By Dan Hebert, PE, Senior Technical Editor
At the recent Wonderware WonderWorld conference in Las Vegas, Tesla Motors founder Martin Eberhard shared his vision for creating the world’s first sexy electric car. As Eberhard demonstrated via his multimedia presentation, electric cars long have been seen by many as glorified golf carts.
Eberhard showed a series of slides that contrasted electric cars surrounded by geeks to gas-powered vehicles draped with lovely bodies. His message was clear: Superior technology will not be enough to sell electric cars to the general public. Electric cars must instead also appeal to our hopes, dreams and aspirations.
For many of us, these aspirations include a sports car that turns the heads of the opposite sex. Hence Eberhard’s decision to create the Tesla Motors Roadster, a car that does 0–60 mph in four seconds while looking every bit the $100,000 that it costs.
The two-seater Roadster might not be practical for many, but Eberhard’s dream car is now in production, and it inspired virtually all of the world’s major automakers to follow suit with electric cars of their own. Typical is GM Vice Chairman Bob Lutz, who said of Tesla Motors: “If some Silicon Valley startup can solve this equation, no one is going to tell me anymore that it’s unfeasible.”
Eberhard always knew that he wanted to make an environmentally friendly sports car, but the fuel source was in question. Electricity won out because it is more efficient in its natural-resource consumption, it has the smallest carbon footprint and it is the most flexible of fuel sources.
In terms of efficiency, Eberhard examined the leading contenders and dismissed them one by one. Hydrogen fuel cells really are not a fuel source, but just a fuel storage device. Fuel must be used to create hydrogen, and a fuel cell vehicle simply depletes the hydrogen as it operates.
The entire process is quite inefficient, especially as electricity typically is used to create hydrogen for fuel cells. Not surprisingly, it is much more efficient to simply use electricity to drive a vehicle’s electric motor rather than progress through the entire hydrogen fuel cell cycle.
How about biofuels such as ethanol? The resources that go into the production of ethanol are truly immense, making it impractical as a replacement for gas on any significant scale. “It would take all of the available arable land in the U.S. to produce enough corn to fuel 50% of U.S. vehicles with corn-based ethanol,” said Eberhard.
Not only do biofuels take up lots of land, they also consume prodigious amounts of energy during production.
Diesel also was examined as a fuel source, but Eberhard found it wanting. Large diesel motors, like large electric motors, are much more efficient than smaller motors. It is thus more efficient to create electricity from a large diesel generator in the megawatt range and use this electricity to run an electric car; as opposed to burning diesel directly in a vehicle.
When Eberhard brought up the point about burning diesel to make electricity, it naturally led into discussion about the fuel flexibility inherent in electric vehicles. Electricity can be produced with many “fuels” including nuclear, natural gas, oil, diesel, biodiesel, hydro, solar, wind, geothermal and others.
The electric vehicle is thus the most flexible of all contenders in terms of fuel sources, a great advantage as the world experiments with various means of power generation to find the optimal mix in terms of cost and environmental impact.
So with all of these advantages, what has held the electric vehicle back?
The first hindrance is economy of scale. Gas-powered cars must be produced in annual quantities of at least 100,000 units to be priced affordably. No electric vehicle has yet to approach these figures.
The second issue is battery price. The Tesla Roadster contains about $15,000 worth of lithium ion batteries, and their cost must come down significantly. “Electric vehicle batteries should continue to improve in cost and performance as manufacturers begin to optimize batteries for cars as opposed to consumer electronic applications” predicted Eberhard.