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| Titel |
Jet stream wind power as a renewable energy resource: little power, big impacts |
| VerfasserIn |
L. M. Miller, F. Gans, A. Kleidon |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 2, no. 2 ; Nr. 2, no. 2 (2011-11-29), S.201-212 |
| Datensatznummer |
250000605
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| Publikation (Nr.) |
 copernicus.org/esd-2-201-2011.pdf |
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| Zusammenfassung |
| Jet streams are regions of sustained high wind speeds in the upper atmosphere
and are seen by some as a substantial renewable energy resource. However, jet
streams are nearly geostrophic flow, that is, they result from the balance
between the pressure gradient and Coriolis force in the near absence of
friction. Therefore, jet stream motion is associated with very small
generation rates of kinetic energy to maintain the high wind velocities, and
it is this generation rate that will ultimately limit the potential use of
jet streams as a renewable energy resource. Here we estimate the maximum
limit of jet stream wind power by considering extraction of kinetic energy as
a term in the free energy balance of kinetic energy that describes the
generation, depletion, and extraction of kinetic energy. We use this balance
as the basis to quantify the maximum limit of how much kinetic energy can be
extracted sustainably from the jet streams of the global atmosphere as well
as the potential climatic impacts of its use. We first use a simple thought
experiment of geostrophic flow to demonstrate why the high wind velocities of
the jet streams are not associated with a high potential for renewable energy
generation. We then use an atmospheric general circulation model to estimate
that the maximum sustainable extraction from jet streams of the global
atmosphere is about 7.5 TW. This estimate is about 200-times less than
previous estimates and is due to the fact that the common expression for
instantaneous wind power 12 ρv3 merely characterizes the
transport of kinetic energy by the flow, but not the generation rate of
kinetic energy. We also find that when maximum wind power is extracted from
the jet streams, it results in significant climatic impacts due to a
substantial increase of heat transport across the jet streams in the upper
atmosphere. This results in upper atmospheric temperature differences of
>20 °C, greater atmospheric stability, substantial reduction in
synoptic activity, and substantial differences in surface climate. We
conclude that jet stream wind power does not have the potential to become a
significant source of renewable energy. |
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