Blog
Hydrogen Fuel Cells
The other night Ruwani and I went to see Who Killed the
Electric Car. Although we wanted to see the film anyway, we happened
to want to get out of our uncomfortably hot apartment and go somewhere cool
too 
.
The film explores the death of electric cars in the state of California and the suspect circumstances that led to it's death. The disappointing result is that auto manufacturers are no longer required to produce zero emission vehicles (ZEV) in California. It's disappointing because the electric car was a success for many people, the demand seemed to be there, and the cars actually existed and were rolled out commercially for a short time. Instead we're left with hybrids, which are a step in the right direction (but why no plug-in hybrids?), and emerging technologies such as fuel cell cars. Why take something off the plate that works and replace it with something like fuel cell cars which are prohibitively expensive, not commercially available, and a potential dead end. The dead end bit is what I want to explore in this post.
Last night I was listening to The Watt weekly podcast with guest speaker Dr. Ulf Bossel on the future of the hydrogen economy. He recently announced at the yearly Lucerne Fuel Cell Conference they would not be continuing the PEMFC Forum series as hydrogen fuel will never contribute to a sustainable world. So that's a bit of a shock, but why would he do this?
Let's take a look at what's involved with the hydrogen fuel cell use life-cycle as it would apply to a fuel cell car. We start with electricity, perform electrolysis to create hydrogen from water, then compress/liquefy the hydrogen for storage and transport, and then consume it in the fuel cell to produce electricity. The problem lies with energy losses due to the electrolysis, compression, and general operating loses of the fuel cell itself. The basic point is that it's an inefficient process, much more inefficient than simply storing the electricity in batteries in the first place.
According to Dr. Ulf Bossel because of the losses in the above process you're only left with 25% of the original energy. Storing and retrieving electricity in batteries on the other hand leaves you with an efficiency in the 50-70% range. The Watt has some worked examples of real numbers to demonstrate this.
Electricity generation is a separate issue. We're facing global
pollution problems, finite supplies of fossil fuels etc... Considering the
electricity generation environment then it seems rather silly to pursue options
such as hydrogen fuel when existing battery technology is already much better
and the efficiency of hydrogen generation, transport, and storage isn't going
to get much better. How we should be producing and conserving energy is a
topic for another post though .
