New catalyst could cut cost of making hydrogen fuel

[OKIsItJustMe]

http://www.news.wisc.edu/21929

[font face=Serif][font size=5]New catalyst could cut cost of making hydrogen fuel[/font]

July 2, 2013 | by David Tenenbaum

[font size=3]A discovery at the University of Wisconsin-Madison may represent a significant advance in the quest to create a "hydrogen economy" that would use this abundant element to store and transfer energy.

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To make the new material, Lukowski and Jin deposit nanostructures of molybdenum disulfide on a disk of graphite and then apply a lithium treatment to create a different structure with different properties.

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"Like graphite, which is made up of a stack of sheets that easily separate, molybdenum disulfide is made up of individual sheets that can come apart, and previous studies have shown that the catalytically active sites are located along the edges of the sheets," says Lukowski.

"The lithium treatment both causes the semiconducting-to-metallic phase change and separates the sheets, creating more edges. We have taken away the limitation from molybdenum disulfide and made the active sites both more pervasive and more reactive."

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http://dx.doi.org/10.1021/ja404523s

[kristopher]

1. Question

How much room for improvement in the overall cost of operating a FC is available in lowering the costs of catalysts for producing H2?

I was under the impression that this aspect of the process was only a small percentage of the total burden. Am I wrong?

[OKIsItJustMe]

2. Clearly any cost reduction is a cost reduction

(Please note, NREL technical report. Copyright concerns are nil.)

(This analysis looks at wind-generated hydrogen.)

http://www.nrel.gov/docs/fy12osti/52640.pdf?

[font face=Serif][font size=5]U.S. Geographic Analysis of the Cost of Hydrogen from Electrolysis[/font]
[font size=4]G. Saur and C. Ainscough[/font]

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Technical Report
NREL/TP-5600-52640 December 2011
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[font size=4]3.1. Electrolyzer[/font]

[font size=3]Electrolyzer performance and costs were taken from an independent review panel report on low- temperature electrolysis [font size=1]⁵[/font]. A 51,020 kg/day electrolyzer was modeled with a peak capacity factor of 98%/year for an adjusted output of 50,000 kg/day, the nominal hydrogen demand. The electricity requirement of the electrolyzer was 106 MW. The electrolyzer size and capital costs are linearly scaleable from 1,000 kg/day to 50,000 kg/day as per the independent review panel [font size=1]⁵[/font].

Many standard H2A economic assumptions [font size=1]^{6, 7}[/font] were used to calculate the electrolyzer costs. These included a 10% internal rate of return and a 40-year plant life. Table 1 shows the capital cost, operations and maintenance (O&M), and several other technical parameters taken from the review panel report to represent the electrolyzer [font size=1]⁵[/font]. Uninstalled costs used were $408/kW ($850/kg/day and 50 kWh/kg). Costs are shown in 2007$.

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[font size=4]4 Results[/font]

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Figure 15 shows the results of the sensitivity analysis. The wind turbine capital cost, which dominated the hydrogen cost in the breakdown (Figure 12), also shows the greatest sensitivity to the cost of the hydrogen with all other factors held constant. A 20% difference in wind turbine capital cost can change the cost of hydrogen by more than $0.50/kg. The electrolyzer cost and performance can also have a significant effect on the cost of hydrogen. The maintenance downtime for the electrolyzer and the wind farm are much less significant. Other sites and scenarios showed similar ranges as that in Figure 15.

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[font size=4]5 Conclusion[/font]

[font size=3]The cost of renewable wind-based hydrogen production is very sensitive to the cost of the wind electricity. Using differently priced grid electricity to supplement the system had only a small effect on the cost of hydrogen; because wind electricity was always used either directly or indirectly to fully generate the hydrogen. Wind classes 3–6 across the U.S. were examined and the costs of hydrogen ranged from $3.74kg to $5.86/kg. These costs do not quite meet the 2015 DOE targets for central or distributed hydrogen production ($3.10/kg and $3.70/kg, respectively), so more work is needed on reducing the cost of wind electricity and the electrolyzers. If the PTC and ITC are claimed, however, many of the sites will meet both targets. For a subset of distributed refueling stations where there is also inexpensive, open space nearby this could be an alternative to central hydrogen production and distribution.

Sensitivity shows that the electricity price, based upon the wind turbine capital cost, can affect the cost of hydrogen more than even the electrolyzer capital cost and performance. This is most visible when the combined effect of the PTC and ITC of $0.02/kWh is applied to the wind electricity. Cost of hydrogen drops by more than $1/kg with a PTC to $2.76-$4.79/kg.

All wind electricity is not equivalent, but even a range of wind class sites can provide renewable, green hydrogen at a cost close to current DOE targets. The use of this renewable fuel could then be used to supplement introduction of fuel cell electric vehicles, energy storage for increased variable renewable electricity penetration, or other industrial uses currently dependent on fossil fuels.

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