Brad, AA1IP, writes to the Flying Pigs QRP mailing list:
The November 2007 issue of Popular Mechanics magazine describes “Breakthrough Awards”, one of
which discusses an interesting power source. Picture a taut membrane clamped at both ends, with a small button magnet affixed near each end. When the wind blows, the membrane vibrates, moving the magnets into and out of two pickup coils. The circuitry isn’t
described, but I imagine that a couple of low forward-voltage-drop diodes steer the coils’ outputs to rechargeable batteries.
Here’s a descriptive video. I could envision using one or more of these in a hilltop location.