With regards to the terrorist threat, it seems that it would be advantageous to have a widely distributed power system. The blackout in the USA in August 2003 showed how vulnerable any country is to an attack on the power grid.

If everyone had a fuel-cell powered car that could be plugged into the house to 1) power the house and 2) feed the power grid; and if communities could have small facilities to generate hydrogen from agricultural by-products; then it would be much more difficult to bring down the entire energy grid.

I havn't done any numbers, but biodiesel could probably be a big player too.

It is CO2 neutral, it can be made now, and modern diesel cars can run on it directly. The distributuion system is there too.

Heck you can even make your own.

The agricultural support is being lowered worldwide so farmers will probably be looking for new crops to grow.

I currently see a lot of movement in the direction that makes bio diesel feasible.

The problem with biodiesel is that it might not be suitable for smaller applications than cars. The beauty of a hydrogen economy would be that you could use the fuel to power laptops and other small applications through fuel cells as well as entire buildings; we want fuel cells since so much equipment need electric power rather than the thermomechanical power of combustion. To my knowledge one cannot do this efficiently with biodiesel, but I might be wrong.

More seriously, biodiesel is not a good way of storing energy produced by fluctuating energy sources like wind, tidal or solar power (in the typical proposal that power is used to electrolyze water into hydrogen fuel that can be stored; biodiesel must be produced from vegetable fats).

One thing that hasn't been addressed, however is that Hydrogen is a fuel but it is not an energy source.

When we use fossil fuels to power things, we get more energy out of it than it took to get a hold of these fossil fuels. The same is not the case for Hydrogen. Indeed, all our current technologies for harvesting hyrdrogen incur a rather signifigant energy deficit and that's before we even deal with the problems you've mentioned.

If these biotech ideas you've mentioned are viable - that is they can convert solar to hydrogen, on large enough scales to be potentially useful and at a price which is economically competitive with oil, then perhaps I might regard a hydrogen economy as being potentially feasible.

But until then, I see it as just being technoutopianism.

Yes, the hydrogen economy needs to get the energy from somewhere. Far too many think we don't need nuclear power because we have electricity :-)

To get the nice distributive effect Rifkin talks about one doesn't need to use hydrogen. Any way of storing, distributing and collecting locally available energy at a good efficiency could allow the stuff he talks about. But if the main energy sources are concentrated and controlled like nuclear has become (see Freeman Dyson's discussion of why and why it was not necessary in _Imagined Worlds_) the energy system likely has less democratic benefits (it would still be superior to the present, of course - we have real trouble storing generated energy).

One of the most interesting observations I encountered at WFS was the major change in energy usage patterns that began in the 70's. The oil crisis triggered a significant move towards greater efficiency and the energy production per capita actually began to decline. See http://dieoff.com/page234_files/image006.jpg for a picture (that site tries to claim it proves we will all die in a big energy crash soon, but if you plot GDP and other indicators of human welfare against the production you will see instead a tremendous growth - we are simply more efficient). Another interesting plot is at
http://www.grida.no/climate/ipcc/emission/2-10.htm
with explanation at http://www.grida.no/climate/ipcc/emission/045.htm#fig210
that shows the predicted development of energy efficiency vs GDP.

One cannot get energy through conservation, but as systems get more efficient we need less dramatic energy sources to run them. With plastic electronics one could integrate solar collector in the cover of all the ubiquitious "smart" devices (like the animated cartoons on the milk carton and its little website showing the freshness history of the carton), with hydrogen power (or something similar) one could make use of all those renewable sources that would be pointless in a traditional lossy power grid.

(This is a tangent, I'm not trying to evade the argument or nitpick. I was just reminded of those infuriating cereal boxes on 'Minority Report'.)

Please for the love of all that is holy tell me we're not going to have animated milk cartons that monitor their own freshness.

I mean, I study marketing and all, but frankly a milk carton that talks to me seems an awful waste of resources when I can just pop it open and give it a sniff. Also, I think I'm not the only one who would find it just plain annoying.

Those graphs were interesting, although I find the use of logarythmic scales confusing.
It's interesting to see Pacific nations are very energy efficient on a GDP basis. Australia would be one of those. I'm going to have fun taking that little graph and shoving it in the faces of the Kyoto Suicide Pact apologists who harp on about how Australia is terribly pollutive on a per-capita basis.

I personally think freshness detection is going to be big. It is useful, especially for goods that are harder to detect whether they are decomposing or not (like spicy conditments). And animation makes for great advertisment and entertainment - first the cereal boxes, then the milk cartons. People are of course going to go nuts over it. So either manufacturers add an "off switch" command to blank the box, or people will start knitting covers for them so one can eat breakfast in peace.

Logarithmic scales are useful, but can be used to mislead. Looking at something which increases very fast on a linear scale tends to make changes very invisible - first nothing happens, then bang a fast rise. Logging things makes the rate of change visible, but tends to make fluctuations harder to see. I think quite a bit of the robustness of the "laws" people see in these graphs are just due to shrinking of the deviations.