More Energy Efficiency and Leverage - It's STILL not about caulking.

I can't make a good decision about how to make my energy usage sustainable unless I know which activities are using the most energy. The chart presented here attempts to give an idea of the scales of energy I've been talking about in previous blog posts.

The total energy usage in the US per year (as noted in this blog post) is ~1x10^20J. For comparison, that is:

• ~1.8 million times the energy released by the atomic bomb dropped on Hiroshima and  
• ~2600 times the energy that the largest atomic weapon in the US arsenal would release if detonated.
• ~ 47 times the energy released by all nuclear tests conducted... ever...

Closer to home, the total electricity used per year by the average US household is about 4x10^10J. While media focus has been on making our homes more energy efficient as a good way to tackle sustainability, it turns out that driving a single car each year uses ~5x more energy than our homes consume*.
Increasing fuel efficiency or reducing miles driven by 20% would be the equivalent of reducing your home electricity usage by 100%. That's big leverage. Better than caulk or fluorescent light bulbs.

Flying is also pretty energy intensive. A single flight from SanFrancisco to Tokyo uses about the same energy as driving a car for a year** or ~3.5x the average annual electricity usage of a home. With about 4 flights per day 365 days/yr that is ~5100x the average annual electricity usage of a home per year of flights... and that's just one destination from one airport...

So shooting for 30% reductions in energy usage in the home may not be entirely where the leverage lies.

*assuming 15,000 mi/yr @ CAFE standard 27.5 mpg.
** assuming 5148 miles @ 5.29 mpg of kerosene.

How many superheroes does San Francisco need?

In the spirit of strange questions google might ask...something to get you thinking a little bit.

How many superheroes are needed in San Francisco?
Let's assume that the superheroes are needed to fight crime. All of it. In that case you'd need as many superheroes as it would take to stop all the crime in the city.

If you look at the FBI's Uniform Crime Report for 2009 you find that San Francisco had ~38,700 crimes in the first 6 months of 2009. That is ~215 crimes per day.
If you assume that all crimes occur at night (say between 8 pm and 5 am), that is ~2.5min per crime.
If you assume that the superhero instantly knows when and where a crime occurs and takes 1 min per crime to stop the evil-doers, that leaves ~1.5 min to travel between crimes.
If you assume that the superhero can fly as "fast as a speeding bullet" and that the bullet in question is from a 45cal Colt Revolver, that's 661 mph or ~11 miles/min. So in 1.5 minutes the hero could go ~16.6 miles (without even a sonic boom to wake people up).
San Francisco land area is roughly 7 miles x 7miles, which means that one superhero could easily cover all the crimes in the city.

So the answer is: One superhero.