HR: 0800h
AN: A31B-0060    [Abstracts]
TI: Reaping Environmental Benefits of a Global Hydrogen Economy: How Large, Fow Soon, and at What Risks?
AU: * Dubey, M K
EM: dubey@lanl.gov
AF: Los Alamos National Labortaory, MS D462, EES-6, LANL, Los Alamos, NM 87545 United States
AU: Horowitz, L W
EM: lwh@gfdl.noaa.gov
AF: Geophysical Fluid Dynamics Labortaory, NOAA, GFDL-NOAA, PO Box 308, Princeton, NJ 08542 United States
AU: Rahn, T A
EM: trahn@lanl.gov
AF: Los Alamos National Labortaory, MS D462, EES-6, LANL, Los Alamos, NM 87545 United States
AU: Kinnison, D E
EM: dkin@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa Road, Boulder, CO 80305 United States
AB: The Western world has taken an aggressive posture to transition to a global hydrogen economy. While numerous technical challenges need to be addressed to achieve this it is timely to examine the environmental benefits and risks of this transition. Hydrogen provides an efficient energy carrier that promises to enhance urban and regional air quality that will benefit human health. It could also reduce risks of climate change if large-scale hydrogen production by renewable or nuclear energy sources becomes viable. While it is well known that the byproduct of energy produced from hydrogen is water vapor, it is not well known that the storage and transfer of hydrogen is inevitably accompanied by measurable leakage of hydrogen. Unintended consequences of hydrogen leakage include reduction in global oxidative capacity, changes in tropospheric ozone, and increase in stratospheric water that would exacerbate halogen induced ozone losses as well as impact the earth's radiation budget and climate. We construct plausible global hydrogen energy use and leak scenarios and assess their impacts using global 3-D simulations by the Model for Ozone And Related Trace species (MOZART). The hydrogen fluxes and photochemistry in our model successfully reproduce the contemporary hydrogen cycle as observed by a network of remote global stations. Our intent is to determine environmentally tolerable leak rates and also facilitate a gradual phasing in of a hydrogen economy over the next several decades as the elimination of the use of halocarbons gradually reduces halogen induced stratospheric ozone loss rates. We stress that the leak rates in global hydrogen infrastructure and the future evolution of microbial soil sink of hydrogen that determines its current lifetime (about 2 years) are principal sources of uncertainty in our assessment.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting