MANAGEMENT AND OPTIMIZATION OF SOLAR POWER CONVERSION TO SUPPLEMENT

TERRESTRIAL POWER SYSTEMS.

BY

Dr. P.S. Tiwari,Group Director & Faculty Mentor,TIT Group of Institutions, Bhopal.

& S.R. Awasthi, Consultant, CECL, Bhopal

CONVENTIONAL RESOURCES

• FOSSIL FUELS

• HYDRO RESOURCES

• NUCLEAR RESOURCES USING FISSION

ENVIRONMENTAL ASPECTS OF ENERGY

• TRADE-OFF BETWEEN ENERGY AND ENVIRONMENT

• ECOLOGICAL UNBALANCE

• GLOBAL WARMING

• RADIATION HAZARDS

NON-CONVENTIONAL RESOURCES

• SOLAR ENERGY• WIND ENERGY• BIOMASS ENERGY• OCEAN WAVE ENERGY• OCEAN THERMAL ENERGY CONVERSION• GEOTHERMAL ENERGY• OCEAN TIDAL ENERGY

AND• NUCLEAR FUSION

LIMITATIONS OF SOLAR ELECTRIC POWER GENERATION INSTALLATIONS ON EARTH

• Effects of day/night cycles

• Shadowing due to clouds, fog, snow, precipitation etc.

• Weather effects

• Reduced solar-radiation intensity

• Overall variable and discontinuous power output

LIMITATIONS OF SOLAR ELECTRIC POWER GENERATION INSTALLATIONS ON EARTH

Contd….

HENCE:

SOLAR POWER SATELLITE CONCEIVED

SALIENT ADVANTAGES OF SPS

• More intense (about eight times on average) solar radiation available

• Unaffected by weather, clouds etc.• SPS illuminated almost all the time (except

eclipse periods). Hence expensive storage not required

• Lack of gravity simplifies structure • Waste heat re-radiated back into space,

instead of warming the biosphere.

SOLAR TO ELECTRIC CONVERSION

• THERMAL ELECTRIC CONVERSION

• SOLAR DYNAMIC CONVERSION

• DIRECT CONVERSION THROUGH PHOTOVOLTAICS

SOLAR TO ELECTRIC CONVERSION

Contd….

POINTS FOR CHOICE:

• Energy conversion efficiency

• Cost effectiveness

• Material and system transportation convenience

• Technology status

• Specific feasibility problems

MAIN PARAMETERS FOR CONSIDERATION OF PHOTOVOLTAIC POWER GENERATION ON SPS

• Energy conversion efficiency

• Life-expectancy

• Tolerance to space-radiation environment

• Power-production capacity per unit area

• Production cost including material cost and processing cost

MAIN PARAMETERS FOR CONSIDERATION OF PHOTOVOLTAIC POWER GENERATION ON SPS

Contd…..

• Amenability to mass production

• Consideration for optimized mass

• Overall bulk and portability

BRIEF HISTORICAL MILESTONES

• 1899-1900 NIKOLA TESLA Proposed use of radio waves power transmission

• 1930’s Use of microwaves proposed for power transmission

• 1945Clarke putforth the concept of geo-stationary satellite in Science-fiction

• 1962Satellite communication begins with Telstar I first rectenna build

BRIEF HISTORICAL MILE-STONES

Contd….

•1963 First rectenna built•1964 W.C. BROWN succeeded in microwave powered helicopter using 2.45 GHz.•1964 IEEE Conference on Energy Sources organized session on Microwave Power Transmission•1965-66 Commercial Satellite Communication Service

Introduced•1968 PETER GLASER proposed Solar Power

Satellites•1973-74 Glaser was granted a patent for possible microwave power transmission from SPS to earth

BRIEF HISTORICAL MILE-STONES

(Contd….)

• 197584% efficient microwave to DC conversion demonstrated

• 1983US Patent for a system for power transmission from SPS & direct conversion to 60 Hz, 3-Phase

• 1999-2000 SPS Exploratory Concept examined by NASA

BRIEF HISTORICAL MILE-STONES

• 2001-2002 Technology Maturation program for SPS pursued by NASA

• 2004A Report on possible design of SPS prepared by NASA

• 2007-2010 many nations in the world considering such projects. Japan announced plans to have its first SPS in operation by 2040.

POSSIBLE TRANSMISSION TECHNIQUES

• MICROWAVES

• LASER BEAMS

METHODOLOGY OF TRANSMISSION AND UTILIZATION

• DIRECT TRANSMISSION (OF MICROWAVE POWER) TO HOMES BY SMALLER ANTENNA FEEDING TO UTILITY SYSTEM/EQUIPMENT

• TRANSMISSION TO LARGE CENTRAL EARTH STATION & FEEDING TO TERRESTRIAL POWER SYSTEM (POWER GRID)

MAIN SUBSYSTEMS OF SOLAR POWER SATELLITE

• SOLAR POWER COLLECTOR AND SUB-TRACKER SUB-SYSTEM

• POWER CONVERSION SUB-SYSTEM• POWER TRANSMISSION SUB-SYSTEM• TELEMETRY, TRACKING & COMMAND SUB-

SYSTEM• ANTENNA SUB-SYSTEM• PROPULSION & ATTITUDE STABILIZATION

SUB-SYSTEM

SOLAR POWER SATTELLITE LOCATION OPTIONS

• GEO-SYNCHRONUS-STATIONARY ORBIT (3600 KM FROM EARCH)

• MEDIUM EARTH ORBIT (MEO: AROUND 10000 KM)

• LOW EARCH ORBIT (LEO: AROUND 800-1000 KM)

• HIGH ALTITUDE PLATFORM (HAP: LESS THAN 100 KM)

MICROWAVE VACUUM DEVICESV/S SOLID STATE DEVICES

VACUUM DEVICES – High Power

Capability– Higher Frequency

Capability– Large Bulk & High

Cost– Devices Level

Integration Difficulty

SOLID STATE DEVICES• Performance Superiority• Lower Voltage

Requirement• Small size and Rugged• Compatible with MIC• Flexibility in Circuit

Configurations• Easy portability• Robustness

POWER COMBINING OPTIONS

• DEVICE LEVEL

• CIRCUIT LEVEL

• SYSTEM LEVEL

POWER COMBINING OPTIONS

Contd….

CHOICE GOVERNED BY

• EFFICIENCY

• BAND WIDTH/SPECTRAL PURITY

• ISOLATION

• HIGHER ORDER MODES

• COMBINER LOSSES

• COMPLEXITIES

IMPORTANT ANTENNA PARAMETERS

• Far Field

• Directivity and its controllability

• Efficiency

• Gain

• Impedance

• Bandwidth

• Beam width and spread

IMPORTANT ANTENNA PARAMTERS

Contd…..

• Steerability

• Beams multiplicity

• Polarization

• Size

• Complexity

SOME TYPICAL ENVISAGED DATA

• FOR ABOUT 5 TO 10 GW OF GENERATED POWER

• Solar Collectors 50 To 150 Sq.Km. depending on quality of PV Cells and sun-trackers design

• Satellite Transmitting Antenna Size Between 1 and 1.5 Km. diameter

• Ground Rectenna around 14 Km. by 10 Km

SOME TYPICAL ENVISAGED DATA

(Contd…..)

• ACCORDING TO SUNSAT ENERGY COUNCIL (AFFILIATED TO UNO), THE MICROWAVE BEAM WOULD BE SO LOW IN DENSITY THAT PERSONS CAN WALK THROUGH IT; SAFE FOR AEROPLANES, BIRDS ETC.

SOME TYPICAL ENVISAGED DATA

(Contd…..).

• ACCORDING TO A PHYSICIST AND VISIONARY GERARD O’ NEILL, (1992) OVER 99% OF MATERIAL FOR SPS CAN BE OBTAINED FROM LUNAR MATERIALS AND REDUCE THE COST OF SPS CONSTRUCTION BY 97%.

CHALLENGES IN IMPLEMENTATION

• CROWDING OF GEOSTATIONARY ORBIT

• LIMITS OF REDUCED ANGULAR SEPARATION

• ALIGNMENT AND HAND OVER PROBLEMS WITH MEO AND LEO

• SATELLITE DIMENSIONS

• NEEDS LARGE SPACE STATION

CHALLENGES IN IMPLEMENTATION

(Contd….)• SOLAR SAILS DIMENSIONS• SATELLITE ECLIPSES• ANTENNA SIZE • FOLDING/UNFOLDING TECHNIQUES FOR

ANTENNA & SOLAR SAILS• EFFICIENT CONVERSION OF D.C. POWER

TO MICROWAVE POWER• OPTIMIZING SOLAR CELLS POWER

OUTPUT UNDER HARSH SPACE ENVIRONMENT.

CHALLENGES IN IMPLEMENTATION

(Contd….)

• ACTIVE & PASSIVE DEVICES OF HUGE POWER CAPABILITY

• EFFECTS OF FREE SPACE ATTENUATION AND OTHER LOSSES ON TRANSMISSION EFFICIENCY AND COMPENSATION TECHNIQUES

• MICROWAVE INTERFERENCE TO TERRESTRIAL SYSETMS

CHALLENGES IN IMPLEMENTATION

(Contd…..)

• EXPLORING TECHNIQUES FOR DIRECT CONVERSION OF MICROWAVE ENERGY TO 50 HZ 3-PHASE SUPPLY

• ECONOMIC FEASIBILITY• TECHNOLOGICAL FEASIBILITY • RADIATION HAZARDS & SAFETY

CONSIDERATIONS• EFFECTS ON SURROUNDINGS/ENVIRONMENT • SOCIAL & POLITICAL CONSIDERATIONS.

SPECIAL FEATURES OF SPACE ENVIRONMENT FOR DESIGN AND DEPLOYMENT OF SOLAR CELLS

• MULTIPLE RADIATIONS MAY DAMAGE THE SOLAR CELLS. DAMAGE BY HIGH ENERGY ELECTRONS AND PROTONS IS SERIOUS IN MEOs PASSING THROUGH VAN ALLEN’S BANDS. NEIGHBOURHOOD OF DIFFERRENT PLANETS AFFECTS DIFFERENTLY: e.g., NEIGHBOURHOOD OF JUPITER PROVIDES HIGH RADIATION ENVIRONMENT.

SPECIAL FEATURES OF SPACE ENVIRONMNET FOR DESIGN AND DEPLOYMENT OF SOLAR CELLS

(Contd…)

• SUNLIGHT IN SPACE, UNFILTERED BY EARTH’S ATMOSPHERE HAS A DIFFERENT SPECTRUM, NEEDING DIFFERENT SOLAR CELL DESIGN AND MATERIALS

• SATTELITES IN HIGH EARTH ORBITS EXPERIENCE DRAMATIC CHANGES IN TEMPERATURE LEADING TO EXTREME THERMAL STRESSES AND IN TURN BIG POWER SURGES

SPECIAL FEATURES OF SPACE ENVIRONMENT FOR DESIGN AND DEPLOYMENT OF SOLAR CELLS

(Contd…)

• MATERIAL PROPERTIES UNDER TYPICAL SPACE ENVIRONMENT NEED SPECIAL PROVISIONS FOR CONSISTENT PERFORMANCE AND RELIABILITY.

PROSPECTIVE CONTRIVANCES FOR FURTHER EXPLORATIONS

• USE OF LEO/MEO• HIGH ALTITUDE PLATFORMS• META-MATERIALS FOR ANTENNAS• SUPER-DIRECTIVE FEATURES FOR

ANTENNAS• USE OF NANO-TECHNOLOGY FOR MORE

EFFICIENT PV CELLS

PROSPECTIVE CONTRIVANCES FOR FURTHER EXPLORATIONS

(Contd….)• NEWER LAUNCHING TECHNOLOGIES LIKE SPACE

ELEVATORS• REPLENISHMENT TECHNOLOGY FOR SPS IN

ORBIT• USE OF LUNAR MATERIALS BY

TRANSPORTATION FROM MOON TO SPS

• EFFICIENT DIRECT TECHNIQUES FOR CONVERSION OF MICROWAVE POWER TO COMMERCIAL FREQUENCY POWER.

EPILOGUE• SUCCESSFUL IMPLEMENTATION OF SUCH A

SCHEME IS STILL INDISTINCT• FURTHER RESEARCH AND EXPERIMENTATION

REQUIRED FOR ANY REALISATION• APPEARS TO BE A PROMISING TECHNIQUE• MANY NATIONS HAVE ASSIGNED AND STARTED

EXPERIMENTAL PROJECTS• IT IS WISHED THAT INDIA SHOULD ALSO

INITIATE WORK IN THIS DIRECTION• SPS COULD BE A SOLUTION FOR A COUPLE OF

CENTURIES UNTIL NUCLEAR FUSION ESTABLISHES ON A FIRM FOOTING.

THANKS

ANY QUERIES?

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