A prototype fuel cell vehicle built by Britain's Riversimple is being hailed as the planet's first practical and affordable
hydrogen car.
The Riversimple electric car is powered by hydrogen fuel cells. (PHOTO COURTESY: RIVERSIMPLE)
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Engineered under top secret conditions until its June unveiling in London, Riversimple's release is a two-seater zero emissions
hydrogen-electric city car with an expected fuel consumption equivalent to 360 miles per gallon, which is six times better
than the hybrid electric vehicles currently available, according to Hugo Spowers, Riversimple's founder and director of the
hydrogen project. He observes that "we believe that we are closer to market with a commercially viable fuel cell car than
anyone else in the world."
Developed in collaboration with Oxford University, Cranfield University and the Asian-based Horizon Fuel Cell Technologies,
the research was also supported in part by England's BOC Group gas company and the Piech family, including Sebastian Piech,
who is a great-grandson of Porsche founder Ferdinand Porsche and a member of the Riversimple project's team.
Integrating a 6 kilowatt Horizon fuel cell, the vehicle maximizes energy efficiency by utilizing lightweight composite materials,
eliminating heavy mechanical components and by networking fuel cells with ultra capacitors and 60 percent regenerative braking
energy into a single symbiotic system. "Horizon's approach to commercialization of fuel cells perfectly complements our approach to bringing hydrogen fuel cell cars
to market," says Spowers, noting that the vehicle is capable of traveling 240 miles on a tank of hydrogen weighing 2.2 pounds.
"The really tricky area has always been the power electronics," he notes. "Amidst divergent and robust opinions on the powertrains
and fuels that will replace the conventional fossil-fueled combustion engine, there is a surprising level of agreement on
one-step change in technology – a shift from a mechanical platform to an electrical platform," says Spowers.
"Ever since this modern trend started, the power electronics have been notorious for being the trickiest area of all in getting
a new vehicle off the drawing board and on to the road. Light, efficient and robust electronics are tough to get right," he
points out.
"We know we really do have a powertrain that works through a regulatory duty cycle," says Spowers as he recounts the various
challenges that needed to be addressed. "Since then, it has been a matter of developing our knowledge – and our confidence
– on how we can get the best performance from the system, and how it will stand up to being driven harder and harder. We're
dealing with high voltages and currents here, and both large and rapid changes and reversals of current. And the consequent
voltage spikes are, of course, what is most prone to damage sensitive components," he adds.
"This next generation hydrogen-electric car brings electric vehicles into a new stage where range, charge-time and cost are
no longer commercial barriers," reports Taras Wankewycz, a Horizon co-founder and vice president of business development.
"Technologies have evolved, but more importantly, Riversimple brought them together as one system, in a way that greatly exceeds
the sum of their individual benefits," he says.
"Many people lost track of the fact that fuel cell cars are electric cars, since fuel cells store and deliver electrical energy,
just like batteries – only with significantly more storable energy per unit of weight. Batteries and ultra capacitors on the
other hand, offer more power per unit of weight, but less storable energy," Wankewycz says.
He goes on to explain that a fuel cell converts the chemical energy of hydrogen into usable electric energy without combustion;
water is the only by-product. "Unlike batteries, fuel cells separate energy storage and energy conversion functions. If used
as a primary source of power like many fuel cell vehicle developments to date, fuel cells can become extremely expensive as
power needs impacts their size. But when changing the configuration and coupling the high energy density quality of fuel cells
with higher power density ultra-capacitors, it is possible to greatly increase the performance of electric vehicles while
reducing their cost, says Wankewycz.
