In most cars, 50 mpg would be terrific. In a plug-in hybrid, 50 mpg is half of what you could expect. Wired has an article on the real-world testing going on in test fleets across the nation and specifically in Seattle. It seems the results are disappointing to some.
But why are the drivers seeing only 50 mpg? It should be possible to get 100-150 mpg in these cars.
So what gives with all these fleets struggling to get half that?That makes a lot of sense to me. City employees that aren't interested in plugging the cars in overnight (or whenever they can) can turn a plug-in hybrid car into a hybrid car. In that case, you can expect to get hybrid car mpg numbers, like they're seeing in Seattle.
EV advocates have a simple answer – the drivers aren’t being told how to maximize fuel efficiency, and they’d don’t care because they aren't paying for the gas.
To get the most from plug-in hybrids, EV advocates say, you've got to us a light touch on the accelerator, mind your speed and plug it in at every opportunity to keep the batteries fully charged.
"Drive impact is really huge," said Francfort. "Aggressive driving effects the mileage of all cars, but with plug-in hybrids there’s more of an impact."
Note also how the hybrids (not plug-ins) are getting 11 mpg less than the plug-ins. That shows no one has bothered to teach the drivers how to drive the hybrids in the first place. But to be fair, even google's rechargeit program is seeing the same issue. Their plug-in Prius is getting 55.4 mpg, about 12 mpg better than their Prius.
Another problem is how little difference there is between 50 and 100 mpg. I've talked about miles per gallon in hybrids before. If we stick to the mpg scale, you would think that going from 50 to 100 mpg means you're driving twice as efficient. But it just doesn't work that way. Over 15,000 miles, the difference between 50 mpg and 100 mpg is 150 gallons of fuel (or about $300 in savings at today's $2 a gallon price). Going from 25 to 50 saves you 300 gallons ($600 in savings). It just isn't a linear function and it's important to keep that in mind.