Much of the debate for reshaping America's energy policies have focused on removing our dependence on foreign oil, which naturally means revamping how we drive. The two most-often cited technologies are plug-in hybrid vehicles (PHeVs) and fully electric vehicles (EVs) - both of which have major advantages and disadvantages. Let's recap their likely impact along key dimensions:
Both PHeVs and EVs are dependent on continued advances in battery technology. Right now, batteries are simply too expensive and their performance too weak. GM's Volt, the closest PHeV or EV to full-scale production has had its expected price tag raised several times, largely because of the challenges with batteries.
However, a second technological problem also exists - the abiltiy to get around if you have to make an extra stop for groceries on the way home or need to run out for something in the middle of the night before your vehicle is fully charged or just want to take a long road trip. While PHeVs have no problem, given the flexiblity to run on gasoline if necessary, the EVs have no back up plan. Simply put, if your battery is dead and you have an EV, you won't be going anywhere for a while - in a PHeV, your vehicle just switches to gas and you keep on trucking.
EVs have no tailpipe emissions, while PHeVs still emit some CO2 and other fumes as they will still run on gas for ~20% of all miles, based on BrightGreen analysis. However, it is important to remember that, unless US electric generation is converted to sustainable, green energy, the very power that both of these vehicles will charge up with could remain very dirty.
Cost to implement:
The cost to create a 'green' fleet of either PHeVs or EVs has two major associated costs: the cost of the batteries and vehicle design, and the cost of the infrastructure needed to support the rollout.
Track record to date:
This is a bit of a joke, as neither PHeVs nor EVs exist in large scale production today. Chevy's Volt is expected to produce ~10,000 vehicles in 2010, ramping up to 60,000 in 2011 and more beyond (here is a great article about the Volt development). Many in the automobile industry are skeptical that GM will be able to pull this off - including such heavyweights as Toyoto (article here).
Summary: The flexibility of PHeVs to run on electric or gas, as well as the lower battery and infrastructure costs seem to make PHeVs the likely long term winner. While a purely environmental lens would favor an EV, I'm guessing most of the American public will take an 80% reduction in gasoline and feel pretty good about it!