Space-Based Solar Power: Science Fiction or Soon-to-Be Reality?
Space-based solar power (SBSP) is the dark horse of the solar industry. Although the concept seems straightforward, the logistics are so complex that only those heavily immersed in the science can really understand its feasibility (or lack thereof). On the other hand, utilities like PG&E are already signing power purchase agreements for SBSP projects that don’t even have funding yet.
Photo Credit: kowh
This creates a conundrum for the rest of us, who are unsure whether SBSP is science fiction or just over the horizon. Certainly some reputable organizations are getting behind the concept. President Obama’s election transition team issued a white paper urging for funding for SBSP, the National Space Society (NSS) came out in favor, the Pentagon as well, and at least one utility, as mentioned above, is jumping on the spacewagon with money in tow.
Yet the logistics are baffling. Here’s how it would work, put quite simply. Several large solar arrays would be deposited in space (within the Earth’s orbit) and positioned to receive sunlight constantly. The collected solar energy would then be concentrated and electromagnetically beamed to large receivers on the surface where it could then be transmitted to cities for immediate use.
The SBSP concept tackles some major hurdles for solar power as a primary source of electricity here on Earth. The main one being intermittency, or solar power at night. Space based solar power would eliminate the problem of nightfall on a solar array.
Also, the concentration of sunlight in space is incredibly higher than on the Earth’s surface. So even at today’s conversion efficiencies for solar panels, the amount of energy produced would be nigh unfathomable. According to the NSS, a single km-wide geosynchronous orbit in space would experience enough solar radiation in one year to equal the energy available in all known conventional oil reserves on Earth today. Needless to say, the potential is there.
At the same time, a lot of variables have yet to be worked out and the mathematics and physics behind the process are staggering, for not only myself, but for a lot of venture capitalists and policymakers as well.
One of these is transmitting the solar power from space to a collector on Earth. The most popular solution, it seems, is to used a specific-frequency, non-ionizing microwave radiation to do the work. And there are several factors that could limit the frequency of those microwaves – certainly an ongoing area of study and experiment for SBSP researchers.
The idea that microwave radiation will be unsafe is apparently unfounded. Yet the long-term effect of microwave radiation is yet to be studied. While cell phones also emit some level of microwave radiation (to no apparent effect), the cell phone industry is still relatively new and long-term or generational effects cannot be known for sure.
Whatever the hiccups, hems and haws, we do need alternative sources of electricity as soon as possible and the NSS asserts that the technology and application could be deployed within the next forty years. If we can pull it off safely, given the immense potential for SBSP, then science fiction could easily become energy reality. The only questions appear to be when and if we can afford it.
And the next question: Who will control all this energy?
Posted on September 1st in Solar News by Dan.