Solar power is relatively pollution free.

  Systems can operate with little maintenance or intervention after initial setup.

   Solar power is becoming more and more economical as costs associated
   with production decreases, the technology becomes more effective in
   energy conversion, and the costs of other energy source alternatives
   increase.

   The US has begun investigating solar power as a viable energy resource
   due in part to comparative costs associated with purchasing energy from
   other sources.

   When grid connected, solar electric generation can displace the highest cost
   electricity during times of peak demand.

Source: wikipedia.org, 2006