Correct Bitt, if one wishes to live "off the grid" one needs to store the energy produced somewhere and a battery is the usual option. Is it perfect? No.

Unless one builds the storage system to cover the possibility of no power produced for several days one needs to obtain power from some where. The over all run time of the generator is usually small. But yes it is polluting.

So your alarm clock is consuming 4.5W, which only cost you $4.32/year and yes that is nothing, but lets add it ALL up.
TV, VCR, DVD, microwave oven clock, wall cube power supply (I know I have many, two cell phones, computer speakers, regular phone, portable power tool charger, laptop), three clock radios, monitor. Plus Tivo, router, wireless, and so on.
I'm not going to pull numbers for all of these, but going by this PDF I'm wasting a chuck of power. When you are attempting to live off the grid you need to chase down all these 4.5W loads and eliminate them, else you have to increase the amount of power you produce, increase the amount of power you store.
So, no, I'm not asking you to replace your alarm clock and save 36cents a month, I'm just advising Doug that he replace his alarm clock and reduce the number of PV & batteries he needs.

As for cost effective, yes it is a long ROI. Think of it more as a life style choice, the ROI is that long.
For me I don't think it is too crazy to spend an additional $10k on a new house to half my eclectic bill, or $5k to have free hot water.
50 years ago houses were poorly insulated, buy hey nuclear power was on the horizon and power would be so cheap we'd not care.