Under this program, Siemens is installing maintenance-free decentralized power supply systems, each consisting of a switchgear cubicle with inverter, battery charge regulator and lead-acid batteries supplied from solar collectors on the roof of the cubicle. These systems have been developed to provide power for medical stations, village schools, homes and street lighting. Typical uses in the country’s remote villages, which are scattered hundreds of kilometers apart, include the refrigeration of life-saving vaccines and the operation of interior and exterior lights, fans and even short-wave receivers and satellite phones.
The solar energy systems for village schools are designed for a peak power of 660W, those for medical stations for 550W, while the systems provided for domestic and street lighting applications operate at 110W. Medical stations and schools are supplied with alternating current at 220V. The electricity is distributed via conventional surface-mounted wiring. The solar power systems for domestic use operate at 12V DC using sockets safeguarded against polarity reversal. In this case, the steel cubicle containing the batteries – minus the inverter – is installed inside the hut and the solar cells are mounted on a steel pole outside. The steel cubicles are of a hermetically-sealed, vermin-proof design. An electronic circuit-breaker in the cubicle automatically reconnects the system following any brief short-circuit or overload. Keys are lodged with the village elder in case any of the cubicles have to be opened at some future date, for example to change the batteries after a six to 10-year service life.
Siemens PTD is working with numerous small local companies in its role as system integrator. The decentralized power supply systems are supplied from Germany as turn-key installations. Once in situ, they simply have to be mounted on concrete strip foundations, connected up to the electrical systems and commissioned for operation. The aim of bringing solar electricity to villages in Gabon is not just to raise living standards and improve communications in this country of 270,000 square kilometers. It is also hoped that this scheme will make it possible to store and refrigerate vaccines and medicines in medical stations to help improve healthcare and reduce Gabon’s high infant mortality rate of 8.7%.