13-10-2012, 05:15 PM
Solar Power Satellites and Microwave Power Transmission
Solar Power Satellites.ppt (Size: 1 MB / Downloads: 527)
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
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.”