Best Replacement Energy to Fossil Fuels
If at some point in the future our fossil fuel resources
were to become completely depleted what would be the best replacement
energy source both for cars as well as for supplying electricity to
homes? I have searched the archives and couldn't find anything that
answered my question, thank you so much for any information you are able
First, a simple point, you start with the condition: "If at some point in
the future our
fossil fuel resources were to become completely depleted..."
The situation is, that at some point in the future, our fossil fuel reserves
will be depleted. When
that will happen is greatly debated, but, we do have enough fossil fuel,
particurlarly coal to last for
many years before it all runs out. According to the department of energy,
the United States has enough coal to last for more than 250 years at our
current rate of consumption, and
enough natural gas to last between 60 and 100 years. Oil, is our least
plentiful. However, we use more
and more energy each day, and no one is really sure how long it will really
The real problem is not necessarily how much we are using, it is how it is
distributed. Fossil fuels account
for 85% of all the energy used in the United states. Oil, our least
plentiful resource, accounts for 40% of
all our energy. The United States doesn't have enough oil production to
meet our needs, and United States alone
has more coal than the rest of the world has oil. So, we could possibly be
out of oil, or the political situation
in the Middle East could become such that we face an oil crisis, relatively
soon. Politically it could happen any
time. We will could use up all the oil reserves sometime in the 21st
Next, Natural Gas accounts for 25% of our energy, and is between oil and
coal in availability, and it is projected
to be depleted in the 21st or 22nd century.
Coal, our most plentiful resource, accounts for 20% of our energy needs,
mostly producing electricity. In fact
most electricity in the United States is in producting coal.
All other energy sources account for 15% of the total energy used. This
includes Atomic, Hydroelectric, Geothermal,
Solar, Wind, and any other type of energy.
Currently there really are no viable alternatives. Atomic power can produce
electricy quite well, but already the
hazardous waste it produces is quite a problem. If we suddenly tripled the
amount of energy produced by it,
waste would become an enormous problem.
We don't have enough hydroelectric power in the United States, even if we
dammed every river, and we have more
sources of hydroelectic power than most countries.
A lot of research is being done in this area, especially in finding new
fuels for cars. This is because cars
use most of the energy, and produce the most pollutants, so finding a clean,
abundant source of energy for
cars would greatly change how much fossil fuels we need.
If all the fossil fuels ran out next year, we could come up with an
alternative. Fuel cells, solar power, or
something, and we would. Right now, however, the greatest obstacles are
social obstacles. People don't want
to spend $75,000 on a car, and some of these alternatives are very
expensive. It is much more convenient
to go buy a cheap car and worry about solving the polution and energy
problems some other time.
I hope this helps a bit.
It would probably be some combination of things depending on how far into
the future you're trying to project. Hydroelectric, wind, solar, tidal,
and biomass energy are renewable energy sources and could go on until the
sun burns out, but whether this could supply enough for 10-20 billion
people at the current (American) consumption rate is
questionable. Improvements in energy efficiency can and will likely be
made. Nuclear fission will probably play a role as well, but there's the
problem of waste disposal and accidental releases, and there's a possible
problem of running out of raw material for that as well. Nuclear fusion
might supply enough power for humans as long as we are on earth, but
current technology is not very close to achieving extended controlled
fusion (uncontrolled fusion, i.e. the hydrogen bomb, does exist).
There is no "best", in absolute terms. This is a problem involving
engineering, scientific research, and economics, in which the source,
transmission, and application of energy will all figure in.
The answers will depend on what technologies are available, and at what
cost, at the time we run out, and in the places where the energy is
needed. The answers will also depend on the rate at which we run out,
because this will influence funding for research and development of
replacements, and determine how directed those efforts are.
Direct conversion of solar energy to electricity is attractive, though
currently expensive. Indirect use of solar energy (e.g., hydroelectric
and wind power, agriculture directed at producing fuel) is attractive,
and the states of the technologies that convert energy produced in
these ways into the actual work that needs to be done will determine
which are most economical. Geothermal energy is certainly great if you
live in Iceland, and we may find economical ways to use it in less
obvious places. The use of nuclear energy is inevitable -- though
many oppose it for some good reasons and some zany ones -- because of
the huge amount of energy that would have to be replaced if fossil
fuels were absent. Energy from tides, lightning, storm surges, etc.
may figure in as well.
One "source" of energy that should not be ignored is conservation --
improvements in the efficiency with which we transmit and apply
We will reach a point where we run out of fossil fuels. That is a
known. When? It depends on how foolishly we squander the fuels. What
might have potential? Wind, waves, sun, fuel cells, methane, corn
alcohol might be an alternative. Much has been written concerning each
type's pros and cons. Have you used your web search engines to look at
any of these items?
The only resource that I know about is solar power. When fossil fuel
resourses are gone, solar energy will be a main source of usable 'fuel'.
Try searching your local library under solar cars, solar panels, and the
like and see if they lead you to your answer.
You are correct that the supply of cheap, easily accessible, and
environmentally suitable fossil fuels will diminish in the future; some
sources sooner than others. For example, at the present rate of
consumption, coal supplies -if I remember it correctly- can last for at
least several hundred years while petroleum for perhaps less than a
hundred years. The key issues throughout are the cost of exploration
and exploitation (technical), and the cost of usage (in terms of
environmental impact). These can make a fuel source viable or
unacceptable in the future. So, complete depletion is not an issue,
There are some attractive alternatives to fossil fuels, including
renewable resources (solar, wind, hydroelectric) and nuclear.
Increasing "cost" of fossil fuels will make these alternative sources
increasingly attractive. In the long run, unless we find other sources
of energy, nuclear energy and conservation (in terms of more energy
efficient products and life-style) seem to be our more reliable choices.
Ali Khounsary, Ph.D.
Advanced Photon Source
Argonne National Laboratory
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Update: June 2012