- Jul 26, 2006
Exclusive Q & A with Elon Musk on the Tesla Roadster and the future of EVs
ABG: How would you describe the initial public reaction to the Roadster?
Musk: Seems to be extremely positive. Most people like the car when they see it, but are still skeptical. That skepticism turns to enthusiasm after they take a ride. The proof is in their willingness to put down hard cash. We have 100 collector's edition cars for sale that require a $100,000 up front deposit for purchase and only a few units are left. The buyers are a who's who of Silicon Valley, Hollywood and Forbes 400 members. Next year's Academy Awards will see a lot of Tesla Roadster's being driven. Compared to the Roadster, the Prius is a gas-guzzling hog!
ABG: When did you first ride in the Roadster? What was your drive like?
Musk: Well, I first rode in an early prototype car called the T-Zero from AC Propulsion over three years ago. Although it was very primitive from an automotive standpoint, the T-Zero convinced me that the technological pieces were in place to make an electric car without compromises. Since then, I've driven various stages of the Roadster development, each one better than the last. I consider the Roadster to be the most exhilarating car I've ever driven and I own a McLaren F1! The torque latency of an electric motor is so much better than an internal combustion that it is hard to appreciate without taking a test drive.
ABG: Does the Roadster live up to your expectations? If not, what will be improved in future versions?
Musk: Actually, the Roadster has exceeded my expectations. The big challenge is making all the little pieces work well, as we want this to have zero bugs when it gets delivered to customers. For example, the car has no external door handles or keyholes and instead uses an electronic touchpad on the inside of an aero feature on the door. It looks really cool, but making sure the latch always opens without sticking is surprisingly tough. At some point, we will probably do a GT version of the Roadster. Making a car with 2.9 second 0-60 mph would be awesome :)
ABG: Speaking of the future, what is the future of Tesla Motors? I've read about a rumored sedan version of the Roadster? Will the Roadster EV technology ever trickle down into a $30,000 family car?
Musk: Definitely. The overarching goal of Tesla is to help reduce carbon emissions and that means low cost and high volume. We will also serve as an example to the auto industry, proving that the technology really works and customers want to buy electric vehicles.
ABG: If it does, then it seems the Tesla Motors brand is able to contain high-end and mass-market products. Is this your goal, a great EV for the masses?
Musk: Yes, we want to make EVs as affordable as gasoline cars. Actually, given the very low cost of recharge ($2.50 for a full "tank" of 250 miles at Northern California PG&E rates) plus minimal service requirements, it should be cheaper to use.
ABG: If it does take Tesla five or ten years to get a mass-market vehicle to market, will that be too late? The Smart is coming to the States in 2008, and the Smart EV can't be too far behind. Feel Good Cars (with the ZENN EV) is another company that could work up to sedan size from their golf cart EV.
Musk: Model 2 will be close to mass market, with a price around $45k to $50k, which is the cost of mid-range sedan or SUV with a few options. Model 3 will be even lower cost and definitely affordable by the average American. However, an ultra low cost model is not currently in our plans. There are just too many compromises necessary to make that happen and we feel more time is needed for energy storage technology to cost optimize.
ABG: Let's say you do, in five or ten years, build a Tesla mom-and-pop car that can go 400 miles a charge and, like the Roadster, costs the end user about a penny a mile to drive. What do you think will be the most difficult hurdle in getting average people to buy one? While everyone knows how to fill up an ICE vehicle and drive it to work, there are a lot of unknowns about battery technology. How do you convince someone that the batteries will last for as many years as the person wants the car to last, and that the power they have on day one is still there in year eight? Will they, even?
Musk: Well, frankly I think we will be production limited, with demand far in excess of supply, on all the Tesla cars at least through model three, which would be about five years out. Around Model 4 is where I expect production will catch up. By that time, there will be a lot of information about how the technology works and the technology itself will be really optimized.
Certainly, issues of cycle life and calendar life will be very well understood by that time. I don't expect any huge surprises and of course Tesla offers a 5 year, 100,000 mile warranty on the vehicle, including the battery pack. What helps a lot is that there are so many individual cells (almost 7000) in the battery pack. If some of them fail early, the effect on your range is tiny. The cells are also arranged in blades, so if a large number of cells in one blade fail for whatever reason, we can just replace the blade.
A fair comparison for performance over time is to look at how a regular mid-range cost sports car, like a Porsche 911 or BMW M5 (those are my daily drivers), would operate at the 100,000-mile point. They certainly won't perform as well as they did in year one and you will probably be dumping a quart of oil in the sump every time you fill the gas tank. To get back to peak acceleration and mileage, you would have to do a major rebuild of the engine, if not replace it.
The same would be true of the Roadster regarding the battery pack. The car will still be very usable, but it won't be as fast or go as far. Since the electric motor is brushless, it should still be in fine shape, but a new pack will be needed to get back to peak performance. Now here is a point that is important to make: the maintenance cost and pain-in-the-ass factor for an electric vehicle is *much* lower than a gasoline vehicle. There are no fuel filters, oil filters, air intake filters (except AC) to be replaced. No oil to be changed or topped up. No periodic tune-ups or engine inspections. No fouled spark plugs that need to be cleaned. No radiator fluid top up. No smog inspections. No catalytic converter replacement.
Since the battery pack has so much energy, you never need to worry about leaving your lights on :) They could stay on for weeks without draining the pack! You could actually power your entire house in a power outage, using your car as a UPS. Another cool feature is that you can leave the AC or heat on in your car, go over to a restaurant for lunch, come back and your car is at exactly the temperature that you want. No need to bake or freeze while waiting for car to get to your desired temperature.
ABG: What is the operating range of the Tesla, meaning, if I do a few 0-60 mph blasts, how far does the range in miles fall?
Musk: You won't even notice the change. At the Tesla unveiling last week, both cars were going almost nonstop from 7pm to 11pm, doing hundreds of max accelerations demos, one after another. They were still pasting people into their seats right up until the end and would have kept going.
ABG: Has Tesla Motors ever thought of entering motorsports in some fashion with the Tesla Roadster?
Musk: Right now, the company is focused on developing really solid vehicles and building a great customer service group. However, I'm sure there will be motorsport events in the future. Martin Eberhard, me and the rest of the Tesla team would love to see the Roadster kicking ass on the track. Also, although we have no plans for this right now, it would be really cool to do a DOT approved GT version with a 0-60mph under 3 seconds. That would even beat my McLaren F1.
ABG: Changing tracks now, what do you say to people who point out that the electricity used to power the Tesla is produced by processes that do contribute to pollution, like coal burning power plants?
Musk: A common rebuttal to electric vehicles as a solution to carbon emissions is that they simply transfer the CO2 emissions to the power plant. An obvious counter is that one can develop grid electric power from a variety of means, many of which, like hydro, wind, geothermal, nuclear, etc. involve no CO2 emissions. However, let's assume for the moment that the electricity is generated from a hydrocarbon source like natural gas, the most popular fuel for US power plants in recent years.
The H-System combined cycle generator from General Electric is 60 efficient, processing is also 97.5 on average. This gives us a well-to-electric-outlet efficiency of 97.5 x 60 = 52.5%.
Despite a body shape, tires and gearing aimed at high performance rather than peak efficiency, the Roadster requires 0.4 MJ per kilometer or, stated another way, will travel 2.53 km per mega-joule of electricity. The full cycle charge and discharge efficiency of the Tesla Roadster is 86%, which means that for every 100 MJ of electricity used to charge the battery, about 86 MJ reaches the motor.
Bringing the math together, we get the final figure of merit of 2.53 km/MJ x 86 = 1.14 km/MJ. Now let's now compare that to the Prius and a few other options normally considered energy efficient.
The fully considered well-to-wheel efficiency of a gasoline-powered car is equal to the energy content of gasoline (34.3 MJ/liter) plus the refinement & transportation losses (18.3%), multiplied by the miles per gallon or km per liter. The Prius at an EPA rated 55 mpg therefore has an energy efficiency of 0.56 km/MJ. This is actually an excellent number compared with a "normal" car like the Toyota Camry at 0.28 km/MJ.
Note: the term hybrid as applied to cars currently on the road is a misnomer. They are really just gasoline-powered cars with a little battery assistance and, unless you are one of the handful who have an aftermarket hack, the little battery has to be charged from the gasoline engine. Therefore, they can be considered simply as slightly more efficient gasoline powered cars. If the EPA-certified mileage is 55 mpg, then it is indistinguishable from a non-hybrid that achieves 55 mpg.
The CO2 content of any given source fuel is well understood. Natural gas is 14.4 grams of carbon per mega-joule and oil is 19.9 grams of carbon per mega-joule. Applying those carbon content levels to the vehicle efficiencies, including as a reference the Honda combusted natural gas and Honda fuel cell natural gas vehicles, the hands down winner is pure electric:
Note: the Roadster still wins by a hefty margin if you assume the average CO2 per joule of US power production. The higher CO2 content of coal power is offset by the negligible CO2 content of hydro, nuclear, geothermal, wind, solar, etc. The exact mixture varies from one part of the country to another and is changing over time, so natural gas is used here as a fixed yardstick.
Now, I should mention that Tesla will be co-marketing sustainable energy products from other companies along with the car. For example, among other choices, we will be offering a modestly sized and priced solar panel from SolarCity, a photovoltaics company (where I am also the principal financier). This system can be installed on your roof in an out of the way location, because of its small size, or set up as a carport and will generate about 50 miles per day of electricity.
If you travel less than 350 miles per week, you will therefore be "energy positive" with respect to your personal transportation. This is a step beyond conserving or even nullifying your use of energy for transport - you will actually be putting more energy back into the system than you consume in transportation.
For a more comprehensive answer, including a more detailed look at fuel cells and other technologies, please see the white paper written by Martin Eberhard and Marc Tarpenning on the Tesla website.
ABG: Was the use of in-wheel electric motors ever considered?
Musk: No, because that adds cost and complexity and is the wrong place to add mass. Better just to have one really efficient motor.
ABG: How transferable is the Roadster's technology to, say, a bus or a motorcycle or a truck?
Musk: It can work in any automotive application, although it is most compelling for low drag, low mass vehicles. For a truck, you need a really big battery pack and that would be cost prohibitive in the short term. However, as battery prices drop and capacity increases, I think we will one day see truck batteries with a 2000-mile transcontinental range.
ABG: With so many alternatives to gasoline-powered cars available to consumers, what do you see is the place for electric cars in the world today? Why not biodiesel or hybrids? How will the market be different in 10 years?
Musk: I think electric cars will be the primary, but not exclusive solution. The great thing about electricity is that it allows separation of the mode of transport from the mode of energy production. If you want to generate energy via plant production, the most efficient way is actually to burn plant matter in a biomass combined cycle power plant at 60 efficient internal combustion engine.
ABG: Will Tesla Motors provide a way for owners to recycle their Roadster's batteries when they have reached the end of their operating lives? Or, what will owners do with the Tesla Roadster's batteries and their potentially toxic components when they have reached the end of their operating lives.
Musk: The Tesla Lithium-Ion battery pack is actually non-toxic and landfill safe, although dumping it would be pointless, since it can be sold to recycling companies (unsubsidized) at the end of its 100,000-mile design life. However, the battery isn't actually dead at that point, it just has a lowered capacity. Just like replacing the engine on a gasoline car to get back to peak performance or living with it as is, you will have the choice of replacing the pack or dealing with lower range and acceleration. As we optimize the battery pack costs over time, which is a big research area for Tesla, I expect the cost of the pack to drop considerably, making it worthwhile to switch out packs earlier than 100,000 miles for those that always want to be at peak efficiency.