Tuesday, February 19, 2008

Future Of Transportation?

Eventually fossil fuels will no longer be our primary fuel source for personal transportation. Not to say that we will completely run out, but once the easy to get to sources are exhausted, it will no longer be cost effective, relative to the alternatives. Even the president of Shell Oil publicly acknowledges this. Hybrid cars can stretch the remaining supply, but crude oil will eventually be replaced. Big oil, the US government, and auto OEMs are discussing new fuel possibilities. Their primary focus, hydrogen.

...the first car driven by a child born
today could be powered by hydrogen,
and pollution-free.
— President Bush,
State of the Union Address,
January 28, 2003

Despite the single mindedness of the Hydrogen-future from these three, hydrogen is certainly not the only option for the future of transportation, there are bio-fuels, compressed air, batteries and many many other options.

So which is the best for the future of transportation? There are lots of factors to consider. One important factor, is the efficiency of the fuel. This factor is one of the reasons that crude has worked so well as a fuel source (despite its pollution and security issues), it has a high energy efficiency. The energy that is takes to pump and refine it is only about 1/5th of the energy that the resulting product provides. Put in 1 unit of effort and get a fuel that has 5 units of energy. That had led to a profitable business. As the industry moves to tar sands and other sources,this efficiency number will get worse. For gasoline, looking at its entire cycle is referred to a "Well-to-Wheel Assessment". These new contenders (hydrogen, compressed air and batteries) to the throne will have to score well on a efficiency of generation vector, as well as be from a renewable source. How do the contenders stack up? From the report “Wind-to-Wheel Energy Assessment” here is a graph that says it all:

You can see that see that Hydrogen does not score well on this scale. Battery powered EVs score significantly better. Looking at the report in detail, this is a conservative estimate for batteries since the battery calculations included losses when comparable losses for the other technologies were overlooked. Even given this, battery transport was 3 times better than hydrogen. A compressed air car even scores better. It would be much easier to build an infrastructure for plug-in transportation or compressed air than a "hydrogen highway". Outdoor electrical outlets are at RV parks across the country. Most gas stations already have coin-op air compressors and you can buy one at any Home Depot for your garage at home.

If these other options score so much better, why the big push for Hydrogen? Simple, it uses the same business model of consumers going to fueling stations. With battery or compressed air, you don't need a gas station. You could plug-in or "pump-up" in your own garage, at work or any parking lot could install coin-op (or free for customers) electrical outlets or compressors. Who can blame big oil for wanting to maintain a revenue stream. They can control the hydrogen market, just as they control the gasoline market, so it is the only future they are interested in helping to create.

Now you understand why many EV proponents refer to hydrogen fuel cells as "fool cells" or "fool sells".

As mentioned at the start of this entry, this is only one aspect to consider. Things such as energy density, refueling time, pollution & many other aspects must be considered for the complete picture. All great future blog topics.

Further Reading:

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