Speaker 1: Welcome to brain Stuff from how Stuffworks dot com where
Speaker 1: smart Happens. I am Marshall Brain with today's question, what
Speaker 1: are all the different ways to store energy? Besides using
Speaker 1: rechargeable batteries? Human beings have been looking for a good
Speaker 1: way to store energy for a long time. One of
Speaker 1: the big things that's been holding up electric cars as
Speaker 1: battery technology. When you compare batteries to gasoline, the differences
Speaker 1: are huge. For example, a typical electric car might carry
Speaker 1: a thousand pounds of lead acid batteries. Those batteries take
Speaker 1: several hours to recharge, and they might give the car
Speaker 1: a hundred mile range. Two or three gallons of gasoline
Speaker 1: give the same range way less than thirty pounds, and
Speaker 1: you can pump that much gasoline in about a minute.
Speaker 1: There's really no comparison between gasoline and batteries. Here's a
Speaker 1: list of some of the other technologies that people commonly
Speaker 1: use to store energy. Some of these working electric car,
Speaker 1: while others are better off for stationary applications. One of
Speaker 1: the oldest techniques people have used is the falling weight.
Speaker 1: You lift the weight to store the energy in it,
Speaker 1: and then you let the weight fall to extract the energy.
Speaker 1: Many grandfather clocks and cuckoo clocks use this technique. By
Speaker 1: running the string attached to the weights through a gear train,
Speaker 1: you can use a heavy weight and let it fall
Speaker 1: over a long period of time. This approach doesn't work
Speaker 1: very well in an electric car, but it's worked well
Speaker 1: in clocks for hundreds of years. Many power plants use
Speaker 1: the falling waight approach in the form of water. The
Speaker 1: water is pumped uphill to a lake at night when
Speaker 1: the power plant has excess capacity, and then during high
Speaker 1: demand daytime periods, the water runs through a termit on
Speaker 1: its way downhill to a lower lake. Another way to
Speaker 1: store energy is in some form of repeatable mechanical deformation.
Speaker 1: This is the idea behind a spring used in a
Speaker 1: wind up clock or a rubber band used in a
Speaker 1: wind up airplane. You store the energy by deforming the
Speaker 1: material in the spring, and the material releases that energy
Speaker 1: as it returns to its original shape. At the scale
Speaker 1: of a car, this technology has problems because of the
Speaker 1: weight of the spring, but it's smaller scales like a
Speaker 1: wrist watch, it works great. Nature has been storing energy
Speaker 1: for a long time, and if you want to think
Speaker 1: about it this way, gasoline is really a form of
Speaker 1: stored natural energy. Plants absorbed sunlight and turn it into carbohydrates.
Speaker 1: Over millions of years, those carbohydrates can turn into oil
Speaker 1: or coal, and that's a form of stored energy. On
Speaker 1: a more human time scale, we burn wood to release
Speaker 1: stored energy stored in the plant, or we turn corn
Speaker 1: into alcohol and burn the alcohol. Another technique that nature
Speaker 1: uses the store energy is fat, which many of us
Speaker 1: are familiar with in a personal way. It's interesting to
Speaker 1: think about a car that somehow eats grass or some
Speaker 1: other form of carbohydrate and stores its fat. You can
Speaker 1: take energy and split water into its hydrogen and oxygen
Speaker 1: atoms using electrolysis. By storing the hydrogen, you can later
Speaker 1: create energy by burning it or by running it through
Speaker 1: a fuel cell. You can use energy to spin up
Speaker 1: a flywheel and then later extract the energy by using
Speaker 1: the flywheel to run a generator. Or you can store
Speaker 1: heat directly and later convert the heat to another form
Speaker 1: of energy like electricity. Molten salt is one way to
Speaker 1: do this. You can use compressed air to store energy,
Speaker 1: or you can compress air a lot and get something
Speaker 1: like liquid nitrogen and use the liquid nitrogen to power
Speaker 1: a car. One of the new technologies that may become
Speaker 1: available in the future involves antimatter. When you combine matter
Speaker 1: with antimatter, you get energy. You can store energy by
Speaker 1: creating antimatter. Right now, none of these techniques can hold
Speaker 1: a candle, which is really another form of stored energy,
Speaker 1: to gasoline in the convenience sense. Fuel cells look to
Speaker 1: be the closest competitor right now, and they'll probably become
Speaker 1: a level to the general public over the next few years.
Speaker 1: Do you have any ideas or suggestions for this podcast?
Speaker 1: If so, please send me an email at podcast at
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