Thursday, September 23, 2010

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:
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.