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What Is the comparative efficiency of the Tesla MS for city driving?

What Is the comparative efficiency of the Tesla MS for city driving?

A key factor for many who buy the Tesla MS is the total avoidance of any
contribution to continued use of fossil fuels, as is the case for many BEV buyers.
But those same Tesla MS buyers seem to forget how the majority of electric
energy in the USA is produced, i.e. via coal. As result, they typically don't even
consider energy efficiency when making their BEV purchase decision, and
thus fail to achieve a minimum resulting use of fossil fuel produced energy.
Furthermore, most MS buyers don't even have any idea of what the majority of
energy losses are of a moving vehicle contributing to energy inefficiency.

Energy losses for a vehicle result from the rolling resistance, i.e. the energy
required to keep a rolling vehicle moving against the resistance developed
between the tire and the road surface which is proportional to the weigh
of the vehicle. Additionally, the drag force of the vehicle as it moves through
the air contributes to an energy loss, but to a much lesser degree at speeds
typically used in city driving, i.e. less than 40-45 mph.

The good news for the Tesla MS, based on its' about 20% less drag coefficient
than other BEVs, is that its' drag efficiency is better than the typical BEV.
The key problem for the Tesla MS, though, is that it is inherently inefficient from
the standpoint of rolling resistance, given its' additional weight of over 1000 lbs
more than the other high selling BEVs, e.g. Volt, Fusion, or Leaf,. That additional
weight for city driving at less 40-45 mph contributes to an inefficient city BEV
vehicle. Rolling resistance power is not only wasted while cruising but also
when using the vehicle's kinetic energy to regenerate the battery, which
contributes to an additional inefficiency.

The key point is that the Tesla MS 'carries around' about 30% more weight
than the typical BEV, which contributes to vehicle inefficiencies and wasted
fossil fuel energy. Even at higher speeds where the MS has a 20% lower
coefficient of drag, that's not enough to over come the 30% increased weigh
affecting the rolling resistance power loss, expect at high speeds. These data
are supported by actual Tesla MS data posted on the Tesla Forum:

@AmpedRealtor: "Two days ago I drove 114 miles of errands and averaged
270 Wh/mi, or 315 miles per charge. I would say that Tesla's claims are quite
realistic and easily achieved."

A number of BEVs can easily achieve over 5 miles per kwh (200 wh/mi) for
city driving which compares to the above higher actual energy consumption
number of 270 wh/mile. Even without any actual data, it should be obvious
to anyone that a heavier vehicle, whether a BEV or ICE, is always less efficient
than a lighter vehicle. So when MS buyers claim that their purchase decision
was influenced buy a reduction of fossil fuel usage, they obviously didn't consider
the most efficient BEV to drive for the majority of driving that the typical driver does,
i.e. 40 - 45 mph city driving.

jjaeger | 26 januari 2014

Yawn.

Low CG | 26 januari 2014

@lorenfb - If you're trying to talk me into a bug-like BEV, you're wasting your time. This forum is for Tesla "enthusiasts." Odd that you spend so much time here.

Haeze | 26 januari 2014

Last I checked, the Model S was never marketed as a city car. The vast majority of people who live in downtown of any city have no dedicated parking, more or less parking with an electric port of any kind nearby. Also, city cars are known for being very small to make parking more accessible, and traffic easier to navigate. This will be the domain of the Gen III model, giving cities enough time to build charging infrastructure.

The Model S is a large car by design. Saying it isn't the best city car of all time is like trying to say the same about a Ford Excursion. People who live and/or work in cities will still buy them, but not because they were the most perfect city car. They will buy them because they sincerely enjoy the car and are willing to accept a slightly less efficient car to get the car they enjoy most.

The same can be seen in the number of Mercedes and BMW vehicles seen in large cities. They are by no means the most efficient vehicle for cities, but people buy them because they enjoy them.

LeonardV | 26 januari 2014

Interesting analysis. However, if you need the carrying capacity and range of a Model S, there seems to be no alternative out there. As I understand, Tesla has gone to great lengths to make the Model S at light as possible with its aluminum body, etc. Any EV with its range will be a bit heavy until we have further breakthroughs in battery technology.

jordanrichard | 26 januari 2014

Ahhhhh only 40% of our electricity is derived from coal, and that is going down. I may have had a public education, but that looks to me to be less than a "majority". Here in New England, it's nuclear/natural gas or hydro.
Have you even looked at the map on Tesla's website, showing where our electricity comes from?

1LuckyGuy | 26 januari 2014

God that was long. I don't care about the green aspect. Whether I buy one or not makes zero difference in the world. I am buying one because it's amazing, fast, beautiful, and cheaper than fuel. Not adding a miniscule amount to the air pollution in southern California is a plus though.

mclary | 26 januari 2014

What?

And the point to your post is what?

Sanjuro | 26 januari 2014

@ lorenfb
But those same Tesla MS buyers seem to forget how the majority of electric
energy in the USA is produced, i.e. via coal.

You seem to forget that many Tesla owners in this poll also have solar panels.

And after the first paragraph, tl;dr

Roamer@AZ USA | 26 januari 2014

I charge both Tesla's with my roof top solar and still sell excess back to the grid. The difference in energy use between my Tesla's and my Leaf's was minuscule compared to the energy use of my BMW.

Silly argument. With my Leafs I was so range limited I still ended up driving the BMW for half my needs. With the Tesla's the BMW is getting flat spots on the tires.

A small limited range, limited capability car is not much of a solution for people that actually have a life.

Just think if we all walked what kind of range per kWh we could have. Silly comparison.

carlk | 26 januari 2014

MS has EPA rated eMPG of 95 MPG. Leaf has 115 EPA eMPG rating. Volt has 98 eMPG rating in the BEV mode but most of its range comes from burning fossil fuel at 38 mpg. Leaf and Volt won't be able to haul your whole family so you might need to take two cars instead one sometimes. Take your pick which one is best for you if you're so environmental conscious. Many pick MS anyway because they also want to put their family is the much safer MS than those real small cars.

Roamer@AZ USA | 26 januari 2014

Just to be clear I liked the Leaf's but hated to have to manage range constantly. They were OK grocery getters and local errand runners but complety useless at highway speeds. With the Tesla I never have to think about range and can actually use the freeway for more than ten miles and still get home.

Your thoughts would be more accurite if you factored in the need to keep a second car when you own a limited range city car EV. Tesla can be an only car that meets all needs everyday. Absolutely amazing.

I suppose you have plenty of time to post while you sit at the charger for 5 hours just so you can drive 50 miles to get home. Maybe that explains the War and Peace post.

hillcountryfun | 26 januari 2014

I suspect that the Model E will be a bit more efficient than the S, but I'm getting the S anyway!

Then I'll probably get an E also...

:-)

carlk | 26 januari 2014

@Roamer You're right what's the point of getting a small EV for some short neighorhood driving while still have to have an ICE that puts out tons of pollutants?

Pungoteague_Dave | 26 januari 2014

And your point is that some cars can have a lower kwh impact on the earth? So? Your analysis completely ignores utility. My Zero electric motorcycle is theoretically far more efficient than the cars you cite, using only about 65 wh/mi in average riding conditions. However, in the epic winter we are having, a motorcycle is essentially useless. And it can never carry five passengers plus our dog and luggage in comfort. Right tool for the right job...

Roamer@AZ USA | 26 januari 2014

I didn't buy a Tesla to stop using fossil fuel. Sorry. I wanted to stop using energy from places that want to kill me. I prefer domestic energy and what is more domestic than the sunshine that lands on my roof. I can satisfy 100% of my routine transportation energy needs using about half of my home roof area.

I also like to breathe so it is an added benefit to drive without a smoke stack.

Tesla has made it possible to achieve personal energy independence.

The green religion drives me nuts because it is never enough. Comparing the efficiency of a Tesla to a Leaf when the world is filled with energy guzzling, smoke belching, ICE cars seems a little ridiculous. You would do more for your cause selling Tesla's than picking at minuscule differences in Wh usage.

Will leave the light on (it's OK it's LED). Maybe stay at a Holiday in Express.

RedShift | 26 januari 2014

What about the long distance driving afforded by the Model S at far fewer emissions than the Leaf/other small EV owner who uses his second ICE car for the same?

SCCRENDO | 26 januari 2014

I also don't understand the point of the post. I do 2500 miles a month. Switching to solar. Could I green up my life further sure. But doing more than most.

1LuckyGuy | 26 januari 2014

@roamer how many kw are your solar panels? We want to get solar and would like to have enough to completely pay for our home use and Tesla(s). Our electric bill last summer was 700-900 bucks a month! F-that.

SCCRENDO | 26 januari 2014

Electric bill with the Tesla is 20000 kWH per year. 3/8 us due to the Tesla. Getting a 13 kW system to try cover my whole bill. 21000 miles in 9 months

lolachampcar | 26 januari 2014

Oh snap!!! I just figured out my old Seven Series was less efficient in town than a Smart......

tezzla.SoCal | 26 januari 2014
tezzla.SoCal | 26 januari 2014

@jw40, if you're in the SoCal area, I'd suggest calling Danny at Simple Solar Inc for a quote (949-345-1688). He installed my system in December, he also owns a P85+.

Bighorn | 26 januari 2014

Your vast oversimplification of rolling resistance negates any conclusion you may have hoped to use against your nemesis, Tesla Motors, Inc. Perhaps we should limit deformation by running on steel wheels, though that may prove unsafe for the feet of urban pedestrians.

Also factor in that the average speed in a city is approximately 25 MPH--the premiere hypermiler duo who surpassed 400 miles on a single charge at that velocity surmised that had the road conditions been smoother they could have cleared 450 miles. This works out to 189kW/m, also better than 5 miles per kW. You can't blame Tesla for bad roads. As it was, they achieved 423 miles which works out to 201 Wh/m. Personally, I'm willing to sacrifice that 1 Wh/m delta to drive the best car on the planet.

Thomas N. | 26 januari 2014

lorenfb -

Do you also go to the Orthodox Jewish forum and post about how Nazi Germany had some really good ideas?

(What's the term coined for the fact that any cyclical Internet discussion will eventually have a reference to Nazi Germany? I just wanted to be the first one to post it in this debacle of a thread!)

Bighorn | 26 januari 2014

@Thomas
That would be Godwin's law.

I'm having trouble finding an electric car that can "easily achieve" 200Wh/m since references weren't provided.

tesla.mahedy | 26 januari 2014

Lorenfb;

Check out the map that has been compiled by Tesla regarding the production of electricity in the US
http://www.teslamotors.com/goelectric#electricity

I believe Atlanta is the only "EV" city where the state produces the majority of its electricity from coal.
All others are Natural Gas, Hydro, and Nuclear.

Obviously my efficiency drops when I drive in Manhattan, I am stoping and starting all the time. It is also very hilly, always congested, and overall slow.

No city that I know of has a speed limit of 45 so I cant give you any wH/mi numbers there. The best I get is around 330 on Park or Madison but that only lasts about a half a mile, then I get stuck at a red light.

Alex

DTsea | 26 januari 2014

the only rational comparison is against comparable cars not little deathtraps. all the subcompacts are failing the new 35 mph offset crash test.

donaldmeacham1 | 26 januari 2014

ZZZZZZZZZ

Roamer@AZ USA | 26 januari 2014

@Jw40.
I am in the Phoenix AZ area. My biggest surprise was that it was easy to get rid of the high summer electrical bills. I am 100 % electric so I heat electric also. My surprise was that the solar panels also shade my roof in the summer and the days are longer, the sun angle better and never cloudy. The shorter, lower sun angle, more cloudy winter months are more difficult to zero out.

Started in 2007 by putting in two large solar water heaters, then watched my usage for a year and installed a 22 kW system in 2008. Three sunny boy 7000 series inverters with 39 panels on each inverter. With all the tax and utility programs I got to an 8 year pay back not including sell back surplus. I over sized the system for my needs thinking at the time I would sell back and improve my long term yield.

I soon realized the utility credited at the cheapest wholesale rate on the planet so started looking for battery cars. Figured it was a better deal to put the excess into a car and not buy gas than sell it back at wholesale rates. Started with Nissan Leaf's. My energy cost came out to 1 cent a mile. That got me looking for better battery cars and that got me to Tesla.

Now I run the house, charge two Tesla's and get an annual credit that pays my monthly meter cost for about 9 months. I am still surprised how possible it all was.

I make so much hot water I wash my cars with a presure washer plumbed to hot water. Uses less water and really gets the bugs off quick. In Arizona I always tell people to start with solar hot water if they have electric water heaters. That's the fastest and cheapest pay back.

When I went to driving Tesla's I converted all my lighting to LED to make sure I could stay zeroed out. The Tesla's use more power because we drive them more and drive them further than the Leafs. I have forgotten how to pump gas or pay an electric bill. It's a funny situation to realize I now do better financially the higher electric rates go.

Roamer@AZ USA | 26 januari 2014

Thomas N....Ya Just Had To Go There..........you know the thread is complete when that happens.

1LuckyGuy | 26 januari 2014

@roamer that's awesome haha

1LuckyGuy | 26 januari 2014

Btw +100 to ANYONE who actually read this long ass OP

Roamer@AZ USA | 26 januari 2014

Jw40. Gave the OP something to do while he waited 5 hours for his Leaf to charge.

DallasTXModelS | 26 januari 2014

95 percent of my driving is city driving. I have a 26 mile commute to work all city driving. The city mpge is 93. Bumper to bumper gridlock rush hour traffic in an ICE which go 20 city and 28 hwy on $3.259 gal gasoline is why I bought a Model S. I'm not rich, this wasn't a toy, a second car or something I entered into lightly. My Model S sales price was twice my annual income. Unfortunately, with gasoline prices fluctuating between $2.999 and $4.549 gal I was spending all of my extra money on gasoline. The way I calculate it I actually have spending money after paying my bills each month. And that continues to improve each year that I drive my Model S. When my 6 year loan is paid off my out of pocket transportation expenses will drop to between $400 and $700 a year for electricity.

Roamer@AZ USA | 26 januari 2014

I find the term BEV to be kind of funny. Do you call them that to make it sound like a GEV is the same (Gas Electric Vehicle).

Just seems redundant to call it a Battery Electric Vehicle. Do they make batteries that put out something other than electricity.

If it's only source of power is stored electricity then it's an EV.

If it uses Gasoline to create energy it's an ICE.

I find it hilarious that they try to confuse the public by saying the Volt has a Gas powered generator. How the internal combustion engine gets it power to the wheels is really irrelevant.

hillcountryfun | 26 januari 2014

While it's great to look for improving efficiency, that's not the only thing to compare...there are more requirements to be concerned with. I think Motor Trend said it best when reviewing how the Model S does across multiple dimensions:

"It drives like a sports car, eager and agile and instantly responsive. But it's also as smoothly effortless as a Rolls-Royce, can carry almost as much stuff as a Chevy Equinox, and is more efficient than a Toyota Prius. Oh, and it'll sashay up to the valet at a luxury hotel like a supermodel working a Paris catwalk."

AoneOne | 26 januari 2014

If you want to respond to this discussion with a defense of the economy, utility, or pleasure of a Model S, go ahead.

For me, I think the case has been extremely well addressed elsewhere. I have no need to feed this OPs nitpicking here or elsewhere with a defense of my choice.

Tanchico | 26 januari 2014

Thought of getting a Leaf to commute to work... realized I'd also need to get back home so I bought an MS.

DallasTXModelS | 26 januari 2014

@Roamer

That's why Tesla is quick to point out Model S is a PBEV plug-in Battery Electric Vehicle. Not to be confused with batteries that are recharged by a gas motor running.

Doug H | 27 januari 2014

1. You dismiss the point that 80% of the energy stored in the battery of an MS is used to propel the vehicle forward vs. 30% of ICEV's fuel.

2. You dismiss the fact that fossil fuels are produced with fossil fuels which also have a carbon footprint, and then burned expanding that footprint. So you get double footprint. Production of fossil fuel includes:
Exploration - electricity (coal) or gas (diesel)
Extraction - electricity or diesel
Transportation to refinery - (pumped through pipelines, transported on ships or trains or all 3)
Refining crude under pressure - electricity, diesel
Transportation through pipelines - electricity
Pumping onto gas distribution trucks - electricity (coal)
Transportation to gas stations - diesel
Pumping into gas station tanks - electricity (coal)
Pumping into automobile - electricity
Transportation of additional weight of gas - gas
Use by automobile produces carbon in addition to the above sources of carbon

3. The number of coal fired power plants is shrinking very fast as natural gas becomes less expensive. Each coal plant that converts to natural gas reduces the carbon footprint of thousand of EVs. There is no way to have a similar multiplicative effect with ICEVs.

4. With an EV you can have a zero carbon footprint for transportation using solar of hydropower TODAY. An ICEV cannot have a zero carbon footprint because burning gas or diesel produces carbon.

5. Comparing the efficiency of an MS to a Volt is like comparing the efficiency of a BMW with a VW Beattle.

Skotty | 27 januari 2014

I actually have a hard time finding MPGe numbers for the Model S. I found a windows sticker image online that showed 88/90 (city/hwy) for a Signature S. Someone else in this thread said it has combined 95. I think at some point the numbers went up. But not sure what the numbers currently are, and if they are different for the S85 vs P85 vs S60.

Roamer@AZ USA | 27 januari 2014

@Skotty. For what it's worth the attached link contains a chart of MPGe for the 60 and the 85.

http://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent

Only the government could invent something like MPGe.

A more meaningful approach for consumers is cost per mile, also shown on the chart.

AoneOne | 27 januari 2014
Sudre_ | 27 januari 2014

I was driving down to a restaurant in Panama City yesterday after reading this topic and decided to see what I could really get my watt/mile down to yet still maintain the speed limits... 35 mph.
It's a little easier than normal because it was 56 degrees and pretty darn flat. There were a few stop lights and not much traffic since it's off season.

(hope this works)

Anyone got any Leaf watt/miles on flat ground at 35 mph? I know there isn't one near me because there would be no way to actually get it here. I am over 800 miles from home! LOL Lot'a good a Leaf would have done me.

Sudre_ | 27 januari 2014

20140126_184039

Brian H | 27 januari 2014

Doug H;
Do your analysis again, this time ignoring the issue of carbon(-dioxide), as the evidence of the last 20 yrs is that temperature and climate does not react in any way to its increase, but widespread agricultural and dryland benefits result.

Focus purely on the issues of efficiency and air quality - and you will still come out ahead (or 'smelling like a rose') with electric.