This reminds me of one Field Day operation back in the late 60's or
early 70's. We made our "renewable resources" contacts by hooking
two bicycle generators (used normally for headlights) together in
series, putting a very large capacitor across the output, and then
powering a QRP transceiver with the Rube Goldberg power source. I
recall that we only needed to make one contact that year, but it
took a while because the amount of energy we could store in the
capacitor was very limited, and we couldn't run the QRP rig for more
than a few minutes at a time.
In later years we realized the folly of the setup, and put a "dead"
wet cell across the output of the generators. After 30 minutes or
so of cranking the generators we had enough power to make enough
contacts, and we didn't even need a voltage regulator.
Even later, one fellow converted a lawn mower engine to run on
ethanol, hooked it to a generator. We bought a quart of 180 proof
drinking ethanol (gasp! what a waste) to power the thing, and had
more than enough power for the 5 or 10 contacts that were required
in subsequent years.