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MODEL S: What's the truth about the carbon footprint?

Discussion in 'Energy, Environment, and Policy' started by Bluhorizan, May 27, 2013.

  1. Bluhorizan

    Bluhorizan Member

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    Just picked up my P85 in the past 3 weeks and have driven over 1000 miles, loving every moment. Colleague at work says, "beautiful car but the carbon footprint must be massive; more than an ICE SUV when you figure the battery manufacturing, build and operation of the vehicle over its lifespan". Researching on the web brings up completely contradictory information with a great deal of political commentary:

    BEV car is 30-40% greener than standard car: The Car Battery's Carbon Footprint - IEEE Spectrum

    Only in 5 states (NH, VT, ID, WA, OR) did the electric car (Nissan LEAF) actually reduce ones carbon footprint: Your Car's Carbon Footprint: Hybrid vs. Gasoline vs. Electric Cars


    Effective CO2 emissions fro Model S sedan are 547g per mile; Jeep Grand Cherokee 443g per mile: Is the Tesla Model S Green? | Watts Up With That?

    What if the Tesla Model S actually generated more CO2 than say, an efficient BMW? Even worse, what if effective Model S CO2 emissions are higher than most large SUVs?: Is The Tesla Model S Green? - Seeking Alpha

    Interestingly these last two references come up first on a Google search and have obvious political agendas with wordings like "Tesla Motors (TSLA) enjoys massive financial support from the Federal government, as well as various state and local governments" and "government environmental credit schemes "

    So what's the truth here?
     
  2. dsm363

    dsm363 Roadster + Sig Model S

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  3. deonb

    deonb Active Member

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    If you look at the Jeep Grand Cherokee study, it's not an apples to apples comparison. They compare the Model S, to the average mpg of all passenger vehicles. Show me a vehicle that gets 27.4 mpg and has the performance of a Model S. Tesla's comparison against 22mpg cars are more accurate. Once Tesla has the Gen III you can start comparing it to 30mpg cars.

    Also, it's also comparing the grid as a whole against where Tesla sells cars. In actuality, Tesla's biggest markets by far is CA and WA, which has virtually no coal in their grids. (If you DO live in a coal-heavy state, perhaps it maybe time to give a call to SolarCity?).

    But even in the cases when there ARE coal plants, in practice EVs are still being charged on baseload since there are very few and they're being charged in the middle of the night. So in actuality it has little or no impact on CO2 emissions today.

    All of these studies are based on the following logic: "If all cars in the U.S. magically change to Model S's, and we make them in Alabama (state that most closely tracks U.S. average grid), and we don't make any changes in the grid sourcing or delivery systems, then we'd be worse off than our current mix of high- and low- emission vehicles."

    That's not where we're at in practice today though, and even if that is where we're heading then someone will figure out that having 70kWh x 200m cars = 14 billion kWh of storage capacity connected to the grid makes a pretty compelling business alternative to running power plants at baseload... It also makes large-scale Solar and Wind generation a lot more viable due to the fact that battery charging can smooth out the supply inconsistency (WA state is already investing in this).
     
  4. ChadS

    ChadS Petroleum is for sissies

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    #4 ChadS, May 27, 2013
    Last edited: May 27, 2013
    Note that Sherry Boschert's link that dsm363 provides was based on the 2007 grid, when coal was 54%. As of late 2012, it was under 1/3. So EV advantages are much stronger than noted in that paper.

    I have read about a dozen newer studies in the past three years, and some good summaries by the DOE, Union of Concerned Scientists, and some universities. It is still POSSIBLE for an EV to be worse (as deonb notes) than an ICE if you're in a 100% coal area and you're comparing a high-performance Model S to a very thrifty ICE like a Prius.

    But if you compare the average EV to the average ICE on the average grid, it's not even close. The EV is way cleaner. Add to that the fact that EVs are being sold disproportionately in clean-electric states, and that the grid is getting cleaner over time, and that many owners source their own cleaner electric sources, and it's absolutely no contest.

    Naysayers like to harp on this because 1. they think eco-hippies are the only people that like EVs and 2. the calculations are complicated and it's easy to say something that sounds smart but is completely misleading, especially since there are so few people that are actually willing to read the studies. Many dozens of studies have been done, many meta-analyses completed, and the results are clear. EVs are much cleaner. (Even if they weren't, I think they have enough other advantages to be well worthwhile!) You can find a handful of studies that say otherwise (and dozens of articles based on them); but if you're even slightly familiar with the field it's not hard to see what they've done wrong if you take the time to read them: ignored gas upstream costs, compared worst-case EV to best-case gas, oversized EV components, understated EV lifetime and battery reuse and recycling, etc.

    The DOE and organizations like the Sierra Club and Union of Concerned Scientists have examined the studies in great depth (believe me, they spent years studying them while orgs like Plug In America were trying to get their support!) and would not be behind vehicle electrification if there was not a clear advantage to EVs.
     
  5. techmaven

    techmaven Active Member

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    This is a complicated and politically charged topic. Unfortunately, due to the inherent complexity and the resulting modeling errors, there are plenty of data points to support any number of sides. It is important to note that many of the aggregation studies rely on data that is very old and in many ways too far removed from the reality of Tesla Model S production to be truly useful.

    Like several articles on SeekingAlpha, Mr. Weiss's series on the greenness of the Model S could seem quite data heavy and reasonable. However, a few tweaks here and there and his findings are quite a ways off the mark. His primary failings include comparing the real world winter usage of Model S's against EPA ratings for Prius's as well as double counting some factors. Further, he relies again on the Hawking paper that was also referenced in this thread which has some completely unrealistic assumptions and modeling simplifications. If you dive into that paper, note the methodology and the date of the data. Anyone critically reading that paper would not apply it directly to Tesla. As for Mr. Weiss's calculations, certainly, if you drive only in the winter with lots of resistive heat energy and drive very little therefore a huge portion of your electricity usage is comprised of the phantom power usage, then Mr. Weiss's data could be accurate.

    As a result the best place to start if you really want to know is probably the GREET life cycle analysis model: GREET - Announcement
    This data underpins the Fuel Economy site which can give you a much more accurate representation of your Model S's carbon footprint as you put in your zip code. The GREET model does include items that Mr. Weiss points out like charging losses and electricity transmission losses. It does not include phantom power loss.

    In one of my comments back to Mr. Weiss, I point out that the areas that have the highest number of Tesla's, CA, Pacific Northwest, and New England have very low utilization of coal for electricity production. Therefore, in those regions, Model S CO2 emissions is somewhere in the 140-160 g/mi... lower than a Prius's 222. Even if you say that Model S real world numbers at 20% worse than EPA and use the Prius at EPA, then the CO2 emissions are still lower. If you live in the northern midwest, then you have the nation's highest utilization of coal and the Model S's resulting CO2 emissions is much higher than the Prius - upwards to 300 g/mi.

    Here are some equivalent gasoline cars in relation to the Model S:

    BMW M5: 692 g/mi
    MB E400 Hybrid: 426 g/mi
    Jaguar XF turbo 4: 482 g/mi
    [FONT=arial, helvetica, clean, sans-serif]Toyota Prius, 222 g/mi[/FONT]
    [FONT=arial, helvetica, clean, sans-serif]Model S 85 kWh: 140-300 g/mi depending on region[/FONT]

    [FONT=arial, helvetica, clean, sans-serif]So it is green? Depends on how you want to interpret the data. In my region, there is a lot of nuclear usage but no hydro for electricity and the Model S scores just under the Prius. Not bad for a 4,600 pound car.[/FONT]

    [FONT=arial, helvetica, clean, sans-serif]There is also value in just getting emissions away from the tailpipe apart from the actual CO2 numbers. Let's say the numbers work out to be the same - then moving the emissions away from the middle of our cities and neighborhoods out to where power plants are built is a benefit also. It also puts onus on cleaning up the power plant emissions.[/FONT]

    Note through all of this I don't mention solar. While solar can reduce the overall CO2 footprint, I believe most people charge their cars at night and the only reasonably cost effective way to do that is from the grid from NG, coal, nuclear, wind, or hydro. The baseline is likely to be a fossil fuel power plant for most people. You can offset your HVAC use, your daytime computer use, your refrigerator, etc. But not likely the car. However, it is also possible that right now, your car is charging from a fossil fuel plant in the middle of the night while that plant is mostly idle - using electricity that would have to be generated anyways due to the minimum idling level. How does one find out if that is the case and account for that? No idea.
     
    • Informative x 2
  6. SwedishAdvocate

    SwedishAdvocate Active Member

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    #6 SwedishAdvocate, May 27, 2013
    Last edited: May 27, 2013
    Would that be what’s summarized here?


    - - - Updated - - -

    When I first saw this thread ChadS had not posted post #4 above, so I started out on a little post about the Jeep Grand Cherokee study above (see below), and basically point to what ChadS summarizes with: “ignored gas upstream costs”. But feel free to skip it. All the info you need is as far as I can tell already in the material from the Union of Concerned Scientists also referenced by ChadS.

    I studied social sciences so I cannot comment on the basic validity/reliability of the Jeep Grand Cherokee study. But it obviously assumes that gasoline somehow magically appears at the gas pump. It does not take into affect the Green House Gases emitted during gas/diesel-production:

    So, there needs to be a drilling-rig. Maybe you even need an off-shore drilling rig. Then you need to drill and line the well with steel. And then you need a pump, and a pipeline/and or a bunch of tanker-trucks and/or a bunch of gigantic oil-tanker ships. And now it’s time for the oil-refineries and a bunch of gigantic cisterns or some other storage facilities. And then it’s time for what? More gigantic oil-tanker ships? And finally a s#!tload of tanker trucks and gas stations? And all of the above needs to be maintained and regularly replaced. How much does that add to the CO2 – footprint of the SUV?

    And, besides being green, on top of that the US and everyone else who’s economy literally depends on oil (yes, including Sweden) needs to all but kiss the ‘royal’ behinds of the oh so democratic rulers of Saudi Arabia, The United Arab Emirates, Qatar, Kuwait, Bahrain and Brunei. And them being so nice to their subjects, especially their women folk and all.
     
  7. ChadS

    ChadS Petroleum is for sissies

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    Yes, that is the UCS study I meant. Direct link HERE. That study is also based off older grid data, so you could make stronger conclusions with today's cleaner grid.

    (I had asked them why they used the older data when newer data was available; I can't find the email and don't remember for sure but think it had something to do with formatting and the ability to automatically insert it into their calculations).
     
  8. yobigd20

    yobigd20 Well-Known Member

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    There are a bazillion research studies on this. Bottom line - in North America, in the worst case scenario (states that still burn fossil fuels for a large amount of energy), a Tesla Model S' carbon footprint is still half of what an ICE vehicle emits per mile driven. The *ONLY* 2 countries where coal is still the PRIMARY source of energy where the carbon footprint of an EV would actually be higher than it's gasoline equivalent are China and India. Drive anywhere else in the entire world, and the Tesla Model S is without a doubt a lower carbon footprint than an ICE vehicle. That is the answer in a nutshell. All of those links you provided (the OP) were written by EV haters that have not done any real research and probably have a lot of investments and/or connections with big oil.

    Also, I love how those EV haters try to add to the Model S's CO2 footprint by factoring in the cost to manufacture lithium ion batteries but they always fail to factor in the cost to drill oil and transport it and refine it for the ICE equivalents, let alone the cost to manufacture the myriad of complex components to make up an ICE engine. lol. They always seem to 'leave that part out' of their calculations trying to make the Model S look worse.
     
  9. richkae

    richkae VIN587

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    There were recent studies funded by the oil industry that claimed that the carbon footprint of building BEVs was vastly more than the operation.
    These were all total garbage. They assumed the vehicle was scrapped and destroyed with no recycling after 7 years, that the motor and inverter used an order of magnitude more metal than they actually do because they got their data from industrial equipment, and that the materials in the car were all sourced from the ground ( aluminum is recycled and reused over and over, anything aluminum you own has likely been many other things already ).
    Any of those things made their arguments invalid, but they used all three.

    If you can trace the money that funded the study back to the oil industry, it is likely bunk, and only peer reviewed by others also on the payroll of the oil industry.
     
  10. caddieo

    caddieo Member

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    Good point, yobigd20. I bring this up with naysayers ever since I read a month or so ago (forgot to write down the source) that refining crude into gas generates over 200 million megatons of CO2 a year.
     
  11. ModelS4Taos

    ModelS4Taos Member

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    This argument always seems to miss the most important fact. It takes 7 kWh of electricity to produce a gallon of gasoline. And because refineries use wholesale electricity, they are using 100% coal to make that gasoline. You can go 20-25 miles on 7 kWh in a small electric car, so 25 miles just to make the fuel. This is before transporting foot print or the burning in a very inefficient ICE engine.

    That is why this is an non-argument for me. Something the oil industry would love to debate until eternity. As long as false questions are raised about EVs, the longer their implementation can be delayed.

    I don't know for a fact that this is the oil industries PR tactic, but it makes sense that they would use it.
     
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  12. ChadS

    ChadS Petroleum is for sissies

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    That is indeed a great argument. And in fact you should note that that energy is only for refining. A lot more energy is used to produce gasoline.

    However, the big complication is that it's not 7kWh of electricity that is measured in those studies - it's 7kWh of energy (actually I usually hear a slightly smaller number, closer to 6kWh). The refineries often produce much (not all! CA refineries are the second largest electricity users in the state) of the electricity they use themselves; and some of it is from byproducts. So while the general thrust is correct, it's hard to use that argument as a direct counterattack. It would be easier if refineries released more information on the process, but of course they are reluctant to do so.
     
  13. ModelS4Taos

    ModelS4Taos Member

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    Thanks for the clarification. I think in other parts of the country they use coal to produce electricity for refining. Its good to be on top of the details but the general truth is whats important and the end result is the same.

    I am just so tired of the long tail pipe argument and think in the end its deceptive instead of informative. I think a lot of PR relies getting people caught in the details so they never understand whats important.

    I think this is a good discussion though. :wink:
     
  14. walla2

    walla2 Member

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    I have had a few people tell me gas in an ICE is more efficient than BEV. I have a hard time believing that given a top of the line, "efficient" ICE engine is only about 20-30% efficient meaning it makes mostly heat and noise and only a small percentage is used to move pistons. I see neither heat or noise produced from the Model S meaning the power going in is used fairly efficiently. There are BEV losses to vampire and also losses in power transmission and conversion that are important to consider, but the same could be said about oil. It does cost a significant amount carbon to find, drill, collect, transport, refine, add ethanol to (grown, harvested, processed, transported), transport, and lug around gasoline in the tank. These issues are never considered when looking at the carbon footprint issue and truthfully, many people just want something (looks, range, carbon, silence, charging, un-American, etc.) to hate about BEV's to justify what they are doing. School children picking on things they don't understand.
     
  15. richkae

    richkae VIN587

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    #15 richkae, May 27, 2013
    Last edited: May 27, 2013
    I crunched some numbers about refining and recorded them here: Refining | High Speed Charging
    The EIA where I got all my numbers from has good hard data. Not much actual electricity is consumed but your numbers are accurate in that the energy consumed to refine oil into gasoline can drive an EV 20-30 miles.

    Also this: Day in the Life of a Pump Jack | High Speed Charging
    Oil pumped out of the ground by a pump jack in California probably takes about 2kWh of electricity to pump out each gallon of gasoline.

    Something else that is ignored is that a large portion of the oil that is turned into gasoline in the US comes from Canadian tar sands.
    Canadian tar sand is the number one source of oil imported into the US, and this dependence is steadily growing. ( actually most oil supplies are getting dirtier/less efficient over time as we use up the light free flowing crude and turn to heavier alternatives )
    Tar sands have a terrible return on the energy input. Even if an ICE car magically could turn the heavy oil from the tar sands directly into motion with no emissions other than unicorn farts - it would be a terrible disaster compared to an EV. The natural gas consumed to turn tar sand ( bitumen ) into oil could drive EVs farther than the gasoline that we get from it. I did back of the envelope calculations to arrive at this conclusion from the claim that 20% of the natural gas consumed in Canada is used to extract bitumen: Two more ethical challenges to Canada's oil sands

    We are far better off leaving marginal oil in the ground and using the extraction energy to drive EVs instead. Hopefully soon we will.
     
  16. NotTarts

    NotTarts Member

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    Some more things to add:

    - Long range EVs like the Model S will almost always charge at night with unutilized off-peak power, where they don't contribute to any increase in overall CO2 production.
    - Tesla is able to recover some 70% of the CO2 released during the production the batteries through recyling.
    - Even once the batteries hit end of life the cells can still be reused in off-grid energy storage applications. I think Nissan even set up a separate company to facilitate this.
     
  17. Robert.Boston

    Robert.Boston Model S VIN P01536

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    #2 and #3 are good points. #1 misunderstands how the power grid works.

    During off-peak period, there is no "untilized off-peak power" that would otherwise be thrown away. There is underutilized capacity to produce and transmit energy, but the energy produced always precisely equals the energy consumed (plus losses). Off-peak energy requires fuel, just the same as on-peak energy.

    So, does charging off-peak result in higher or lower air emissions? That depends; there are three general cases:
    1. Emissions can (rarely) be zero: Off-peak wind generation is so high that wind or nuclear is being curtailed. We are seeing wind curtailments in some hours in Oregon, and in Ontario nuclear units are being ramped down to accommodate all the wind on the system. In this (fairly rare) case, additional energy demand allows higher utilization of zero-carbon resources.
    2. Emissions can be lower than on-peak: In places like California and New England, natural gas is the marginal fuel around the clock. Off-peak, there's spare generation capacity at highly efficient plants that produce relatively low emissions per kWh. On-peak, the system operator will use less efficient, more costly generation to meet incremental demand.
    3. Emissions can be higher than on-peak: In places like the Midwest, coal is on the margin overnight, while on-peak marginal generation comes either from coal or natural gas. If natural gas is on the margin on-peak, than the emissions/kWh are lower than the off-peak power from coal. Unfortunately, you can't easily know whether NG or coal is at the margin from the real-time information available to the public.
     
  18. yobigd20

    yobigd20 Well-Known Member

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  19. Alfred

    Alfred Member

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    Gasoline Engine Efficiency

    To Walla2:
    A gasoline engine powered drive train will achieve under ideal test-cycle conditions about 14-26% (EPA). In the real world even less as the discrepancy between tested and real mileages document. Much of actual runs do not permit the engine to operate in its ideal operating range and if the engine is cold e.g. it will not only operate much less efficiently, but will also emit a lot more pollutants until, among other things, the cat has reached operating temperature. These are effects electric engines do not know. They remain about as efficient as the driver permits them to be, often over 80% for the whole drive train. There are few studies that mention this type of effects or quantify them, but they are believed to be relatively significant as a fairly large proportion of the fuel is thought to be burnt under unfavorable operating conditions with cold engines in slow local traffic. I saw one undocumented estimate that perhaps 50% of fuel use might be burnt very inefficiently. The 20-30% figures are reminiscences of testbed data with all auxiliaries disconnected, but seem to be difficult to get out of the way in discussions.

    P.S. How efficient the conversion of heat to mechanical energy can be was studied and analyzed by Sadi Carnot in 1824.
     
  20. kishdude

    kishdude P #130

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    Model S same carbon footprint as a honda civic?

    I'm responding to this article:

    Tesla's Carbon Footprint Is No Better Than A Honda Civic's - Forbes

    Here are some obvious issues. First the Model S is a much larger more powerful car. Also the author doesn't take into account the carbon footprint of transporting and refining the gasoline. Lots of smart people here. Lets discuss this.
     

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