Well this company disagrees with you.
http://www.motioncharge.com/

In fact here is their statement from their website.

Motion Charge Company has developed two revolutionary technologies called "MotionCharge" and "KeyCharge" that address power problems in portable electronic devices. These technologies, which are currently patent pending, enable a portable device such as a portable computer or cell phone to automatically recharge it's battery from (1) routine motion of the user, such as walking (in the case of MotionCharge), and (b) from motion derived from a users utilization of the keyboard (in the case of KeyCharge).

In this manner, the battery in a portable electronic device is continually recharged by routine activities of the user, effectively significantly increasing battery capacity. For example, the very act of utilizing a computer or walking around with a cell phone recharges the battery.

These technologies are inexpensive to produce and would be very easy to integrate into existing devices as well as future models. In addition, MotionCharge can be provided to the user as an external accessory.

If you company is interested in learning more about the above-described technologies, please contact us. For a more detailed background of the challenges addressed by our technologies, please see The Challenge and The Solution, Click here.

I looked up their patents at uspto.gov and found this patent
# 7,105,939
Sep 12, 2006
was granted

For a fridgeputer, you want something like a magnetic N800. You might use it on the fridge to bring up a calendar or to add an item to a shopping list, but you also want to be able to lift it off to show people stuff or to use it on the kitchen table. You don't want to have to unplug it every time you use it.

So a solar solution that provides infinite standby (and maybe even a bit of a recharge) is fine. Then, once every couple of weeks if necessary you plug it in (but still on the fridge).

Probably want something a little larger than an N800 for this use case though.

Regards,
Roger