It is
estimated that in the wind there is a quantity of energy equal to
hundred times
the total human energy requirement.
Until now the
use of windmills has allowed us to exploit a very small part of this
energy,
the one finding in the area from 20 to 150 meters in height.
The
development of the high altitude wind (where you can find the biggest
quantity
of wind energy) seems to be very late insomuch as today there are no
operative
systems yet.
The
importance of this resource, that can become very shortly one of the
main power
sources, seems to be ignored from the European Union which denies its
existence
a priori without considering it in the research calls for the renewable
energies.
For a better
and more detailed knowledge of this sector we list below:
- historical
references
- last
innovations
- main
projects
- problems for the development of the altitude wind energy
Last innovations
The rotary Wing
In 1930 the first flight trials
of a
system with rotary wings from Telefunken were carried out. The system
was studied
with the purpose of producing electrical energy exploiting the altitude
wind.
Once reached 700 meters in height the trial failed because of the build
up of
electrostatic charges on the interconnection electrical cable.
An innovative and simple
mechanical way
of transmitting the energy, which is generated at altitude by using new
types
of fibre cables as showed here follows in the Heli Wind Power project,
allows
overcoming the obstacles previously met.
Light profiles
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The most important projects
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SkySails
The SAIL POWER project that enables the
traction of vessels thanks to a sail at altitude represents the highest
level
of industrialisation that has been reached in the studies for the
applications
for kite as possible means for producing energy. In the website http://www.skysails.info you can find a wide
documentation of the project and you can see a
documentary film of the realised applications that show beyond doubt
the big
interest in examining the research of the possibilities of taking
advantage of
the altitude wind. The extreme manoeuvrability of kites and their
profile with characteristics similar to the ones of the wing of an
aircraft
enables a quick movement and a following catching of energy that is not
linked
to the dimension of the kite but to the area where it realises its
performances. Kite Wind Generator
Different projects generating
energy for
traction (as the one of http://www.physorg.com/news137388314.htm Then there is the Kite Gen
project for big
powers shown in the next picture. Many Kites alternate phases of
traction on
the arms of a big rotor with recovery phases that allow recovering the
position
of the beginning of the cycle in the same way as sailboats can sail
directly
into the wind. RotoKite
 The
Rotokite is
an innovative project which was developed by a group of Engineers from It uses
aerodynamic profiles similar
to the ones of kites. These profiles have been rotated on their own
axis for
emulating the performances of a big propeller at altitude. The
use of the
rotation principle simplifies radically the difficult problem of the
flight control
and eliminates the technical difficulties due to the lengths of cables
enabling
the production of wind energy at very low costs. Operation video of the RotoKite Operation description in a pdf file The Magenn's project
While the projects presented up
to now use a
part of the energy for the levitation, the company Magenn, specialised
in the
construction of modern aerostatic balloons, has realised a prototype
that uses
light gas for the levitation. See the website The rotation of the central
body generates lift
and powers electric generators that are installed to the sides. The
produced
energy is transmitted to the ground through an electric cable. The
forecast is
to realise a system of generation with variable powers from 10 to 1000
kw in
the period 2009/16. Laddermill A project of Prof. Okels and
f students from
the You can see a film on Youtube
at the
address: http://it.youtube.com/watch?v=Si5lVNiKsz4 Flying Electric Generator
The Austrialian Professor Bryan Roberts has realised a
prototype of wind
generator that has been called Flying Electric Generator (FEG). In this
project
the previously mentioned generation principle from Telefunken has been
taken
back. The project of
Prof. Roberts Bryan
was given a prize from Time as TIME’S BEST INVENTIONS OF 2008 The project and all problems
concerning the energy
generation at altitude are well recorded on the website http://www.skywindpower.com/ww/index.htm The weight of the structure of
catching and
transformation of the energy foresees the use in the areas with strong
wind or
at high altitude. You can see the flight of the
first prototype
on Youtube at the address: http://it.youtube.com/watch?v=gExAQq2VzgQ The Heli Wind Power
The project regards from one side the
lightening of rotors by using tie-rods and from the other side the
mechanical
transmission to the ground of the energy which has been generated at
altitude. The recent innovations
regarding the field of
fibres have permitted to think about a very light closed cable that
operating
with an innovative system of interconnected pulleys allows the
realisation of a
very light power transmission at long distances (the missing link of
the wind
energy). You can see a summary of the
project
opening the below file:
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Problems
of
development of the upper wind
- A problem:
the
patents
It can be strange but the
patents
are, in our opinion, the main reason the altitude wind energy has been
not developed
yet.
The several projects concerning
the
use of the kites or other enough intuitive techniques with the aim of
generating energy have given place to the recording of hundreds of
patents,
sometimes very general ones but in any case sufficient to permit an
action
against companies that will invest money for checking the real
development
possibilities.
In this way the sector is
suffering
from a background that is completely hostile to the research and the
testing
because each essay can be affected by a legal action.
The resulting failure of important initiatives of research has given birth to a general scepticism regarding the actual possibilities of the wind generation at altitude without taking into account the technical data and the studies that on the contrary demonstrate the real application possibilities.
- A
lack: the
attention and the financing of the research for the altitude wind
It is clear that
The European Union, even if
paladin
of the renewable energies, for the wind research finances only the
development
of what was invented 4500 years ago. We fear that, without any
promotion from
the outside, it will be necessary long time to take into consideration
what was
thought in an authoritative way in 1930 and in more recent times.
This site aims to be an invitation for the European Union to think rapidly about the choices taken up today as far as the financing of research is concerned.
- A false problem: the flight
areas
When a project of generation at
altitude
is presented, the most frequent objection is that this system can be a
danger
for the flight.
Today all aircrafts are
equipped
with satellite positioning systems so this means that the delimitation
of wind
areas or even individual facilities, provided they are properly marked,
does
not represent a danger for the Air Navigation.
Today there are several areas
that
are interdicted to the flight and, as explained in the Sky Wind Power
project,
the presence of aerostatic balloons in the borders
- A simple calculation: the
efficiency of the systems
The altitude wind blows with
stronger intensity and continuity compared to the wind on the ground
and even
the simple observation of the clouds gives evidence of this.
By rising at an altitude of
400/800
meters it is easy to have winds with an intensity that is double
compared with
those that can be found with a traditional wind generator operating at
an
average height of 70 meters. By doubling the speed of the wind, the
energy will
increase with the cube, i.e. eight times.
Furthermore, at altitude, the
time
for having winds suitable for the energy generation increases. So, it
is
realistic to foresee at least a doubling of working hours.
We can say approximately that
at
middle altitudes there is energy equal to at least 16 times the one you
can
have in a site that is already suitable to the wind generation.
It is clear that, even a less efficiency of wing profiles of the generation systems at altitude, will not be significant, considering the very big increase of available energy.
- A big exemplification: the
support
facilities
The catching of the altitude
wind
does not need the realisation of support facilities because all
assumptions
that have been done so far just determine traction between the link
point to
the ground or on a vessel and the aerodynamic element at high altitude.
The
windmills need towers of almost 100 metres in height with significant
problems
for the foundations and for the structures that are highly stressed.
What above mentioned does not only determine big cost reductions but especially permits to place easily the generators for example on small floating platforms or even in deep waters where it is difficult to intervene with other technologies.
- The environmental impact
The space that is occupied on
the
ground is extremely reduced compared with the majority of other systems
and
does not present any problems of acoustic pollution that are common in
strongly
populated areas.
Furthermore, the possibility of
placing the systems of generation at relatively high altitudes can
strongly
reduce the visual impact.
Even if for the moment we can
not do
sure estimations on the climatic impact that will be produced from the
altitude
wind, we think that it causes less problems than the impact produced
from the windmills
that generate a mixing of the atmospheric stratification next to the
ground.
- Looking at the sky: the
ubiquity
Looking at the map of winds
that
blow in
http://www.windpower.org/en/tour/wres/euromap.htm
If we increase the altitude,
the
situation changes completely. And, adding the possibility to operate in
the
sea, the majority of the earth surface appears suitable for the
exploiting of
the wind energy.
http://farm3.static.flickr.com/2356/1601661229_60b6c9ce4b.jpg
- Costs
The wind generation on the
ground in
the winding sites of the North Sea has an estimated cost of 0,06 euro
cents
each Kw, for sure the lowest cost, without taking into account the
hydroelectric one as far as the renewable energies are concerned. It is
estimated a cost less than 0,01 euro each Kw for the systems at high
altitudes
that are simpler as far as facilities and operation are concerned.
In a period of rapid
technological
growth the low costs for the building of the plant and the
following rapid
amortisation of the systems of altitude wind energy generation permit
them to
be replaced with new technologies without any losses.
The low investment capital in the new installations makes this energy source necessary to avoid that the developing countries use highly polluting systems.
- Ideas for the development
There are many systems for the
production of energy that can be developed but the generation at high
altitudes, despite the exceptional potentialities, seems to be a system
with fewer
resources for the research and with fewer expectations without any
reasons.
The most important obstacles,
as
already explained, are the privatisation of the research, the concerns
for the
occupation of the airspace.
The realisation of a valid
demonstrative project of wind generation could give birth to
perspectives that
are unimaginable today.
A big technological
competition,
recalling the great technological challenges of the last century with
the
participation of hundreds of researchers and universities, would be
less spectacular
than the American Cup but less expensive and infinitely more useful.
- Contacts
For additional information send an email to: gianni.vergnano _at_ sequoia.it
