Orbital Solar Power Stations, a need to push someone?

[Graham2001]

've been reading the 1978/1981 period Orbital Solar Power Station files that are kept over at the NTRS... and like most such things it makes me depressed that at the time no-one seems to have really pushed for something to come out of all the planning and paperwork, had it been done, the first stations would be online already with more on the way.

Instead the idea seems to have been allowed to lie almost fallow with only minor studies being done here and there. Worse those groups that should be pushing for some effort to be made (such as the Greens...) don't want to on the grounds that someone might get rich doing so, an attitude that I cannot understand.

In the 1960's the US raced to the moon because it was a hard task and it was expensive, orbital solar power is expensive and it may be hard to achieve, but so far no one seems to be even trying to get the concept off the ground in the form of a test platform...

I feel now, more than ever that the time has come for the space community to push towards a goal that can unite much of the planet, but I don't even know where to begin, so I've decided to start here, with this rant, I wonder who else is willing to help see the great ships fly.

[Ronald Brak]

The reason this idea is not getting off the ground is because it is so much cheaper to simply keep the solar cells on the ground. It appears that the low cost solar cells can now be produced for under $1 a watt when mass produced:

http://thefraserdomain.typepad.com/e...hips.html#more

But the current cost of getting them into space is enormous. Because of the atmosphere and the rotation of the earth solar cells in geosynchronous orbit might recieve over 6 times as much sunlight as a very sunny location on earth. However, they won't cost 6 times as much as solar cells on earth, with today's technology they will cost over a thousand times as much as solar cells on earth. At the moment they are just not ecomonically feasible. In the more distant future when robot factories can manufacture them from materials in space they may become practical.

[Trebuchet]

Not to mention the difficulty with keeping the array working and pointing at the sun. Look at the ISS for an example. On the other hand, building a space-based power station would be a terrific developer of other space technologies.

[Ronald Brak]

Whoops, in my first post I said they will cost over a thousand times as much as solar cells on the ground, as if I actually know for sure how much it will cost. That was just my guess. I don't actually know, but it would be vastly more expensive than ground based solar power.

[Larry Jacks]

Not to mention the difficulty with keeping the array working and pointing at the sun. Look at the ISS for an example.

This really isn't all that hard at geosynch. You need to establish a stable platform with the antennas pointing at the Earth and rotate the solar arrays 360 degrees per day (15 degrees per hour). This is something geosynch communications satellites have been doing for decades.

[KaiYeves]

This is a very good idea, and you are smart to write about it on BAUT. We get lots of visitors, after all.
People power!

[Graham2001]

In the more distant future when robot factories can manufacture them from materials in space they may become practical.

NASA (Or more precisely General Dynamics/Convair) had worked that bit out in the 1970's, according to one of the 'battleship' studies I was looking through it turned out to be cheaper over the life of the program to shift part of the mining/manufacturing capacity to the moon.

The problem of course is getting there and setting up the support infrastructure. Which is why there is an urgent need to not only fight off future threats to manned spaceflight, but reverse those which have come to pass, such has the most recent US Budget which forbids NASA from research that might lead to a manned flight to Mars, we need the lift capacity one way or the other...

References:

1. Lunar resources utilization for space construction. Volume 1: Executive summary

2. Lunar resources utilization for space construction. Volume 2: Study results

3. Lunar resources utilization for space construction. Volume 3: Appendices

[Van Rijn]

NASA (Or more precisely General Dynamics/Convair) had worked that bit out in the 1970's, according to one of the 'battleship' studies I was looking through it turned out to be cheaper over the life of the program to shift part of the mining/manufacturing capacity to the moon.

It certainly would be cheaper for a large SPS program than shipping everything up from Earth. The question is if SPS could compete on price with ground based sources of energy. I doubt SPS could compete unless we got near to self replicating systems, something like what NASA was talking about around '80. In that idea, you put a "seed factory" on the moon. We probably wouldn't try to make it produce everything (low mass computer chips and some other parts would be, in effect, "vitamins" that would be shipped up), but if a factory could produce most of what was needed, in place, the price might be reasonable.

[TrAI]

The reason we can't have things like this is that you just know someone is going to play around with it as a joke, like the people Bessler007 talks about here, or worse.

Any satellite with a microwave link capable of beaming down a really useful amount of power in a tight enough area is a rather dangerous thing...

[Van Rijn]

The reason we can't have things like this is that you just know someone is going to play around with it as a joke, like the people Bessler007 talks about here, or worse.

Any satellite with a microwave link capable of beaming down a really useful amount of power in a tight enough area is a rather dangerous thing...

The energy density of the proposed beam for the ten gigawatt Geostationary SPS was, as I recall, about 1 1/2 times that of sunlight. Despite the low energy density, the proposed advantages were that the beam would be received 24 hours a day, the rectenna would be fairly simple and cheap, and it would be far more efficient (around 80% at the groundside) than an equivalent area of groundbased PV panels. They planned on a "homing beam" as well: As long as the SPS received a signal from the ground location, it would stay focused on the rectenna, but would be designed to "defocus" otherwise.

Admittedly, there were ideas for other designs that used lasers, perhaps even for powering aircraft. Those we'd have to handle with care.

[galacsi]

And there are some other problems nobody talk about :

Who will own these space power stations ? Who will establish the price , be paid for it and make the profit ?

Energy is life , I don't want any Corporation or alien country to control my suply of energy and give it the ability to blackmail me at any moment.
And It is a far too much centralized system with a too heavy and political management.

I am must more at ease with solar cells on the roof of my house !

So actually , even if we give a semblance of value to the idea and play a lip service to it , nobody civilian really interested.

Sorry to torpedo your techno utopia

[Graham2001]

I am must more at ease with solar cells on the roof of my house !

And you think that Solar Cell manufacturers are not going to make money off the millions of roof set-ups.

It might interest you to know that the best place for ground sites would probably be in countries with lots of empty space, starting with much of Saharan Africa, and that is the part of the world that needs clean energy more than anywhere else at the moment.

What annoys me more than anything else is that no-one wants to even try the hard solutions..

[TrAI]

The energy density of the proposed beam for the ten gigawatt Geostationary SPS was, as I recall, about 1 1/2 times that of sunlight. Despite the low energy density, the proposed advantages were that the beam would be received 24 hours a day, the rectenna would be fairly simple and cheap, and it would be far more efficient (around 80% at the groundside) than an equivalent area of groundbased PV panels. They planned on a "homing beam" as well: As long as the SPS received a signal from the ground location, it would stay focused on the rectenna, but would be designed to "defocus" otherwise.

Admittedly, there were ideas for other designs that used lasers, perhaps even for powering aircraft. Those we'd have to handle with care.

1.5 times that of sunlight... That is a statement that would be open to interpretation, but I suppose they mean that the total energy density will be 1.5 times the total recieved from the sun on a sunny day, so the target area would recieve up to about 2 kW/m2 of microwave radiation...

That's strange, wouldn't you need a 5 km2 recieving array to get 10GW of power? But perhaps it was going to supply 10GW/h over a period of 24 hours(That would be about 417MW, wouldn't it)? Still, the reciever array would be large... Perhaps I messed up some calculations somewere....

[galacsi]

And you think that Solar Cell manufacturers are not going to make money off the millions of roof set-ups.

The money is not the problem , it is the control !

It might interest you to know that the best place for ground sites would probably be in countries with lots of empty space, starting with much of Saharan Africa, and that is the part of the world that needs clean energy more than anywhere else at the moment.

NO , because in north Africa Algeria , Libya have lot of hydrocarbon and are big exporters , Egypt also has oil. So I don't know why north Africa is so special for you ? And at the moment ??? Please can you expand on this ?

On the other hand for us Europeans , importing electricity from north Africa is not much better than importing oil or gas.

What annoys me more than anything else is that no-one wants to even try the hard solutions..

There is no question solar energy works in space , it is being used from a long time for whatever it is economic to use. I am a big fan of electric propulsion with solar power , we don't need nukes in space.

[Ronald Brak]

What annoys me more than anything else is that no-one wants to even try the hard solutions..

People are willing to work hard and take risks, provided there are payoffs to be had. But at the moment anyone trying to get clean energy from space will be effortlessly outcompeted by people supplying clean energy on the ground. There is just no way that someone can make a profit from space solar power at the moment and people with money to invest can see that.

However, there are plenty of other ways to make money from space. If you feel bitter about the lack of interest in space based solar power, perhaps you should look at space tourism, entertainment, scientific research and colonisation in space, all of which have huge potential.

[mugaliens]

But the current cost of getting them into space is enormous. Because of the atmosphere and the rotation of the earth solar cells in geosynchronous orbit might recieve over 6 times as much sunlight as a very sunny location on earth. However, they won't cost 6 times as much as solar cells on earth, with today's technology they will cost over a thousand times as much as solar cells on earth. At the moment they are just not ecomonically feasible. In the more distant future when robot factories can manufacture them from materials in space they may become practical.

Until then, for once California has done a good thing and is backing the new, 10x cheaper die-based solar cell effort for use in areas such as solar cell roofs, a good match for sunny California. Nevada, particularly Vegas, is following suite.

[Van Rijn]

1.5 times that of sunlight... That is a statement that would be open to interpretation, but I suppose they mean that the total energy density will be 1.5 times the total recieved from the sun on a sunny day, so the target area would recieve up to about 2 kW/m2 of microwave radiation...

That's strange, wouldn't you need a 5 km2 recieving array to get 10GW of power? But perhaps it was going to supply 10GW/h over a period of 24 hours(That would be about 417MW, wouldn't it)? Still, the reciever array would be large... Perhaps I messed up some calculations somewere....

They definitely were figuring large rectennas. The 1.5 figure was from old memory. Here's a page with some better numbers:

http://www.freemars.org/history/sps.html

The result of this study was a design for an SPS which consisted of a 5 x 10 kilometer (3 x 6 mile) rectangular solar collector and a 1-kilometer-diameter (0.6 mile) circular transmitting antenna array. The SPS would weigh 30,000 to 50,000 metric tons. The power would be beamed to the Earth in the form of microwaves at a frequency of 2.45 GHz (2450 MHz), which can pass unimpeded through clouds and rain. [snip] The rectenna array would be an ellipse 10 x 13 kilometers (6 x 8 miles) in size. It could be designed to let light through, so that crops, or even solar panels, could be placed underneath it. The amount of power available to consumers from one such SPS is 5 billion watts.

[Noclevername]

As much a fan of the concept as I am, I have to agree that the time for orbital powersats beaming to ground targets just isn't here yet. It'll have to wait until a mature space-based mining and manufaturing infrastructure is built; then it'll be cost-effective, because it'll be just one more structure that can be manufactured there, like habitats, large orbital telescopes and interplanetary spacecraft. Such industrial efforts would require large solar power collectors anyway. Sending a bit of that extra energy Earthward would be an afterthought.

Sometime late this century, maybe early next.

[RecoveringYuppy]

DOD and Palau are planning a demonstartion to be completed by 2012:

http://www.treehugger.com/files/2007...agon_space.php

[Ronald Brak]

How about a compromise? Large solar power arrays are built on the ground in desert areas in Africa, Australia and the Americas. Then the power is beamed up to satellites which then beam power to where ever it is needed, providing 24 hour solar power to the world. Unfortunately, with the cost of building transmitters and recievers on the ground and launching them into space, even this compromise system would be far too expensive to be practical. But at least I guess it is more practical than it was.

[Maksutov]

[edit]Energy is life , I don't want any Corporation or alien country to control my suply of energy and give it the ability to blackmail me at any moment....

Sshhh, don't tell anyone, but, if you live in the US and use electric power from the grid, then, what you've described is already the case.

[Maksutov]

How about a compromise? Large solar power arrays are built on the ground in desert areas in Africa, Australia and the Americas. Then the power is beamed up to satellites which then beam power to where ever it is needed, providing 24 hour solar power to the world. Unfortunately, with the cost of building transmitters and recievers on the ground and launching them into space, even this compromise system would be far too expensive to be practical. But at least I guess it is more practical than it was.

Ah, from each according to their ability to each according to their need.

Sounds familiar...

Meanwhile, I'm pretty sure that for point-to-point Earth locations, landlines would be considerably more efficient at transmitting power than microwaves into and back from space. As you pointed out re "practical".

[galacsi]

In the industrial countries there are so much commercial centers, warehouses , factories, covered parkings and business buildings that if you covers their flat roofs with solar cells you will produce much of the energy you need and bother nobody. And it can be a bonus for the owners.

The energy will be produced just where it is needed ! A miracle !

So even if in space sun shines 24 hours a day and so solar cells are much more efficient , there is no need to build space solar power stations.

[neilzero]

There might be a million commercial flat roofs in the USA that are sort of suitable for photovoltaic panels, with an average of 10,000 square feet that is suitable for photovoltaic = ten billion square feet. Late in June, there will be a few days these will average ten watts per square foot for about an hour about noon central time. 100 billion watts is produced and 80 billion watts might be used, since losses are low due to using the watts close to the source. That is 80 gigawatts equal to perhaps ten very large electric plants. This is an important and helpful contribution, but a long ways short of the energy needs of the USA. We cannot expect much more than 80% as much of the power needs to be converted from dc to ac for existing appliences. Direct curent outlets may be practical in some buildings which will use batteries to provide emergency power. The dc can be used to charge electric and hybred vehicles, but that thought also has complications.
At $50 per square foot = 1/2 trillion dollars, this is too costly, but may be ok if we can get the cost down to $200 billion. Some factors to consider are: the thin film photovoltaic is the roofing material that keeps the roof from leaking. Will it last 20 years without coating it with glop that will block the sun? Maybe, if the contractor does a better than average job. The extra cost will be a good investment as typical flat roofs start leaking about the 5 th year.
There are a few things that make this slighty more attractive. New construction can have lots of roof area that faces South or SW, instead of flat. This increases the output of the photovoltaic a bit in June and a lot in December, especially in Northern cities such as Chicago and Boston. Very steep South facing roof is good in these Northern cities, but is likely too costly, unless we decide steep roofs are archetectually beautiful. We can put the photovoltaic on racks attached to the building, but this presently is cost prohibitive as is steerable photovoltaic. Putting the panels 5 to 10 feet above the roof greatly increases the wind loading, requiring the whole building to be built stronger, but this does simplify roof repair, and may make the roof suitable for people as the panels provides shade. Racks and steerable also get the photovoltaic above most of the vent pipes, airconditioning and refrigeration units which shade the photovoltaic significantly.
New private homes can also have photovoltaic panels on South and South west facing roofs, until the trees grow tall enough to shade the roofs. Neil

[Noclevername]

How does the cost of manufacturing such vast amounts of roof-ready photocells compare to powersats? (Taking into account not just the cells but transporting them, installation, protective materials, power storage for each home, replacements after storms, etc.)

[Onlooker]

Instead the idea seems to have been allowed to lie almost fallow with only minor studies being done here and there. Worse those groups that should be pushing for some effort to be made (such as the Greens...) don\'t want to on the grounds that someone might get rich doing so, an attitude that I cannot understand.

If people thought they could get rich off this project, they wouldn\'t need any pushing. They\'re not doing it because they think it will result in their getting poor, not getting rich.

Why don\'t you do it?