hydrogen from biofuels, lithium from underground

I wrote in July that hydrogen as an energy storage medium uses more energy than you can get from it - using energy directly is more efficient than converting it to other forms. It took a commenter to remind me that this is a simple law of thermodynamics. Duh! The point of energy storage - whether in conventional batteries or hydrogen cells or fuel in your car tank - is to be able to use it when and where you want to. And that's key to most forms of transportation.

(One reason I like the suburban trains in South Africa and parts of Toronto's TTC public transit system is that they run on overhead electric cables, making it possible to use absolutely any energy source you care to pump into the grid. You can change the energy source without requiring an overhaul of the transport vehicles. But these are more the exception than the rule.)

So improving energy storage efficiency and cost is going to be important for transport, whether public or private. Last week it was reported at the American Chemical Society meeting in Philadelphia that a new, efficient catalyst has been discovered to convert biofuels into hydrogen with a 90% yield, at a lower cost than other methods being developed.

And for many vehicles, the obvious competitor to hydrogen is good ol' batteries. The Tesla Roadster, a high-performance electric sports car, uses lithium ion batteries, just like your cell phone. While car manufacturers are investing heavily in electric car technologies, AutoBlogGreen asks whether it's realistic to expect the price of lithium-based batteries to fall far enough to make them a viable storage medium for cars. As with nuclear energy, it's easy to forget that supplies of the mined raw material are sometimes limited. In the case of lithium, that doesn't appear to be the case, but with mining there are always other impacts to consider. We need to maintain a diversity of options.