There are many factors that need to be considered before deciding on the economics of going solar such as:
1.Size of system needed.
2.Cost of system.
8.Plan to make home energy-efficient and its cost.
9.Net metering laws and practices.
10Local electric rates.
11. Future inflation of rates. Rates have averaged 2.5 cents increase per year in Texas for several years. That is severe. However, it is generally accepted that all standard sources of producing energy will escalate rapidly now.
You must also consider:
Amount of sunshine/shade if solar.
Wind velocity relative to height and amount of property owned if wind.
Drilling parameters and amount of property owned if geothermal.
Strangely enough, the time it will take for your system to pay for itself depends pretty much on the same items.
If you use a consultant, they will help you get this information together and analyze it on paper.