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Plug in Hybrids are Green (Duh!)

By Joe Romm

"Plug in Hybrids are Green (Duh!)"

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The definitive study on the global warming impact of plug-in hybrid electric vehicles (PHEVs) is out. And it confirms what Climate Progress has long been saying:

The widespread use of plug-in hybrid vehicles — which could be driven up to 40 miles on electric power alone — would significantly reduce greenhouse gas emissions in the United States without overloading the nation’s power grid, according to a new study.

The study, “Environmental Assessment of Plug-In Hybrid Electric Vehicles,” is by the Electric Power Research Institute and the Natural Resources Defense Council (whose new blog is the oddly-named Switchboard). Here’s a key chart:

epri-figure.png

Here are some more details on the study’s conclusions:

The study found that if 60 percent of Americans shifted to plug-in hybrids by 2050, it would lead to an increase in electricity usage of 7 to 8 percent — a relatively small increase, indicating that hybrids would not necessarily require a surge of new power plant construction. Plug-in hybrids are charged mostly at night, when demand for electricity is low.

At the same time, the report estimates that electric hybrids would displace the need for 3 million to 4 million barrels of oil per day by 2050, more than twice what the United States imports each day from Saudi Arabia.

Researchers also found that plug-in hybrids reduced greenhouse gases no matter what energy source was used to produce the electricity, whether coal, nuclear, hydroelectric, wind or solar. Electric hybrids generated 40 to 65 percent less greenhouse gas than gas-fueled vehicles and 7 to 46 percent less than conventional hybrids.

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6 Responses to Plug in Hybrids are Green (Duh!)

  1. Earl Killian says:

    I was recently looking at the data for vehicle miles traveled (VMT) in the U.S. (From the BTS website: http://tinyurl.com/2dva4s)
    From 1995 to 2005 VMT increased 2.12%/yr (ending up at 2.8 trillion miles). Extrapolate to 2050 and you get 7.1 trillion VMT/yr. If 60% of Americans drive PHEVs (as suggested by the report) at 0.3 pounds/mi (the low number in the graph), and 40% drive conventional vehicles at 1.0 pounds per mile, you get 0.6 pounds/mile. Thus annual vehicle GHG emissions would increase from 1.3 gigatonnes to 1.9 gigatonnes, despite the improvement from PHEVs. 60% PHEV-20s in 2050 is not good enough. Even 50% PHEV-20s in 2025 leaves the annual vehicle GHG emissions unchanged when we need a substantial reduction (25%) by then to meet the Hansen targets.

    We need to run as fast as we can just to stay in the same place.
    (Or we need to run as fast as we can just to keep up with our driving.)

  2. Joe says:

    Thanks for this post. I think there are a few factors that might mitigate against what you say. First, I’d be wary of projecting VMT out another four decades. Note that higher energy prices do seem to have slowed VMT growth recently — and there is obviously a limit to how many miles individuals can drive.

    Second, if PHEVs are practical, I seriously doubt people will be driving PHEV-20s in 2050 — probably more like PHEV-60s (if not all electrics). Third, that chart does not include the possibility that cellulosic ethanol will be blended in with gasoline. If most vehicles are using E85 in 2050, and are PHEV-60s, (and gasoline prices are several dollars a gallon) then we can probably come close to the Hansen targets.

  3. Earl Killian says:

    I agree with your points. It is just that the VMT trend was a bit scary, and it seemed worthy of a little bit of highlighting. I looked up the US population growth from 1995 to 2005, and it was 1.1%/yr, so that explains about half of the VMT increase. Projected population growth from 2005 to 2050 is 0.8%/yr, which might slow VMT a little. (The Census Bureau projects 420M in 2050. Gulp.) One hopes that oil prices will do a bit of slowing as well (let’s hope Peak Oil is soon).

    Ignoring PHEVs for a moment, even if efficiency causes the US per capita electric use to fall 44% from 2003′s 11,997 kWh to California’s 6,732 kWh, the increase in population to 420M means total US electricity use only falls 19%. That means we need roughly another factor of eight reduction in g CO2/kWh in greenhouse gas intensity to meet the Hansen target.

  4. msn nickleri says:

    Ignoring PHEVs for a moment, even if efficiency causes the US per capita electric use to fall 44% from 2003’s 11,997 kWh to California’s 6,732 kWh, the increase in population to 420M means total US electricity use only falls 19%. That means we need roughly another factor of eight reduction in g CO2/kWh in greenhouse gas intensity to meet the Hansen target.

  5. sesli chat says:

    I agree with your points. It is just that the VMT trend was a bit scary, and it seemed worthy of a little bit of highlighting. I looked up the US population growth from 1995 to 2005, and it was 1.1%/yr, so that explains about half of the VMT increase. Projected population growth from 2005 to 2050 is 0.8%/yr, which might slow VMT a little. (The Census Bureau projects 420M in 2050. Gulp.) One hopes that oil prices will do a bit of slowing as well (let’s hope Peak Oil is soon).

  6. That means we need roughly another factor of eight reduction in g CO2/kWh in greenhouse gas intensity to meet the Hansen target.