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?"