner or operator should be made aware of the
importance of proper maintenance, trained with maintenance activities, and have
access to maintenance supplies and replacement units.
Portable solar lantern products are the most affordable form of PV lighting available
and currently in widespread use across Southern Asia and East Africa. A number
of models are available that are high quality, durable and relatively low cost. These
products are suitable for mass marketing models that use local retail networks and
can potentially be used to support the development of new micro enterprises where
appropriate. An example of this is the Christian Aid supported ToughStuff pilot
project in Kenya (see the PPE intranet site link below) or the D.light Design.15
Renewable Energy to Reduce Poverty in Africa