A study published earlier this year by researchers at MIT’s Center for Advanced Nuclear Energy Systems (CANES) concluded that producing synthetic transportation fuels from nuclear hydrogen and captured carbon dioxide would be technically viable.
Based on a reference year 2025 case, the report found that 43.1% of the CO2 projected to be emitted from coal plants could serve to produce the 6.6 billion barrels of ethanol required to displace gasoline use in the US. For the production of that much ethanol, there would need to be between 700 and 900 GWth (gigawatts thermal) of nuclear power to produce the needed hydrogen and energy for the synthesis of the fuel.
|Nuclear power requirements for transportation hydrogen. Click to enlarge. Source: General Atomics|
Estimates for the amount of nuclear power required to generate sufficient hydrogen to fuel a hydrogen fleet vary based on the efficiency of the vehicle fleet. General Atomics earlier this year estimated a required range of between 1,000 to 2,000 GWth to produce hydrogen for half of the current US fleet.
The study also concludes that replacing the entire world’s projected consumption of gasoline with 16.87 billion barrels of ethanol in 2025 would required the capture of 29.5% of the total emitted CO2 and a nuclear power requirement of between 1,800 and 2,300 GWth.
These numbers show that there is a very wide market for using nuclear power to aid in the production of alternative fuels to aid in the transition to the hydrogen economy. The large fraction of emitted CO2 that need to be captured shows that a benefit of this process would be to significantly decrease the total greenhouse gas emissions. A total cycle analysis reveals that the total reduction in CO2 emissions will be slightly more than 12%...A second benefit would be to decrease a nation’s dependence on imported petroleum.
The study also explored the production of methanol as a substitute.
Tne study incorporated a review of the literature on the use of nuclear power to produce hydrogen, as well as a review of possible nuclear reactor concepts. The researchers also concluded that nuclear power could be utilized in the production of oil from sand and shale.
Several nuclear cycles have potential application for the production of hydrogen, including High Temperature Steam Electrolysis, the Sulfur Iodine Cycle and UT-3. The report focuses on the High Temperature Steam Electrolysis option.
A number of possible new nuclear reactor concepts show potential in producing hydrogen, although many have drawbacks, according to the study.
Ultimately the report focuses on the High-Temperature Gas Cooled Reactor (HTGR), which uses helium coolant, and a modified version of the Advanced Gas Reactor (AGR) using supercritical CO2 as the coolant (S-AGR).
The reactor concepts selected for aiding production of oil from tar sands are the Advanced Candu Reactor (ACR-700), the Pebble Bed Modular Reactor (PBMR), and the Advanced Passive pressurized water reactor (AP600).
Separately, last week the Department of Energy announced that the Idaho National Laboratory (INL) will make awards valued at about $8 million to three companies to perform engineering studies and develop a pre-conceptual design to guide research on the Next Generation Nuclear Plant (NGNP).
The INL will issue a contract to Westinghouse Electric Company for the pre-conceptual design of the NGNP, and will later issue contracts to AREVA NP and General Atomics to perform complimentary engineering studies in the areas of technology and design tradeoffs, initial cost estimates and selected plant arrangements.
NGNP is a very high-temperature reactor concept capable of producing high temperature process heat suitable for the economical production of hydrogen, electricity and other energy sources. The NGNP research and development program is part of DOE’s Generation IV nuclear energy systems initiative aimed at developing next generation reactor technologies and is authorized by Congress in the Energy Policy Act of 2005.
“An Alternative to Gasoline: Synthetic Fuels from Nuclear Hydrogen and Captured CO2”; Middleton, B.D. and M.S. Kazimi; MIT-NES-TR-006, July 2006.
Nuclear Fission and Fusion (General Atomics)