Hi Jonathan,
That sounds like a good project to work on! We need more people to think about great ways to live in the future.
Today's cities are already largely powered by electromagnetism,
with electric current passing through underground (and aboveground
wires). We also use energy from burning fossil fuels, and even the
electric energy we use usually can be traced back to burning fossil
fuels, to using nuclear reactors, or to using renewable energy sources
such as hydropower, wind power, solar power, or geothermal power.
The reason we have such a variety of energy sources today is that
energy does not come for free. Energy can be changed from one form to
another, but it cannot be created from nothing.
The good news is that magnetic fields store energy. You can use a
big electromagnet a bit like a battery. You still have to power it up
however, getting energy from some other source. A permanent magnet will
also have a magnetic field, but since it doesn't change, you can't get
the energy out of it. Also, the energy storage ability of a magnetic
field is not very large or convenient compared to, say, the energy
stored in fuels like oil or coal. And it's easier to move gasoline and
coal around than to move big magnets.
But speaking of moving magnets, that's pretty much how we generate
the electricity in a power plant. A big loop of wire (actually, many
loops all coiled together) is turned around on an axis in a magnetic
field. This procedure generates a voltage in the loop of wire,
following Faraday's law of induction. The energy needed to turn the
loop of wire is usually gotten from a steam turbine, and the steam is
generated from burning fuel. Windmills and water turbines in rivers
also do the job.
So yes, you can build the city of your dreams, but be sure to have a source of energy to keep things going!
Tom
(published on 10/22/2007)
