John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
This prototype "green" e-cycle can creep forward on the power of the sun alone, no battery required.
It's not exactly Ed Begley Jr.'s self-satisfaction-powered go-cart, but it's close: an ultra-green electric bike so festooned with solar panels it looks like it fell off of the International Space Station.
The Solar-Cross concept cycle is a one-off invention from Terry Hope, a former schooner engineer who lives near Vancouver, British Columbia. Hope cobbled together the earth-loving thingamajig from a mountain bike, a 1,000-watt motor, yards of wire and black tape, and 32 photovoltaic cells weighing about 5 pounds together. He claims that the resulting 48-pound ride is the "world's lightest hybrid solar vehicle." The cost for all the components is roughly $500; just don't ride under any low bridges, or you might have to ante up some more for repairs.
Unlike many other sun-fueled e-bikes, Hope's two-wheeler doesn't need a battery to run. He just aims skyward his impressive solar array, including a rear fender stretched way out like a dragonfly's tail, and it starts creeping forward. The tinkerer has honed his design well enough that the bike can scoot up modest hills on 10-volt juice, albeit rather slowly. But there's always the option to use his feet, which is necessary when the clouds are out, as he explains:
When the sun is shining and the ground is level my electric mountain bike will continue to roll forward with no pedaling or battery power required, powered only by sunshine. When I do pedal however... the e-bike becomes a solar assisted vehicle.
Have a look at the Solar-Cross in action, and if you're interested in the prototype that preceded it here's info on Hope's KPV, a net-zero cycle that squeezes inside a suitcase.