Your solar electric system will continue to produce electricity as regularly as the rising of the sun each day. And utility rates can be practically guaranteed to continue to rise. So your investment in solar is fairly low risk. Because there are no moving parts in a solar system, and silicon based solar modules have been operating for decades (some for as long as 50 years), manufacturers expect each solar module on a home to operate for at least thirty years. You could compare the value of the electricity produced by a solar electric system to an annunity payment you receive each year. The electricity you produce means you have to spend less of your after tax income to pay out for the electricity you need.