Space-based solar power (SBSP) is an idea of collecting solar power in space for use on Earth. SBSP would differ from current solar collection methods in that the means used to collect energy would reside on an orbiting satellite instead of on Earth’s surface.
Part of the solar energy is lost on its way through the atmosphere by the effects of reflection and absorption. Space-based solar power systems convert sunlight to microwaves outside the atmosphere, avoiding these losses, and the downtime (and cosine losses, for fixed flat-plate collectors) due to the Earth’s rotation.
Space-Based Solar Power Advantages
- • The SBSP concept is attractive because space has several major advantages over the Earth’s surface for the collection of solar power.
- • There is no air in space, so the collecting surfaces could receive much more intense sunlight, unobstructed by the filtering effects of atmospheric gasses, cloud cover, and other weather events. Consequently, collection in orbit is approximately 144% of the maximum attainable on Earth’s surface.
- • A satellite could be illuminated over 99% of the time, and be in Earth’s shadow on only 75 minutes per night at the spring and fall equinoxes. Orbiting satellites can be exposed to a consistently high degree of solar radiation, generally for 24 hours per day, whereas surface panels can collect for 12 hours per day at most.
- • Relatively quick redirecting of power directly to areas that need it most. A collecting satellite could possibly direct power on demand to different surface locations based on geographical baseload or peak load power needs.
• Elimination of plant and wildlife interference.
Space-Based Solar Power Disadvantages
- The SBSP concept also has a number of problems.
- The large cost of launching a satellite into space
- Inaccessibility: Maintenance of an earth-based solar panel is relatively simple, but performing maintenance on a solar panel in space incurs the extra cost of transporting a team of astronauts into space.
- The space environment is hostile; panels suffer about 8 times the degradation they would on Earth. System lifetimes on the order of a decade would be expected, which makes it difficult to produce enough power to be economical.
- Space debris is a major hazard to large objects in space, and all large structures such as SBSP systems have been mentioned as potential sources of orbital debris.
- The broadcast frequency of the microwave downlink (if used) would require isolating the SBSP systems away from other satellites. GEO space is already well used and it is considered unlikely the ITU would allow an SPS to be launched.