27-06-2012, 05:24 PM
Solar Power Satellites and Microwave Power Transmission
Solar Power Satellites.ppt (Size: 1 MB / Downloads: 52)
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
From the Satellite
Solar power from the satellite is sent to Earth using a microwave transmitter
Received at a “rectenna” located on Earth
Recent developments suggest that power could be sent to Earth using a laser
Microwaves
Frequency 2.45 GHz microwave beam
Retro directive beam control capability
Power level is well below international safety standard
Rectenna Design
Currently there are two different design types being looked at
Wire mesh reflector
Built on a rigid frame above the ground
Visually transparent so that it would not interfere with plant life
Magic carpet
Material pegged to the ground
Power to Mobile Devices
If microwave beams carrying power could be beamed uniformly over the earth they could power cell phones
Biggest problem is that the antenna would have to be 25-30 cm square
Low Orbit
Communications industry proposing to have hundreds of satellites in low earth orbit
These satellites will use microwaves to beam communications to the ground
Could also be used to beam power
Since a low orbit microwave beam would spread less, the ground based rectenna could be smaller
Would allow collectors on the ground of a few hundred meters across instead of 10 kilometers
In low orbit they circle the Earth in about every 90 minutes
Solar Power Satellites.ppt (Size: 1 MB / Downloads: 52)
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
From the Satellite
Solar power from the satellite is sent to Earth using a microwave transmitter
Received at a “rectenna” located on Earth
Recent developments suggest that power could be sent to Earth using a laser
Microwaves
Frequency 2.45 GHz microwave beam
Retro directive beam control capability
Power level is well below international safety standard
Rectenna Design
Currently there are two different design types being looked at
Wire mesh reflector
Built on a rigid frame above the ground
Visually transparent so that it would not interfere with plant life
Magic carpet
Material pegged to the ground
Power to Mobile Devices
If microwave beams carrying power could be beamed uniformly over the earth they could power cell phones
Biggest problem is that the antenna would have to be 25-30 cm square
Low Orbit
Communications industry proposing to have hundreds of satellites in low earth orbit
These satellites will use microwaves to beam communications to the ground
Could also be used to beam power
Since a low orbit microwave beam would spread less, the ground based rectenna could be smaller
Would allow collectors on the ground of a few hundred meters across instead of 10 kilometers
In low orbit they circle the Earth in about every 90 minutes