Excerpt:

The next time you change a bike tire, think about upgrading your power as
well. Scientists at MIT are testing a new power generation, storage and
propulsion system known as the GreenWheel that will turn any pedal bicycle
into an electric hog.

"Just take the wheel off, put a GreenWheel equipped wheel on in its place,
plug it in and it should work just fine," said Ryan Chin, one of the
GreenWheel designers. "The whole thing has been designed so all the parts
except the throttle are enclosed in the wheel."

From the outside, the GreenWheel has the radius of a small dinner plate
and is about 2 inches thick. Inside the aluminum frame sits the three
major GreenWheel components: an electric generator, batteries and an
electric motor.
...
Under its current configuration, a bike powered solely by a single
GreenWheel (front, rear or both wheel can be equipped with a GreenWheel)
has an estimated range of 25 miles. Pedaling the bike doubles the range
under electric power, provided the rider isn't traveling at the nearly top
speed of 30 miles an hour. The bike can be charged by pedaling or by
plugging it into the electric grid.

A GreenWheel equipped bike is a smooth ride, as Discovery News found out
during a recent afternoon test ride around MIT's campus. Turning the
handle mounted throttle, like any motorcycle, just a few small degrees
produces a noticeable increase in power and a light electric hum. The
handle-mounted throttle is connected wirelessly to the electric motor in
the wheel.

The GreenWheel is also durable. The team estimates its range at 40,000
miles, or about eight years work of travel at an estimated 20 miles per
business day.

"You'll have to replace the bike before you replace the batteries," Lin
told Discovery News.

By this spring the GreenWheel team hopes to pass out more than a dozen
different GreenWheel configurations to both hard-core bike messenger types
and novice riders.

Once the optimal configuration of power, speed and cost is determined the
team hopes to begin large scale production.

Copenhagen and South Africa, in preparation for the 2010 World Cup, have
already expressed interest in adding GreenWheel-equipped bikes to their
public transportation systems. The rough idea right now is to follow a
popular bike share program in Paris. Subsidized by advertising revenue and
an annual subscription, the first 30 minutes are free, and any time after
that incurs a small fee.

MSNBC: Green wheel turns pedal bike into electric hog
MIT trades bike tires for power generation, storage and propulsion system
http://www.msnbc.msn.com/id/29259226/