Tiny (nano-sized) particles of Haematite (crystalline iron oxide, or rust) have been shown to split water into hydrogen and oxygen in the presence of solar energy. This week, Nature Materials is publishing an article on this subject. EPFL researchers, working with Avner Rotschild from Technion (Israel), have managed to accurately characterize the iron oxide nano structures to be used in order to produce hydrogen at the lowest possible cost. The researchers claim to use an exceptionally abundant, stable and cheap material: rust.
According to Science Daily:
By using transmission electron microscopy (TEM) techniques, researchers were able to precisely characterize the movement of the electrons through the cauliflower-looking nanostructures forming the iron oxide particles, laid on electrodes during the manufacturing process. “These measures have helped us understand the reason why we get performance differences depending on the electrodes manufacturing process,” says Grätzel.
By comparing several electrodes, whose manufacturing method is now mastered, scientists were able to identify the “champion” structure. A 10×10 cm prototype has been produced and its effectiveness is in line with expectations. The next step will be the development of the industrial process to large-scale manufacturing. A European funding and the Swiss federal government could provide support for this last part.
This has been the breaking story this week in hydrogen and science news services. Already we can break down hydrogen and oxygen using traditional electrolysis using solar power, but this was simplicity itself. I was even more excited to read that the reaction occurred instantly. Then came the let down missed by all other media. . To illustrate the problem I quote from Scientific Daily:
“Evidently, the long-term goal is to produce hydrogen — the fuel of the future — in an environmentally friendly and especially competitive way. For Michael Grätzel, “current methods, in which a conventional photo voltaic cell is coupled to an electrolyzer for producing hydrogen, cost 15 € ( $19.50 USD) per kilo at their cheapest. We’re aiming at a € 5 ($6.50 USD) charge per kilo.”
This is where it all goes belly up. It takes between 35 kw and 50 kw to produce a kilo of hydrogen. Take out compressor charges etc if solar power was say 15c kwH then it will cost between $5.25 and $7.50 a kilo to produce. No idea where they got the $19.50 from.
According to the DOE using steam reformation of gas the production cost of hydrogen is sub $5.00. so apart from tech logistics of easily being able to produce it on site I am lost at the point of $7.50 production cost given that’s about the retail price of hydrogen at refilling stations at present.
I remember reading an excellent article a few years back that did a comparison of Hydrogen production costs and related it to running a fuel cell powered automobile. This is from the H2carblog by GREG BLENCOE on NOVEMBER 9, 2009
Cost of hydrogen from different sources
This is a simple question without a simple answer. The cost of hydrogen per kilogram depends on many factors. For example, how is the hydrogen produced? Is it produced from natural gas, wind, nuclear, solar, or some other way? If it is produced from natural gas, is the hydrogen made at the fueling station? Or is it produced off-site and then delivered by truck?
If hydrogen is produced from wind power, how far away is the hydrogen fueling station from the wind-to-hydrogen production facility? Is it closer to 10 miles, 100 miles, or 1000 miles away? And is the fueling station in a very expensive location like Beverly Hills, California or a very inexpensive location like Amarillo, Texas?The point is that there are a large number of factors that will affect the cost of hydrogen.
Miles per kilogram of hydrogen
Before estimating the cost of hydrogen per kilogram from various sources, the benefits of a kilogram of hydrogen need to be shown. How does a kilogram of hydrogen used in a fuel cell vehicle compare with a gallon of gasoline used in an internal combustion engine vehicle?
The Toyota FCHV-adv hydrogen fuel cell vehicle (mid-size SUV) is basically a Toyota Highlander Hybrid with a fuel cell. The Toyota FCHV-adv recently achieved 68.3 miles per kilogram in a real-world test with the Department of Energy. On the other hand, the Toyota Highlander Hybrid gets an EPA-rated26 miles per gallon.
The Toyota fuel cell vehicle is 2.63 times as efficient as the gasoline version. Furthermore, a rule of thumb is that fuel cells are 2-3 times as efficient as internal combustion engines.
Therefore, a reasonable figure to use is 2.5 times as efficient. This means the cost estimates below need to be divided by 2.5 to get the equivalent cost of a gallon of gasoline (i.e. $4 to $12 per kilogram of hydrogen is equivalent to gasoline at $1.60 to $4.80 per gallon).
Points to mention before showing cost estimates
Before providing the cost figures, a few things need to be mentioned:
1. Taxes are included. The average cost for gasoline taxes in the U.S. is currently about $0.50 per gallon. Since a kilogram of hydrogen in a fuel cell will power a vehicle approximately 2.5 times as far as a gallon of gasoline in an internal combustion engine, the current average for gasoline taxes has been multiplied by 2.5 to get a figure of $1.25 per kilogram of hydrogen for taxes.
2. The cost estimates assume mass production.
3. All subsidies were taken out. For example, the cost of wind power used below in the wind-to-hydrogen estimate is around 7 cents per kilowatt hour (which multiplied by the approximately 50 kilowatt hours of electricity needed to produce a kilogram of hydrogen via electrolysis would equal $3.50 for the energy costs). This is an unsubsidized cost figure for electricity produced at large wind farms.
4. As a point of reference, hydrogen (likely from natural gas) sold for $8.18 per kilogram at the Washington, D.C. Benning Road Shell fueling station in September 2008. Moreover, hydrogen produced from hydroelectric power sold for $6.28 per kilogram in Norway back in May.
5. There is absolutely no way of knowing what the exact cost of hydrogen would be right now in the scenarios below if millions of hydrogen fuel cell cars were on the road. The estimates below are educated guesses based on what I have learned over the past five years.
Estimated cost of hydrogen per kilogram in a variety of scenarios
With all of this in mind, here are the cost estimates per kilogram (which each include $1.25 for taxes):
- Hydrogen from natural gas (produced via steam reforming at fueling station) $4 – $5 per kilogram of hydrogen
- Hydrogen from natural gas (produced via steam reforming off-site and delivered by truck)$6 – $8 per kilogram of hydrogen
- Hydrogen from wind (via electrolysis) $8 – $10 per kilogram of hydrogen
- Hydrogen from nuclear (via electrolysis) $7.50 – $9.50 per kilogram of hydrogen
- Hydrogen from nuclear (via thermo chemical cycles – assuming the technology works on a large scale) $6.50 – $8.50 per kilogram of hydrogen
- Hydrogen from solar (via electrolysis) $10 – $12 per kilogram of hydrogen
- Hydrogen from solar (via thermo chemical cycles – assuming the technology works on a large scale) $7.50 – $9.50 per kilogram of hydrogen
So this now brings us back to the original article, given the reduction in solar costs what are the economic advantages? It will have to do a lot better than $7.50 per kilo.
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By mark dansie | July 10, 2013 - 11:38 am