Comerica Bank has joined with solar installer Akeena to develop financing options that instantly become cash flow positive.

Solar power is more expensive that fossil-fuel electricity in most states, but the combination of tax incentives and write-offs can make it cost effective. States with net metering that allow you to sell excess power during the day can make the systems even more lucrative

"... In most cases, the monthly after-tax HELOC (home equity line of credit) payments will be less than the electric savings from the solar power system – providing positive cash flow for our customers the moment the system is switched on,” says Barry Cinnamon, CEO of Akeena in a press release.

By financing the solar system you can add value to your home while adding a backup power system using batteries.

Cities in Silicon Valley are providing special incentives to get people to install solar. SolarCity has teamed up with the cities of San Carlos, Mountain View, and San Jose to offer up to 20 percent off the installation price of a solar system. Along with California, New York, New Jersey and others, Rhode Island offers up to a 25 percent incentive on solar installations.

Even though I'm generally old school about paying for things, with solar it doesn't pay to use cash.