Energy, post 5: The obstacle to oil independence

Before I steer this series into how a few policies and economic incentives might help speed the arrival of oil independence day, I need to summarize the state of the art in transportation energy.  I freely admit that, with this attempt to condense the technical aspects into a few graphics and brief descriptions, I am taking the significant risk of violating Einstein’s principle:

Everything should be made as simple as possible, but not simpler.

So be it.  I need this as a technical foundation for the subsequent articles.  I’ll let you decide whether I oversimplified. 

I’ve already stated my judgment that the top priority for energy policy is national security for Americans, not carbon dioxide emissions by Americans.  By focusing on the primary goal of becoming oil independent, we’d compartmentalize the overall task; as a side benefit, we might even speed up the process of making North America an even deeper carbon sink than it already is.  Wouldn’t that be nice?  In any case, here’s a reminder of the challenge:

Forty percent of our energy usage comes from oil; half of the oil is imported.  If we could reduce our demand for oil to a small fraction of its current level because of a technological breakthrough in powering personal transportation vehicles, we could become net exporters of energy systems, products, and know-how.  North America would be able to supply itself with all the oil we’d still need for such things as jet fuel and feedstock for plastics, but we wouldn't need ocean-crossing oil tankers any more.  We might need a few tankers to navigate our intracoastal waterways on both coasts, but those waterways are a lot easier and cheaper to defend. 

The bad news is, it will take a significant technological breakthrough, not to mention potentially significant time to scale it up.   The good news is that a number of potential breakthroughs are starting to look promising in laboratory settings.  (I’ll list several examples in the next article in this series.)

For the near-term future, the heat engine and hydroelectric equipment will generate most of our primary electrical power; the heat engine and the electric motor will generate most of our end-use power needs.  [Wind and solar power will most likely remain a small, single-digit percentage for at least the near-term, mainly because they are stranded far from the time and place their power is needed; very large scale, very inexpensive energy storage systems will be needed to alter that situation.]

The heat engine includes the internal combustion engine (gasoline and diesel engines), the external combustion engine (Stirling engines, gas turbines, steam boilers), and any noncombustible with a sufficient temperature difference between the hot side and the cold side (geothermal, or even the ocean’s temperature gradient). 

The heat engine generates the vast majority of the power we use.  The bigger the temperature difference between the hot side and the cold side, the closer to 100% efficient it gets—although the Second Law of Thermodynamics dictates that there will always be at least some waste heat, i.e., that we’ll never get all the way to 100%.  [Tickler for engineers: Maxwell’s Demon would be a big help here, wouldn’t it?  Believe it or not, a pseudo version of it is now emerging from the laboratory; it’s called the Cool Chip, intended initially for cooling CPU’s, but it’s scalable.] 

The electric motor is a downstream way of changing electric power into mechanical power, and it is in theory an alternative source of mechanical power for driving the wheels of our personal vehicles.  When the motor is stationary, it can be hard-wired into the power grid; when it must be mobile, it needs a source of stored electrons (i.e., batteries, fuel cells, capacitors).   

The most important aspect of the above diagrams is the yellow box: stored energy.  The big reason the heat engine predominates in personal vehicles today is that gasoline and petroleum-diesel are very, very efficient at storing 300 vehicle-miles of energy in that small, sufficiently safe, mobile container we call our “gas tank.”  We can fill our tanks quickly with gasoline, and discharge them at a sufficient rate to give our heat engines the ability to accelerate our cars (and our kids and their soccer equipment) from 0-60mph in five or six seconds. 

So far, there’s no electric motor based system that can even come close to matching all those performance stats in a personal vehicle:  300 vehicle-miles of energy in a similarly small, safe, mobile package, capable of starting immediately in all seasons, accelerating from 0-60mph in five seconds [...okay, six], and hauling four kids plus equipment to a soccer game.  Oh, I almost forgot one minor detail: It must also be as affordable as the beloved SUV, or very close. 

Nonetheless, a no-petroleum personal transportation vehicle that meets all those criteria is what it will take for our nation to become oil independent.  That’s the challenge.  Next time, we’ll take a look at several possible solutions to that problem, already in the works—along with several possible ways of speeding up the entire process.  Hint: Carrot economics will be involved.

==========
Here are links to all seven articles in the energy series:

• Article 1: Energy facts, certainties, and possibilities
• Article 2: Government spending and its consequences
• Article 3: Yes, growth DOES require more energy
• Article 4: Dissenting from Mr. Gore
• Article 5: The obstacle to oil independence
• Article 6: A tankful of electrons
• Article 7: A 21st Century “GI Bill”