AirScape Engineer's Blog

Since energy is a topic of conversation in our office, and I have been doing some bicycle commuting, it suddenly became important to have a table of transportation energy use.

Conclusions:

• Bicycle wins the efficiency contest.
• Electric car could win the efficiency contest if you fit 5+ people in your car.
• Escalating that war, the tandem would probably be the next weapon of choice.
• Trains are pretty good (no surprise), and perhaps could get better with regenerative braking.

Assumptions:

• Bicycle uses 50 kcal/mile
• 747 90 mpg (FAA figure is lower,but…)
• Electric car: .25 kwh/mile (from Tesla  if you trust software ‘geniuses’  posing as a car company, or if you trust the old fashioned car company GM, their ‘Volt’ appears to be .34 kW-h/mile)
• <rant> Tesla presents data like a software vendor (no surprise).  Their claim a 70amp @220 volt charger, running for 3.5 hours charges the battery fully (capacity listed as 55kw-h). Energy = efficiency (always less than 1.0) x 70 x 220 x 3.5 = 53.9. Clearly credibility = 1/ efficiency </rant>
• SUV 15 mpg
• Train (swiss) .082kwh/passenger-mile
• Pint of beer has 220 kcal
• kcal (kilocalories) are the kind we eat (aka Calories with a big ‘C’)  Yep, our system of measurement is THAT stupid. Small calories x1000 = Calories =  kilocalories.

Conversion Notes:

• It’s assumed that all liquid fuels have the same energy content as gasoline: 36.6 kwh/ gallon.
• Liquid fuels have crappy energy conversion, unlike electricity which can be 100% efficient.

Even though railroads are much more energy efficient and deliver lower transportation costs without federal subsidies, why are trucks the preferred mode of transportation?

I think that the answer lies in the fact that the highway truck combination is effectively open source.  The term open source is commonly used in the software world, but it applies here as well.

The platform is a highway, which just about anybody can use, provided they obey rules for weight, size, and safety of their modules (trucks in this case). This gives a tremendous amount of freedom to truckers and shippers to control their own destiny.  Ask anybody who has used the railroads for shipping and you will see that a rigid central planning department controls how and when your freight arrives.

How about this for an idea. Let’s make the railroads into a regulated monopoly. (It works for electricity, water, and gas BTW). The railroad makes its income by maintaining the infrastructure.