Solar Power Satellites and Microwave Power Transmission

[seminar class]

Presented By
Siva shanker.K
Pradeep reddy.B

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Nikola Tesla
 1856-1943
 Innovations:
 Alternating current
 Wireless power transmission experiments at Wardenclyffe
Wardenclyffe
 1899
 Able to light lamps over 25 miles away without using wires
 High frequency current, of a Tesla coil, could light lamps filled with gas (like neon)
1940’s to Present
 World War II developed ability to convert energy to microwaves using a magnetron, no method for converting microwaves back to electricity
 1964 William C. Brown demonstrated a rectenna which could convert microwave power to electricity
Brief History of Solar Power
 1940-50’s Development of the Photovoltaic cell
 1958 First US Satellite that used Solar Power
 1970’s Oil embargo brought increased interest and study
Solar Power from Satellites
 1968’s idea for Solar Power Satellites proposed by Peter Glaser
 Would use microwaves to transmit power to Earth from Solar Powered Satellites
 Idea gained momentum during the Oil Crises of 1970’s, but after prices stabilized idea was dropped
 US Department of Energy research program 1978-1981
Details of the DOE Study
 Construct the satellites in space
 Each SPS would have 400 million solar cells
 Use the Space Shuttle to get pieces to a low orbit station
 Tow pieces to the assembly point using a purpose built space tug (similar to space shuttle)
Advantages over Earth based solar power
 More intense sunlight
 In geosynchronous orbit, 36,000 km (22,369 miles) an SPS would be illuminated over 99% of the time
 No need for costly storage devices for when the sun is not in view
 Only a few days at spring and fall equinox would the satellite be in shadow
 Waste heat is radiated back into space
 Power can be beamed to the location where it is needed, don’t have to invest in as large a grid
 No air or water pollution is created during generation
Problems
 Issues identified during the DOE study
 Complexity—30 years to complete
 Size—6.5 miles long by 3.3 miles wide
Transmitting antenna ½ mile in diameter(1 km)
 Cost—prototype would have cost $74 billion
 Microwave transmission
 Interference with other electronic devices
 Health and environmental effects
1980’s to Present
 Japanese continued to study the idea of SPS throughout the 1980’s
 In 1995 NASA began a Fresh Look Study
 Set up a research, technology, and investment schedule
NASA Fresh Look Report
 SPS could be competitive with other energy sources and deserves further study
 Research aimed at an SPS system of 250 MW
 Would cost around $10 billion and take 20 years
 National Research Council found the research worthwhile but under funded to achieve its goals
Specifications
 Collector area must be between 50 (19 sq miles) and 150 square kilometers (57 sq miles)
 50 Tons of material
 Current rates on the Space Shuttle run between $3500 and $5000 per pound
 50 tons (112,000lbs)=$392,000,000
 There are advantages
 Possible power generation of 5 to 10 gigawatts
 “If the largest conceivable space power station were built and operated 24 hours a day all year round, it could produce the equivalent output of ten 1 million kilowatt-class nuclear power stations.”