If I understand this correctly, this is a method for using electrical power to produce hydrogen fuel. Why the focus on solar? Isn't this just as beneficial for wind? Wouldn't using nuclear baseload power to produce H2 fuel to meet peakload demand or motive power also make sense?
I'm sure this technology is revolutionary, but (unless I am mistaken) the implications are far broader than this story makes out. It's almost misleading. Am I wrong?
In some ways you're right. The system can use electricity from any source. But there are a couple of reasons to focus on solar. First, the ultimate goal of the research is artificial photosynthesis, because solar power is the biggest source of energy we've got.
The second is a more practical issue. Note that, near the end, the article talks about the need to improve the rate of oxygen production. Right now, the rate is very close to what would be needed in artificial photosynthesis, but not fast enough to be practical in conjunction with wind power or other sources of electricity, according to NREL's John Turner.
Here's what John Turner of NREL says. In the case of artificial photosynthesis, the catalyst would be incorporated directly into a solar panel system that includes materials that absorb sunlight and generate electrons, membranes, and the catalyst that converts protons into hydrogen gas.
In such a system, the catalyst wouldn't be supplied with much of a current, which translates into pretty slow rates of water splitting. It'd be on the order of 30 to 40 mA/cm^2. Nocera says his catalyst works at about 5 mA/cm^2, so it's pretty close.
But if you don't have an artificial photosynthesis system, you are going to need two separate devices: the electricity generator plus a separate electrolyser that includes Nocera's catalyst. That's going to cost more. You can minimize these capital costs if you have catalyst that works at a higher current density and produces hydrogen at a faster rater (the faster, the smaller the system you need). There are also space considerations. In this case, you'd probably want a catalyst that works at high current densities. Today's, albeit expensive, electrolysers, for example, can work at 800 mA/cm^2 or more. It seems likely that you wouldn't need to go quite that far, since Nocera's system would be cheaper. But you'd want significantly higher densities than 30 to 40 mA/cm^2, Turner says.
Nocera actually has a different take. He thinks electrolysers based on his catalysts could be cost effective using photovoltaics as the power source, provided the current densities are improved a bit. This is especially true if you are using only part of the current from the PVs to power the electrolysis, using the rest to power your home during the day.
"... if Hydrogen Automobiles ever become practical (maybe in 30 or 40 years?)."
It would appear that Honda is putting hydrogen fueled automobiles in the hands of consumers in California TODAY:
TORRANCE, USA, July 25, 2008, 2008 - American Honda Motor Co., Inc.,
announced that Ron Yerxa and Annette Ballester took delivery of their
hydrogen fuel cell-powered FCX Clarity on Friday, July 25, 2008 at
Honda of Santa Monica, one of three dealerships in Southern California
that are part of the first fuel cell vehicle dealership network.
Full Story:
http://world.honda.com/news/2008/4080725FCX-Clarity/
Photo Index (3 photos):
http://world.honda.com/news/2008/4080725FCX-Clarity/photo/
Hopefully this is a real advance, we'll be needing it ... and the real way to "win" the war on terror is to get off of oil.
But, apparently he splits oxygen and also produces hydrogen ions. It's unclear what this means. Does the process produce: Two H^+ H_3O^+ other? Depending on the exact output, this process is more or less useful.
Massachusetts Institute of Technology
brock_cusick
1
Solar is just an application
I'm sure this technology is revolutionary, but (unless I am mistaken) the implications are far broader than this story makes out. It's almost misleading. Am I wrong?