DougS wrote:"Is reeling the answer to AWE, or is it a dead end?"
Both.

PierreB

Correction: performing universities.

PierreB

DaveS,


You failed to understand my post. I know positive feature in each thing (it is the sense of my post), so I think beside solid work from performing universities, you make fine realizations: tripod, Mothra are interesting as moving kite-art.

PierreB

For me and for some others AW(E)S seemed to be attractive:high altitude winds are more persistent and powerful; in a first simplified analysis, power/mass ratio  is better; and more wind can be harnessed. But I made the same error than others by considering AW(E)S by itself without considering its environment.

The main feature is tether vs tower. A tether is lighter than a tower. So the tether should be the solution. But, in association with the flying member, the tether is the killer.Land and space used are huge (tether as radius, add safety zone), since no obstacle, no inhabitant, no other activities can exist with required safety.  It is the same for the major part of an airport, while planes have no tethers.

So an exclusive zone of 1 km²  for AW(E)S corresponds in an exclusive zone for only the area of tower(s) of HAWT, only tens of m². I mentioned the inconvenience of space and land used in AWEC2013. The great difference between the system by itself and the system within its environment makes possible such an error of assessment.

So to make AW(E)S competitive over HAWT other features should take huge advantage. Is it the case?About efficiency? No, the contrary. About safety? No, the contrary. About maintenance? No, the contrary. About lightness? Yes concerning implementation, but maybe no using during years,by taking account of replacement of elements due to structural stresses on moving materials. Better winds?Yes but not too much since HAWT reach more altitude, and above all since farshore the gradient between high and low altitude is not high. 

Concerning un-tethered AWE, there are some interesting possibilities as dynamic soaring to provide energy for instruments aloft, and for electric motor itself (from existing applications of regenerative soaring towards eventual energetic autonomy, by alternating electric motor and generator uses). Such uses aloft of energy from dynamic soaring look natural. Others uses as transfers towards ground stations sound unnatural and are both not technically feasible and not economically viable, unless teleportation of energy is invented. 

We can found very suitable applications (see JoeF's enumerations) for Airborne Wind Systems (being able to inclure some wind turbine), but wind energy as such is not among them. What is the present and the future concerning renewables? Great development of HAWT and solar in the world while badmouthing fancies on AWES Forum. So take us realistic and suitable directions for AWS.

PierreB

Some correction in the end of my two precedent posts (sorry for doubles):

"So let us take realistic and suitable directions for AWS."

PierreB

Another correction:"Other uses as transfers towards ground stations sound unnatural..." (other, not others).

PierreB 

The wind resource for AWES over ground-hugger towered turbines is more than just persistent and faster. Shorting the resource can lead to missed opportunity. This topic thread is dedicated to describing the resource wind for AWES in contrast to the poorer resource open to ground-hugging towered turbines. 

Start: 

1. Resource is reachable with greater flexibility by use of variable-lengthed tether systems. 

2. Resource is THICKER vertically for AWES in comparison to the nearly 2D resource of towered turbines.  For AWES: 3D and very tall. But not just tall, but all of the resource from low to tall. Frequently, it seems, this asset of the resource is neglected in studies.

3. Choice: AWES may fly to current  best resource and not be fixed in option as the towered ground-hugging turbines. 

4. Distributive:  AWES may locate with much more ease than high-capital site fixation found in utility-scale towered turbines. Good resource may be reached by rope and tether tactics from remote ground stations when there is a challenge with site.

5. WIDER:   In the 3D space one AWES may have width working asset that far exceeds the poor fixed width of a working towered turbine. 

6. High faster winds for AWES is much more available to AWES than to the low-working towered turbines.  The cube of velocity gives the win here. 

7. Stability of resource faced is tunable by AWES in ways that towered turbines cannot experience:  Fly AWES to the resource characteristics wanted within the 3D resource. Towered turbines must accept the variability at its fixed relatively 2D situation. 

Others are invited to note resource assets not mentioned that AWES may face in contrast to the more limited resource being faced by towered turbines. 

~ JoeF

DaveS,

You recently wrote:"Make no mistake, the AWE we intend will kill tower farms by out-competing for the same sites and markets, from Germany to Australia."

You denigrate (I do not use your terms) existing successful wind energy, proposing replacing tower farms by http://youtu.be/uV1aRsHXLmo or by http://youtu.be/fCU7SA8K5gw . So you denigrate renewables with an irresponsible sentence matched by one "we" very careless.

PierreB 

Land use is less a problem in deserts where perhaps only the area of ground installations (near zero) can be considered (?). Here www.desertec.org/

is a long term solar project in Sahara.Wind energy is also considered. And there is a subtropical Jet Stream above north Africa.

PierreB