THE WIRELESS TRANSMISSION OF ELECTRICAL ENERGY
In our present electricity generation system we waste
more than half of its resources. Especially the transmission
and distribution losses are the main concern of the present
power technology. Much of this power is wasted during
transmission from power plant generators to the consumer.
The resistance of the wire used in the electrical grid
distribution system causes a loss of 26-30% of the energy
generated. This loss implies that our present system of
electrical distribution is only 70-74% efficient. We have to
think of alternate state - of - art technology to transmit and
distribute the electricity. Now- a- days global scenario has
been changed a lot and there are tremendous development in
every field. If we don't keep pace with the development of
new power technology we have to face a decreasing trend in
the development of power sector. The transmission of power
without wires may be one noble alternative for electricity
transmission
THE TECHNOLOGIES AVAILABLE
In this remarkable discovery of the "True Wireless" and
the principles upon which transmission and reception, even in
the present day systems, are based, Dr. Nikola Tesla shows us
that he is indeed the "Father of the Wireless." The most wellknown
and famous Wardenclyffe Tower (Tesla Tower) was
designed and constructed mainly for wireless transmission of
electrical power, rather than telegraphy [1]. The most popular
concept known is Tesla Theory in which it was firmly
believed that Wardenclyffe (Fig.1) would permit wireless
transmission and reception across large distances with
negligible losses [2]. In spite of this he had made numerous
experiments of high quality to validate his claim of possibility
of wireless transmission of electricity (Fig.2). But this was an
unfortunate incidence that people of that century was not in a
position to recognise his splendid work otherwise today we
may transmit electricity wirelessly and will convert our
mother earth a wonderful adobe full of electricity.
The modern ideas are dominated by microwave power
transmission (MPT, Figure 3) called Solar power satellite to
be built in high earth orbit to collect sunlight and convert that
energy into microwaves, then beamed to a very large antenna
on earth, the microwaves would be converted into
conventional electrical power.
William C. Brown, the leading authority on wireless
power transmission technology, has loaned this demonstration
unit to the Texas Space Grant Consortium to show how power
can be transferred through free space by microwaves. A block
diagram of the demonstration components is shown below.
The primary components include a microwave source, a
transmitting antenna, and a receiving rectenna.
The microwave source consists of a microwave oven
magnetron with electronics to control the output power. The
output microwave power ranges from 50 W to 200 W at 2.45
GHz. A coaxial cable connects the output of the microwave
source to a coax-to-waveguide adapter. This adapter is
connected to a waveguide ferrite circulator which protects the
microwave source from reflected power. The circulator is
connected to a tuning waveguide section to match the
waveguide impedance to the antenna input impedance.
The slotted waveguide antenna consists of 8 waveguide
sections with 8 slots on each section. These 64 slots radiate
the power uniformly through free space to the rectenna. The
slotted waveguide antenna is ideal for power transmission
because of its high aperture efficiency (> 95%) and high
power handling capability.
A rectifying antenna called a rectenna receives the
transmitted power and converts the microwave power to direct
current (DC) power. This demonstration rectenna consists of 6
rows of dipoles antennas where 8 dipoles belong to each row.
Each row is connected to a rectifying circuit which consists of
low pass filters and a rectifier. The rectifier is a Ga As
Schottky barrier diode that is impedance matched to the
dipoles by a low pass filter. The 6 rectifying diodes are
connected to light bulbs for indicating that the power is
received. The light bulbs also dissipated the received power.
This rectenna has a 25% collection and conversion efficiency,
but rectennas have been tested with greater than 90%
efficiency at 2.45 GHz[4].
The transmission of power without wires is not a theory
or a mere possibility, it is now a reality. The electrical energy
can be economically transmitted without wires to any
terrestrial distance, many researchers have established in
numerous observations, experiments and measurements,
qualitative and quantitative [5-9]. These have demonstrated
that it is practicable to distribute power from a central plant in
unlimited amounts, with a loss not exceeding a small fraction
of one per cent, in the transmission, even to the greatest
distance, twelve thousand miles - to the opposite end of the
globe. This seemingly impossible feat can now be readily
performed by electrical researchers familiar with the design
and construction of my "high-potential magnifying
transmitter," There were three popular theories present in the
literature of the late 1800's and early 1900's. They were:
1. Transmission through or along the Earth,
2. Propagation as a result of terrestrial resonances,
3. Coupling to the ionosphere using propagation through
electrified gases(Fig.4&5)
It has been proven that electrical energy can be
propagated around the world between the surface of the Earth
and the ionosphere at extreme low frequencies in what is
known as the Schumann Cavity. Knowing that a resonant
cavity can be excited and that power can be delivered to that
cavity similar to the methods used in microwave ovens for
home use, it should be possible to resonate and deliver power
via the Schumann Cavity to any point on Earth. This will
result in practical wireless transmission of electrical power.
The intent of the experiments and the laboratory Tesla
had constructed was to prove that wireless transmission of
electrical power was possible. Although Tesla was not able to
commercially market a system to transmit power around the
globe, modern scientific theory and mathematical calculations
support his contention that the wireless propagation of
electrical power is possible and a feasible alternative to the
extensive and costly grid of electrical transmission lines used
today for electrical power distribution.
Power transmission system using directional ultrasound
for power transmission includes a transmitting device and a
receiving device. The transmitting device has a set of
ultrasound transducers forming an ultrasound transducer
array, wherein the array is a set of spaced individual
transducers placed in the X-Y plane disposed to generate an
ultrasound beam in the Z direction (Fig.6) [6].
Another possibility is to use highly efficient fibre lasers
for wireless power transmission where the possibilities are
similar to microwaves concept but lasers emit energy at
frequencies much higher that microwaves.
For several years NASA, ENTECH, and UAH have been
working on various aspects of collection of the laser radiation
and conversion to electrical power for laser wireless power
transmission
III. MERITS, DEMERITS & ECONOMICS OF
WIRELESS TECHNOLOGIES
3.1. Merits
An electrical distribution system, based on this method
would eliminate the need for an inefficient, costly, and capital
intensive grid of cables, towers, and substations. The system
would reduce the cost of electrical energy used by the
consumer and rid the landscape of wires, cables, and
transmission towers.
There are areas of the world where the need for electrical
power exists, yet there is no method for delivering power.
Africa is in need of power to run pumps to tap into the vast
resources of water under the Sahara Desert. Rural areas, such
as those in China, require the electrical power necessary to
bring them into the 20th century and to equal standing with
western nations. The wireless transmission will solve many of
these problems
The electrical energy can be economically transmitted
without wires to any terrestrial distance, so there will be no
transmission and distribution loss.
More efficient energy distribution systems and sources are
needed by both developed and under developed nations. In
regards to the new systems, the market for wireless power
transmission is enormous. It has the potential to become a
multi-billion dollar per year market.
The increasing demand for electrical energy in industrial
nations is well documented. If we include the demand of third
world nations, pushed by their increasing rate of growth, we
could expect an even
Faster rise in the demand for electrical power in the near
future. These systems can only meet these requirements with
90–94 %efficient transmission [3, 8].
High Transmission Integrity and Low Loss: - To transmit
wireless power to any distance without limit. It makes no
difference what the distance is. The efficiency of the
transmission can be as high as 96 or 97 per cent, and there are
practically no losses.
3.2. Demerits
Biological Impact: - One common criticism of the Tesla
wireless power system is regarding its possible biological
effects. Calculating the circulating reactive power, it was
found that the frequency is very small and such a frequency is
very biologically compatible [3, 8].
3.3.Economic Impact
The concept looks to be costly initially. The investment
cost of Tesla Tower was $150,000 (1905). In terms of
economic theory, many countries will benefit from this
service. Only private, dispersed receiving stations will be
needed. Just like television and radio, a single resonant energy
receiver is required, which may eventually be built into
appliances, so no power cord will be necessary! Monthly
electric utility bills from old-fashioned, fossil-fuelled, lossprone
electrified wire-grid delivery services will be optional,
much like "cable TV" of today. In the 21st century, "Direct
TV" is the rage, which is an exact parallel of Tesla's "Direct
Electricity."
IV. ADDITIONAL REMARKS
Many concepts, research papers, patents are available on
wireless transmission of electricity but most research work
were carried out in isolation, so it needs a joint collaborative
efforts to get a very useful results on this advanced technology
on power transmission for the benefit of mankind globally in
future. Whatever the future may bring, the universal
application of these great principles is fully assured, though it
may be long in coming. With the opening of the first power
plant, incredulity will give way to wonderment, and this to
ingratitude, as ever before.
The world is still not able to achieve the benefit of the
God gifted potential of Dr N.Tesla. People neglected him and
his good work. He deserved much better treatment from the
tycoons of his age, than to spend the last 40 years of his life in
abject poverty. However, he was too much of a gentleman to
hold a grudge. Instead, regarding the magnifying transmitter,
Tesla wrote in his autobiography, "I am unwilling to accord to
some small-minded and jealous individuals the satisfaction of
having thwarted my efforts. These men are to me nothing
more than microbes of a nasty disease. My project was
retarded by laws of nature. The world was not prepared for it.
It was too far ahead of time. But the same laws will prevail in
the end and make it a triumphal success." [3, 8-9]. If this has had
not been happened, then today we will be in a wonder world of
plenty of power using the technology of wireless transmission of
electricity.
V. CONCLUSION
The transmission of power without wires is not a theory
or a mere possibility, it is now a reality. The electrical energy
can be economically transmitted without wires to any
terrestrial distance. Many researchers have established in
numerous observations, experiments and measurements,
qualitative and quantitative. Dr.N.Tesla is the pioneer of this
invention.
Wireless transmission of electricity have tremendous
merits like high transmission integrity and Low Loss (90 – 97
% efficient) and can be transmitted to any where in the globe
and eliminate the need for an inefficient, costly, and capital
intensive grid of cables, towers, and substations. The system
would reduce the cost of electrical energy used by the
consumer and get rid of the landscape of wires, cables, and
transmission towers. It has negligible demerits like reactive
power which was found insignificant and biologically
compatible.
It has a tremendous economic impact to human society.
Many countries will benefit from this service. Monthly
electric utility bills from old-fashioned, fossil-fuelled, lossprone
electrified wire-grid delivery services will be optional,
much like "cable TV" of today.
Christian Argenis Umaña Zambrano
Ci:17678077
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