“Poly-silicon” or polycrystalline silicon
PV Modules are safe on their own, but when connected special care should be taken as there are high electrical currents and as with all electrical operations, only qualified competent people should be involved in the operations and construction process.
This depends on method of manufacturing; mono crystalline is more expensive than poly crystalline. During the recent years (5 to 10) the cost of panel manufacturing in South Africa has reduced dramatically and given the decrease in costs, PV panel installations are almost at grid parity to the rest of world.
A PV panel can generate power and energy for over 40-years, but the expected lifetime of a panel is 20 to 25 years of optimal production. Each year the panel will lose some generating capacity, not a lot but some.
Damage to PV panels is most likely to be caused by blunt force i.e. rocks, hammers or people jumping on them. They are rated and tested against quite large forces and hail or heavy rain will not cause damage.
Dust can reduce the ability to generate at maximum, but only slightly.
As there is no light at night, no energy will be produced. The PV plant will import energy from the utility to keep operations on site going.
The PV panels are cleaned manually. There is a staff of 16 local people responsible for panel cleaning and vegetation control. They work early and late, to avoid interrupting production during the high sun hours.
A single table containing 95 modules can be installed in less than 30 minutes by a trained labourer i.e. 20 seconds per PV panel.
The panels will generate energy if any light falls on it, cloud causes indirect light and this is also good enough for the panels. Power generated is directly proportional of the amount of irradiance (light) falling on the panel. So if reduced the panel will have a reduced output.
Solar is still more expensive than wind at this stage, with cost per MW higher than that of wind.