The final frontier: Solar power from space
Pacific Gas & Electric is going to great lengths--all the way to space--in its quest for renewable energy.
The California utility on Monday said that it will seek approval from regulators to purchase 200 megawatts worth of solar energy delivered from stealth space solar power company Solaren over 15 years.
(Credit:
Space Energy)
The idea of space-based solar power (SBSP) is to place a device in space that can convert solar energy into a usable form and have it transmitted wirelessly to Earth. Scientists have thought to capture solar energy from space for decades but has it has never been done commercially.
Solaren proposes placing solar panels on a satellite to generate electricity that is converted to radio frequency energy on-board and sent to a ground station in California. The receiver then converts the radio frequency energy to electricity and it is fed into the power grid.
The goal of the project is to provide electricity to PG&E by 2016, said Solaren CEO Gary Spirnak in a Q and A posted on PG&E's company blog.
"While a system of this scale and exact configuration has not been built, the underlying technology is very mature and is based on communications satellite technology. For over 45 years, satellites have collected solar energy in earth orbit via solar cells, and converted it to radio frequency energy for transmissions to earth receive stations. This is the same energy conversion process Solaren uses for its (space solar power) plant," he said.
PG&E, which has significant investments in different forms of renewable energy, said that there is no risk to the utility since it only pays for power produced.
The advantage of space solar power is that energy can be harnessed at all times, even at night or when it's cloudy. Solaren's contract calls for it to deliver baseload power, the electricity needed to meet customer demand.
In its posting, PG&E executives said that generating space solar power cost effectively is a major challenge, but the people at Solaren have a lot of experience in space and satellites. The field also can also draw on years of research.
Another company called Space Energy has been formed to also tap solar energy from space using a similar technique as Solaren.
Martin LaMonica is a senior writer for CNET's Green Tech blog. He started at CNET News in 2002, covering IT and Web development. Before that, he was executive editor at IT publication InfoWorld. E-mail Martin. 
If you wnat to get solar energy from space to earth, the cheapest way I can think of doing it is to put mirrors up in geosynchronous orbit that reflect down to a mirrior farm here in the ground. The cost of putting stuff in orbit is the same, but some most reflective materials are much cheaper than fabricated solar cells. Also, the energy goes through fewer energy conversions, leading to less loss that way.
I'm curious where you got your 2% efficiency number. I have trouble believing that the Earth's atmosphere blocks 90% of the light coming at it. True, converting from electicity to radio is fairly efficient, but this efficiency is inversely proportional to the amount of power you are transmitting. So with a high voltage transmission, you will loose 5% to 10% of your power (depending of your frequency, amount of power, and quality of components) . Remember, you are doing this twice, once to transmit, and once to recieve.
Finally, a massive amount of power will be lost through attenuation in the atmosphere. Most people don't realize how much energy it take to transmit a radio signal. True, there are UHF and VHF transmitters out there that can cover thousands of miles on 1 watt, but this is more due to the high quality of the equipment recieving the signal than the amount of power. Most of the power is lost within a few hundered feet of the transmitter. If you don't believe this there is a simple experiment you can do that will prove it. Get a chrystal radio, you can find kits for them online, and go to a local radio tower. Chrystal radios are great because they use the transmitted signal as the power source, much like this power from space idea. Get close to the tower and turn your radio on. You should be getting a pretty strong (loud) signal. Now move back about 300 yards. Your radio will be noticeably quieter. Note that chrystal radios only work within a few miles of a commercial broadcast transmitter... Also note that the smallest commercial broadcast transmitter broadcasts at about 20,000 Volts.
A radio laser (Raser?) will be able to get much more energy to one spot than a general broadcast tower, but there is still a massive amount of loss from atmospheric attenuation (Think 60% to 95%).
http://www.energy.gov/news/4503.htm
Or perhaps you should read cnet more thoroughly?
http://news.cnet.com/Solar-cell-breaks-efficiency-record/2100-11395_3-6141527.html
This is news that is over 2 years old. Why not try to stay up to date on topics before you decide you are smart enough to comment on them
I don't know of a term for a theory that has been shown false before the theory is stated. Perhaps you are a little behind on your knowledge of solar technology. But I guess that happens all the time because some people cannot seem to get their minds to wrap around the fact that technology has changed since the 1950s. Or the fact that technological knowledge CAN change at all
It does, at first blush, doesn't it? Fortunately, the concept was proved in the 1970s at the Jet Propulsion Laboratory's Goldstone facility. ATT, participating engineers spoke of 60-70 percent transmission efficiency.
The concept of power from the sun was first conceptualized in a "Science" article in 1968 ("Power from the Sun: It's future"). It's nice that someone is putting up a little money to take some risk. Maybe the naysayers will be proved correct, but it's certainly a worthy effort. --mark d.
As for your mirror idea, this fails tremendously on a cloudy day, the idea of putting the solar panels in low orbit would get the panels into the open space where the sun is not obstructed by cloud cover. Plus the mirrors would have to constantly adjust themselves and maintenance costs would be extremely high for these satellites. Where as an orbital ring would allow for living quarters in stations along the ring to maintain it.
Sure initial costs would be very very high, but over all it would allow us to have a large source of energy for all the continents, as well increase our reach into space by living in Low orbit.
And regarding the mirrors, there is a funny story too(http://en.wikipedia.org/wiki/Crimes_of_the_Hot).
But how about a rotaring sterling engine and a quite large nanotube wire? Since the rotation make a nice 200+ degrees change, a sterling engine might be able to move a generator and its output can be send via nanowire to a couple of repeater stations down to Earth.
Oh wait, we do. Its called nuclear power.
We do not have a shortage of electricity - we have a shortage in the political will needed to stand up to the extreme eco-whacko movement that has stifled nuclear power despite it being the cleanest form of energy available.
Fusion reaction only goes on as long as there is fuel and a very controlled environment. Any disruption to this environment results in a collapse of the reaction - not an explosion such as what can occur in a fission reaction.
Thanks, I'm aware that fusion is clean source of energy and nobody is opposed to it. However "nuclear power" term is still reserved for fission, because of its wide adoption around the world. Risks of running fission plants are extremely high, when even minor accidents are devastating to entire areas. So i don't understand how people can still advocate its use. If fission was so nice to use, why don't we have fission powered cars then?
Unless, of course, they want their burgers to come from 3-headed cows.
Nuclear has a couple of huge problems: 1) - Long term disposal / storage of nuclear waste; 2) - potential for use of radioactive materials as weapons; 3) - Fear of all cancers;
Solve those and nuclear has a chance.
When you can find solvent private insurers willing to provide liability insurance for a nuclear plant without government subsidy, then you can declare nuclear power (as done in the U.S.) to be safe.
Until then the best that can be argued is that it is extremely risky, but necessary.
2) Fusion doesn't produce "weaponized" or "weaponizable" byproducts.
3) You're more likely to get cancer from having sex or the background radiation in your home than you are to get from being exposed to radiation of any US nuclear power plant - fission or fusion.
The big nuclear scare is from people getting sick of radiation poisoning and being told there was only a minor leak when in actuality there was a major problem. Further, that's a fission problem, not a fusion. Nuclear fusion is the most efficient and safest method of generating heat, light, and as a result, power - we've got several projects currently working on this, such as the ITER facility in Europe, and the laser fusion testing center in California.
But consider this:
- The Hanford site currently contains 53 million gallons of high-level radioactive waste (http://en.wikipedia.org/wiki/Hanford_Site) - and that's just some of the total amount of radioactive waste in existance.
- Achieving escape velocity for that amount of material would cost astronomical amounts of energy and money.
- Would you risk sending 1000's and 1000's of rockets with radioactive waste into space knowing that some percentage (say 5% or so) fails in spectacular ways?
A sidenote on that is that perhaps a space-elevater (http://en.wikipedia.org/wiki/Space_elevator) would be somewhate safer and more economical but that's science fiction for now.
So sorry - but the nuclear waste we're producing now is going to stay with us for the forseeable future.
We have so much rf energy bouncing around us from multiple sources already, with the biological effects largely unknown or if they are they are kept from public knowledge. The jury is still out on microwave energy dangers as well as EMF, (though surely PG & E is one of those who will say all those teachers in Fresno who got rare cancers after teaching in classrooms along a high voltage transmission line were "random" or "allowable risks") I don't think this is an acceptable solution.
One thing not discussed, is getting all this up into space is going to require a lot of launches by the biggest vehicles available. The type of propulsion varies, and eaach has its own damage factors to the environment.
While we don't expect too many of these:
http://www.liveleak.com/view?i=20f489a8e7
we can expect damage to the ozone layer as even the more environmentally friendly non-hypergolic liquid propulsion systems burn their combustible fuels at that altitude, as discussed here:
http://www.thespacereview.com/article/1395/1
The entire system relies on RF power transmission. The ONLY modern day test over any distance (only 148 km - geostationary orbit is 36,000 km) failed to receive any more than 1/1000th of 1% of the power transmitted. Do the math and calulate how much power needs to be transmitted to receive 200MW...
The RF power transmission technology does not exist!
Show me a test over 36,000 km at 90-90% efficiency and then we'll start saying this is even remotely feasible! Besides that technical hurdle it will ALWAYS be cheaper to install PV cells on the ground!
http://www.gizmag.com/solar-power-space-satellite/11064/
With bases planned for the Moon and Mars NASA maybe pitching in a little support on this one. Both are dusty places with low gravity, add a little human activity and solar's effectiveness may drop dramatically in these two locals.
With any of these approaches the international political considerations need to be weighed heavily. With Star Wars and now Obama's talk about merging NASA with the Defence Department (very bad idea) more then a few of our neighbors might be raising an eye brow or two over these sorts of plans.
I'm continually amazed that the only State seemingly behind solar is California. This should be the domain of the Mid-West with the most to loose during gasoline price spikes. Maybe being the largest "populous" state in the Nation has something to do with it, maybe, or simply this might be a "hook" for R&D dollars. Do they do research in the cold of the Mid-West? Yes, I realize we don't have a beach but the Great Lakes are pretty nice,. besides you can drive a car on them in the Winter, that is if Winter returns.
- by Axil128 April 15, 2009 5:46 PM PDT
- The answer to abundant energy is the Thorium fuel cycle and the Liquid Fluoride Thorium Reactor (LFTR). Dr. Edward Teller, the father of Fusion, after a lifetime of work on every aspect of nuclear technology had at the end of his life come to this conclusion in his final study: the LFTR is the best of all possible reactor types.
- Like this Reply to this comment
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(36 Comments)The LFTR is a very simple, efficient, and elegant type of reactor. It can start up on any kind of nuclear fuel, bomb material, or nuclear waste product to produce very high temperature heat and at the same time breed more fuel in the bargain. This thrifty approach to nuclear energy greatly appeals to me, but I became even more interested in the LFTR when the details of a new patent were revealed by Dr LeBlanc (see below @ minute 53). It opens up the possibility of building a very compact but powerful reactor that can run for 30 years without refueling. It can be operated remotely in an unattended fully automated intrusion detecting mode and sited underground while it breeds self perpetuating new fuel within the thorium structure of the reactor itself.
In order to get to its fuel, U233 that has been produced inside the very solid metal walls of this 200 ton reactor containment vessel, a proliferator must destroy and disassemble the reactor, lift its heavy reactor core out of a 100 meter deep reinforced aircraft crash proof hole in the ground, then cut the thorium containment vessel up into small pieces while enduring heavy killing gamma radiation exposure, next reprocess these reactor pieces using isotopic separation since the U233 is denatured with enough U238 to make chemical separation of bomb grade U233 impossible, and do all this without being detected. Now, this is a tall order for any proliferator and may just be an impossible assignment.
At the end of the service life of the Lftr, the reactor vessel is sent back to the factory where it is reduced to liquid fluoride salts that become the feedstock of a next new Lftr. This feedstock can only be used by the new Lftr and not for bombs. A few handfuls of waste products are held at the factory for a few hundred years to cool down before they are mined for the many precious elements contained within like platinum and iridium. Now that is what I call a safe, efficient and thrifty mode of operation!
To learn more see one of the following:
Aim High
http://rethinkingnuclearpower.googlepages.com/aimhigh
What Fusion Wanted To Be
http://www.youtube.com/watch?v=AHs2Ugxo7-8
Liquid Fluoride Reactors: A New Beginning for an Old Idea
http://www.youtube.com/watch?v=8F0tUDJ35So
The Center for International and Security Studies at Maryland has some good things to say about thorium as follows:
http://www.cissm.umd.edu/papers/files/future_nuclear_power.pdf