Move this up a notch to the Enertia electric motorcycle, found at www.brammo.com; I actually own one of these. They intentionally left off regenerative braking from this vehicle for the very reasons stated in this article- there isn't really that much energy to be recovered, and with the appropriate riding style there is no need as the brakes aren't used much.
Also, I'll add that the generator hub goes back a long, long time. I have a vintage 1950's era generator hub made by Sturmey-Archer. But it's performance pails in comparision to the contemporary offerings commerically available today. These hubs are generally used to power headlights. From a systematic perspective it's probably still a very inefficient way to power a headlight, but at least the energy source is always available and that convenience and reliability is the key.
I bicycle a lot, and
the regenerative recovery mech
makes great sense in hilly areas.
I wind up zooming down hills
@ 30 mph, only to grind up
the other side @ 8 mph.
The regenerative recovery
would be used to reduce decent
to like 10 mph to reduce drag.
That recovered energy would be used
(partly) to climb the other side.
In that sense, its quite useful, plus
the afore mentioned advantages.
Very true. Third-World countries are "greener" than more developed countries because they depend on concealed costs in the form of food for humans or animals, and they deliver less power per person for healthy and comfortable life styles. Life-spans are shorter and diseases are more plentiful (although not "green", bacteria are, after all, wild plants).
Also, in a Third-World context, the work-time lost cycling for 30 minutes is of no matter when compared with the same travel for 10 minutes in an automobile. Third-World time is cheap, as is the labor. This is not so, in a highly competitive, industrialized environment.
The benefit of the bicycle is that it involves only about 100 kg or less of "equipment" (mostly the rider), whereas an automobile involves more like 1000 kg. Eating 50 cal per day more of food to compensate for unavailability of regenerative braking should mean nothing to a cyclist, Third-World or not.
Regenerative braking may make cycling in a hilly area a little less stressful, but it has no other "green" benefit, no matter what MIT might claim.
"any half-way decent cyclist doesn't use the brakes very often"
I believe the device in question in intended for city communing. Even a "half-way decent cyclist" has to yield to other traffic at times.
"Either you'll have to pedal harder to maintain your target speed"
I took from the article that the rider can control when the generator is active.
"That's a very inefficient process when you look at the total energy chain from growing and transporting the food, to converting muscle power to electrical power."
Many people over eat as is. It'll be better to have the extra calories be used for work instead of carried around as fat. Also, a lot of "green silliness" is going into reducing the energy required to grow and transport food (e.g. encouraging the consumption of seasonal and local food).
Bill's observations are cogent, but there is one aspect to the human "progress" that he does not touch upon.
The move from inefficient animal power to engines of various types was nearly always a move from renewable energy to the non-renweable consumption of coal and oil. And it is that "free-ride" from the consumption of natural resources that is not sustainable and which the planet is struggling to accommodate.
So, in which direction does progress lie?
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.