Are Plug-Ins Really Zero Emission Vehicles?

Discussion in 'Environmental Discussion' started by bighouse, Jan 8, 2010.

  1. bighouse

    bighouse Active Member

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    Nothing comes free. I understand, basically, how a Plug-In works...kind of like my DeWalt cordless tools. But, what I can't help but wonder is, what with like 60% or so of the USA's electricity supplied by burning coal, what kind of real benefit using that type of electricity to charge a car really creates for the car in the way of emissions?

    Can someone point me to some kind of data that shows, in the USA, what kind of cost there is to the environment for a Plug-In vs. say a Prius? I'm hoping it takes into account manufacturing and operation as well as eventual recycling/removal of the vehicle as well.
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Do you feel your Dewalt would pollute less with a tiny gas engine attached?

    Ask your self this question. Would it be cheaper to built pollution controls on one fixed plant or hundreds of thousands of mobile vehicles? Transferring the pollution issues to a limited number of fixed plants would seem to simplify the difficulty of providing Zero Emissions considerably. It would still need doing, but it should be an easier problem.

    So 'Zero Emission' vehicles simplify our solutions, they do not eliminate the problem. If your concern is Nickel, there is less Nickel in a Prius than in a 'Chrome' edition Ford Superduty, for example.

    2010 Ford Super Duty Photos | The Official Site of the 2010 Ford Super Duty | FordVehicles.com

    Most 'modern' Plug ins use Lithium batteries, not Nickel.
     
  3. NevadaPrius

    NevadaPrius New Member

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    Hey!

    I can't point you to any data, but from what I understand, the electrical company's generators are very efficient at generating electricity. They are more efficient (in terms of "creating" energy) than the gas engine in your vehicle is.

    If we used nuclear energy.... that would be badass :)
     
  4. qbee42

    qbee42 My other car is a boat

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    The OP's concerns are valid: nothing comes for free. Even green energy such as wind turbines and solar panels have a cost associated with manufacturing, transportation, and installation.

    Jimbo's comments are also correct. Even a very dirty energy source such as coal is better when its use is consolidated. It's much easier and cheaper to remove the pollution at one location than at many small mobile points.

    Of course, in the ideal world we would conserve as much as possible, and then use the cleanest and most sustainable energy sources. The real world, however, is full of compromises. Using plug-in vehicles allows us to use a variety of energy sources. Electrons are electrons - it doesn't matter the source. This gives us flexibility to start with dirtier sources and replace them as better forms of energy become feasible.

    Tom
     
  5. efusco

    efusco Moderator Emeritus
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    They CAN be zero emissions...which no gas car every can be. While you're correct about our current energy sources, many places are going to cleaner coal and cleaner energy. Many people are starting to install solar on their homes thanks to increasing incentives and lower cost. I fully intend to have more than enough solar and wind power to compensate for my energy use when I get my Tesla so that I will be zero emissions. Darell is zero with his EVs.
     
  6. bighouse

    bighouse Active Member

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    Efusco,
    I'd love to install solar on my house...but I fear that living amidst the redwoods doesn't give me great solar access. Still, once prices continue to fall I think I'll look more into it.
     
  7. chogan2

    chogan2 Senior Member

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    I have a decent estimate of the operating portion and an approximate answer for the manufacture/scrappage portion.

    I have a PHEV Prius. I estimate that I get about 4 electrical miles to the KWH -- in line with what you'll read if you Google it, and in line with the national labs early tests of PHEV mod Prius.

    Virgina power emits 1.16 lbs C02/KWH, net for its generating mix. The data for the country can be seen here: (Actually, this is a decade out of date, but the C02 numbers change pretty slowly anyway).

    http://www.eia.doe.gov/pub/oiaf/1605/cdrom/pdf/e-supdoc.pdf

    More detail on methods is here:

    CO2 Emissions Report


    So, for 46 miles, the electricity would create about 13.4 lbs C02.

    If you burn a gallon of gasoline to go (the EPA estimated) 46 miles, you'd get 19.4 lbs C02.

    Emission Facts: Average Carbon Dioxide Emissions Resulting from Gasoline and Diesel Fuel | US EPA

    Do the math and the electrical miles produce almost one-third less C02. Charging from the grid, in Virginia. Not a miracle cure, but not a bad step.

    If I were to add in the upstream C02 for producing the fuel, well, that gets a little shaky, but as near as I can tell, you'd add about 15% to the gasoline cost (for the cost of extracting and refining the oil), and you'd add a much, much lower percentage to the coal cost (for the energy cost of mining and moving the coal). OTOH, you've got losses in charging the battery. On net, basically, to heck with it, it's not worth figuring.

    But for my purposes, about one-third less seems to match the actual accuracy of the calculation.

    It's instructive to see how dirty the electrical generation can be before you no longer come ahead with electrical transport. Answer: About 1.8 lbs C02/KWH is the cutoff. Looking at the data, there are plenty of states exceeding that.

    Let me emphasize that these numbers look less favorable than what you might see elsewhere because the standard of comparison is the Prius, not a standard gas car. The Prius is roughly twice as efficient as the average 2009 new car, in terms of interior cubic feet x miles per gallon. (I calculated that one time from the EPA mileage data, downloadable at Fuel Economy.)

    So if the comparison were between (say) a stock Chevy and an EV conversion of a Chevy, this would look a lot more favorable toward electric transport. But I don't think that's very realistic, in the modern world. I think the number of people who'd turn up their nose at a hybrid but embrace a BEV is small. So if we're taking PHEV, I think the right standard is the best PHEV you can get right now, which would be the Prius.

    On the manufacturing cost, the best I can do is catch-as-catch-can internet references. This guy says 1.9 megajoules per watt-hour of lithium ion battery, when produced from virgin materials. That surely has to be an upper bound, I'd think, based on manufacture of small cells.

    http://www.ebikes.ca/sustainability/Ebike_Energy.pdf

    That would make the 5 KWH Hymotion pack = 5000*1.9 MJ of energy to produce.

    This US national lab lists the energy of a gallon of gas at 121 megajoules:

    Bioenergy Conversion Factors

    Do the math, the energy cost of the battery is about 78 gallons of gasoline. That seems plausible-but-high to me, for an object that weighs about 100 lbs. (I mean, that's about 500 lbs of gasoline, to produce a 100 lb object.) So, based on similar numbers for (e.g.) washers or cars, that seems pretty high.

    So be it. How many times to I have to drain the battery to break even, C02-wise, given where I live? Doing the math, I come up with a little over 500 full discharges (at 20 miles per discharge) to reach break-even. Basically, I have to run the thing for two years before I'm coming head on C02. Again, that's clearly in the ballpark of what I've seen for other devices. (Thats calculated this way: 78 gallons takes me 78*46 miles on gasoline. But electric miles only save a third of the C02 -- so I have to go 78*46*3 electric miles to save all the C02 in that much gas, or just over 10,000 miles. You get 20 electric miles to the full charge, so I have to do 78*46*3/20 full charges (= 538 full charge/discharge cycles) fully to offset the carbon incurred in manufacturing the battery. Or thereabouts. Call it two years of steady use.)

    Final thoughts: We really need PHEVs and a clean grid. When I bought the hymotion system, I was at that point able to purchase wind power directly through my utility. With (nearly) carbon-free electricity, well, all the numbers look a whole lot better. Virginia Power took away that option last year, so I'm back on the grid. With 20-20 hindsight, if your options are to put in solar hot water, solar electric, or get a hymotion conversion and charge it off the (Virginia) grid, your cost per ton of C02 avoided is lower for the solar options than it is for grid-charged electrical transport at this time.

    Conclusions: I own a PHEV Prius. I wanted to support the technology. I had clean electricity when I bought it, I no longer do, but even with that, the electrical miles in the PHEV Prius are modestly cleaner than the gas miles, and yes, I'm pretty sure it will pay back the C02 in manufacture within a relatively short time period. But if you're going to charge off a dirty grid, at current prices, your money is better spent on solar (or insulation, etc.)
     
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  8. hill

    hill High Fiber Member

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    These gasoline figures are astoundingly skewed. The C02 (as well as other waste) does not account for our trillion dollar military losses, protecting our oil interests in countries that hate us.

    At least with renewable energy, we can have U.S. made electrons.
    .
     
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  9. The Electric Me

    The Electric Me Go Speed Go!

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    Are Plug-Ins Really Zero Emission Vehicles?

    I don't think it matters.

    The reality of electrics might be clouded by the reality that a lot of our electricity is produced by coal...but ultimately I don't think it matters.

    Baby steps. Electrics offer "Transportation, and Automobiles" without the dependency on imported oil. This is what matters.

    I think as Electrics and Plug-Ins become more popular and hopefully more mainstream then we can work for progress as far as efficiency and responsibilty in our electricity producing infrastructure. But I'm happy to see vehicles like Prius, Plug-In Prius, Volt, Leaf...and hopefully more and more, become reality.

    So my answer is, Are Plug-Ins really zero emission vehicles? Only in their final operating form. They are not perfect. But I'd rather face the future challenge of trying to figure out how to produce enough electricity to run electric automobiles, then face a future of continued dependency on foreign oil and burning of a finite resource.
     
  10. icarus

    icarus Senior Member

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    Plug in hybrids/Evs and Pv solar go together like bread and butter! While I am under no illusion that Pv and Ev will solve all the energy/environmental issues that face us, the fact that most cars sit 23/7 and can use a smart grid effectively (in both directions!) they may not be zero emission vehicles, but surly they are a huge step in the right direction. In fact several steps.
     
  11. hyo silver

    hyo silver Awaaaaay

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    Even with home grown solar, his bicycles emit less than the EV. No matter what he has for dinner. ;)
     
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