2009 Mini E: I Did the MPG Math

Another great post, best one I've seen on this. Yes, 65 mpg-c is good, but it's not what folks think they're getting with their super-'green' e-cars...

I'm all for the green/electric car revolution. I do want to see green energy too. I'd get an electric car and throw some solar panels on the roof at my office. How great would it be to get 3-5 miles of free sun power while working! I drive 15 miles each way...which is probably a near average commute.

Gas stations are going to revolt..lol.

After doing a google search for 65 mpg the only mass produced car is a 2009 Ero-Ford Fiesta ECOnetic. And with it being diesel if one were able to consistently make your own biodiesel it could be made to be cheaper still.

If you wanted to stay electric then in order raise the 65 mpg-c higher would if the price of power went down so it would more powerplants or more efficient plants.

Now the problem with both is of course the classic infrastructure question.

Diesel = Not enough locations have diesel to economically service large portions of any given major city. Higher taxes on diesel due to its use by commercial drivers.

Cost = Fairly High one time for gas companies possibly the government in the loss of tax income.(ify I know)

Solution = Above ground diesel tanks with own pumps would speed up the expansion of diesel where possible pending response from environmentalists.

Electric = Dated power grid lacking the beef needed to handle widespread daily recharging of cars. Low voltage leads to slow recharge times unless especially equipped. The trend towards "Green" energy (Solar and Wind mostly) means in order meet demands the number and size of plants that would have to be built would be inherently inefficient.

Cost = Massively High due to grid overhaul and needing build large numbers of solar and wind plants to meet demand and prepare for future demand. Land. How much acreage would a wind farm need?

Solution = Upgrading the grid is unavoidable at this point (We could really use it now to be honest) For producing the power a combo of 25-30% Solar, 25-30% Wind, 30-45% Nuclear (Heavy Research into waste disposal needed), 3-5% Coal and other sources of energy would be ideal for producing the raw amount of power needed to lower the cost of power and keep it there.

Am I making any sense?

I agree with (1), with the caveat that they SHOULD have the "equivalent to 104 MPG" in large bold print almost as big as the "33" and "36" numbers.

The thing I WOULD change is to get rid of the MPG metric in the first place and replace it with Gallons per 100 miles. If electricity is rated in KW/100 miles, Gallons/100 miles is a logical step.

A few notes from an engineer who's bored at work:
1) For the love of God, why can't we use Joules or kilojoules as a unit of energy?!!?! It makes the math so easy!

2) Chasing down equivalence to MPG is silly. We don't really care how many gallons of gas our car uses, we care -->what it costs per mile to operate<--, meaning basically option (3), but don't convert it back to MPG.

This is why you have to do math every time someone talks about MPG or cost of diesel, biodiesel, LPG or Ethanol. LPG's cheap, but you get lousy mileage.

The real problem is that kW-H/100 miles is an upside-down efficiency metric compared to miles/gal. They should flip it to miles/kW-H.

Either way, they should just break it down to cost/mile for comparison sake.

You're roughly $0.0396/mile and a 30mpg car is $0.0852.

Last caveat: if you're drawing a lot of power charging your electric car or plug-in (I have no idea how many kW-H I use in a month), you could push yourself of the graduated rate scale to something like .36c/kW-H.

Great post! I can easily wrap my head around all three ways of thinking and see value in all of them. Very well explained.

I am firmly in the gallons per 100 miles camp for gasoline. It goes along nicely with kWh/100 for electrics. Consumption (and reducing it) is the focus of each. MPG is a dinosaur and the unit is non-linear from top to bottom. A 1 mpg improvement from 10 to 11 mpg has much greater conservation and environmental impact in terms of fewer gallons burned and less CO2 emitted than an improvment from 40 to 41 mpg.

But I understand that consumers have target fixation on MPG and I doubt it can be done away with, even though it deserves to be scrapped. Replacing MPG might be worse than trying to adopt the metric system, something that failed horribly the last time they tried it.

If an mpg equivalency must be there somewhere, I don't like the mpg-e method because shoppers want more than anything to be able to end up knowing how much they'll pay for fuel. Mpg-e does not give them an accurate picture of that at all.

@hybris: I didn't check that Euro-Ford ECOnetic's web page, but I bet that the 65 mpg figure is based on imperial gallons. U.S. gallons are 20% smaller. That would make the actual economy 54 mpg in U.S. gallons.

You might be right the Business Week article that I'm running off of doesn't specify what units they measure with so it could be either way.

Man my electricity is expensive in NJ. I am paying all in about 19c/kWh (supply + delivery). I have attached a link to my August numbers for Mini-E #269. It came out to about 8c/mile for electricity. Let me know if you think i have gotten this right...

Mike G

http://mikegrahamjr.blogspot.com/2009/09/recent-electric-usage-billing.html

I average 8.4L/100km in my car. V6. At at cost $0.915/L for gas, after 24,000km (15,000miles) I would have spent a little over $1900 for fuel. The mini-E would cost more to charge and drive that distance and also would have the more limited range and longer 'refuel' time.

However, I do believe that electric cars will eventually start to get the range and quicker charge times. And I, for only a couple hundred bucks more a year to travel, would consider getting one when they come to the mass market. Would also give me a great excuse to put up solar panels on my house/yard and a wind generator.

I like #3 in that it compares cost to drive a distance. The word economy relates to economics relates to money. Fuel economy. Cost per mile. But it should be dollars/mile, not related back to gallons. The sticker should also include fuel efficiency for those people who are interested in not being wasteful. Isn't fuel efficiency the same as fuel economy? No. Efficiencies are measures of 'completeness', and have no units. My furnace is 90% efficient. It converts 90% of the energy in the fuel into heat. My truck is 31% efficient on the highway. It converts 31% of the energy in the diesel fuel into work. The tricky thing about efficiency is that it should really be on a 'well-to-wheels' basis for the best comparison of different propulsion technologies, which is going to require certain assumptions about extraction, transmission, etc. But as long as all that is stated and agreed upon... So, perhaps an economy measurement and an efficiency measurement, both city and highway. And as others have said, best tracked in a database, since a lot of the assumptions and costs that go into these change based on time and geographical area. And what about 'miles per gallon'? It is neither fuel economy nor fuel efficiency, and we shouldn't be tracking it or regulating to it, in my opinion.

I sorta like Option C. It seems the most meaningful. Then again, if I was driving an electric car I wouldn't car about comparing to MPG at all so really, total operating cost or cost per km is the only reasonable way to look at it.

I now see the point of electric cars, but let's not forget that the overall process for producing electricity and then using it to power a car is less efficient than an internal combustion engine. What we need now is an environmentally friendly and renewable source of electricity. If we can do that the only factor preventing electric cars from taking over the market will be battery life. Of course they could do this even without a clean way to produce electricity, but they would not be solving our long term environmental issues, which is the whole point.

I understand the 'experimental' nature of these electric cars. But as others have pointed out, there are some major practicality issues to work out:
- I live in the great white north, where we can go weeks with a daily high temperature of -25C in winter. The radio constantly runs PSAs about conserving electricity during the 'rush hour', i.e. don't run your dishwasher / washer etc until after 8PM. What would happen when everyone one the block plugs in there car? I am sure southerners have the same issue with A/C units.
- The majority of power up here comes from coal fired plants. These 'green' cars may have less immediate emissions than conventional vehicles, but what about all the CO2 from the power plants?
- What happens to all of these batteries in 3-5 years when the need to be replaced? How well can the metals be recycled and at what cost (financial and environmental)?

There appears to be a lot more figurin' left to do.

P.S. I also find the energy unit / distance measurement (i.e. litres / 100 km) much more intuitive

i put $30 a week into my 02 Civic EX, which gets 30 MPG right now. That last me about 360-380 miles before I have to fill up again. I don't see how you can knock the "fuel economy" of the Mini-E. under any metric it's better then even the best fuel efficient cars. only thing that sucks is the range and whatever charge time is involved.

@wable: On batteries. I think there are a lot of myths out there.
1) Hybrid & electric car batteries are required by law to be covered under the mandated emissions warranty. That's 10 years/150,000 miles in the 11 California-regulation states and 8 years/80,000 miles in federal-regulation states. You can bet these batteries are good for 10 years or more because the carmakers would go broke if they didn't make it to the end and had to be replaced under warranty. These are not consumable items like brake pads.

They achieve this life by very carefully regulating the charging and discharging of the batteries. A computer monitors charging to make sure they are never charged to 100% or discharged to 0%. Your cordless Makita that goes through a battery per year or two doesn't do this.

2) The salvage value of the batteries is liable to be large. People currently steal catalytic converters to get money from scrapping the guts inside, yet everyone worried about the recyclability of those devices when they first appeared on cars, too. Electric car batteries may not be the subject of theft because they're so big, but a recycling marketplace is sure to develop, just the same.

On the subject of coal, I'm right there with you. Here in California our electricity supply depends upon much less coal, but that's not true everywhere else, not by a long shot.

@southphillyman: I'm not knocking the Mini-E's energy consumption. I'm just pointing out that 65 MPG-c isn't that far off, costwise, from a Prius.

And if the all-electric Mini E costs the same to refuel as a 65 MPG car, what does that say about Chevy's 230 MPG claim for the Volt, a gasoline-electric hybrid?

Oh, and this Mini has a sticker price of $49,950. Even with a $7,500 tax credit figured-in, you'd have to drive this thing 38 years to make up the price difference over a regular Mini Cooper -- that drops to 20 years if the electricity is 100% free.

Electric cars have to get a LOT cheaper to make financial sense to the public. The Mini E is a field test demonstration vehicle. Let's hope that the things they learn bring the price down to earth, too.

Karl and I actually had this discussion the other day. We agreed that we should have an annualized cost of ownership.

Cost of energy product * (6K miles Highway + 6K miles City + 1K hours Idling) = Annualized Cost

I intentionally left out mnx and battery replacement costs because those are so subjective right now.

I still like monthly costs instead of annual. No one I know budgets or pays bills annually.

I think the bottom line is that these cars are for people who care more about their "carbon footprint" than their actual out of pocket expenses. The challenge is to get people who respond primarily to financial incentives to start caring more about the polar bears than their children's college funds.

@ahightower: No disagreement there. But the source of the electricity confuses that issue immensenly.

Electric cars have to be scrutinized on a well-to-wheels basis, not just a plug-to-wheels basis. And if that electricity comes from coal, they fail the carbon footprint test. In California, where the percentage of coal-based electricity is low, you do come out ahead. If you have solar panels, you're golden.

@mikegrahamjr: My calculations show a consumption rate of 41.4 kWh/100. You must leadfootin' your Mini E something fierce.

At your local electricity rate of 19.1 cents/kWh. My calculations come back with 7.9 cents per mile.

At the national average rate I used above, 11.64 cents per kWh, it would cost 4.8 cents per mile.

A 2010 Prius burning gas priced at the national average of $2.58 and achieving the EPA combined mileage of 50 MPG costs 5.2 cents per mile.