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MODEL S: What's the truth about the carbon footprint?
- Thread starter Bluhorizan
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- Energy Environment Policy
Efficient use of fuel
While we can't build a Carnot cycle engine to get the maximum theoretical efficiency, we can at least use a commercial off-the-shelf combined cycle turbine generator (using the Brayton and Rankine cycles) and an EV to get closer to the maximum possible efficiency.
Otto and Diesel cycle engines, using crude reciprocating pistons instead of turbines, seem rather primitive by comparison.
GSP
While we can't build a Carnot cycle engine to get the maximum theoretical efficiency, we can at least use a commercial off-the-shelf combined cycle turbine generator (using the Brayton and Rankine cycles) and an EV to get closer to the maximum possible efficiency.
Otto and Diesel cycle engines, using crude reciprocating pistons instead of turbines, seem rather primitive by comparison.
GSP
Depends on what mix of electricity sources are used to generate the power stored in the battery. Here in California where we get 20% from renewables and 0% from coal, the Model S will always do better than a civic.
Side note: People often neglect smog forming emissions and instead only focus on tailpipe CO2. However, in an area like SoCal smog reductions are just as important and an often overlooked benefit of driving electric.
Side note: People often neglect smog forming emissions and instead only focus on tailpipe CO2. However, in an area like SoCal smog reductions are just as important and an often overlooked benefit of driving electric.
the author has already admitted he hasn't compared apples to apples by taking 'well-to-wheel' figures for the tesla but not for the civic. a whole host of emissions and waste is in the supply chain of refining and transporting oil from source well to gas tank. also, as one reader assiduously points out, the efficiency of an electric drive train over an ice one is huge. another factor. and while we can't all claim to have solar on our roof's, many of us do -- i generate more than 50kWh/day and thus none of my driving comes from fossil fuel sources. that may be a small factor now, but it will steadily increase. and as several other reader comments pointed out, the tesla is a huge step in the right direction - you can't fault tm if our power companies still rely heavily on fossil extracts for production. what's elon supposed to do, overhaul the entire electric grid as well?? (not that he isn't trying.)
i would feel better if the slant of these articles wasn't so... well, slanted. there is a point to make here about where our electricity comes from, but to fault tm for it and libel their flagship product with it, is just obnoxious. the headlines are just meant to be arresting and sensational, once you dig into the, ahem, FACTS, it becomes much less sensational. this stuff really angers me.
i would feel better if the slant of these articles wasn't so... well, slanted. there is a point to make here about where our electricity comes from, but to fault tm for it and libel their flagship product with it, is just obnoxious. the headlines are just meant to be arresting and sensational, once you dig into the, ahem, FACTS, it becomes much less sensational. this stuff really angers me.
steve841
Active Member
Let me toss in my Libertarian point of view:
I love my Model S.
Carbon footprint? I wont be around to enjoy the melting of the polar ice caps anyhow.
Money spent at gas stations: ZERO. That's a number I can live with.
Increase in my electric bill: ZERO. I charge at work.
Bottom line: WIN WIN!
I love my Model S.
Carbon footprint? I wont be around to enjoy the melting of the polar ice caps anyhow.
Money spent at gas stations: ZERO. That's a number I can live with.
Increase in my electric bill: ZERO. I charge at work.
Bottom line: WIN WIN!
steve841
Active Member
Correct ... but the logic is my life doesnt revolve around my carbon footprint.
And I don't buy in to the global warming issue as "my fault" or "my responsibility" per se ...
Developing nations, those having more than one child, animals, .... all hold more blame than my impact could ever make.
I know Mother Nature will correct itself at some point .... H1N9 or something will fix the infestation.
deonb
Active Member
There is quite a difference between people and cars:
1) Is taking a plant (that would have died and rotten anyway), putting it into a cow, and then putting the cow into a human. This is CO2 that's just being moved from one location to another on the earth's surface over the span of say 100 years. This easily and naturally reverses itself.
2) Is taking CO2 that has painstakingly been buried over millions of years and suddenly releasing it in the span of 50 years. (To move this back to where it came from would take millions of years again.)
Keep in mind that over the last 60 years we about doubled the CO2 in the atmosphere to 400 ppm. No Human being has lived through 400 ppm before. If we just-over double it again to 900ppm (I feel we can do it in 50 years, whose with me??), nothing on the planet has lived through it. If we double it 5 more times after that (to > 20000 ppm), it's outright toxic to all mammals. At our current rate of expansion, that's < 300 years away.
I'm sorry to say, but Tesla is going to take the ~ $15'000 profit they made off you and use it to fund development of the Gen III, and probably license out the power train to even lower cost vehicle manufacturers, which in turn will make its way over to Tata, which will make its way over to developing nations.
So as much as you would like to be part of the problem, I'm sorry to say, you ended up being part of the solution...
PS: Those developing nations have multiple children because they don't think having just 1 child is likely to grow up to adulthood. H1N9 is not going to help with that. Everybody in my family tree had > 5 children up to 2 generations ago. What (abruptly) changed things was access to hygiene and medicine, not exposure to disease.
That is an incorrect statement.
According to NOAA the CO2 was just below 320 ppm 1960.
We are now at 400.
There was no doubling.
Trends in Carbon Dioxide
It's exaggerations like this that make people doubt AGW.
deonb
Active Member
Sorry, I meant to say the CO2 emissions rate doubled over the last 60 years (from 4 to 9 PgC/yr). Not the actual CO2 atmospheric level - we of course had a base before that.
I still feel 900 ppm is doable within 50 to 60 years. The ICC high-end estimate is currently 1150 ppm within 85 years.
I agree wording in this area should be very exact.
steve841
Active Member
You made my argument .... nature will cure the problem. H1N9, plague ... whatever, nature will fix it.
Again, I'm a Tesla enthusiast. I am all for development of a Gen III. That's why I poured extra money in to Tesla by buying a Sig Model S. I am all for it! My motivation is not green energy, it's green backs ... as in keeping our money here in the USA.
stopcrazypp
Well-Known Member
Trying to say on topic:
The EPA has a new tool just for this matter:
http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=33368&#tab2
Click the "Energy and Environment" tab, then under "Greenhouse Gas Emissions", chose to show "Tailpipe & upstream GHG".
It'll take you to this page:
http://www.fueleconomy.gov/feg/Find.do?action=bt2&year=2013&vehicleId=33368
Enter your zip code and it'll give you the GHG emissions from your power company if you used a Model S. For the Model S 85kWh, the US average is 250g/mi, for my area (Bay Area, CA) it's 130g/mi. Take a random gasoline car (I took the most efficient gas car the Prius at 50mpg and 222g/mi) and you get a conversion factor of 11.1kg of GHG per gallon gasoline when including upstream emissions.
That means the US average GHG emissions of the Model S is equivalent to a 44mpg (11.1kg/gal divided by 250g/mi) gas car and in the Bay Area a 85mpg car.
It seems this comparison (like the other which said the Model S is worse than the Jeep Cherokee) the common mistake of trying to do an apples to orange comparison by using "real world" efficiency numbers for the Model S (including vampire load) and then only EPA numbers for the Civic while ignoring upstream for the Civic. Also he's mixing energy efficiency (GJ of energy) with carbon footprint when they are completely different things.
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CapitalistOppressor
Active Member
I believe in Global Warming, but I also feel that innovative companies like Tesla are what is really needed to solve the problem. Even a carbon tax is just a means of creating an additional incentive for such companies to form.
Regardless, my belief in EV's far predates any worry about global warming. California (where I live) passed its ZEV mandate in 1991 to control regular emissions. At the time, as a Republican, I fully supported that after having grown up in Los Angeles where I routinely was not able to see a mountain that was about a 1/3rd of a mile from my house.
By the 90's it was obvious that California's clean air regulations were working, and that gave me a reason to feel EV's were necessary. But the national security implications were what really pushed me over the top. My major in college was International Relations, and the national security and economic issues involved with keeping an oil based economy were just ridiculous. Practical EV transportation and infrastructure is just a no-brainer.
I always got the sense that the Brent Scowcroft and George H.W. Bush wing of the Republican party (which was more or less where I was at) wanted an EV transportation system bad enough to make their teeth bleed. Global Warming is not even necessary for it to make a ton of sense to switch to EV's as soon as practicably possible.
Tesla's Carbon Footprint Is No Better Than A Honda Civic's - Forbes
Tesla's Carbon Footprint Is No Better Than A Honda Civic's
The beautiful Tesla Model S electric sports sedan has been an object of desire, rapture and ignominy to driving enthusiasts, eco-champions and eco-skeptics, respectively. It’s also outselling some Mercedes, BMW and Audis. But does Tesla merit this much attention for being green? Short answer: no, or at least, not yet. For one thing, its sales are miniscule in the grand scheme of things and, as for reducing vehicular carbon impact, you’d do just as well buying a Civic.
This is the eye-opening conclusion tucked into this week’s newsletter from Michael Cembalest, global head of investment strategy at JPMorgan. He’s watched the success of the Model S with interest, and went looking for the car’s broader carbon-footprint meaning. His first call was to Vaclav Smil, a professor emeritus at the University of Manitoba and a world-class expert on energy and climate. Other than being a great-looking sportscar, the Tesla, Smil says, is a distraction in regards to the issue of transportation and environmental efficiency.
Cembalest pulled together some charts to illustrate his points. The one below shows where Tesla sits on the price and production curve, net of the $7,500 credit that buyers receive, and after Tesla benefits from zero-emission vehicle and greenhouse-gas credits paid to it by its competitors.
The second chart compares the current fossil fuel footprint (in gigajoules of energy required per year) of the Tesla to the Honda Civic, and the Civic Hybrid, a car that gets all of its electricity through regenerative braking rather from than the electricity grid. (Click here or scroll to bottom of post to see Cembalest’s estimates of the current fossil fuel footprint of the Tesla vs. Civic chart.)
The Tesla Model S could theoretically have a smaller fossil-fuel footprint than a Civic, and Cembalest presents four scenarios that would take it there. You be the judge on whether those scenarios are iffy or solid.
Scenario #1 assumes that Tesla figures out how to reduce its vampire (standby) electricity loss by 80%, an issue in the car’s software which some users report as draining ~3.5 kWh per day from the battery when the car is idle.
Scenario #2 assume scenario #1 and that America’s electricity-generation split between coal and natural gas, which is currently 63/37, falls to 50/50 as older coal plants continue to be shut down and more natural gas plants are built.
Scenario #3 assumes scenarios #1 and #2 and that fossil fuels fall from their current 67% share of US electricity generation to 60%. This sounds manageable, but keep in mind that they have ranged from 65% to 72% share for the last 30 years in the US. For a larger decline, more nuclear and/or a break-through on battery storage of intermittent renewable energy would probably be needed.
Scenario #4 assumes scenarios #1, #2 and #3, and that thermal efficiency of coal and gas plants rise closer to theoretical maximums. However, on coal, emissions standards and greater coal plant cycling impose parasitic loads that may make theoretical maximums hard to reach.
One of Cembalest’s colleagues at J.P. Morgan believes that Tesla’s long-range plan is to provide proof of concept at the luxury end of the market, and then eventually commoditize the concept at lower prices. If that’s what happens, and if the electricity “ifs” shown above take place, then Tesla would merit the attention it’s getting for current annual production of 20,000 units on a base of 15 million U.S. cars sold each year. Otherwise, Cembalest writes, “what we may be witnessing is simply a green revolution where green represents the buying power of the Tesla’s wealthy driver rather than a substantial environmental benefit. The broader point is that the oft-promised rose garden of substantially lower environmental footprints from electric vehicles may be decades away from blooming, at least in the US.” In some countries, renewable energy makes up a larger % of total electricity generation than in the US. However, where renewables make up >30% of total generation, hydro-electric usually makes up 75%-100% of that amount (Austria, Brazil, Canada, Chile, Colombia, New Zealand, Norway, Paraguay, Venezuela, Sweden and Switzerland). Some exceptions: Finland, Portugal, the Philippines and Spain.
In the meantime, he writes, “modest improvements in the internal combustion engine, changes in driving patterns and a move away from heavier, low-mpg cars could get to a similar place.”
Calculations for gigajoule comparison (click image to enlarge):
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How does this compare with the EPA MPGe calculation on the sticker? Doesn't the Tesla get an MPGe of something like 85? Based on the above I would have expected the 44. Obviously there's something different about the two calculations.
Anyway, I love that my car CAN run without burning anything, even if the actual electrons I put in don't always come that way. Psychology is a funny thing. I put in a 10kw solar system when I got my Roadster, which generates way more power than my car can use. I could have done this before and had the same environmental impact, but I didn't.
stopcrazypp
Well-Known Member
You "would" or "wouldn't" have expected the 44? I'm guessing "wouldn't"?
The Model S is rated 89MPGe. This number is from measuring the amount of electricity used from the EVSE (so it includes charging losses) and converts it to the energy equivalent of gallons (33.7kWh is the energy in a gallon of gasoline). This is essentially the plug-to-wheel efficiency of the car and is an apples-to-apples comparison to the pump-to-wheel rating for gasoline cars (which does not take into account upstream energy use).
http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=33368
The 44mpg equivalent I posted includes transmission losses and upstream emissions from the average power mix of the US. It's all based on the ANL GREET model (the most comprehensive energy/emissions model out there).
You can plug in your zip code and get the upstream emissions of your Model S when running on electricity from your utility. Given you are also in California, it's probably still extremely low.
http://www.fueleconomy.gov/feg/Find.do?action=bt2&year=2013&vehicleId=33368
I meant I would have expected a 44 MPGe from the EPA, given your calc, not the actual published EPA figure of 89.
But you've explained the difference I guess. Plug to wheel vs. well to wheel. I'm still somewhat confused as to how the EPA can even get an "equivalent" MPG without some assumed average upstream calc. I'm probably just being dense.
But you've explained the difference I guess. Plug to wheel vs. well to wheel. I'm still somewhat confused as to how the EPA can even get an "equivalent" MPG without some assumed average upstream calc. I'm probably just being dense.
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