The Hydrogen Economy Opportunities, Costs, Barriers, and R&D Needs (2004) / Chapter Skim
Currently Skimming:
Appendix G: Hydrogen Production Technologies: Additional Discussion
Appendix G: Hydrogen Production Technologies: Additional Discussion
Pages 198-239
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 198... ...
As include a brief description of the current technology; pos a result, the committee considers natural gas to be a transisible improvements for future technology; refer to Chapter 5 tional fuel for distributed generation units, not a long-range and Appendix E (which presents spreadsheet data from the fuel for central station plants for the hydrogen economy. committee's cost analyses)
|
From page 199... ...
Partial Oxidation Partial oxidation (POX) of natural gas with oxygen is car Natural Gas Conversion Today ried out in a high-pressure, refractory-lined reactor.
|
From page 200... ...
At least one for the hydrogen economy, and it should be possible to lower company is fabricating commercial SMR hydrogen plants as the cost of these generators significantly through mass prosmall as 300 kg/day using components of fixed design, one duction of a generation "appliance." Such appliances may be of the elements of mass production.5 further improved by tailoring the design to the fueling appli Partial oxidation utilizing natural gas is fully developed cation. For example, hydrogen would likely be stored at and used commercially.
|
From page 201... ...
hBased on lower heating values for natural gas and hydrogen; includes hydrogen generation, purification, and compression, and energy imported from offsite, as well as distribution and dispensing. that could have the greatest impact on the introduction of As illustrated in Figure G-3, hydrogen cost7 in the largest hydrogen fuel.
|
From page 202... ...
FIGURE G-3 Estimated costs for conversion of natural gas to hydrogen in plants of three sizes, current and possible future cases, with and without sequestration of CO2.
|
From page 203... ...
cars would increase natural gas consumption significantly. Hydrogen cost using steam methane reforming is sensitive to the price of natural gas, as shown in Figure G-4.
|
From page 204... ...
FIGURE G-4 Estimated effects of the price of natural gas on the cost of hydrogen at plants of three sizes using steam methane reforming. Costs based on current technology.
|
From page 205... ...
A substantial coal infrastructure already exways to improve the technology and make it even more com- ists, commercial technologies for converting coal to hydropetitive for medium- and large-scale plants. gen are available from several licensors, the cost of hydrogen Publications from the DOE hydrogen program indicate from coal is among the lowest available, and technology imthat the program on distributed generation will include dem- provements are identified that should reach future DOE cost onstration of a "low-cost, small-footprint plant" (DOE, targets.
|
From page 206... ...
. Clean Coal Technologies Potentially the most significant future issue for coal combustion is CO2 emissions, since on a net energy basis coal Clean coal technologies use alternative ways of convertcombustion produces 80 percent more CO2 than the com- ing coal so as to reduce plant emissions and increase plant bustion of natural gas does, and 20 percent more than does thermal efficiency, leading to an overall cost of electricity residual fuel oil, which is the most widely used other fuel for that is lower than the cost for electricity from conventional power generation (EIA [2001]
|
From page 207... ...
This pricing reflects costs for producing hydrogen from very large, central station plants at which hydrogen Oxygen-Blown Versus Air-Blown Gasification will be distributed through pipelines. In these plants a single Gasification plants exist that use either air-blown or gasifier can produce more than 100 million scf/day H2.
|
From page 208... ...
In terms of its stage of development, coal gasification is a less mature commercial process than coal combustion processes and other hydrogen generation processes using Department of Energy Programs for Coal to Hydrogen other fossil fuels, especially in the aspects of capturing The DOE programs for making hydrogen from coal reCO2 and providing flexibility in hydrogen and electricity side in the Office of Fossil Energy and are related to proproduction. In that sense the potential for improvement grams to make electricity from coal.
|
From page 209... ...
Coupling gasing systems, one of these being coal-fueled systems. A part cooled reactors to a direct or indirect gas turbine Brayton of the Department of Energy's hydrogen program is aimed power cycle can yield thermal efficiencies much higher than at developing safe and economic methods of sequestering the 33 percent of current LWRs.
|
From page 210... ...
This process reduces but does not In 2002, several reactor concepts were selected by an in- eliminate the CO2 emissions associated with conventional ternational team representing 10 countries as promising tech- SMR. It also reduces the amount of natural gas required for nologies that should be further explored for availability be- hydrogen production.
|
From page 211... ...
coupled to a direct While the demand for heat energy is increased, the decrease supercritical CO2 power cycle. The cycle was originally in the electrical energy demand improves the overall ther- proposed for fast reactors (Dostal et al., 2002)
|
From page 212... ...
Nuclear reactors coupled to HTES are capital-intensive technologies, due to both the nuclear plant and the electroly Thermochemical Water Splitting sis plant. The development of economical and durable HTES unit materials, which can be similar to those of the solid A recent screening of several hundred possible reactions oxide fuel cell materials, can contribute to cost reduction.
|
From page 213... ...
this process is about the same as that of the SI process, but is Reactor materials that are temperature-, irradiation- and influenced by the efficiency of the electrical power cycle. It corrosion-resistant would be needed.
|
From page 214... ...
Courtesy of Charles Forsberg, Oak Ridge National Laboratory. tion in the capital cost may result from improved catalytic Fe3O4 + 8HBr 3FeBr2 + 4H2O + Br2 (220°C)
|
From page 215... ...
The SMR process requires high temperature, hydrogen production. Today this cost is about a factor of 3 and the most common means of providing the heat for the higher than what is achievable by conventional SMR, with process is through the burning of natural gas in the reform- natural gas prices at $4.5/million Btu, even when the cost of ing furnaces, as described in the section "Hydrogen from hydrogen distribution is taken into account.
|
From page 216... ...
and replacing the electric generation capacity with a thermochemical plant, the total plant capital cost was found to be Disadvantages of Nuclear Energy Use about $750/MWth. (A recent review of the costs of nuclear for Hydrogen Production power at recent plants -- built in the past 10 years in Korea, Finland, and Japan -- finds the overnight costs of plants to be · Efficiency of the conventional electrolysis process.
|
From page 217... ...
The the desired high temperatures, electrolyzer units can use materials similar to those of fuel · Qualification of the irradiation properties of graphite cells that operate at high temperatures, and a synergistic and other structural materials at the desired range of tem materials program may be possible. Finally, both electrolyperatures, and sis and thermochemistry are potentially applicable to the use · Operation and control of the helium power cycle at of solar energy for hydrogen production.
|
From page 218... ...
Further, gen production appears to favor thermochemical processing there are geographical regions in the nation and around the over the high-temperature electrolysis path. A more balanced world where hydrocarbons (especially natural gas, the preapproach would be wiser in order to make use of potentially dominant source of hydrogen reformation)
|
From page 219... ...
include the previously mentioned remote fertilizer market in which natural gas feedstock is not available. The other major Electrochemical Efficiency commercial market for electrolysis today is the distributed, or "merchant," industrial hydrogen market.
|
From page 220... ...
range of current densities, but this higher reaction efficiency is offset at least in part by higher compression and purifica Equipment Costs tion costs, as well as by higher costs associated with managing the liquid electrolyte itself. Regarding capital cost recovery, the cost of the 480 kg/ The committee believes that current technology is capable day system, excluding compression and dispensing, is asof producing an electrolyzer-based fueling facility having sumed at $1000/kW input.
|
From page 221... ...
Renewables generate dc power available technology is summarized in Table G-6. This table that can be applied to the dc-using electrolyzer cell stack withassumes a 14 percent capital cost-recovery factor, and pre- out inversion.
|
From page 222... ...
Lawrence Livermore National Laboratory, involve solid oxide electrolyzer/hydrocarbon hybrids. The hybrid concept Environmental Impacts of Electrolysis involves enhancing the efficiency of the already-hightemperature electrolysis process by using the oxidation of The environmental impact of the use of electrolysis to natural gas as a means of intensifying the migration of oxy- produce hydrogen depends on the source of electricity.
|
From page 223... ...
Elec- electrolyzers can utilize existing water and electricity infra tricity from nuclear plants is also non-emitting on a green- structures to a considerable extent, obviating the need for house gas emissions basis, but the outlook for additional a new pipeline or surface hydrogen transport infrastructure nuclear plants is uncertain at best. that would be required of larger, central station hydrogen Power from the grid is assumed to derive from the grid's production technologies.
|
From page 224... ...
The issues for its successful cheap oil and natural gas and improvements in gas generatdevelopment and deployment are threefold: (1) further reduc- ing technology, coupled with the expiration of federal tax ing the cost of wind turbine technology and the cost of the elec- credits at the end of 1985, meant that wind energy remained tricity generated by wind, (2)
|
From page 225... ...
, wind The main technical parameter determining the economic availability is estimated to be 3250 GW, equivalent to the success of a wind turbine system is its annual energy output, above value for a capacity factor of 35 percent. In 2002, which in turn is determined by parameters such as average installed wind capacity was about 5 GW generating 12.16 wind speed, statistical wind speed distribution, distribution billion kWh, corresponding to a capacity factor of 29 perof occurring wind directions, turbulence intensities, and cent (EIA, 2003)
|
From page 226... ...
. In the committee's analysis, for possible future techEconomics of Wind Energy nologies it is assumed that the cost of electricity generated Larger turbines, more efficient manufacturing, and care- using wind turbines decreases to 4 cents/kWh (including ful siting of wind machines have brought the installed capi- transmission costs)
|
From page 227... ...
While the technical potential of wind power to ful- duction in the capital cost of the electrolyzer and cost of fill the need for energy services is substantial, the economic wind-generated electricity results in eliminating the need for potential of wind energy will remain dependent on the cost using grid electricity (price still pegged at 7 cents/kWh) as a of wind turbine systems as well as the economics of alterna- backup.
|
From page 228... ...
Furthermore, a repair to one wind turbine does Advantages and Disadvantages not affect the power production of all the others. Second, the There are obvious environmental advantages to hydrogen energy generated by wind turbines can pay for the materials produced from wind power.
|
From page 229... ...
These address two of the major public benefits of a move to a hydro- processes have in common the capturing and conversion of gen energy system, and wind energy is the closest to practical solar energy into chemical energy mediated by photosynutilization with the technical potential to produce a sizable thetic processes. In both cases, solar energy serves ultimately percentage of future hydrogen, it deserves continued, focused as the primary energy source for the production of molecular attention in the DOE's hydrogen program.
|
From page 230... ...
(2003) consid ered two management scenarios for profitable bioenergy crop production: one to achieve high biomass production 22 Mark Pastor, Department of Energy, "DOE's Hydrogen Feedstock Strat- (production management scenario, or PMS)
|
From page 231... ...
with the total biomass produced. A shift of cropland use from traditional agricultural crops to bioenergy crops will also result in higher prices for traditional crops.
|
From page 232... ...
heterogeneity of biomass, its localized production, and the relatively high costs of gathering and transporting biomass. Therefore, current biomass gasification plants are associated Environmental Impact of Biomass inherently with unit capital costs that are at least five times Used for Hydrogen Production as high as those for coal gasification (see Figure 5-2 in Chap In the overall process of biomass production and gasifica- ter 5)
|
From page 233... ...
Because solar energy yield of switchgrass can be increased by 50 percent. The harvesting technologies are competing for land use among committee also assumed that the future biomass is derived each other and with other societal activities, such as farming, from bioenergy crops at a price of $50/dt, as opposed to com- housing, and recreation, the overall efficiency of a solar en ing from less expensive biomass residues, although it is pos- ergy conversion process will be a key determinant for its sible that a mixture of bioenergy crops and residues could be economic viability.
|
From page 234... ...
Thus cheaper, though less when coupled to CO2 capture and sequestration on a larger plentiful, biomass residue could supplant bioenergy crops as technical scale, this technology might be the most important feedstock. Using residue biomass would also have a much means to achieve a net reduction of atmospheric CO2 (see less significant impact on the environment than would farmChapter 6, Figures 6-9 and 6-10)
|
From page 235... ...
, with the total module output approaching 20 V The hydrogen generated from distributed natural gas.
|
From page 236... ...
Florida State University NREL Euro-CIS AstroPower Solarex ARCO Boeing 12 Kodak Boeing Boeing United AMETEK Solar Masushita United Solar Kodak Boeing 8 Monosolar AstroPower Photon Boeing RCA Solarex Energy University California University Berkeley Princeton 4 of Maine RCA RCA University RCA RCA Konstanz RCA NREL RCA 0 1975 1980 1985 1990 1995 2000 Year FIGURE G-15 Best research cell efficiencies for multijunction concentrator, thin-film, crystalline silicon, and emerging photovoltaic technologies. SOURCE: National Renewable Energy Laboratory.
|
From page 237... ...
It is hoped that one would be able Solar Cases to cast thin-film solar cells of such materials at a high speed, Hydrogen resulting in low cost. Installed Electricity Cost with Regarding production costs, all of the technologies dis Cost Cost Electrolyzer cussed so far convert solar energy into electricity and use the Case ($/kW)
|
From page 238... ...
Com- coal or natural gas plants. It implies that photoelectropared with this, the cost of hydrogen from a future central chemical devices should recover hydrogen at an energy coal plant at the dispensing station is estimated to be $1.63/ equivalent of $0.4 to $0.5/Wp.
|
From page 239... ...
when compared with electrolyte material in dye-sensitized cells (Grätzel cells) has hydrogen production from coal or natural gas plants.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.