Solar / Photovoltaic technology is promising for Pakistan. The govt. is providing subsidy on imports of these panels hence we can have them as low as for PKR 70/ watt in wholesale. The average life of solar panel is 10 - 25 years. I have been playing with solar based power solutions for last 3 years. The major issues that one can face is :
1. Replacement of batteries. The average life of liquid battery is not more than a year. They need to be changed and thus add up in cost.
2. Over-rated panels. As far as Chinese solar panels are concerned (about 95% available in market) are very over-rated. One should not expect more than 50 watts from a 100 watt panel.
Yes, the panels can be made at home provided you import raw-material from factory. Solar is ideal solution when you need portable power solution (like at war-fields , forests , hiking etc). I have made a brief case packed prototype of portable solution for my use. However, for a replacement of Wapda / KESC at our homes, I will suggest a solar-thermal solution.
The solar thermal solution becomes more cost-effective and reliable when applied for greater than 500 Watts application. Also, it is ideal for Pakistani climate.