Wind Matters
- This topic might become a table of wind topics.
- Upper Wind Compared to all other Renewable
Energy Sources (topic)
- Discuss what wind topics matter. Then we may form topics on those particular wind matters.
- windfinder.com/
- Terms
and teasers that might lead to wind matters important to energy kite
systems, AWES, kite sailing, and any sector of kite systems:
- wind rose
- prevailing winds
- thermals
- hemispheric winds
- winds by latitudes
- seasonal winds
- changes in wind
- upper atmospheric winds
- calm
- temperature of the air in winds
- moisture content in the air of winds
- characterizing the dependability of winds
- gustiness of winds
- sizes of winds
- wind reports
- https://www.academia.edu/6793148/wind-energy Book. Wind-energy explained. 705 pages.
- J. F. Manwell and J. G. McGowan
Department of Mechanical and Industrial Engineering, University of Massachusetts, USA
A. L. Rogers
DNV – Global Energy Concepts, Washington, USA - BTM :: Biospheric Theory and Modelling https://www.bgc-jena.mpg.de/index.php/BTM/Topics
- MPI :: Max Planck Insttitute
- Biogeochemistry wiki
- Coriolis force wiki
- ECMWF :: European Centre for Medium-Range Weather Forecasts
- KEBA :: Kinetic Energy Budget of the Atmosphere
- Mull offer: "Inasmuch
as friction brings heat, such heat may be shared to the air causing
pressure changes and updrafts; and thus wind slowed by surface friction
still brings wind. Wind slowed births wind?"
~ JpF, Sept. 2, 2020
- Corrigenda wiki
Any Current Total Estimate of Upper Wind Power?
Thank You very much, Axel, for the notes and links. This quote from [Miller, Kleidon, 2017] puts to rest the misconception that you and Lee were "anti-wind" in trying to quantify the free-energy component:
"Wind power is a renewable energy source that could meet the primary human energy demand with extensive large-scale deployment."
It is evidently Scientific Consensus that Upper Wind could "power civilization," but emerging Airborne Wind Energy technology must be applied correctly. It is taking some time for everyone involved to update understanding of AWE potentials and impacts from a decade ago; rereading old papers, reading new papers, and considering novel ideas. In AWE R&D there is increased (unpublished) discussion of major geoengineering possibilities for mitigating anthropogenic climate damage.
For example, large formations polymer kite sails might both shade-cool surface areas selectively and reflect some shortwave solar energy back to space. AWE extraction is therefore favored by day, if not by night; much as jet transport condensate-trails are cooling by day, but greenhouse warming by night (and need to be regulated so).
Ever stronger AWE interventions are possible by vast kite formations acting meteorologically as virtual mountain ranges, with rain maximums windward and rain shadows leeward. These may be best placed on the leeward side of continents to capture moisture that would otherwise overfly land-masses. Concern is advisable about wind farms creating local rain shadows.
Selective upper water-vapor reduction by kite-formations could reduce greenhouse warming. Weather systems could be sensitively steered to favor drought-stressed populations and ecosystems. Destructive cyclogenesis might be disrupted. Water could be lifted up for transport as cloud or vapor, as well as harvested for precise rainmaking.
A huge open question as to how the global wind field, in general, could be favorably modified to cancel warming effects, like damming heat flow to higher latitudes and cold flow to lower latitudes. This may involve harvesting Jet Stream meanders preferentially, maintaining shorter straighter West-East Jet flow. Harvesting Polar fronts and summer breezes would tend to dam and conserve cold in higher latitudes. Harvesting beneficial winds might be avoided.
For the pure geophysicists reading this, there are emerging AWE engineering schemes, under Technical University research, employing vast lattices of unit-kites. Fully developed, these AWES will be able to reach 10-km altitudes by the proven kite-train principle of staged lift at every altitude, just as weather kite trains routinely reached high altitude a century ago. Keep in mind that polymer-lattice AWE technology is also applicable to ocean-current geo-flow, at comparable mega-scale.
It is time for urgently expanded research into geophysical AWE factors. The 2030 timeframe is seen as both a Climate Change societal response and AWE Engineering inflection point.
Re: Any Current Total Estimate of Upper Wind Power?
I would first distinguish a resource potential for airborne wind energy between energy taken out of the atmospheric boundary layer (the lower 1-2 km of the atmosphere) from energy taken out of the free atmosphere (above 2 km). This distinction is important. In the atmospheric boundary layer, kinetic energy is dissipated due to surface friction anyway, so the impact of wind energy is comparatively small. In the free atmosphere, large-scale use of wind energy would interfere quite strongly with atmospheric dynamics, and potentially reduce the ability of the atmosphere to generate kinetic energy (as we showed in the jet stream paper in 2011). I think doing the latter is not a good idea.
At the large-scale, the 1000 TW generation rate of kinetic energy we estimated earlier still holds up. They essentially reflect the maximum generation rate of kinetic energy that the atmosphere can accomplish (from thermodynamics), which yield a large-scale mean value of 2 W m^-2 per surface area (although with large regional variations), and which is dissipated mostly in the boundary layer due to friction. Yes, I agree that there is a component, mostly from the Hadley circulation, that is driven by convection and that adds to the mean kinetic energy, which can explain why ECMWF-based estimates of atmospheric energetics are somewhat larger (this contribution seems comparatively small though, given that ECMWF-based estimates are within 2.1 - 2.5 W m^-2). However, you cannot use all of it as renewable energy, but at best 26% at large scales, because you cannot avoid frictional losses when kinetic energy is being transported. This is the number we obtained earlier, also in 2011, and since then we confirmed this in further simulations (e.g., here: https://www.pnas.org/content/1
So if you talk airborne wind energy within the lower 2 km, then I think this could achieve a higher efficiency than surface-based wind power, and get close to the 26% of the 2 W m^-2 (In light of this, the 10 TW you aim for are no longer so small anymore). This is because some of the kinetic energy brought down from the free atmosphere is already dissipated above surface-based wind farms, so by being airborne and reaching higher, you may be able to tap into this dissipative loss and divert some of it into yield.
At smaller scales, you may get, of course, higher yields. But that the turbine yield declines with wind energy use at larger scales seems unavoidable - we just had a paper accepted which explains why (basic energetics) and can estimate this effect quantitatively quite well (https://gmd.copernicus.org/pr
I would think that the same reduction effects would apply to airborne wind energy, although airborne may be more flexible in distributing or adjusting to this effect by greater spatial spread.
I hope this helps.
Best,
Axel
Re: Any Current Total Estimate of Upper Wind Power?
Two interesting points:
1) It's not just Solar Radiation that creates thermodynamic Wind Power, but solar absorption's vertical convection exciting interaction with Coriolis Force, effectively extracting half of Wind Power from planetary rotation, as the Geostrophic Balance.
2) Available Jet Stream Power may not be as grim as predicted if the Jet Streams do not completely "steer" air masses, as popularly supposed, but are in fact back-steered by them as well, in a balance of forces. If so, climate effects of tapping them may be less than feared.
Seeing ~1000 TW offered as a Max Planck Institute's Biospheric Theory and Modelling's biogeochemistry wind power estimate seen noted on the graphic copied below, suggesting that 10TW of extraction might be almost negligible in negative impacts if done right.
Click image for large size:
Re: Ken's post of Aug. 31.
Looking forward to reading those two papers!
Ken's summarized thesis seems like a reiteration of basic aerodynamic balance-of-forces, of kinetic and potential energy. Basically,
what is being said is expected by Navier Stokes dynamics; that both
kinetic and potential windfield energy work in dynamic balance, much
like a pendulum. A wing or wind-farm is an added damping factor.
The
kinetic energy of wind impinging on a wing or a wind farm creates a low
pressure shadow, which creates a standing energy potential "well" in
the wind field, whereby surrounding higher pressure would indeed seek
to flow into low pressure, toward equilibrium, in a static case. There
is also a standing high pressure field upwind of a wing or farm, that
does not dissipate, also maintained. These pressure wells divert
kinetic flow around themselves. High and low pressure is roughly in
equilibrium overall, in sustained structure-windfield interaction. The
shed wake vortices are kinetic-potential energy cells too. Kinetic flow is pulled along with gradient infill flow, that together create a turbulent trailing wake.
AWE
The only new thing we have with wind energy is two papers almost in press on basic physics of wind energy.
---
Many people have thought that the kinetic energy removed by wind turbines at the scale of very large wind farms was replaced by transport of kinetic energy from the surrounding winds.
We show that the replenishing force is mostly the large-scale pressure field.
WInds are normally geostrophic, with coriolis forces balancing pressure gradient forces.
In the presence of drag, winds slow and the coriolis force diminishes, no longer balancing the pressure gradient force.
Therefore, the pressure gradient force accelerates the air mass.
At regional scale, the energy extracted by wind turbines is replenished primarily by the available potential energy associated with the large-scale pressure field, and not primarily by local transport from surrounding regions.
Ken Caldeira
Senior Scientist (Emeritus)
Carnegie Institution for Science
Dept of Global Ecology
Any Current Total Estimate of Upper Wind Power?
Hi Lee, Alex,
Recall
your 2011 finding that Jet Stream wind power could only be a marginal
resource. Since then you further caution that Surface Wind is more
limited in potential than hoped. That still leaves around 10km vertical
extent of Upper Winds distributed far broader horizontally than Jet
Streams and Surface Wind-sites.
Do
you have any rough estimation, a lower-limit, of how much
sustainably-extractable Upper Wind Power there is, disregarding Jet
Stream, Surface Wind, and undue local impacts? In
Airborne Wind Energy research (AWE), we estimate 10TW of sustainable
extraction would make a critical difference for civilization and
countering climate-change.
You
both have been unfairly cast as "anti-wind" (and anti-AWE), even touted
by rabid anti-wind (pro-coal, pro-nuke) cranks. It would be nice to
know if you think AWE can reasonably hope for its 10TW identified
demand. We understand the severe local shadowing impacts possible, but
also vast low-impact scenarios, and potentially positive geoengineering
interventions.
Thanks for any rough number of how few TW you conservatively consider available for AWE, as a whole; a key number for the world.
AWE technology is relentlessly advancing, and Germany continues to lead
technical progress. There are serious GW-scale polymer-lattice AWE
concepts taking shape at a German technical university, with MPI
affiliation. More information available.
Best,
Dave Santos
Austin
Joe Faust
Los Angeles
kPower
Global Wind Atlas
Discover your own wind paradise!
One of the best wind prospecting tools yet, here is the world's fine-grained averaged wind data in one place, previously scattered across partial regional maps. Still missing is seasonal wind rose data at every point, the last major wind atlas data frontier.
NASA CO2 Video as terrific Wind Power Visualization
Once again, the suggestion that perhaps AWE should perhaps migrate between North and South Hemispheres, in opposed-cycle to bird migration. Winter and and upper latitudes favored. CO2 strongly surface-based, so lower winds most prominent in this animation: