The Energy Information Administration (www.eia.doe.gov) has huge amounts of data (and PDF reports). Unfortunately it can be difficult to compare across reports because they often use different units and definitions, but I made a stab at it earlier this year. This post finally prompted me to write up what I had now, rather than keep postponing it until I had worked out harder numbers (which was beginning to look like never).

According to the EIA, in 2005, transportation amounted to 28% of our energy use, 32% was industrial, and 22% residential and 18% commercial. Residential energy was 68% electricity, commercial was 77% electricity, and industrial was 35%, (transportation was less than a rounding error).

(This skews the "energy use" stats a bit, because that's electricity generated, not how much energy it took to generate it. Carma.org and other sites may have the data, but it would take a lot to figure out, but for the purposes of this post, it's really a different problem.)

Now residential use is subject to the ideas talked about here. Without buying a new house or any huge investments, 70% reductions are within reach. For new houses, there's no reason builders can't superinsulate and figure out which way south is, so that new houses reduce it even more. Apartment dwellers have fewer options to seriously reduce their energy use, but the possibilities for the owners and builders of apartment buildings are even greater than they are for homeowners (if they'd just stop thinking as landlords).

Commercial is somewhat easier than residential: some modern office buildings are net generators right now. No reason the roofs of malls couldn't be covered in solar panels. Not like your typical mall roof gets much shade. Or their parking lots. They probably are using efficient lighting already, but I bet heating and cooling are fairly primitive.

So, saying we use 100 units of energy (as a nation, for all purposes) right now, without rebuilding, in a few years we should be able to reduce residential from 22 units to 7. Give commercial a bit longer to get from 18 units to 6, but the total drops to 73 or so, using known, and easy retrofits on our homes, stores and office buildings. If we rebuilt, we could get that to 60 (or even less, since we could actually be generating in many cases). Lets say in 5 years of moderate effort, we're down to 70 national units from 100.

I couldn't find any breakdown of transportation between household and freight. But the effing Model T got 25 mpg, no reason we shouldn't now be doing 50 for household use. No reason we can't be using existing railroad right of ways (something around 40x as efficient). Take that 28 units down to somewhere between 8 and 14 in 5 or 10 years, so a total now of 50 to 56. That's without worrying about electric cars or exotic biofuels.

We're now at close to half without touching industry. Assuming their engineering is of the same basic age as the rest of our infrastructure, I don't see why similar numbers can't be applied. But let's say they're ahead of us already (new ones may well be, old ones certainly are not), so they can only do a 50% reduction. That brings the 100 units down to someplace between 34 and 40 - a national reduction of 60% to 66%. And as we rebuild, and the technology gets better, it stays low or gets lower, even assuming population growth.

What are the changes in lifestyle? If everybody (including industry and government) is pointed in the same direction, it's wear a sweater indoors in the winter, let it get up to 78F indoors in the summer (unless you buy a new green-engineered house), and don't expect to turn brodies or burn rubber 'cause you won't be driving a muscle car. Oh, and you'll have to stop trying to be the gaudiest house in the neighborhood at Christmas.

The only reason it currently takes disciplined, personal sacrifice to seriously reduce your carbon footprint is you have to do it all on your own - fighting the auto industry, fighting appliance makers, even fighting the government.

And what does it take to get everyone pointed in the same direction?

A carbon tax. Pure and simple. Suddenly, they'll all be on your side.

And the next generation of green technologies will come that much sooner, and be that much better.