This is something I (and a lot of other people) have been wondering about for a while in regards to plug-in electric vehicles (PHEVs, like the Chevy Volt) and pure electric vehicles (EVs, like the Lightning GT and Subaru R1e). PHEVs are not a new thing, and they have been discussed on Gas2.0 before, but there is some interesting news that recently came out of Carnegie Mellon University suggesting that if we don’t make our power generation system less carbon intensive, PHEVs could have little benefit over regular hybrids (HEVs).
Unfortunately, if you want to see the original article, you’ll have to buy it, but for the rest of us, Green Car Congress has written a good article about the findings and the implications of this study.
There is no doubt that PHEVs result in good fuel economy figures — GM is currently touting its PHEV-to be, the Volt, as getting 150MPG over all. However, they aren’t necessarily super efficient. Instead, they achieve these high numbers by supplementing the power produced by their gasoline engines with power taken from the grid. This has caused controversy lately, as hybrid-opponents often claim that battery production and the use of energy from the grid actually makes these cars bigger GHG polluters. However, if you look at this chart posted by GCC, you can see that both HEVs and PHEVs have a clear advantage over conventional cars, even when battery production is factored in:
This chart assumes the national mix of power from the grid, and as I said, shows pretty clearly the advantage of HEVs over conventional vehicles (CVs), but also shows that with the current mix of power sources on the grid, PHEVs aren’t that much better than your standard HEVs. I don’t say this to suggest that we should be shutting down PHEV research or production, but rather I think we should embrace the ability to consolidate our efforts in “greening” only one particular industry rather than trying to attack every one separately.
What I mean by this is that if our vehicles all drew power from the grid, making the grid more efficient would both improve standard energy usage as well as make motor vehicles less polluting. As it stands now there is a huge rift, where some are trying to improve the grid by adding things like wind power and others are trying to improve vehicle fuel economy or introduce hydrogen cars.
In fact, as noted by GCC, if the grid were low-carbon, PHEVs would reduce lifecycle GHG emissions of 51-63%, something anyone would admit is a huge improvement for motor vehicles.
You can check out this chart (if you can read it, click for a bigger version) to see how the different vehicles compare under different scenarios:
How do you all feel about PHEVs? Are they the new thing of the future or just another set-back on the way to pure EVs? Or is a hydrogen economy in store for us in the future?
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