Seems like a fair bit has changed in 15 years, batteries (Lead Acid, really?), inverters, even generators are way more efficient. At the end of the day it's only 100-150W in, but even at 50% chain efficiency, 100W for 1h = 50Wh = 10000mAh = ~ 2 phone charges, which is not nothing.
The flywheel (replacing bike and rider inertia) for greater biomechanical efficiency is a well taken point and would lead to a more consistent power output.
Rebuilding it as a general purpose rotating spindle which could attach to a generator, a blender, a multi function food processor, grinder, sewing machine etc. could go a long way towards making a useful device.
