The Electric Bandwagon
Wednesday, December 1, 2010 at 04:18PMWithin the last few days the Chevy Volt has been named Motor Trend Car of the Year and the Nissan Leaf European Car of the Year. Clearly, the Volt and Leaf are leading the electric car bandwagon and we feel it’s time to share some thoughts.
Rating an electric car’s actual energy consumption can be a bit of a challenge. Even choosing the units is difficult: who can visualize watt hours per mile? The X-Prize handled this question by expressing energy consumption in terms of what’s in a gallon of gasoline: they called this mpge or miles per gallon energy equivalent. The conversion factor between gasoline and electricity (1 gallon of gas = 33.8 kilowatt hours) is fixed and not in dispute. We’re pleased the EPA have also now chosen mpge as their electric energy consumption unit.
In stark contrast to published claims by Chevy of 230 mpge and Nissan of 367 mpge, the EPA has recently rated the Volt at 93 mpge (when running on its batteries) and the Leaf at 99 mpge. Once its range extending gas backup engine kicks in, the Volt’s energy mileage drops further still, to 37 mpge.
The EPA arrived at these numbers by measuring the consumption of electricity actually delivered to the vehicle, the “plug to wheels” standard. This is directly equivalent to counting the energy of the gasoline pumped into the tank, or “pump to wheels”.
Whether it’s fair or accurate to use plug to wheels as the standard is another question. A Forbes essay, for example, says the EPA’s numbers ignore the considerably less than perfect efficiency of the power stations that generate the electricity the Volt and Leaf use. Therefore, Forbes argues, the two cars’ real energy consumption is significantly higher than the EPA reports. But, in turn, Forbes (and other websites we’ve seen commenting on the same question) ignores the energy cost of extracting, refining and transporting to the gas station the gasoline burned in regular cars.
There’s some real sticker shock with both the Volt and Leaf’s electric range: 37 and 77 miles respectively. After that, the Volt’s gas engine has to kick on and the Leaf simply stops moving. Electric car range is a tricky thing, very dependent on weather and driving style. Wipers, heat, A/C and lights all draw their power solely from the battery and highway driving offers little opportunity for regenerative braking. But the plain fact is, neither car will go very far on its battery. So, for now at least, we think the Volt is the better idea because its gas backup engine can always get you home.
Of course, for the Leaf or Volt to have any electric range at all, owners must remember and find the time and place to recharge them.
We feel the EPA sticker glosses over the very serious issue of emissions. While Nissan may claim in ads the Leaf emits no pollution and the EPA’s sticker shows zero, the fine print in both says it all: they mean no “tailpipe” emissions. It’s certainly the case that generating the electricity on which electric cars run causes pollution.
The majority of the United States’ electricity is generated by burning coal and the majority of the remainder by burning natural gas. Although it varies by just exactly where you are in the nation, wind, solar, hydro and tidal electricity generation are small parts of the overall picture. Argonne National Labs’ GREET (Greenhouse Gases, Regulated Emissions and Energy Use in Transportation) model – which was used by the X-Prize – takes into account the underlying emissions from electricity generation. On this basis, the Leaf’s 99 mpge means the power stations producing its electricity emit about 230 grams of CO2 for each mile the car runs. This is about 2.8 times the amount measured by an EPA certified lab for the Very Light Car.
It’s worth pointing out that neither the Leaf nor the Volt meet the performance, efficiency and emissions requirements of the X Prize. In fact, they’re a long way short. Edison2’s Very Light Car won; the Leaf and Volt would have been eliminated.
Edison2 is an optimistic organization and looks to the positive. We are thrilled that Chevy and Nissan are working towards more efficient cars, demonstrated by the Volt and Leaf. Both are worthy efforts and we congratulate the engineers who worked on them. We were parked next to a Volt at the Virginia Governor’s Energy Conference in October and were impressed by what we saw. But at the end of the day, both the Leaf and Volt are 3500 lb cars with unexceptional aerodynamics and therefore, whatever drives them, their efficiency is limited.
Edison2 is energy source agnostic. We simply make a much more efficient car. Because of that, whether it runs on electricity or gas, the Very Light Car uses less of either to drive and causes less pollution.
Reader Comments (9)
Yes, it's very sad that most people expect successful results from repeating the same task that failed them before only with a very slight change in approach. (3500lb same shape car, only now it's electric) I know it must be aggravating for you guys. I've certainly had quite a hard time addressing issues to people I know of the un-sustainability of throwing all of our valuable (to nature it's valuable) "waste", defecating into toilet drinking water (it is drinking water) as it's later dumped either into lakes or land fills and how we could thermophilic compost it like nature had intended, and in so doing recover valuable long lasting nutrients to be returned to agricultural use.
My point is so many people I've talked to about many environmental issues just don't even care, let alone conduct research how to do anything about it.
I hope I'm wrong on this, but it may come down to the last poisoned water hole being drunk out of, and the last antibiotic/feces filled animal eaten, and the last drop of oil burned for people to realize that they can't eat money.
A hybrid, it sounds technical and advanced, so it must be better, while in actuality there is one truth in any hybrid car of today. Two different power plants, each require almost as separate environments as the earth and the moon when considering the support systems, ideal rpms, temperature regulation systems for all devices, and yet to power all of those systems in a hybrid it still all has to come from the same source, the fuel. All fossil fuels are anachronistic forms of indirect solar energy.
One thing guys that I've always wondered about,... if the x-prize's goal was to introduce the possibility of task built vehicles to consumers, in this case affordable, maximally efficient, personal transportation, then why didn't they have a 1 seater class?
Anyway, Edison 2 I can clearly understand your point of view and have felt that way for a long time, but keep trying to get the message out to broader circles.
I know sometimes I feel like a humming bird trying to put out a forest fire while all of the other large animals just watch, but at least we humming birds know that we are doing the best we can.
Ok, so just how heavy will your car be in its production version and what will be the mpg at that 2000 or so pounds?
It's unclear from the article whether the Leaf's GREET emissions are 2.8 times your measured tailpipe emissions or your GREET emissions, could you clarify.
Our emissions were measured directly from the tailpipe; the Leaf's were calculated using the GREET model.
I regret you swallowed the line about 'not counting oil refining etc.' when comparing efficiencies. Transporting of coal easily balances this. And coal will indeed be the fuel used to respond to an aggregate load when there is a meaningful number of electric vehicles.
As I recall the new EPA sticker allows the EV to claim zero tailpipe emissions, which is of course true, but incredibly and deliberately misleading.
We have long known the rule for comparing efficiency of engine driven systems based on the heat energy that is the input to the engine. Electric systems merely serve as an alternative to a drive shaft, and carry energy just as a drive train carries it from one spinning shaft to another. This rule is represented in the Laws of Thermodynamics. The EPA system repeals the Second of these Laws and tromps on the First.
At least the emission results of Xprize show the fundamental falsehood of the MPGe system. And even the Greet model includes substantial chicanery to pump up electric vehicles.
In a fair rating system none of the EVs would have qualified for the 100 MPG test, and Edison2 would have stood alone in the winners circle.
biologist 111
I harangued the Xprize rule makers for about a year and a half to just get a tandem seating vehicle into the competition.
Single seating is not so important as in-line seating. In-line seating enables major aerodynamic advances, though the possibility of these was not pursued in the Edison2 tandem seating vehicle.
Guys, this is an exciting car. If you made it, I would buy it. (Provided the cost is competitive with a conventional small car and 100,000 miles worth of fuel, OR is able to deliver on other emotional aspects of vehicular purchase decisions).
But I see that you would rather take on a consulting role to the industry and I can see the wisdom in that approach. Being involved in the industry, making cars is an almost incomprehensibly huge task. The validation testing alone can cost millions of dollars... for each component!
I totally agree with your philosophy. Make the vehicle as efficient as possible. Both electric and fuel based power trains are to benefit. But of course market forces are a huge factor as well. I believe most people in the business of cars, don't seem to believe that people would drive a Cessna without wings. And someone would have to prove that such a shaped vehicle could pass crash testing and other safety standards. Producibility and so many other matters would need to be considered.
As with another's comments above, most people aren't concerned with evangelist environmentalists. It seems to be economics to me. If fuel is cheap. No worries. But as and immediately when fuel becomes expensive, people will change their taste in vehicles just as soon as the pump price become intolerable.
It is really that simple.
But certain car geeks like me love your car for the pure beauty of the efficiency. Many car nuts love cars that go 0-60mph in (4,5,6,..) seconds, but this passe to me. It has already been done so many times. But we love it because it is extreme. Just the same, I think certain car geeks would love a car that gets 100mpg, for the same reason. It is extreme. It is a kind of beauty. Even if we can afford the fuel for a 500hp monster, that is yesterday's technology. High mpg is a new interesting challenge. It is also political and a societal statement as well.
I just don't know what the market has to bear with this kind of thinking, but let us hope it is good.
I hope to see this type of vehicle on the road some day.
We thank you for the inspiration, and I hope for your commercial success with your ideas.
Volt and Leaf? How about a Tesla Roadster or S Model with a 300 mile battery. How does Tesla measure up? Last time I checked, the Roadster was the King of the Electric cars. :P
Thank you for this article.