ILEA Leaf #10: WHAT KIND OF CAR?
You're concerned about the environment, but you need to drive. Which
car will do the least damage? There's no easy answer, and you will
have to make some tradeoffs between your budget and your determination
to help change the world. But you will also need to think about what
"changing the world" means to you:
Is it more important to (a) help reduce future emissions an uncertain
amount by investing in advanced technology or (b) reduce immediate
emissions a known amount with existing technology?
Is it more important to (a) fight climate change and foreign oil
dependence by reducing fossil fuel use or (b) help clean the air in
your region by reducing traditional pollutants from the car tailpipe?
At ILEA we are all about life-cycle assessment, so we like to take
the big picture approach: advancing technology trumps personal
emissions, and greenhouse gases trump local pollutants. If you answer
the questions differently, keep those differences in mind as you read
through our recommendations; near the end of the email there's a
comparison table to help you do this.
Below are five basic choices you can take, beginning with the most
conventional and ending with the most adventurous.[1] <#_edn1> We
think the most adventurous steps probably have the most impact on the
big picture, but if you answered the questions differently than we
do, you may want to take one of the other choices.
#5: High-efficiency conventional cars
If none of the more advanced options meet your needs, then you can
still reduce both your greenhouse gas and your traditional pollutant
emissions by being careful to choose a car with the highest fuel
economy. Keep in mind though, this option will do little to advance
new technologies.
The U.S. EPA's fuel economy website <http://www.fueleconomy.gov/>
provides comparative ratings of nearly all cars available in the U.S.
The American Council for an Energy Efficient Economy publishes the
Green Book <http://www.greenercars.com/> , which provides even more
detailed environmental information. Though the EPA website is free,
the Green Book is not: a month of access costs $8.95.
Diesel engines are on average more efficient than gasoline engines.
Just as one example, a manual transmission, 2005 VW Jetta Wagon is
rated 36 city and 47 highway
<http://www.fueleconomy.gov/feg/findacar.htm> . In the United States
we tend to think of diesel cars as dirty, and indeed historically the
tailpipe emissions have been much worse than for gasoline cars. But
beginning in mid-2006 all automotive diesel fuel in the U.S. will be
ultra-low sulfur
<http://www.epa.gov/otaq/regs/fuels/diesel/diesel.htm> , allowing
better emissions control and eliminating nearly all of the irritating
exhaust fumes we normally expect from diesel engines. That means
beginning in 2007, many diesel vehicles will be preferable to their
gasoline counterparts. Also, if you choose a diesel vehicle, you will
always be able to leapfrog to the much more aggressive biodiesel
solution, #3 below.
#4: Gasoline-electric hybrids
Gasoline-electric hybrids (usually just called "hybrids") have by far
been the most popular choice of environmentally conscientious car
buyers over the past few years. Hybrids are fueled at the gas pump
just like any other gasoline-powered car, but boast particularly
impressive mileage (the 2005 Toyota Prius does 60 city and 51 highway
<http://www.fueleconomy.gov/feg/findacar.htm> ).[2] <#_edn2>
A hybrid car has both a gasoline engine and an electric motor, but it
does not need to be plugged in. The gasoline engine takes care of
charging the electric motor's battery. The battery is also charged
when the driver steps on the brakes: the electric motor works in
reverse to stop the wheels by converting their rotational energy to
electricity saved in the battery. Hybrids also cut out the gasoline
engine when the car drives very slowly or stops, minimizing energy
wasted in idling.
Gasoline-electric hybrids are an excellent choice for the
environmentally aware consumer. Because of their high fuel economy,
hybrids reduce both greenhouse gases and traditional pollutants, like
any other high-mileage vehicle. But buying a hybrid gives the
environment an extra boost because you are helping introduce an
important, cutting-edge technology. So far, Honda and Toyota have
released hybrid passenger cars, and Ford has released a hybrid SUV.
You can expect to see many more models appear over the coming few
years.
#3: Biodiesel
You can nearly eliminate your greenhouse gas emissions by buying an
ordinary, high-efficiency diesel vehicle and filling the tank with
biodiesel. Biodiesel is made from recycled vegetable oils or from
by-product oils of crops grown for other purposes. The net greenhouse
gas emissions from making the biodiesel are extremely low, and when
burned in a diesel engine biodiesel is cleaner at the tailpipe too.[3]
As of early 2005, biodiesel sells for about $1 more per
gallon in the U.S. (on average) than fossil diesel, but a new federal
tax credit promises to lower the price down to nearly the same as
fossil diesel.
With this choice you are boosting the toddler biodiesel fuel
industry. Biodiesel will always be an environmental niche product,
because there is not enough land area in the U.S. to grow crops for
the entire vehicle fleet.[4] <#_edn4> Still, it may be an important
part of a future transportation solution. Because your car will
always be able to burn fossil diesel fuel, it is important that you
are committed to the effort to buy biodiesel, even if it means going
out of your way each time you need to refill your tank. Before you
make this choice, make absolutely sure that biodiesel is available in
your area
<http://www.biodiesel.org/buyingbiodiesel/retailfuelingsites/> .[5]
<#_edn5> If it isn't and you are particularly excited about
biodiesel, get together with some other enthusiasts and you can make
your own <http://forums.biodieselnow.com/> .
#2: Electric cars
A warning here. Once you step past option #3, biodiesel, you are
stepping into the realm of the difficult, the expensive and oftentimes
the nerdy. You may end up importing cars or car parts from other
states or even countries, and engineering skill (or at least the
skills necessary to talk to engineers) can get you more of what you
want in a custom car. If you feel motivated for a technical
adventure, read on.
Electric cars are falsely perceived as short in performance and short
in range. In fact, electric cars can be stunning performers, as
members of the National Electric Drag Racing Association
<http://www.nedra.com/> will be all too happy to tell you (or show
you). Though performance limitations are pure myth, range limitations
are real. But recent advances in lithium-ion battery technology are
bringing 300 mile ranges
<http://www.acpropulsion.com/ACP_tzero/SEMAtrip2003.htm> within
reach.
Electricity is not always the best environmental choice
<http://www.ilea.org/lcas/taharaetal2001.html> . Though the car is
zero-emissions on the road, the electric generator can sometimes be a
terrible emitter of both greenhouse gases and traditional pollutants,
especially if you live in a coal state
<http://www.eia.doe.gov/cneaf/coal/statepro/imagemap/usaimagemap.htm>
. Fortunately, there is a solution. You can make sure to buy
exclusively green electricity <http://www.green-e.org/> to charge
your car; electricity is so much cheaper than gasoline that even the
slightly more expensive green electricity will still come in well
under the cost of gasoline.
Even without using green electricity, promoting electric cars has an
enormous value for long-term energy policy. Electricity is by far the
best way <http://www.ilea.org/articles/CEF.html> to get renewable
resources to cars, and helping to get electric cars onto the market is
an important enabling step for renewable energy in general. If you
want to buy an electric car, start by visiting the Electric Drive
Transportation Association <http://www.electricdrive.org/> website.
#1: Plug-in hybrids
Driving a plug-in hybrid is probably the most edgy and
policy-advancing choice you can make, but getting your hands on a
plug-in hybrid will make buying an electric car look like a piece of
cake: there are no commercial models available in the United States.
A plug-in hybrid is similar to a gasoline-electric hybrid, but it has
a larger battery and can be plugged into a wall socket as well as
fueled with gasoline. The plug-in hybrid can drive entirely on
electric energy for twenty, thirty or forty miles depending on how
large the battery is. Because most people use their cars for commutes
of a few tens of miles at the most, a plug-in hybrid that is recharged
each night can run almost exclusively on electricity, kicking in the
gasoline engine only for longer trips.
Though you can't buy one, a sufficiently motivated enthusiast can
convert a Toyota Prius <http://www.calcars.org/priusplus.html> to
plug-in mode – at a steep cost. If you lack either the money or the
technical savvy to do that, best just stay in tune
<http://www.calcars.org/history.html> with the evolving technology,
and wait for your chance to buy one off the shelf.
Why is ILEA advocating a plug-in hybrid as the most edgy choice, when
all-electric cars might seem more like the ultimate goal for
transportation technology? Though engineers are well on their way to
solving the all-electric range problem, they're not there yet.
Plug-in hybrids are an extremely valuable bridge technology, because
they retain the convenience of unlimited range that consumers are used
to, while simultaneously advancing the large automotive batteries that
can be the foundation for all-electric cars.
But maybe plug-in hybrids are in fact the best, ultimate goal for
sustainable transportation. An advanced, plug-in hybrid with a 100
mile range would need to be fueled only a few times a year, in most
cases. Such a low rate of liquid fuel consumption, if it pervades the
car market, would enable us to fuel all of our vehicles with a
renewable liquid fuel like ethanol or biodiesel, getting the best of
both approaches.
advancing technology greenhouse gases
tailpipe pollutants
#5: high-efficiency conventional cars +/- +
+
#4: gasoline-electric hybrids + +
+
#3: biodiesel +
++ +
#2: electric cars ++ +/-
++
#1: plug-in hybrids ++ +
+
Comparing the five options on the basis of advancing technology,
reducing greenhouse gases, and reducing traditional pollutants. ++
excellent performance + good performance +/- ambiguous performance,
all relative to a typical, 2005-model year, U.S. automobile.
#0: No car at all
Even a zero-emissions car results in environmental impacts from
generating the electricity or biofuel that powers it; upstream
emissions from the car manufacturing plant; and indirect impacts from
the roads and parking lots that support it. The best car is no car.
If you can avoid purchasing a car by using one or more of the
alternatives below, you will have the biggest personal impact on the
environment possible:
• carpooling can easily triple your fuel economy on a per-passenger
basis;
• using vanpools or public transit saves gas and saves you
road-rage;
• car-share programs might give you just enough access to a vehicle
that you don't have to buy one;
• combining your trips saves you time as well as gas;
• living in an urban neighborhood near your workplace, shops and
other resources can eliminate most of your car trips;
• and of course, anytime you can walk or bicycle instead of drive,
take the opportunity to get some healthy exercise!
Sincerely,
The ILEA staff.
ILEA environmental accuracy
www.ilea.org
[1] Some of you may notice the absence of
"flexible-fuel" vehicles that can accept either gasoline or ethanol.
ILEA is not promoting this solution because most ethanol available in
the U.S. is starch-based, inefficiently using only a portion of the
crop (usually corn) that generates the ethanol. Flexible-fuel
vehicles will make more sense once cellulosic ethanol, which makes
efficient use of the entire plant, becomes more widely available.
Also, "flexible-fuel" vehicles are not a significant technological
advance: their design is nearly identical to an ordinary,
gasoline-fueled car.
[2] Hybrids have the curious property of achieving
better mileage in-city than on the highway. The hybrid technology can
take great advantage of the slow, stop-and-start driving, but is
incapable of mitigating the wind resistance at highway speed.
[3] Office of Transportation and Air Quality. A
Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions.
Washington, DC. U.S. EPA. 2002. EPA420-P-02-001.
[4] Charles L. Peterson. Potential Production of
Biodiesel. University of Idaho.
[5] In some areas you may be limited to blends of
biodiesel with fossil diesel. Blends are labeled with "B" numbers,
for instance B20 is a blend of 20% biodiesel with 80% fossil diesel,
B100 is 100% biodiesel (pure or neat" biodiesel). In cold climates a
blend may be necessary, because without additives B100 begins to gel
around 32 degrees F, while B20 won't begin to gel until as low as 7
degrees F.
Homestead Inc.
www.yellowbiodiesel.com
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