Here Comes Hypercar! Despite the fact that the price of gasoline seems stuck around $2.00
per gallon, gas-guzzling SUVs and pickups remain as popular as ever among
Americans. The United States produces 25% of the world’s greenhouse
gas emissions; cars and light trucks account for around 20% of the nation’s
energy-related greenhouse gas emissions, according to the U.S. Energy
Information Administration. It would appear that a gas-saving, nonpolluting
car for the U.S. masses will need to be something that even car enthusiast
magazines could applaud. It will need to equal or beat conventional cars
in handling, performance, size, safety, and amenities, and do so at a
competitive cost. It’s a tall order, but Amory Lovins, chief executive
officer of the nonprofit Rocky Mountain Institute (RMI) in Snowmass,
Colorado, thinks he may have just the car to meet it: the Hypercar®.
The latest version of Lovins’s Hypercar concept is a detailed
virtual design illustrating an SUV crossover vehicle that would fully
compete with today’s midsize entry-level luxury SUVs. Powered by
a hybridized hydrogen fuel cell, the concept, dubbed Revolution, would
achieve Environmental Protection Agency mileage ratings equivalent to
108 miles per gallon (mpg) of gasoline; as a Prius-like gasoline hybrid,
62 mpg, and with a good nonhybrid gasoline engine, 45 mpg, according
to extensive RMI simulations.
The gasoline hybrid version could sell profitably for $40,000-45,000
(in year 2000 dollars), at standard markups based on what
Lovins calls extensive supplier price quotations for 82% of the components,
plus bottom-up cost modeling by RMI and independent consultants
for technologies not yet in production. Further development
could pare the price to about $35,000.
But Lovins’s concept goes beyond transportation. A national fleet
of fuel cell-powered Hypercar-class vehicles could contribute to the
national electricity grid when they are parked--which averages about
96% of the time, according to the Population Reference Bureau. And according
to RMI, if Hypercars captured half of the world’s market by 2020,
global carbon dioxide emissions from cars and trucks would fall 25%,
instead of rising by 12%. (This estimate assumes that the efficiency
of conventional cars improves by 25%, and vehicle miles traveled increases
by 50%.)
Light Years Ahead?
Lovins’s big idea that makes the Hypercar seem attainable is
what he calls “the snowballing of weight savings.” Essentially,
if you lose enough weight by trading a car’s steel body for composite
fiber, then power requirements will drop. The engine, drive train, and
suspension can all be less massive, reducing weight still further. At
this point, systems such as power steering and power brakes may become
superfluous; the need for such systems is largely a function of weight.
At 1,887 pounds, the five-seat Revolution would weigh less than half
as much as a conventional counterpart and about the same as the two-seat
aluminum Honda Insight, currently one of the most fuel-efficient vehicles
in the United States.
Stopping traffic. The 2000 Hypercar Revolution models the virtual design
of a midsize SUV. The carbon fiber body makes it lighter, safer,
and--at 114 mpg with a fuel cell--far more fuel-efficient
than traditional cars.
image: RMI |
All this lightweighting has yet another benefit. Fuel cells are so
expensive today--Consumer Reports put the price at around
$19,000 in 2004--that they are commonly viewed as a couple of decades
from practical automotive application. But the combination of light weight,
streamlining, and low-friction tires would enable the Revolution to cruise
at 55 miles per hour (mph) on the same power to the wheels that a normal
SUV uses on a hot day just to run its air conditioner, according to Lovins.
That means the car could use a fuel cell stack one-third the size needed
for a comparable conventional light-duty vehicle. Plus, hydrogen storage
tanks that are already available could be used in the cars, providing
a range of 330 miles before refueling.
The Revolution power train integrates a 35-kilowatt (47 horsepower)
ambient-pressure fuel cell, 35-kilowatt nickel metal hydride buffer batteries,
and four electric motors connected to the wheels with single-stage reduction
gears. The batteries store energy captured through regenerative braking,
meaning that when you apply the brakes, a generator does the braking,
recharging the batteries. This provides extra oomph for fast acceleration,
climbing hills while loaded, and other bursts of energy.
Twenty-five percent of the Revolution’s weight reduction over
comparable conventional cars is achieved by building the body from carbon
fiber-reinforced composite. The enormous strength of carbon fiber composites
can make cars extremely safe. Drivers have walked away from 200-mph crashes
in ultralight carbon fiber Formula One race cars. The Revolution is designed
to protect passengers from serious injury in a 30-mph head-on crash with
a vehicle twice its weight.
Carbon fiber structures can absorb five or more times the energy per
pound as steel, and can do so more smoothly. Metal absorbs crash energy
by bending and folding; a 1-foot tube of aluminum might fold 8 times
until it’s fully compressed. Carbon fiber structures, on the other
hand, sustain microscopic cracks; a foot of composite might sustain 10,000
microcracks, each essentially representing a unit of energy absorption.
The front end of the Revolution is a welded-aluminum tubular structure
that incorporates some composite crush structure as well, and the vehicle
is designed so that damaged material can be removed and replaced.
Hypercar Hurdles
The Hypercar’s light weight does present a couple of challenges.
One has to do with the ratio of the fully loaded car to the empty car,
which would bearound 1.5 to 1--not all that different from pickup trucks
used for commercial hauling. With a traditional suspension, Hypercars
could, like pickups, tend to bounce around on the road when empty.
To deal with this problem, the Hypercar would have a “semi-active” suspension.
It would be sprung on air, and a compressor would increase stiffness
as needed. The shock absorbers would be linear motors that could be adjusted
for a firmer or softer suspension. The shock absorbers would also be
able to recover electrical energy from going over bumps.
The carbon fiber structures also face technical and economic hurdles.
One problem is the long time it takes to fabricate parts out of carbon
fiber. One solution is to stamp thermoplastic composites (a type of carbon
fiber material), which can take less than 1-2 minutes. A composite sheet
would be heated up and shuttled into a press, and stamped into shape
similar to the way sheet metal is stamped out.
Dream car dissected. Ultralight vehicles suggest a solution
to the problem of storing hydrogen for fuel cell-powered engines.
A diagram of the Revolution concept SUV shows that efficiency-tripling
platform physics can shrink the hydrogen tanks by threefold. The three
tanks shown in this design provide a 330-mile average driving range on
3.4 kilograms or 138 liters of hydrogen at 5,000 pounds per square inch,
yet allow an interior that can hold five adults and up to 69 cubic feet
of cargo space with the rear seats folded flat. Such tanks have been demonstrated
to be highly crashworthy, in part because they’re supported by interior
pressure. The transverse tanks in this design have room to move axially
in a side-impact collision. The fuel cell also becomes three times smaller
and more affordable.
image: RMI |
Nonetheless, 1-2 minutes is still a long cycle time, says David Cole,
chairman of The Center for Automotive Research in Ann Arbor, Michigan. “The
economics are tightly entwined with the speed of the process,” he
says. “You would have to have a lot more machinery and dies because
of the low volume of any one part of the process. That becomes a real
concern.”
Yet, speed isn’t everything, says Lovins. Composites can be molded
into a single complex part, and the composite manufacturing methods are
more conducive to forming complex parts. In contrast, metal parts typically
are made from several stamped parts of relatively simple shapes that
are then welded together to form the complex shape desired. The body
of a Revolution would include 65% fewer major parts and 77% fewer total
parts than a comparable conventional steel body, and molding each composite
part would need one die set compared to the average of four needed to
stamp steel, says Lovins. Plus, the composite parts would have color
molded into them, eliminating the need for painting the vehicle.
At volume, Lovins believes such characteristics can make automaking
two-fifths less capital-intensive than today’s leanest plant. According
to the 2004 RMI report Winning the Oil Endgame, once you take
into account the simpler assembly, the eliminated paint shop, and the
smaller propulsion system, the extra per-car cost of the Hypercar drops
to approximately zero.
Cole sees several economic and cultural hurdles to the Hypercar concept,
but none that can’t be overcome. Besides the economics of panel
fabrication, these hurdles include a current lack of body repair shops
that can handle carbon fiber composites, and the inertia of an industry
that has enormous capital invested in conventional methods. The car industry
has to see something to believe it, says Cole. “[Manufacturers]
really want to see it demonstrated,” he says. “[But] if Amory
can do what he thinks he can do, it will turn the world upside-down.”
Hydrogen Transition
If the value of hydrogen fuel cell-powered cars extended beyond transportation,
it could possibly hasten their adoption. According to Brett Williams,
a researcher and Ph.D. candidate at the University of California, Davis,
Institute of Transportation Studies, these cars could provide power companies
with “spinning reserves”--a term that comes from the image
of power-generating turbines spinning disconnected from the grid, ready
to be brought online when needed. The cars could also be plugged into
the electric grid while their drivers work--initially, motorists might
even be paid for their cars’ services as generators in special
power-generating parking lots, says Williams.
One oft-cited hurdle to alternative vehicle use is the chicken-and-egg
problem of cars and filling stations--you can’t have the hydrogen
cars without the hydrogen filling stations, and you can’t have
the filling stations without the cars. In response to this obstacle,
Lovins points to a self-financing solution he and Williams presented
in 1999 at the 10th annual National Hydrogen Association meeting and
outlined in their paper titled “A Strategy for the Hydrogen Transition.” In
this strategy, fuel cells would be adopted to provide power not only
to vehicles but also to homes, office buildings, and other settings.
Retail refueling stations would produce hydrogen from natural gas. The
result, ultimately, would be an interactive, self-regenerative hydrogen
infrastructure. Lovins and Williams write that the strategy relies on
existing technologies, can begin immediately, and proceeds in a logical
and viable sequence.
The capital intensity of such a hydrogen refueling infrastructure is
probably less than the capital intensity of sustaining the existing gasoline
fueling infrastructure, according to Lovins. “Hydrogen can be used
so much more efficiently than hydrocarbons,” he says, “that
reforming natural gas into hydrogen scarcely increases its demand, [when
you account for] the resulting savings in refineries, power plants, furnaces,
and boilers.”
David C. Holzman
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