[ToddF]

First, I would separate solar electric from solar thermal.

Since most (if not all) states require buy back deals from the utility, battery banks are only used for off-the-grid applications. You sell extra electricity to the utility during the day and buy it at night. This is called grid tied.

I would list expense (about the same as coal generated) as a drawback of photovoltaic power along with a world wide shortage of PV panels the last year.

As far as solar thermal, lots of upside. It produces about six times the power per square foot as photovoltaic. The hot water panels cost less than half as much per square foot, too. Solar thermal pays for itself in 5-10 years and lasts at least 30 years.

As far as a downside, copper used in the absorber plates and pipes is through the roof. But its kind of like oil: a doubling of oil prices only marginally raises the price of gas since the raw material is only one expense. Manufacture and distribution of solar panels does not rise as quickly as the copper, thank god.

I could go on forever about solar thermal. It is the best idea no one knows about, as evedenced by your omission. Thanks for the forum.