The cost of hydrogen produced via the Zn=ZnO solar thermochemical cycle is compared to the cost of hydrogen produced via steam methane reforming and via electrolysis combined with wind and photovoltaic electricity. Prior work projects that H2 produced by the
Zn=ZnO cycle will cost between $5 (7) and $8 (28) per kilogram. In comparison, electrolysis combined with wind is calculated to cost between $4:76=kg and $5:60=kg, and electrolysis with PV electricity is calculated to cost between $13:30=kg and $21=kg. Hydrogen pro-
duced by SMR is found to cost between $2=kg and $4=kg. The cost di#27;erence between H2 produced via SMR and via the Zn=ZnO cycle is too great to be overcome with a carbon tax. Thus, policies that lead to public and private investment in the new technology will be necessary if the technology is ever to become cost competitive.
The time frame for the Zn=ZnO cycle to become economically viable is assessed through the use of experience curves under di#27;erent policy scenarios. Future costs of hydrogen produced via the Zn=ZnO cycle are projected for progress ratios of 0:77, 0:82, and 0:87
using initial cost and batch sizes predicted in the literature (28). Future cost of hydrogen produced by SMR are predicted assuming increasing costs due to the rising cost of methane mitigated by a learning e#27;ect on the SMR plant operation and maintenance costs. Under the minimal input policy scenario, a small scale plant (producing 50 kg hr ) goes on-line in 2040 and a mid-sized plant (producing 250 kg hr ) goes on-line in 2070. Under this policy, and
PR = 0:82, the Zn=ZnO cycle is expected to become cost competitive by 2070. Under the mid-range policy, the small scale and medium scale plants begin operating in 2025 and 2040, respectively. In this case, the Zn=ZnO cycle becomes cost competitive by 2050, again
assuming PR = 0:82. Under the aggressive policy, the small scale plant begins operating in 2016, the medium scale plant goes on line in 2020, and a large scale plant (producing 792 kg hr ) goes on line in 2030. Under the aggressive policy scenario, the Zn=ZnO cycle
becomes cost competitive in 2032. A sensitivity analysis on the assumptions used to predict these break even points indicates that the conclusions are relatively robust to 10% changes in the assumptions, with the exception of the progress ratio, which is accurate within 10 years given 5% changes in the assumed value.
Haltiwanger, Julia. Renewable Hydrogen: A Cost and Policy Analysis. July 14 2009. August 3 2009. Hubert H Humphrey Institute of Public Affairs.
plan b paper in partial fulfillment of the Master of Science Technology and Environmental Policy degree requirement
Renewable Hydrogen: A Cost and Policy Analysis.
Hubert H Humphrey Institute of Public Affairs.
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