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A Marriage Made In Heaven - My Explanation Of The Volt

7.8K views 25 replies 16 participants last post by  saghost  
#1 · (Edited)
For over a hundred years people have been trying to design practical cars that did not rely on petroleum - cars that run on electricity. But they always hit a road block. Electric cars have had one major drawback. They afflicted their owners with a gut wrenching condition referred to as range anxiety. It didn't matter whether the car had the 70 mile range of a Leaf or the 250 mile range of a Tesla, range anxiety was always there. Few people want as their only vehicle a car that that they can only drive ten, fifty, two hundred miles, if they then have to wait hours to recharge. Even on short trips, the moment you get in such a car you start thinking about whether you have enough juice to get back. Every attempt at building a truly practical electric car that average drivers could use as their only car failed. Yes, as battery technology improved you could increase the distance that could be driven on a charge and even reduce somewhat charging times but range anxiety was an ever present dread.

Genesis

Enter Bob Lutz, GM Vice Chairman and Chief of Global Product Development and Johnathan Lauckner, Vice President for Global Program Management. Working together they conceived of an electric car that that would use a state of the art lithium-ion battery and solve the problem of range anxiety. They conceived of a car that seventy to eighty percent of people would be able to drive in their daily commute using only electricity but that would also have a gasoline powered generator that would enable them to basically go unlimited distances when they needed to, just like any other car with a gas tank. They also wanted to make it sporty, practical and fun to drive.

The result is a marriage made in heaven. A car that you can charge up at home, work or wherever, and that you will usually drive without ever using a drop of gasoline. A car that is smooth, seamless and quiet. A car that is very quick because it has an electric motor with 273 lb.-ft. of torque that is immediately available the moment you step on the "gas." And make no mistake, it is always an electric car. Even when the gas engine is running it is producing electricity that is powering the electric motor. It is a car that will accelerate with the best of them but do it without a sound and with no herky jerky transmission shifts. Basically, it is more fun to drive than almost any car on the road.

But this car is so much more. Unlike any other electric car you can drive it 100 miles, a thousand miles, across the country, or around the world (with a little help over the oceans) without having to wait hours to recharge the battery. You can do this because this electric car has its own on-board generator powered by a gasoline engine. When you deplete the battery, the generator starts up. And when the change happens, you don't hear or feel anything. You just see an icon change on the dashboard telling you that the "extended range" motor is now running, but that's about it. Like so many other aspects of the Volt, "seamless" is the best word to describe it.

The Car

So what does it all mean? The EPA says that you can expect to average 35 miles on a fully charged battery and that you will get 95 MPGe when running on that charge. MPGe is miles per gallon equivalent, which represents the number of electric miles that can driven on the amount of energy contained in a gallon of gasoline. EPA also says that when you run solely on the gasoline "extended range" motor your average should be 37 mpg. To make these numbers more meaningful the EPA then calculates the actual cost of driving by factoring in an average gasoline price of $3.70/gallon and an average electricity cost of 12 cents/KWH. According to the EPA, if you drive 12,000 miles per year you can expect to spend $601 when running solely on electricity and $1,302 when running solely on gasoline.
http://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent

So what are the real life experiences of Volt drivers? Voltstats http://www.voltstats.net is a site that logs real time data on thousands of Volts. The fleet total mpg, which is miles driven divided by gasoline burned is 126.7 mpg. Since that does not count the cost of electricity they also computed the MPGe of the fleet, which is 64.3 MPGe. The fuel economy of the gasoline engine alone is 36.5 mpg. Volts are running on battery power for 71% of the miles driven and on gasoline the remaining 29% of the miles driven.

My experience is somewhat better. I drive about 90 percent of my miles on electricity and my off-peak electric rate is 4.6 cents/KWH, far lower that the 12 cent national average. I am currently driving about 47 electric miles on a full charge and my cost is about 1 cent per mile. In my first 1,000 miles I drove 950 miles on electricity and averaged 4.34 miles/KW. The total cost of the electricity consumed was $10.07. I also drove 50 miles on gasoline, using 1.4 gallons of gas. At a cost of $3.79 per gallon I spent $5.30 on gas. So it cost me $15.37 to drive 1,000 miles which works out to 1.5 cents per mile.

The car I traded got 20 mpg. Driving it 1,000 miles would have consumed 50 gallons at a cost of $189.50. My savings driving the Volt for that 1,000 miles was $174.13. Amazing.

Maybe more importantly we love driving the Volt. Except when we have to drive both cars or when hauling large loads, the Volt is the car of choice for both my wife and I. It is so smooth, so quiet, so well put together and so cool. Of all the 25 cars I've owned it is my favorite. Our other car is an Acura MDX. It is a really good car, but when I drive it now it feels positively clunky compared to the Volt.

Environment and the Nation

People ask whether electric cars are really better for the environment and the nation. The answer is clearly "yes." Based on EPA data http://en.wikipedia.org/wiki/Electric_car the average internal combustion engine car produces 500 g/mile of greenhouse gasses. On average a Volt running on battery power will produce 260 g/mile, or roughly half that of a gasoline powered car. These are averages of course and the numbers vary widely depending on the fuel used to produce the electricity. Here is a really good article http://energy.typepad.com/the-energy-blog/2010/04/greenhouse-gas-emissions-electric-vs-gasoline-cars.html explaining the differences between fuels. In summary,

the average Coal burning power plant emits 2.17 pounds of CO2 for every kilowatt-hour it produces. (EIA) Now, coal makes up only 48% of our electrical generation. Natural Gas produces 20% and it also emits CO2 (1.4 pounds per kWh). But, 30% comes from nuclear and renewable sources. So, taken together, our national electrical supply generates, on the high side, 1.51 pounds of CO2 per kWh.

Similarly emissions of gasoline engines vary widely depending upon the efficiency of the engine. The best are 28% efficient while the worst are only 15% efficient. Consequently, the emission of CO2 of gasoline engines ranges between 1.9 lbs/kWh and 3.59 lbs/kWh. Thus the most efficient engines produce slightly less CO2 than coal plants but substantially more than gas, nuclear or renewable electricity. And the least efficient engines are far behind all sources of electricity.

But it's not all about CO2. It's also about reducing our dependance on oil and staying out of conflicts whose primary motivations seem to revolve around oil. In May GM noted http://www.chevroletvoltage.com/index.php/volt-blog/18-volt/2638-chevrolet-volt-saves-supertanker-of-gas-.html that Volt drivers had travelled 40 million miles, saving 2.1 million gallons of gasoline and saving themselves $8 million in the process. That 2.1 million gallons would have filled an entire super-tanker. That is impressive. And this was achieved with fewer than 17,000 thousand Volts on the road. Imagine the impact if 10, 20, or 30 percent of us were driving extended range electric cars like the Volt.

A Chevy?

There's one more thing. Before the Volt I had only bought one other American car and it was a special purpose vehicle. Walking into a Chevrolet showroom and buying a Chevy was not part of my life experience. Guess what? This car is great. The engineering is second to none. The design and execution of the car is fantastic. Everything feels right, works right and looks right. The quality is as good and in some respects better than that of any comparable car.

My eyes have been opened. Chevy hit a home run and my whole attitude towards American cars and GM in particular has changed. On car forums people often ask how Volts drive and what are they comparable to. The frequent answer is that it feels like a BMW three series - every bit as tight, not quite as grippy, and a whole lot smoother and quieter. Remembering that, it was fascinating to read in this article http://www.thestreet.com/story/11451833/2/how-the-chevy-volt-became-a-bmw.html that BMW has hired away many Volt engineers and that the upcoming BMW i8 will be largely based on the Volt architecture. Chevrolet has over 200 patents on the Volt that they will work around but the signs are clear. The extended range electric vehicle pioneered by GM is here to stay and truly is a marriage made in heaven.

The Real Financial Cost

The Volt sells for between $39,000 and $44,000 depending on how well optioned it is. Even though the base Volt is pretty well loaded its price is more than the average new car which which is now just shy of $31,000. http://www.autoblog.com/2012/04/11/average-price-of-new-cars-hits-all-time-record/ But the Federal Government has a $7,500 tax credit that reduces the $39,000 cost to $31,500. And many states have additional incentives, such as Colorado, which has an additional $6,000 tax credit. When I also considered that the VOLT would save me $2,400 per year in energy costs the deal was too good to pass up.

All Things Considered

The Volt reduces our dependance on oil, saves money in operating costs, is an absolute blast to drive, is made in America, reduces greenhouse emissions, and is the smoothest, quietest, and quickest ride you can imagine. Also, it is way cool and has a UAW sticker on the door jam.

Anyone who is in the market for a mid-size sedan is doing themselves and our country a real disservice if they don't consider the Volt.



There is much detail about the Volt that is omitted for this post in order to keep it at a manageable length. For example, it has two electric motors, not one, but both are there to maximize efficiency. Under very rare circumstances the gas engine can drive the wheels directly, if it improves efficiency. Also, the battery is unique for several reasons. To maximize longevity it has a sophisticated heating and cooling system that keeps it at the optimal temperature. And to maximize longevity, it is never fully charged or discharged, generally using only about 65% of its total capacity.
 
#2 ·
An excellant summation. The only quibble I have is with the first paragraph under "the Car." MPGe is actually related to energy, not cost - the EPA considers a gallon of gas to be equal to 33.7kWh (which is somewhere close to it's high heat value - the heat you'd get from burning it.) Thus, MPGe for an electric car is the number of miles it can drive (under their test conditions and factors) on 33.7 kWh of power.

Since the EV doesn't have to go through an Otto-Cycle to make the power useful, they routinely come up with numbers far beyond the most efficient gas or diesel cars.
 
#3 · (Edited)
Thanks. Correction made. I was doing a shortcut to explain that cost comparisons between electric and gasoline driving factor in average gasoline prices and electric rates. But in the process I made a hash of it. Appreciate the comment.
 
#5 ·
To more realistically compare cars powered by electricity vs cars powered by gasoline, you also need to consider the emissions from producing the gasoline, not just the emissions from burning the gasoline in the car.

The Union of Concerned Scientists has looked at that, and has produced an extensive report, available at:

http://www.ucsusa.org/assets/documents/clean_vehicles/electric-car-global-warming-emissions-report.pdf

Here is an excerpt from the report:

To most accurately compare electric and gasoline vehicles, the emissions from producing the fuel as well as from consuming it must be taken into account. For gasoline vehicles, this means including emissions not only from propelling the car—i.e., by combusting the fuel in the engine—but also the emissions associated with extracting petroleum, refining it, and delivering it to the vehicle. For EVs, no tailpipe emissions occur from consuming electricity to propel the vehicle. However, as described above, there are emissions from producing the electricity. Thus in comparing EVs with gasoline vehicles we include the “wells-to-wheels” emissions, which account for the full fuel cycle.
The result is that electric cars compare favorably to gasoline cars, even is parts of the US that get most of their electricity from coal burning powerplants.
 
#9 ·
To more realistically compare cars powered by electricity vs cars powered by gasoline, you also need to consider the emissions from producing the gasoline, not just the emissions from burning the gasoline in the car.

The Union of Concerned Scientists has looked at that, and has produced an extensive report, available at:

http://www.ucsusa.org/assets/documents/clean_vehicles/electric-car-global-warming-emissions-report.pdf

Here is an excerpt from the report:



The result is that electric cars compare favorably to gasoline cars, even is parts of the US that get most of their electricity from coal burning powerplants.
Agree completely. But for the sake okaying this a reasonable length that is one of many things I didn't touch on.
 
#6 · (Edited)
Havent read it all through yet but spotted one mistake under genesis.

Bob Lutz was never CEO of GM. He held a few titles while at GM his last position was Vice Chairman of Global Product Development. The CEO of GM through most of the Volts development was Rick Wagoner.

Jon Lauckner who was Vice President for Global Vehicle Development convinced Bub Lutz that this was the best approach. I would say that Jon was the brain child and Bob had the political capital within GM to make it happen.
 
#7 ·
#8 ·
Nice write up.. a few point.. you forgot the 7500 tax credit
Not su if tis is just for us. or you are going to post it somewhere else too ?



The MPGe on voltstats presume one uses electricity at the EPA level (its not computed on actual use).


You might mention (and explore for your self) that Volt owners can buy Renewable energy or install their own solar panels to further reduce the environmental impact.


The last paragraph about some, but not nearly all, things missing from the article seemed a bit wierd


A extend-range EV is not really a new concept invented by GM, the first gas-eletric hybrid was a porche back in 1901 (yeah 1901). As I recall the first modern plug in was GM Xp833 (which inspired me to design one while in highschool in the 70's, though I never finished building it), see http://en.wikipedia.org/wiki/General_Motors_XP-883
 
#10 ·
Yes. I have edited it to mention Lauckner's role. I was trying to keep that part of the discussion simple but it was a mistake to exclude him.
 
#13 ·
Depends.

The emissions of a coal burning planet is not linear to its load. For example, at it minimum idle would be worst for emission to power generated ratio, as you increase to the plants power output to maximum efficiency, the emissions ratio to power output gets better, then from maximum efficiency to maximum output, it get worse again
 
#15 ·
There is a big problem in Texas that lots of wind power is generated at night when it isn't needed (and therefore wasted). Reliant has started a "free from 10pm to 6am" plan to try to get people to shift their usage to those hours. Sounds perfect for people charging EVs. Only problem is that the $/kWh the rest of the day is high enough that there are cheaper plans (I pay about $0.073/kWh right now).
 
#16 ·
It is really to bad Voltstats can't have a way to add in real kWh costs and related emissions for those kWh. We charge mostly when the sun is up and therefore rates are the higher, BUT we don't buy one single watt of that high priced power. Our watts are completly green and coal free and OPEC free. The wife has 6K miles on 2.2 gallons since we took delivery. Our cost are nil to to drive this engineering marvel.
 
#17 ·
Great writeup. Obviously a lot of thought, time, and effort went into it. The only information I would add is to the environment section. The Volt either removes other pollutants completely from the emission equation or moves them out of the city center. In congested areas, which are gettin worse not better, the Volt loses little if anything in efficiency and it's emission footprint. Traditional ICE vehicles...not so much. They get worse and go way below the EPA rated numbers. It also drastically reduces particulates, both from the exhaust and perhaps even more importantly from braking. There is no question much of urban pollution comes from cars. There is a huge societal healthcare cost associated with this.

We often hear critiques about the federal incentive not being cost justified in societal savings from each vehicle receiving the incentive based on the gas savings from that vehicle but of course those arguments ignore the whole point of driving a market and all of the non-incentivized vehicles that come with it. Those arguments also isolate one tangible benefit but leave out of the rest of the Volt's societal benefits such as in-city pollution.

Lastly, the Volt's worst emissions for CD mode are in the beginning of service life and only get better as the GRID gets cleaner. Traditional ICE vehicle's best emissions are in the beginning of service life and only get worse. Also, the studies used to compare emissions either ignore or understate much of the production and distribution emissions associated with gasoline. The studies have a hard time keeping up with the changing mix of oil supply. Newer tight oil supply is much more energy intense than tradition wells. So, not only are the wrong numbers used for today but those numbers get worse as time goes by.
 
#18 ·
Gary -

(Nice write-up, by the way!)

I commented in an earlier append that one needs to consider the emissions cost of producing gasoline, as well as the emissions cost of producing electricity.

You replied:
Agree completely. But for the sake okaying this a reasonable length that is one of many things I didn't touch on.
I agree that it is sometimes hard keeping something to a reasonable length, but I also think that we still might have a slight difference of opinion.

In your write-up, you said:
Similarly emissions of gasoline engines vary widely depending on their efficiency, which ranges between 15% and 28%. The emission of CO2 of gasoline engines ranges between 1.9 lbs/kWh and 3.59 lbs/kWh. Thus the most efficient engines are slightly produce slightly less CO2 than coal plants but substantially more than gas, nuclear or renewable electricity.
It still sounds like you are still considering only the CO2 produced by burning the gasoline in cars, but are ignoring the CO2 produced in the whole process of getting and refining the crude oil. It may just be the wording - it is not clear whether or not you include the emissions resulting from the production of gasoline.

The Union of Concerned Scientists report noted that in most of the US, even with some coal contribution to electricity generation, electric cars were superior to even the best gasoline cars. It is only when you are 100% coal for electricity generation that the relative CO2 costs are a toss-up, and that situation exists in only a few parts of the US.
 
#19 ·
Gary -

(Nice write-up, by the way!)

I commented in an earlier append that one needs to consider the emissions cost of producing gasoline, as well as the emissions cost of producing electricity.

You replied:


I agree that it is sometimes hard keeping something to a reasonable length, but I also think that we still might have a slight difference of opinion.

In your write-up, you said:


It still sounds like you are still considering only the CO2 produced by burning the gasoline in cars, but are ignoring the CO2 produced in the whole process of getting and refining the crude oil. It may just be the wording - it is not clear whether or not you include the emissions resulting from the production of gasoline.

The Union of Concerned Scientists report noted that in most of the US, even with some coal contribution to electricity generation, electric cars were superior to even the best gasoline cars. It is only when you are 100% coal for electricity generation that the relative CO2 costs are a toss-up, and that situation exists in only a few parts of the US.
Thanks. The wiki article I linked to discusses the UCS 2012 study, including this,

"The Union of Concerned Scientists (UCS) published in 2012 a report with an assessment of average greenhouse gas emissions resulting from charging plug-in car batteries considering the full life-cycle (well-to-wheel analysis) and according to fuel and technology used to generate electric power by region in the U.S. The study used the Nissan Leaf all-electric car to establish the analysis's baseline. The UCS study expressed the results in terms of miles per gallon instead of the conventional unit of grams of carbon dioxide emissions per year. The study found that in areas where electricity is generated from natural gas, nuclear, hydroelectric or other renewable sources, the potential of plug-in electric cars to reduce greenhouse emissions is significant. On the other hand, in regions where a high proportion of power is generated from coal, hybrid electric cars produce less CO2 emissions than plug-in electric cars, and the best fuel efficient gasoline-powered subcompact car produces slightly less emissions than a plug-in car. In the worst-case scenario, the study estimated that for a region where all energy is generated from coal, a plug-in electric car would emit greenhouse gas emissions equivalent to a gasoline car rated at a combined city/highway fuel economy of 30 mpg-US (7.8 L/100 km; 36 mpg-imp). In contrast, in a region that is completely reliant on natural gas, the plug-in would be equivalent to a gasoline-powered car rated at 50 mpg-US (4.7 L/100 km; 60 mpg-imp)combined.[84][85]"

What I wrote is in line with this. When it is 100% coal it's a wash or slightly worse. However I also factor in that all gas engines are not equally efficient. While the most efficient gasoline engines are slightly better than coal the less efficient gas engines are worse than coal. All gas engines are worse than all other sources for electricity. The paragraph taken as a whole, especially with the lead in, makes clear that electric cars are better for the environment than gasoline cars.
 
#21 ·
Very nice write up that covers a lot of ground. Thanks for sharing. In case you are intending this for wider distribution, there are some typos you may want to address:

  • "They also wanted to make it to make it sporty,"
  • "it has an electric motor with 270 ft/lbs of torque" It's 273. http://www.chevrolet.com/volt-electric-car/features-specs/ and normally expressed as "lb.-ft."
  • "a car that is more fun to drive that almost any car"
  • "So what does it all mean." A question mark is called for.
  • "Similarly emissions of gasoline engines vary widely depending on their efficiency, which ranges between 15% and 28%." Perhaps "Similarly, emissions of gasoline engines vary widely—ranging between 15% and 28%—depending on their efficiency."
  • "Thus the most efficient engines are slightly produce slightly less"
  • "some respects better as on any comparable car" instead of "as on" use than
 
#23 ·
Wow! I must have really been out of it when I read the original post. I'm usually meticulous about the details, and I don't remember noticing any of those. (I try not to be a grammar nazi here, but I usually see it, and as you did, I'd likely point some out in something like this that looks like it'll go somewhere.)
 
#25 ·
If the EPA is equating 33.7 Kwh with a gallon of gasoline and rates the original Volt at 93 mpge then I'm assuming that equates to 2.76 miles /kwh. I think most people on this post are seeing more like 4 miles / kwh like I am. Especially in the southern areas which even on comfort AC settings are not seeing ranges of only 28 miles electric. In a very cold winter environment maybe but I think these figures should be amortized over a range of temperature and driving conditions. My Volt mpge rating is more like 141.5.
 
#26 ·
The EPA rating is from the wall, including the ~20% charging losses. The EPA also attempts to factor in winter cold weather driving (if you use the heater much, you won't get that 35 miles...) among other things. It's supposed to be a universal refence number, and I think it is a reasonable one when you include the winter driving - if you just climb in the car, put the HVAC in comfort, and drive it like any other car. It isn't hard to do a lot better in decent weather with a little effort.