4 different ways you can power a car
Historically, most cars have run
on gasoline,
but that doesn’t have to be
the case in the future:
other liquid fuels and electricity
can also power cars.
So what are the differences
between these options?
And which one’s best?
Gasoline is refined from crude oil,
a fossil fuel extracted
from deep underground.
The energy in gasoline comes from a class
of molecules called hydrocarbons.
There are hundreds of different
hydrocarbons in crude oil,
and different ones are used
to make gasoline and diesel—
which is why you can't use
them interchangeably.
Fuels derived from crude oil
are extremely energy dense,
bringing a lot of bang for your buck.
Unfortunately, they have many drawbacks.
Oil spills cause environmental damage
and cost billions of dollars to clean up.
Air pollution from burning
fossil fuels like these
kills 4.5 million people each year.
And transportation accounts for 16%
of global greenhouse gas emissions,
almost half of which comes
from passenger cars burning fossil fuels.
These emissions warm the planet
and make weather more extreme.
In the U.S. alone,
storms caused by climate change
caused $500 billion of damage
in the last five years.
So while gas is efficient,
something so destructive
can't be the best fuel.
The most common alternative
is electricity.
Electric cars use a battery pack
and electric motor
instead of the internal combustion engine
found in gas-powered cars,
and must be charged at charging stations.
With the right power infrastructure, they
can be as efficient as gas-powered cars.
If powered by electricity generated
without fossil fuels,
they can avoid greenhouse gas emissions
entirely.
They’re more expensive
than gas-powered cars,
but the cost difference has been
shrinking rapidly since 2010.
The other alternatives to gasoline
are other liquid fuels.
Many of these can be shipped and stored
using the same infrastructure as gasoline,
and used in the same cars.
They can also be carbon-neutral
if they’re made using carbon dioxide
from the atmosphere—
meaning when we burn them, we release that
same carbon dioxide back into the air,
and don't add to overall emissions.
One approach to carbon-neutral fuel
is to capture carbon dioxide
from the atmosphere and combine its carbon
with the hydrogen in water.
This creates hydrocarbons,
the source of energy in fossil fuels—
but without any emissions if the fuels
are made using clean electricity.
These fuels take up more space
than an energetically equivalent
amount of gasoline—
an obstacle to using them in cars.
Another approach is to make carbon-neutral
fuels from plants,
which sequester carbon from the air
through photosynthesis.
But growing the plants also has
to be carbon neutral—
which rules out many crops
that require fertilizer,
a big contributor
to greenhouse gas emissions.
So the next generation of these fuels
must be made from either plant waste
or plants that don't require
fertilizer to grow.
Biofuels can be about as efficient
as gasoline, though not all are.
For a fuel to be the best option,
people have to be able to afford it.
Unfortunately, the high upfront costs
of implementing new technologies
and heavy subsidies for the producers
of fossil fuels,
mean that almost every green technology
is more expensive than
its fossil-fuel-based cousin.
This cost difference is known
as a green premium.
Governments have already started
subsidizing electric vehicles
to help make up the difference.
In some places, depending
on the costs of electricity and gas,
electric cars can already
be cheaper overall,
despite the higher cost of the car.
The other alternatives are trickier,
for now—
zero-carbon liquid fuels can be
double the price of gasoline or more.
Innovators are doing everything
they can to bring green premiums down,
because in the end, the best fuel
will be both affordable for consumers
and sustainable for our planet.
