May 06, 2009
Fleet Pluggable Hybrids Disappoint On Fuel Efficiency

A few months ago I did a post on how cars converted to run as pluggable hybrids to run in fleets are disappointing on fuel efficiency. Wired magazine picks up on this development with a story on how fleet pluggable hybrids are disappointing in Seattle.

Having racked up some 17,000 miles, the plug-in Prius hybrids are averaging just 51 mpg. That's raising uncomfortable questions about the value and effectiveness of plug-in technology, even as President Obama pledges to have 1 million of them on the road by 2015.

"Getting 51 miles per gallon sounds fine compared to most gas cars," railed Seattle Times columnist Danny Westneat. "But it's a black eye for a technology that trumpets it will get twice that."

Well, it works great in theory. It works great when hypermilers are behind the wheel. But most people can't be bothered to be hypermilers.

Is Seattle an exception? Nope.

Idaho National Laboratory is seeing similar results among the plug-in fleets it is monitoring nationwide.

Also see my original post and you can check out Google's pluggable hybrids fleet.

One problem with the existing pluggables is that they shift over to gasoline power if pushed hard. A pluggable that can accelerate rapidly under pure electric power will do better than a converted Prius. So we can expect better results from a Chevy Volt for example.

Another problem is that one has to bother to plug in the car. People don't want to add another daily ritual to their lives. Come home, pull out a cord, plug in, and only then go inside. The come out to go to the store (need ketchup or steaks for dinner) and do not forget to unplug. Then come back and plug in again. Is this the last errand tonight? Maybe not. So don't bother to plug in. Then forget to plug in before going to bed. It is this frequent nagging task that people will resist.

We can look at Europe to see what high gasoline prices will do to modify behavior. Mostly people shift down to smaller cars with manual transmissions. They also live closer to work. Contrary to popular impressions mass transit plays a small role in moving people around Europe. See this page at Figure 1: Motorised Travel (passenger-kms per capita per annum) in 2003 where it compares many European countries for public transport use. Also see "Figure 3: Overall mode share of distance travelled (%) in 2003". What leaps out at me is that after all the mass transit subsidies and high taxes on gasoline well over 80% of passenger miles traveled on the ground in Europe are done by car.

Share |      Randall Parker, 2009 May 06 02:57 PM  Energy Transportation

Brian Wang said at May 6, 2009 3:44 PM:

On remembering to Plug the car in. There should be a reminder alarm to do it. Just like there are pinging alarms for
when you leave your key in or your lights on.

In Canada in winter and other cold places, people have to plug in the engine block heater on their cars in cold weather.
If they don't then they are unlikely to be able to start their car when they go back to their car.

Therefore, I think it is possible to nag people into a high compliance rate. Although they have to have the infrastructure to make it easy.
Extension cords. Plugs positioned in private garages, public garages and public parking spaces.

there is a system that works with cruise control and digital maps to help people hypermile automatically.

matt said at May 6, 2009 3:46 PM:

and most car accidents happen only 5 miles from home. You are confused. A city dweller takes the train 3 miles each way to work. In a rural area someone might drive 15 miles each way and it still takes him less time than the city commuter. Time spent commuting is probably a better metric.

th said at May 6, 2009 4:50 PM:

I think this is great news, but not a big surprise. Even with "an extra battery in the trunk" the little big dreams of windbag flute players can't even do much better than a 1989 mazda 626 4 cylinder. This is truly hilarious, I love it, why don't they take the back and side passenger seats out and add another battery, in the inimitable words of the great logician barney frank when asked how much stimulus is enough... "we won't stop doing it until it stops working".

JAY said at May 7, 2009 5:21 AM:

Is that 51 mpg plus electricity costs?

In said at May 7, 2009 9:09 AM:

"It is this frequent nagging task that people will resist."

Not necessarily, if the price of gas gets high enough.

David A. Young said at May 7, 2009 9:31 AM:

Plugging-in electric cars manually should be a stop-gap measure. It doesn't seem like it should be an exceptionally difficult engineering task to design the cars, and their power-up systems, so that the cars connect and disconnect to their power sources automatically. One scenario: the plug's situated on the underside of the car. On the floor of the garage is a "docking station." As the tires roll over pressure plates on the docking station, it sends a wireless message to the dashboard to "park." The driver puts the car in park and turns off the car, which sends a message to the docking station to deploy the connector. When the car is next turned on, a message is sent to automatically disconnect.

Sounds complicated, but none of it's beyond even our current capabilities. The trick would be standardizing things and making them available in convenient "packages." The docking stations wouldn't have to be any more complicated to install than a garage door opener (and could even be portable).

Anyway, details aside, if we want to make adoption of electric cars widespread, we're going to have to start thinking of ways to make the switch as easy, cheap, and painless as possible.

Engineer-Poet said at May 7, 2009 12:01 PM:

Face it, if the Prius conversion was programmed with the performance limitations of a 2CV then everyone would hypermile.  (The average driver would bitch like crazy too, at least until they saw their mileage figures... or if gas went over $4.00/gallon again.)

I drive a 3400+ pound 5-passenger sedan with an automatic, and got 40.0 MPG on my last tank.  Yes, it's a 1.9 liter diesel, but I drive very sedately too.  If the car had the 1.4-liter engine which is really all it needs, it would probably get 45-50 MPG; if it was an air hybrid, it would probably do as well or better.

The problem isn't that saving fuel isn't easy; it is (and it costs me nothing).  The problem is that most people are not bright enough to connect their driving habits to what they pay at the pump (or the repair shop).  If you show them the connection with a real-time dashboard display, many will change their habits.  As for the rest... mandatory performance restriction for teenager, speeders, road-rage addicts and the like?

Greg said at May 7, 2009 5:34 PM:

Fleet use for plug-in hybrids strikes me as a hell of a testbed for figuring out the gas mileage. Did they really expect the users to care about plugging in the car when the users don't pay for gas?

David A. Young: you're thinking in a right direction, but your idea isn't workable. Car underbody is an extremely dirty, rusty and often wet or icy place. Besides, if the system breaks or needs a tune-up, it's not much pleasure to service it.
I have a better design but I'm patenting it right now so don't ask...

David A. Young said at May 8, 2009 9:05 AM:

Greg: Yeah, I knew the positioning was problematic -- you'd have to add a retractable cover of some sort, which would add complexity. I mainly just wanted to convey the idea that the process could be automated with reasonable ingenuity and minimal expense.

Nick G said at May 8, 2009 1:24 PM:

I agree with the comments about un-motivated fleet drivers, and automation of plugs.

We can look at Europe to see what high gasoline prices will do to modify behavior. Mostly people shift down to smaller cars with manual transmissions. They also live closer to work. .

I think this isn't the right way to look at it. First, Europeans never had large cars, so they didn't "shift down". Also, they never lived far away, so they didn't move closer.

I agree that there will be some downsizing. OTOH, a lot of people will just pay a premium for a comparable hybrid or ErEV. Really, which makes more sense: pay $100K-$200K more for a closer home, or pay $3k-9K for a hybrid or ErEV?? Heck, for some people, the new window treatments alone will pay the hybrid premium...

Randall Parker said at May 9, 2009 7:27 PM:

Brian Wang,

I think plugging in cars works in Canada because people have no other option. The car otherwise will not start. But if you don't plug in the car you can just pay more for gasoline. People will pay for convenience.

So then the question becomes: what price convenience? Fleet car operators prefer the convenience because they aren't paying the fuel costs. Whether individuals will pay cash or do the annoying chore will depend on level of affluence, how busy a person is, their discount rate, the level of convenience given where they park their car, and other considerations.

I'd like to see tests of pluggable hybrids using non-fleet users.

Engineer-Poet said at May 10, 2009 9:09 AM:

Fuelling is a major inconvenience for me.  I would much rather deal with the bulk of it by plugging in an extension cord when I get home, and writing a slightly bigger check for my electric bill once a month.

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