Reducing energy cost with solar power is a white hot topic today. Many people understand that solar power can help reduce energy but do not understand how. Nothing reduces energy like a free energy source (the sun).
For a non-technical explanation of how a solar power(photovoltaic system) works and how a solar hot water system works, Duke Energy has a good article here.
For a good explanation of how to size and install a solar power system, Duke Energy has a good article here.