Solar In-depth: From Sun To Nanoparticles To Electricity

Solar In-depth: From Sun To Nanoparticles To Electricity

 


The ultimate solar power station is in outer space. As shown in the
sketch at the far left, there are energy losses as the sun's rays are
reflected from the atmosphere, clouds, dust, the day-night cycle and
seasonal changes.
Only about 50% of the sun's energy reaches the earth and then only
15% to 25% of that reaches the grid. As shown on the right hand side of
the sketch, a Space Based Solar Power (SBSP)
system would collect solar energy by a satellite 24 hours a day,
convert it to microwaves, transmit the microwave radiation to earth
where it would be captured by a very large ground antenna and converted
into usable electricity on the grid. The energy efficiency from the
space station to the grid would be about 50%, roughly the same as
fossil fuel electrical plants. The SBSP
concept was first published in November 1968 by Dr. Peter Glaser. In
1973 he was granted a U.S. patent for his method of transmitting power
from a satellite using microwaves sent from a large antenna to a
combination rectifier-antenna, now called a "rectenna" on the ground.
NASA began to study the concept in 1974. They found that the concept
had several major problems - the huge expense of putting the solar
satellite in orbit requiring hundreds of space trips and the lack of
experience in space for projects of this scale. The proposal showed
enough promise to merit further research. Research has continued to
this day.




There have been enormous improvements in solar panel efficiency.
Research has continued to this day. There have been enormous
improvements in solar panel efficiency reducing the size of the panel
array in space. (See an artist's sketch of a proposed satellite system
at the left.) Rocketry has also improved, but not sufficiently enough
that "hundreds of transport trips" can be undertaken cost effectively at
this time. Satellite transportation costs remain the biggest obsticle
to this technology being implemented. Many noted scientists believe that
if the US "concentrated" on this effort, the costs of transporting the
spacecraft materials to space would come down and the whole project
would be cost competitive with fossil fuels.


As we come to the later part of the 21st century and with the
availability of fossil fuels declining resulting in extremely high fuel
prices, many scientists believe SBSP will be seen as the ultimate
answer. The real question is "Will we by then be ready to exploit this
endless source of cheap electrical power?" For a more detailed discussion of SBSP see the Solar High Brochure by Dr. Philip Chapman former NASA Astronaut, Physics Professor at MIT, and Employee of Dr. Peter Glaser.


Ohio University has initiated a "SunSat Design Competition" which is
"an international competition intended to accelerate the design,
manufacture, launch and operation of the next generation satellites that
will collect energy in space and deliver it to earth as electricity.



The Mission of the SunSat Design Initiative is to move space solar power
out of the research labs and onto the public agenda. This will be
done by virtual story telling and networking on a global basis,
explaining what space solar power is and how and why it will become
the ultimate renewable energy resource for Planet Earth." See the Ohio University SunSat Design Competition.


For a very interesting NASA video featuring a commentary by Dr. Peter Glaser himself click here.