Solar PV Module Mount Rail

Would like to know price list and minimum order quantity for;
1.Solar mounting system at metal roof inclusive all necessary accessories and rail
2. Ditto for concrete roofing tile roof

How far can the rails span between the angle supports?

List and explain different techniques that can be used to gather and make use of solar energy.

Like any utilization of the environment, solar power is connected with some negative impacts. Discuss these effects and explain procedures that can be taken to minimize these effects.