OT: Hybrid cars

[Oleg Goldshmidt]

Mord Behar <mordbe0 at gmail.com> writes:

> Hi
> I know that this is off-topic, but I really don't know who to ask.
> See, I need a large pool of Linux-like brains that live in Israel for
> this.
> I mean, people (like me) who track gas liters and kilometerage, wear
> and tear on the car, insurance and things like that.
>
> Does anybody have numbers and experience to show how economical it is
> to buy a hybrid car, and which one?
> At what point of city-driving and non-city-driving does it pay to buy
> a hybrid car? Gas is really expensive now, and probably just going to
> go up. But hybrid cars are expensive too and the shelf life of the
> battery is 5-10 years...
> And I suppose that the terrain matters as well. In Jerusalem the
> hybrid car will use more gasoline than in Tel Aviv.

I'll bite. I don't own a hybrid, but I am generally interested in cars
and I try to follow, and I used to have fun jotting down some numbers on
the back of a napkin. Any numbers below are theoretical, not
measurements. Nor am I by any means a trusted expert - all I'll try to
do is list some considerations. I hope you'll find some of what follows
useful.

Disclaimer: I assume the issue is cost and not saving the planet. I
don't even want to go in that direction, that's personal and the
objective is hardly quantifiable.

To start with, define "hybrid". The only principal difference of any
consequence is if your hybrid is a plug-in, i.e., you can drive some
distance (let's say, your daily commute is short) on battery only, then
plug the car into the grid overnight, lather, rinse, repeat. Then you
can say that you drive and don't use any fuel, or at least much less
fuel. I don't know if in this country plug-in hybrids exist (the Toyota
site has a Prius plug-in on offer, at least) or are practical. Plug-in
cars lead to interesting considerations that I'll defer till I get to
numbers below. I'll assume first that you mean a non-plug-in hybrid.

If your hybrid is not a plug-in then the only source of power is the
fuel[1], and basically you have a normal car that has two power
trains. The car will have some fuel efficiency, and you can look at the
numbers[2] from the manufacturer or consumer reviews or from your
friends and acquaintances who own a Prius or an Insight or whatever, and
compare with the numbers (again, from manufacturers, reviews, or
acquaintances) of competing "normal" petrol or diesel cars. You may or
may not be surprised, depending on what oranges you compare to your
apples: modern diesel and internal combustion engines - especially
European - are very efficient indeed, and a normal car does not have to
move a few hundred extra kilos of the battery and the second engine
around. There are hybrid makes (Volvo V60, for instance, not sure if it
is available in Israel, especially as it is a plug-in) that have
non-hybrid versions - non-hybrid versions are often more fuel-efficient
for the same engine volume[2].

Bottom line: for a non-plug-in hybrid just forget about its "hybrid"
character and try to get as reliable an assessment of its fuel
efficiency and as detailed a comparison with competing brands/makes as
you can. Then compare performance, conveniences, fittings and trimmings,
and in the end just pick a car you like better overall, hybrid or
not. One thing that I would do: most popular hybrids are Japanese
(Toyotas and Hondas) - I would include European cars in comparison, as
Japanese cars tend to be rather thirsty. 

For a plug-in hybrid, consider your usage patterns - see below.

Now, to some back-of-the-envelope stuff.

Note that many oft-quoted characteristics of hybrid cars are relevant
only or mostly to plug-ins. E.g., the maximal distance on battery only
(~25km for a new model Prius with an extended Li-ion battery pack) - if
your daily commute is less than that and you recharge nightly, it's
important. If you cannot plug in and your tank allows you 600km the
difference is not huge. The max speed on battery only (~48km/h for newer
Priuses) is also important mainly if you drive in town on battery and
recharge.

Even if your car is a plug-in there are things to consider. Take a new
Prius with an extended Li-ion battery with capacity of 4.4kWh. I pay
ILS0.54/kWh at home, so at 80% efficiency a full charge will set you
back about 3 shekels. At ILS8/l this is about 0.375l of 95 octane
petrol. Thus, if you buy petrol instead of charging the battery, at
15km/l you will drive about 5.5km instead of 25km for the same money. A
clear win for Prius. However, consider this: a Prius plug-in is *at
least* ILS180K on the Toyota site, whereas a Corolla starts at
ILS124K. That's 56,000 difference, equivalent to 7000l of 95 octane
petrol (at 8 shekels/l). Let's download PDF catalogs with fuel
consumption data from the site. To cover the 7000l of fuel equivalent of
the price difference between a plug-in Prius (25.6km/l) and a Corolla
(17.9km/l) you need to decide whether or not you believe the 25.6km/l
figure (cf. [2] below). If you do, you'll break even after ~420,000km
[7000/(1/17.9-1/25.6)]. Convert into years for yourself.

A similar back-of-the-envelope hand-waving can be applied to non-plug-in
cars. E.g., the same Toyota site has a hybrid and a non-hybrid Camry,
the former is 20K more expensive (assume the basic configuration is the
same - I did not check; a non-plug-in Prius is 24K more expensive than a
Corolla, i you prefer that). At ILS8/l you need to save 2500l of petrol
to break even. The catalog you can download from the site lists 14.3km/l
for the petrol Camry vs. 20.4km/l for the hybrid one. This tells me that
you will break even after a bit more than 120,000km
[2500/(1/14.3-1/20.4)], somewhat more realistic than the previous
comparison. Of the order of 5 years with moderate usage? This does not
take into account the possible difference in service prices,
amortization, more stuff that can break down (two power trains), etc. -
I have no data, but I figure 6000km per 1000 shekels of difference in
expenses, from the above?

Now, these are Toyota to Toyota, and hybrid to petrol comparisons. In my
experience, when I rent cars in Europe (or drive my friends' cars there)
they are usually diesel, and mileage quite a bit above 20 km/l,
sometimes a *lot* above 20km/l, is the rule. A hybrid, even with the
manufacturer's consumption figures, would have no advantage over
European diesels, in my mind. Diesels are available here, and they also
are expensive for unknown reasons. Have a look - a diesel may suit your
priorities.

Newer European petrol engines yield 18-20 km/l often. Cheaper cars are
often less efficient.
 
[1] The trick whereby the battery is charged a bit when you break a) is
    clever, but not noticeably significant; b) glances over the fact
    that if you break often your fuel efficiency sucks, so all it does
    is make you a bit less wasteful. If you manage to drive smoothly you
    will do a lot better in terms of fuel efficiency.

[2] Beware: a) manufacturer numbers for plug-ins are meaningless - they
    depend on how much you drive between re-chargings; e.g., I read a
    detailed review of a hybrid (plug-in) Volvo V60 where the reviewer
    measured ~57mpg, compared to official manufacturer's 155mpg, and to
    70mpg for a non-hybrid version of the same car; b) American numbers
    are meaningless for comparison because their models are different,
    e.g., you will not see a VW Jetta with a smaller than 2.0L engine in
    American reviews, whereas in Israel you can get a 1.2L or 1.4L TSI
    Jetta that is quite likely to be more economical than a 1.5L (or
    1.8L) Prius (no, I did not check). Even after you become aware of
    this, according to www.fueleconomy.gov a 1.4L Hybrid Jetta has a bit
    lower mileage than a 2.0L Diesel one, in *user* testing.
 
-- 
Oleg Goldshmidt | pub at goldshmidt.org