performance of the system and environmental conditions is important

The useful life of photovoltaic systems between 20 and 25 years. The useful life depends on the performance of the system and environmental conditions , That in normal conditions 25 years.

Dear Ali

Places no gas pipeline to transport fuel is quite costly.

In the mountainous countryside and cold , but the sun is good.

Places where safety and technical reasons , to use electricity or gas for heating does not exist.

Dear Ali, 

You need to perform a Life Cycle Cost Analysis in which you compare the Capital and O&M costs of the solar technology to the conventional technology that might be used in the place in consideration (generally diesel/gasoline genset). Then, according to the energy availability and the technology performance you need to estimate the yearly generation and run cashflow analysis to determine the advantage or disadvantage of your proposed solution.

One easy to use and free software is RETScreen (www.retscreen.net) and it will help you to do the analysis, including GHG emission reduction and sensitivity/risk analysis to give you plenty of information of the robustness of your solution.

I hope it helps!

Luis

performance of the system and environmental conditions is important

Luis said "LCA, the Capital and O&M costs, the yearly generation and run cashflow analysis, the advantage or disadvantage,..."

+ environment factors

It can be evaluated as 20 years because of loss of efficiency.

These factors must be taken into consideration.

Then, you must ask yourself

Is it feasible? Ok: Lets start.

Is it feasible? No: What is a feasible investment for me?