This document discusses satellite-based solar power using wireless power transmission (witricity). It proposes collecting solar power from satellites in space and transmitting it to Earth using microwave beams. Key points covered include the basic principles of the technology, a brief history of its development, orbital considerations, solar cell and wireless power transmission designs, advantages like high efficiency and availability, and challenges like high costs. The conclusion discusses its potential as a clean energy source but that initial studies show it is not yet competitive with current technologies.

1. A SEMINAR ON
SATELLITE BASED SOLAR POWER USING
WITRICITY
By,
SHIYABUDDIN GK
S sahyadri college mangalore 4sf11m110
INSTA : @shiyabuddin_gk
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2. CONTENTS
INTRODUCTION
SATELLITE BASED SOLAR POWER- A BASIC PRINCIPLE
A BRIEF HISTORY
SELECTION OF ORBITALS
SOLAR CELL STRUCTURE
WITRICITY
MICROWAVE TRANSMISSION
ADVANTAGES & DISADVANTAGES
CONCLUSION
REFERENCES
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3. INTRODUCTION
 The world population has reached over 7 billion .there is a acute
shortage of power to meet the world energy requirements.
 SOLAR power is the largest source of renewable source 20 TW of
power which possibly can meet the future power hunger up to
certain extent.
 SATELLITE BASED SOLAR POWER is one of the promising way
of obtaining solar power from sky.
 By using advanced technology called WITRICITY, power
transmission could be done without transmission lines.
 No transmission lines means no transmission losses, efficiency will
be very high and running cost will be very low.
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4. SATELLITE BASED SOLAR POWER – A BASIC PRINCIPLE
 Solar Power from Space is a proposed concept to place a gigantic
solar power station in space orbiting around the earth.
 It uses microwave transmission beam to direct the power obtained
from the solar panels.
 The satellites that are being used to capture the solar radiations are
placed at geo-synchronous orbit around the earth.
 In order to place the satellites in the orbit it requires a special launching
vehicles which should carry 25% extra pay load than conventional one.
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5. Concept of SBSP 5

6. Pictorial view of Satellite based solar power 6
Modular sandwich type SBSP

7. A BRIEF HISTORY
 The concept was first proposed by Peter Glaser in 1968,showed
that the solar radiation is intense in outer space which could be
harnessed efficiently to obtain power.
 IN 1973 he got a patent from US and the idea was taken over by
ERDA/NASA for further investigations in solar power.
 3-years later SPS concept development and evaluation program,
one costing $12 million and one $19 million was undertaken by US
Govt. in 1978-1981.
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8. solar radiation dispersion and absorption over Earth 8
Why satellite power ?

9. Selection of orbital
 Placement of satellites should satisfy two conditions,
 the solar energy collection system (SECS) must point at the sun.
 the microwave power transmission system (MPTS) must point at
the ground station.
 The launch vehicle supposed to carry 25% heavier payload
compared to normal lift-offs.
 Similarly, requirements for large amounts of propellants (oxygen,
hydrogen, argon) are required more than 100 of hydrocarbon
propellants are used.
 NASA selected 3 different types of vehicles to carry out the
operation in the outer sky called HLLV.(heavy lift launch vehicles)
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10. SOLAR CELL STRUCTURE
 Normal solar PV cells cannot be used as the temperature conditions
at which they are used are very high.
 No cooling system is possible as there is no coolant medium exists in
outer sky.
 A special type semi transparent PV Gallium aluminium-arsenaide
cells are used called Metal-Metal junction cavity solar cell which has
very high thermal resistivity and electrical conductivity.
 The sun rays falling over the mirror is reflected from both primary and
secondary mirror and concentrated over the solar panel. There by
increasing the concentration ratio.
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11. WITRICITY
 Once the DC power is generated using solar panels it needs to be
transmitted to earth. For which Witricity technology is used.
 In 1899, Sir Nikola Tesla Proposed a method of Wireless Power
Transmission.
 It uses the electromagnetic induction,
electric resonance Principle to transmit
Electricity without wires.
 When both equipments are at same
frequency resonance occurs by which Sir Nikola Tesla
resonant frequency coupling could be
Achieved. There by transmitting of power between two could be
achieved without wires.
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12. 1.Primary supply
2.Source torroid coil
3.Electromagnetic beam
4.Receiving end torroid coil
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13. Applications of Witricity. 13

14. MICROWAVE TRANSMISSION
 The transmission system involves 2 antennas called SPACETENNA
& RECTENNA .
 The SPACETENNA is constructed as a phased-array antenna,
which is a large number of dipoles attached to the same flat
surface.
 The frequency and strength of microwave is around 2.5GHz or
5.8Ghz (International accepted standard) and radiates back to
earth. It is purely dependent on the input voltage.
 The bandwidth of beam is quite narrow since an essentially
monochromatic wave is used without modulation.
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15. RECTENNA
 On land we have got a receiving antenna called RECTANNA circular
mode which spreads over 1.6-2km in diameter .total area required may
be around 5 to 6 sq.km.
 The appear like heliostats with antennas at its focal point. By using
power electronic devices the power frequency from 2.5Ghz to 50hz
can be converted.
 By using inverter technology DC power could be converted to AC
 For the construction of rectenna the area should be flat and free from
obstacles.
 The cost of 5 GW rectenna is around $. 0.6/ft 2
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16. PROPOSED RECTANNA
DESIGN
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17. Microwave generation & transmission sequence
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18. ADVANTAGES
 Most promising & highly efficient solar power technology converts about
89% off solar energy to electricity.
 There is no rain, clouds in space, so the collecting surfaces could receive
much more intense sunlight, unobstructed by weather.
 A satellite could be illuminated over 99% of the time, 24hrs a day and be in
Earth's shadow on only 75 minutes per night at the spring and fall
equinoxes.
 Higher collection rate: collection in orbit is approximately 144% of the
maximum attainable on Earth's surface.
 Elimination of plant and wildlife interference
 A collecting satellite could possibly direct power on demand to different
surface locations based on geographical base load or peak load power
needs with pin point precision. 18

19. DISADVANTAGES
 Requires very high capital cost for each expedition to outer sky.
 Design of launch vehicles is very difficult which is supposed to carry
25% heavy payloads than normal one.
 Space debris are a major hazard to satellites .solar panels are
easily damaged by these stray objects.
 Difficult to select place in GEO as it is filled with other satellites.
 High frequency microwave affects telecommunication systems.
 If it falls to wrong hands it could be used as military weapon of mass
destruction
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20. CONCLUSION
 The space-based power can provide the necessary new source of
clean energy for earth in the next century to loosen our dependence on
fossil fuels. It can easily meet the power requirements for the future
generation.
 Efficient use of microwaves and solar conversion technology can
accommodate more power and loss less transmission.
 No air ,noise, land pollution makes it an efficient green source of
energy.
 Initial studies and technology demonstrations have shown that space-
based energy supplies are technologically feasible but not competitive
yet with current state-of-art technologies.
 R&D works are on progress the first flight is scheduled in the year 2025
A D with 5GW capacity.
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21. REFERENCES
 W.C. Brown, "The history of power transmission by radio waves," IEEE
 Trans .Microwave Theory Techno., vol. 32, no. 9, pp. 1230-1242, Sept. 1984.
 Advanced Concepts Office, NASA Headquarters, and Advanced Space Analysis Office, NASA
LeRC, "Space solar power, an advanced concepts study project" in Proceedings of SSP
Technical Interchange Meeting, Washington D.C., Sept. 19-20, 1995.
 L.Summerer, “Solar power satellites” proceeded by ESA-ESTAC, Advanced concepts team,
Leopold.summerer@esa.int. Jan 1979.UK
 DOE/NASA, “Satellite power system concept development and evaluation program”, HCP/ R-
4024-05, US. Department of Energy Office of Energy Research Satellite Power System
Project Office Washington, D.C. 20545
 William C. Brown, Raytheon Company Waltham, Massachusetts 02254, 6 June 1981, “The
solar power satellite as a source of base load electrical power”. IEEE transactions on power
apparatus and systems, vol. pas-100,
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22.  http://www.treehugger.com/solar-technology/japans-moonshot-21-
billion-invested-in-space-based-solar-power.html
 http://www.nss.org/settlement/ssp/library/index.html
 http://en.wikipedia.org/wiki/Space-based_solar_power
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