Power of the brain

How much power does the human body use?  Evolution is less survival of the fittest, and more survival of the most efficient.  The calculation is simple.  A typical caloric intake is 2500 kilocalories—known simply as Calories, in the United States—per day.  This is the equivalent of 120 watts.  This is rather impressive.  You and I are kept alive with about as much power as in used by a standard incandescent light-bulb.  Furthermore, the brain only requires 20% of the body's energy usage, which comes—that is, 24 watts.

How does this compare to computers?  Personal computers use a modest 65 to 250 watts, but don't possess the ability to match the functions of the human mind.  Artificial intelligence is, for now, run on supercomputers.  For example, WATSON consumes 85 kilowatts—the equivalent of roughly 1,000 PCs.  Koomey's law is similar to Moore's law, but deals with the energy usage of computers.  It states that the number of calculations for every unit of energy doubles every one-and-a-half years.  A quick calculation shows that WATSON could match the human brain in energy usage by the 2030s.  These computers only mimic one aspect of human cognition, but how these technologies will be used remains uncertain—there are a number of possibilities I intend to explore more fully.

That being said, I'm confident that human minds are not at risk of obsolescence.  The human brain is incredibly efficient, and already possesses a powerful set of skills.  Furthermore, the problem solving capabilities of groups of people exceeds the sum of the parts.  What is not clear is the number of people who will be able to take part in these kinds of activities.

Replacing fossil fuels

"The future is already here—it's just not very evenly distributed." ― William Gibson

It is trivial to say that wind and solar will replace fossil fuels, because in many places they already have.  Given that these sources produce less pollution and provide more autonomy in energy production, why haven't we been using them all along?  The simple answer is that fossil fuels are just easier to use.  They store a large amount of energy per pound and can provide energy consistently to the grid.  Most of all, they are easy to transport.

via NREL.

There are approximately 48,000 wind turbines in the U.S., supplying 4% of our electricity.  To supply our full electricity demand would require on the order of 1 million wind turbines. However, building these turbines would require a large amount of steel and copper, and they would need to be replaced every twenty to thirty years.  Wind farms also require more space than conventional power plants, and may not provide power with the same consistency.

via NREL.

Solar energy has experienced fast growth, recently, though it suffers from a similar set of disadvantages as wind.  There are other problems with the availability of the materials needed to make more efficient solar panels—though, we will visit this issue later.  We may have to settle for relatively inefficient silicon-based solar panels.



However, this entire discussion ignores that electricity generation is only 40% of our energy usage.  Almost none of the energy used for transportation is electric.  The question then becomes
"How will we provide transportation without petroleum?"

How is energy made?

"It is important to realize that in physics today, we have no knowledge what energy is.  We do not have a picture that energy comes in little blobs of a definite amount.  It is not that way." ― Richard Feynman, The Feynman Lectures on Physics

It is a myth to say that we produce energy.  It is impossible to create—or destroy—energy.  Instead, we extract it from energy-rich sources, like coal or petroleum.  The problem then becomes how to make it do what we want.  In the 18th century, engineers were able to build machines that could turn chemical energy into motion.  In the 19th century, engineers were able to build machines that could turn motion into electrical energy.  And in the 20th century, engineers were able to build machines that could turn nuclear energy into heat.  However, at this point, most methods of extracting energy are in place.

via LLNL and DOE. (Full size).

Above is one of the best infographics I've seen.  It shows the energy sources and uses for the United States—by far, the largest energy consumer in the world.  Let's begin the controversy.  Fossil fuels are, undoubtedly, a limited resource.  The notion that we will reach—or have reached—a point where we are no longer able to increase the available supply of petroleum is called the peak oil hypothesis.  Looking at this chart, though, we see that over 80% of our total energy needs comes from fossil fuels, and over 95% of energy used for transportation comes from fossil fuels.  Tomorrow, we'll look at what sources may replace fossil fuels in the future.