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You hear a lot of claims that, once you include manufacturing and battery replacement, hybrids pollute more than an efficient, more conventional engine. Are there any end-to-end studies measuring any type of pollution for both types of vehicles, which demonstrate that one is superior, even when the manufacturing (and pollution to generate electricity) is included for consideration?

Note, I'm not talking about comparisons to Hummers.

Pollution to include CO2 and other emissions commonly attributed to and regulation in relation to the combustion of gasoline in motor vehicles.

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    Pollution is a vague term. Do you mean CO2 emissions, lead emissions, or something else? – Borror0 Mar 4 '11 at 22:54
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    How do you calculate an exchange rate, when technique A produces more of the harmful x, and technique B produces more of the harmful y? – user unknown Mar 5 '11 at 4:50
  • Updated the question to be more specific -- Given the lack of response, I'm wondering if anyone has actually performed an end to end analysis for both types of vehicle. – Russell Steen Mar 5 '11 at 16:59
  • Something that seems to have been ignored so far is the fact that electric and hybrid vehicles can recapture energy from the braking process turning it back into electricity. In fuel burning vehicles this energy is lost as heat (in the brake pads and disks) – user16193 Nov 15 '13 at 2:09
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    @Tendulkar: I believe that is incorporated into the fuel-efficiency metrics of city-driving cycles, so it is not being ignored. – Oddthinking Nov 15 '13 at 3:41
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If you asked about Nickel Metal Hybrid batteries, the answer would be extremely easy. A large amount of studies have been done with these, usually concluding that they have lifespan comparable to those internal combustion engine vehicles. To cite the 100,000-Mile Evaluation of the Toyota RAV4 EV study,

The five-vehicle test is demonstrating the long-term durability of Nickel Metal Hydride batteries and of electric drive-trains. Only slight performance degradation has been observed to date with the highest mileage vehicles. Test data provide strong evidence that all five vehicles will exceed the 100,000-mile mark and SCE’s positive experience points to the very strong likelihood of a 130,000 to 150,000-mile battery and drive-train operational life. This is achieved by full or mostly full range use after every charge. EVs can therefore match or exceed the lifecycle miles of comparable internal combustion engine vehicles.

As such, the reduction of greenhouse gases is simply a net benefit for the environment. However, you asked for lithium-ion batteries. That makes the answer harder to answer. Lithium-ion batteries are used in hybrid cars since only very recently. Little information is available on the subject.

Don't take my word for it. It's the first thing said in the only peer-reviewed study I could find on the subject, published in August 2010:

Battery-powered electric cars (BEVs) play a key role in future mobility scenarios. However, little is known about the environmental impacts of the production, use and disposal of the lithium ion (Li-ion) battery. This makes it difficult to compare the environmental impacts of BEVs with those of internal combustion engine cars (ICEVs).

The study made several assumptions that were favorable to ICEVs:

  • Used a car more energy efficient than the average car sold in Europe in 2009. They used 5.2 L of gasoline per 100 km, instead of 5.7 L of diesel /100 km 6.6 L of gasoline /100 km.
  • "All expenditures for the exploitation of the lithium salts were allocated to the lithium salts, even though the saline brine yields other byproduct as well."
  • All the burden from production are allocated to the first life of each product even though the product might be reused or recycled. As explained in the study, this assumption heavily penalizes BEVs since recycling of electric batteries is high and since recycling of lithium is more energy efficient than production of it.

In spite of that, electric cars perform far better than conventional cars on all four indicators (abiotic depletion potential, global warming potential, cumulative energy demand, and eco-indicator 99):

enter image description here

In fact, the research concludes that

All the facts taken together, the results of the LCA, the various sensitivity analyses, the modeling applied for EOL, the assumption for the used electricity mix, etc., suggest that E-mobility is environmentally beneficial compared to conventional mobility. The Li-ion battery plays a minor role in the assessment of the environmental burden of E-Mobility. Thus, a Li-ion battery in an BEV does not lead to an overcompensation of the potential benefits of the higher efficiency of BEV compared to an ICEV.

They note, however, that it's not always necessarily always the case. A few very small and efficient internal combustion engine vehicles can perform as well as electric cars:

A break even analysis shows that an ICEV would need to consume less than 3.9 L/100km to cause lower CED than a BEV or less than 2.6 L/100km to cause a lower EI99 H/A score. Consumptions in this range are achieved by some small and very efficient diesel ICEVs, for example, from Ford and Volkswagen (13, 39).

They also note that the means by which the energy is produced influences the how environmentally-friendly BEVs are. The study used the average electricity production mix in Europe to give a general idea. If electricity comes from "an average hard coal power plant", the environmental burden is increased by 13.4%. On the other hand, if the electricity comes from hydropower plants, the environmental burden is decreased by 40.2%. As such, as countries move toward green energy, the environmental burden of electric cars will decrease.

The study does not address the cost of manufacturing the automobiles, but those costs are not significant. As a recent Argonne National Lab study concluded that, while hybrid cars cost more to produce, hybrid cars make up for their greater manufacture energy costs by being more environmentally-friendly on the road - especially if recycled materials are used in the vehicle's fabrication.

To cite the study's conclusion,

The energy use and GHG emissions that result from vehicle production and disposal of advanced-powertrain vehicles (HEV and FCV) may be greater than those for ICEVs because of (1) the use of energyi-ntensive materials in the fuel cell system of the FCV, and (2) the increased use of aluminum in both the HEV and FCV. However, the use of recycled materials can reduce these impacts. Conversely, the use of energy-intensive materials such as aluminum and carbon fiber composites does not necessarily increase the vehicle-cycle energy use and GHG emissions of lightweight vehicles; with a reduction in total weight, the results are about the same and could be improved with additional recycling.

To put vehicle-cycle results into a broad perspective, we conducted a total energy-cycle analysis that included the vehicle-cycle, fuel-cycle, and vehicle-operation stages. Our vehicle-cycle analysis revealed that lightweight materials can reduce the weight of a vehicle and improve its fuel economy, but that production of these materials can be energy intensive if recycled materials are not used. Our total energy-cycle analysis further shows that, when examining vehicle technologies and lightweight materials on a total energy-cycle basis, there can be a significant net benefit in terms of energy use and emissions reduction by substituting lightweight materials for conventional materials.

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    The quote about NMH batteries only covers their production cost though, right? They still have to be charged. Doesn’t this have to be considered in the energy consumption (and thus pollution) as well? – Konrad Rudolph Mar 7 '11 at 18:22
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    @KonradRudolph: The quote about NMH only talks about their lifespan. To answer your question, though, hybrid cars powered NHM batteries are also better for the environment than conventional cars. – Borror0 Mar 7 '11 at 18:32
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    The charging of NMH and LI batteries charge in the same way. There may be some differences in the power lost in the change, and in their lifecycle, but for the most part, they work just like the LI batteries. – Ustice Mar 7 '11 at 18:34
  • @Borror0 That’s an interesting factoid that was (for me at least) missing. Great answer. – Konrad Rudolph Mar 7 '11 at 18:35
  • @Borror0 -- Nicely done, I read it all and all the references and it looks solid to me. +1 (will see what shakes out before I accept as answer) – Russell Steen Mar 7 '11 at 21:43
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This article explains that if the goal is to reduce aggregate gasoline consumption, the most savings is found by spreading smaller batteries over more cars, rather than larger batteries over few cars. This is because a scarcity of battery materials limits production.

The greatest savings-per-battery-materials comes from upgrading a gasoline car's battery such that it can handle the strain of turning the car off every time it stops. Upgrading N cars with such batteries saves more gasoline than upgrading proportionally fewer cars as hybrids or electrics.

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Even if you'd disregard how much pollution is created while making batteries, just the fuel efficiency of hybrid cars is actually much worse than that of modern eco-turbodiesel. Especially VolksWagen's BlueMotion (aka EcoMotive in SEATs and Greenline in Škodas) line of engines is exceptionally fuel efficient. Fuel efficiency translates to less pollution.

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    I already pointed that out in my answer... – Borror0 Jun 27 '11 at 16:06
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    This answer incorrectly assumes that "hybrid" and "diesel" are exclusive. The peugeot 3008 is in fact available as a hybrid diesel. – MSalters Jun 28 '11 at 13:20
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    @MS: no it doesn't assume it. It assumes, "diesel" in this context means "diesel-only" car, which isn't dragging along batteries and electric engine. – vartec Jun 28 '11 at 13:22
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    @vartec then you need to compare it with a diesel hybrid, not a gas hybrid. Diesel fuel has more energy in it than gas, which is why it gets higher mpg at optimal highway cruising speed. It might have ever so slightly less CO2 emission, but has higher particulate and NOx emissions. – psusi Jul 1 '11 at 14:41
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    The points about VW diesels should probably be updated given the revelations regarding VW's gaming of emissions testing. – JAB Jun 16 '16 at 14:18

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