Free Solar Power Satellites and Microwave Power Transmission Presentations in PowerPoint format

OUTLINE:
Background
Solar Power Satellite
Microwave Power TransmissionCurrent Designs
Legal Issues
Conclusion

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
lUse 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)

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

Microwave vs. Laser Transmission

Microwave

–More developed
–High efficiency up to 85%
–Beams is far below the lethal levels of concentration even for a prolonged exposure
–Cause interference with satellite communication industry

Laser

–Recently developed solid state lasers allow efficient transfer of power
–Range of 10% to 20% efficiency within a few years
–Conform to limits on eye and skin damage