Investing in a Solar Electric System is similar to investing in an IRA.  The first year you will get a 30% return (tax refund) that you would have otherwise paid to the Federal government.  Then the electricity the system generates is the interest  you earn each month for 25+ years.  Plus, your savings will increase as the price of electricity climbs.

Imagine if 5 years ago you bought a tanker full of gas (assuming you had a place to store it).  At today's gas prices that would look like a great investment.  Buying solar is similar (except you don't have to store it).  Investing in Solar Electric is essentially 'buying' electricity at today's prices and locking in that price for the next 25+ years!