What are other ways to store energy besides batteries?

Batteries are a common way to store energy, but there are many others. Discover more energy storage techniques, from falling weights to fuel cells, in this podcast from HowStuffWorks.com.

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Episode Transcript

Speaker 1 (00:00):
Welcome to brain Stuff from how Stuffworks dot com where
smart Happens. I am Marshall Brain with today's question, what
are all the different ways to store energy? Besides using
rechargeable batteries? Human beings have been looking for a good

(00:22):
way to store energy for a long time. One of
the big things that's been holding up electric cars as
battery technology. When you compare batteries to gasoline, the differences
are huge. For example, a typical electric car might carry
a thousand pounds of lead acid batteries. Those batteries take
several hours to recharge, and they might give the car
a hundred mile range. Two or three gallons of gasoline

(00:45):
give the same range way less than thirty pounds, and
you can pump that much gasoline in about a minute.
There's really no comparison between gasoline and batteries. Here's a
list of some of the other technologies that people commonly
use to store energy. Some of these working electric car,
while others are better off for stationary applications. One of

(01:06):
the oldest techniques people have used is the falling weight.
You lift the weight to store the energy in it,
and then you let the weight fall to extract the energy.
Many grandfather clocks and cuckoo clocks use this technique. By
running the string attached to the weights through a gear train,
you can use a heavy weight and let it fall
over a long period of time. This approach doesn't work

(01:28):
very well in an electric car, but it's worked well
in clocks for hundreds of years. Many power plants use
the falling waight approach in the form of water. The
water is pumped uphill to a lake at night when
the power plant has excess capacity, and then during high
demand daytime periods, the water runs through a termit on
its way downhill to a lower lake. Another way to

(01:51):
store energy is in some form of repeatable mechanical deformation.
This is the idea behind a spring used in a
wind up clock or a rubber band used in a
wind up airplane. You store the energy by deforming the
material in the spring, and the material releases that energy
as it returns to its original shape. At the scale

(02:11):
of a car, this technology has problems because of the
weight of the spring, but it's smaller scales like a
wrist watch, it works great. Nature has been storing energy
for a long time, and if you want to think
about it this way, gasoline is really a form of
stored natural energy. Plants absorbed sunlight and turn it into carbohydrates.
Over millions of years, those carbohydrates can turn into oil

(02:33):
or coal, and that's a form of stored energy. On
a more human time scale, we burn wood to release
stored energy stored in the plant, or we turn corn
into alcohol and burn the alcohol. Another technique that nature
uses the store energy is fat, which many of us
are familiar with in a personal way. It's interesting to
think about a car that somehow eats grass or some

(02:56):
other form of carbohydrate and stores its fat. You can
take energy and split water into its hydrogen and oxygen
atoms using electrolysis. By storing the hydrogen, you can later
create energy by burning it or by running it through
a fuel cell. You can use energy to spin up
a flywheel and then later extract the energy by using

(03:16):
the flywheel to run a generator. Or you can store
heat directly and later convert the heat to another form
of energy like electricity. Molten salt is one way to
do this. You can use compressed air to store energy,
or you can compress air a lot and get something
like liquid nitrogen and use the liquid nitrogen to power
a car. One of the new technologies that may become

(03:38):
available in the future involves antimatter. When you combine matter
with antimatter, you get energy. You can store energy by
creating antimatter. Right now, none of these techniques can hold
a candle, which is really another form of stored energy,
to gasoline in the convenience sense. Fuel cells look to
be the closest competitor right now, and they'll probably become

(03:59):
a level to the general public over the next few years.
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