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Space Power

PG&E Makes Deal For Solar Power From Space 392

Posted by Soulskill
from the just-watch-out-for-the-shadow-square-wire dept.
N!NJA writes "California's biggest energy utility announced a deal Monday to purchase 200 megawatts of electricity from a startup company that plans to beam the power down to Earth from outer space, beginning in 2016. Solaren would generate the power using solar panels in Earth orbit and convert it to radio-frequency transmissions that would be beamed down to a receiving station in Fresno, PG&E said. From there, the energy would be converted into electricity and fed into PG&E's power grid."
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PG&E Makes Deal For Solar Power From Space

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  • Bad idea (Score:2, Insightful)

    by forand (530402)
    This is a horrible idea. What happens when the beamer is hit by a micro meteor nocking out the com and pointing the sat at SF?
    • Re: (Score:3, Funny)

      by xTantrum (919048)
      yeah this should make it way easier for the aliens to knock out our power systems and take over the earth. *sigh*
    • Re:Bad idea (Score:4, Interesting)

      by Rosco P. Coltrane (209368) on Tuesday April 14, 2009 @07:24AM (#27568577)

      This is a horrible idea. What happens when the beamer is hit by a micro meteor nocking out the com and pointing the sat at SF?

      Forget micrometeors. The real question is: what happens when Solaren goes the Enron way (and isn't bailed out by your tax dollar) and their satellite is allowed to go derelict and drift? Will it leave a narrow trail of roasted humans across California?

      • Re: (Score:3, Interesting)

        Will it leave a narrow trail of roasted humans across California?

        No. The microwaves are the wrong frequency, they don't interact with water and will pass straight through any living creature.

        • is somebody better run this by the HAM radio operators.

          They say that hell hath no fury like a woman scorned, but that saying came into being before HAMs were on the scene.

    • What happens when the beamer is hit by a micro meteor nocking out the com and pointing the sat at SF?

      Then San Francisco residents finally get to be warm [igougo.com].

    • Re:Bad idea (Score:5, Funny)

      by TheRaven64 (641858) on Tuesday April 14, 2009 @07:33AM (#27568655) Journal
      I'm sorry, maybe it's too early in the morning for my brain to be working, but could you be a little more specific about what you consider the downside to be?
    • Re:Bad idea (Score:5, Funny)

      by JamesP (688957) on Tuesday April 14, 2009 @07:36AM (#27568689)

      The effects of microwave radiation on high density airborne smug are still unknown

    • Re: (Score:3, Interesting)

      by Lloyd_Bryant (73136)

      I take it you never heard of the concept of "failsafe" systems? For instance - the ground station is transmitting a "keep alive" signal to the satellite once every 100ms. The satellite hardware is designed so that if the keep-alive isn't received after 250ms, it automatically cuts off the transmitter.

      And the ground station is set so that if it detects the power beam moving over a certain distance off-center of the receiver, it cuts the keep-alive.

      The only part of this concept that's "rocket science" is th

      • by Ihlosi (895663)
        I take it you never heard of the concept of "failsafe" systems? For instance - the ground station is transmitting a "keep alive" signal to the satellite once every 100ms. The satellite hardware is designed so that if the keep-alive isn't received after 250ms, it automatically cuts off the transmitter.

        Considering how far the beam might deviate in 250 ms, I think the reaction time should be made much, much short. Microseconds.

        • Re:Bad idea (Score:4, Interesting)

          by Lloyd_Bryant (73136) on Tuesday April 14, 2009 @07:52AM (#27568813)

          Considering how far the beam might deviate in 250 ms, I think the reaction time should be made much, much short. Microseconds.

          True - the reaction time should be shorter. So try this: The ground station is transmitting a laser signal, which the satellite receives using a system with a VERY limited field of vision. If the signal is interrupted, the power cuts off. That way if the satellite's orientation is disturbed enough to miss the receiver, it won't be able to see the laser...

          The keep-alive idea I originally posted doesn't hold up on closer inspection - there's over 100ms of latency in a radio link from the Earth's surface to geosynchronous orbit...

          • Re: (Score:3, Insightful)

            by Ihlosi (895663)
            The keep-alive idea I originally posted doesn't hold up on closer inspection - there's over 100ms of latency in a radio link from the Earth's surface to geosynchronous orbit...

            The problem is that a laser beam doesn't go any faster than light speed, either.

            The satellite would have to determine on its own whether it's still pointing the right way.

            • Re:Bad idea (Score:5, Insightful)

              by Lloyd_Bryant (73136) on Tuesday April 14, 2009 @08:07AM (#27569031)

              The problem is that a laser beam doesn't go any faster than light speed, either.

              The satellite would have to determine on its own whether it's still pointing the right way.

              That's why I specified that the *receiver* have a very limited field of vision. If the satellite rotates enough to be off target, it can no longer see the laser. Thus no latency issues.

              • Re: (Score:3, Interesting)

                by Ihlosi (895663)
                That's why I specified that the *receiver* have a very limited field of vision. If the satellite rotates enough to be off target, it can no longer see the laser. Thus no latency issues.

                Oh ... right. My bad. That should work as intended.

              • Re: (Score:3, Informative)

                by drinkypoo (153816)

                The transmitting antenna of the system will presumably be a phased array which among other things can detect direction and strength of incoming signals. Sample the transmitting antennas at the same point in the wave each time (the aiming signal will be broadcast at a multiple of the power wave) and you don't even need any separate system. I would propose to do it with an analog system on sapphire insulator or similar, with redundant systems... not with a microprocessor. Hence you get your 'failsafe' aspect.

    • Mr. Freeze (Score:3, Funny)

      by Ogive17 (691899)
      It's no coincidence that Mr. Freeze was played by the current governor of California...
    • by corsec67 (627446)

      They solve the population problem?

    • As long as you have good fire coverage you should be able to put the fires out fast with little damage.

    • Interlock (Score:5, Informative)

      by Doc Ruby (173196) on Tuesday April 14, 2009 @07:55AM (#27568861) Homepage Journal

      These beaming systems have interlocks pointed back from the ground receiver to the satellite. If the two get out of alignment, the satellite immediately loses the ground signal, and immediately stops transmitting.

      Besides, the beamed power density doesn't have to be very high per square meter. If it's just concentrated 5x from its density in space, it's 6.5KW:m^2. At this system's 2MW transmission rate, is only 308m^2, or a square 17.5m on a side. If it's really RF, even if the interlock failsafe failed, the beam wouldn't do much except fry some unshielded electronics in the way until something else shut it down. I'm sure the multiple layers of government regulators will ensure a lot of "deadman switches" to stop the only thing that everyone guesses could go wrong.

    • Re: (Score:3, Insightful)

      by EdZ (755139)
      Any micrometeor with sufficient energy to give a massive solar power array enough rotational velocity to point it in a wildly different direction before the change is noticed and corrected will likely smash it to bits anyway.
    • Re: (Score:3, Funny)

      by furby076 (1461805)
      Free tans for everyone?
  • I've seen this (Score:3, Interesting)

    by ArcherB (796902) on Tuesday April 14, 2009 @07:16AM (#27568519) Journal

    They mentioned it in the first Robocop movie.

  • by Cornwallis (1188489) * on Tuesday April 14, 2009 @07:17AM (#27568527)
    couldn't this also be used as a weapon?
  • makes no sense (Score:3, Insightful)

    by speedtux (1307149) on Tuesday April 14, 2009 @07:18AM (#27568533)

    If you're lucky, you gain a factor of 2-4 in efficiency by going into space, but the costs per photocell are astronomically higher compared to installation in a desert.

    That's, of course, assuming you can actually get other nations to agree to let you place a massive power plant and emitter in orbit, something that could easily be weaponized.

    • Re: (Score:3, Insightful)

      by QuantumG (50515) *

      Ya know what else is astronomically more expensive? Getting power from a desert to where it is needed, and buying all that land in a desert. I'm not saying SSP is remotely close to being cost effective yet, but there's simply more to crunching the numbers than you think there is.

      • Re:makes no sense (Score:5, Interesting)

        by Doc Ruby (173196) on Tuesday April 14, 2009 @08:33AM (#27569413) Homepage Journal

        Buying desert land isn't "astronomically expensive". It's about the cheapest land there is. There happens to be huge deserts of dirt-cheap (cheaper: sand-cheap) land all around California. Besides, this 2MW satellite probably doesn't even need more than about 25m^2 to receive its beam at 5x solar density. If they wanted to be really safe, they probably could diffuse it over 2500m^2, for 5W:m^2, which doesn't hurt anyone.

        The efficiency here is the 30% extra incoming solar power that is otherwise lost in the atmosphere (minus some small lost amount they're tuning the beam to minimize), times the 24/7 uptime instead of about 25% terrestrial due to night/weather/seasons. That's a starting point of 520%. But the other advantage is the much larger area that thin collector sheets can cover in space. Launching costs money per mass, but the collectors can unfurl across kilometers. And the maintenance costs in microgravity/femtopressure are much lower over years, despite the remoteness. After the large initial costs, the ongoing costs per watt are extremely low.

        2MW would require only about 40x40m collectors. A square kilometer collector would bring 1.3GW. The geosync satellite beaming to Fresno could receive from collectors in all kinds of other orbits pointing at the hub. This infrastructure could conceivably bring all 17TW of Earth's energy consumption into a series of ground stations from only about 114*114 Km of collectors. A few score hubs around the equator each using a few dozen GW lasers could replace all the coal currently burned for stationary power. The sky is literally the limit.

    • by oneiros27 (46144)

      The only other factor that I can think of are land cost and maintenance costs. I'd assume you'd still want a large area of land, just in case the system should go off course, so that one might not be a significant difference, so that just leaves us with maintenance -- how much effort is it to keep a similarly producing land-based system, vs. keeping an eye on the satellite and keeping a smaller ground-based receiver going?

  • by BadAnalogyGuy (945258) <BadAnalogyGuy@gmail.com> on Tuesday April 14, 2009 @07:19AM (#27568535)

    As long as you turn off disasters, beamed solar energy is actually a fairly cost effective power solution.

  • No, these don't work like SimCity. The microwaves are not the frequency used in ovens -- ie that heat up water. Otherwise they wouldn't be much use on a cloudy day.

    It's a very positive development. Orbital solar power is the best foothold for the colonisation, industrialisation and settlement of intrasolar space.

    • Near the receiving station, there is no such thing as a cloudy day.

      Especially if it is the same frequency as water.

      "Fresno, home of the 5 minute tan!!*"

      *: Some limitations apply.

      • You've misread me. I said it does not interact with water.

        The point is that if you want to transmit power, you want to minimise power losses. If you choose a frequency that does not interact with atmospheric gasses -- including water vapour -- then you minimise those losses.

        It does not interact with water, including the water which makes up your person.

    • by mc1138 (718275)
      Wow I wish I'd read through all the comments first... I just made a Sim City joke. Though mine was more of a reference to what happened when the beam missed rather than something specific about the mechanics of the process.
      • Pretty much any time orbital solar gets discussed on Slashdot, there's a bunch of jokes about Sim City, somebody wonders if it can be weaponised and somebody else thinks we're all going to be cooked. It makes me grind my teeth, orbital solar is one of my areas of interest. Usually I'm too late to add to the discussion, but not this time! :D

        Still, for a bunch of geeks, Slashdot users sometimes seem to know very little about space. :/

  • by Ihlosi (895663) on Tuesday April 14, 2009 @07:23AM (#27568573)
    Or are they really saying they're going to install roughly 200000 m^2 worth of solar collectors in space? That's a square of roughly 450x450m. And "some startup" is planning a feat like that?
    • Re: (Score:3, Interesting)

      by tomtomtom777 (1148633)

      Or are they really saying they're going to install roughly 200000 m^2 worth of solar collectors in space? That's a square of roughly 450x450m. And "some startup" is planning a feat like that?

      Nope. The amount of sunlight per m2 in space is several factors higher than on earth.

      • by Jacques Chester (151652) on Tuesday April 14, 2009 @07:35AM (#27568669)

        Plus in space solar power is available constantly, rather than being affected by night time, winter hours and weather. As they point out you don't have to pay for the real estate, just the trip to get there.

        And it gives more consistent power because you don't get dust settling on the panels. I realise that sounds stupid, but dust can reduce efficiency by a lot in a few years; your costs go up because you have to pay people to be cleaning acres and acres of solar panels.

        • by dykofone (787059)
          If you put the panels in orbit to be constantly on the day-side of the earth, then yeah, the power is constant. My question is how they plan to beam that energy around the earth to Fresno at night. Seems you'd have to have the array in geosynchronous orbit above Fresno to maintain that beam, which means the array will be in the earth's shadow just less than half the time.
          • by Jacques Chester (151652) on Tuesday April 14, 2009 @07:53AM (#27568827)

            There are a number of points you can choose that are geostationary and in shadow less than 2% of the time (as I recall the 1970s proposal). Other schemes call for having multiple satellites that hand off to each other. This proposal is I think of the former variety.

          • Re: (Score:2, Informative)

            by ATestR (1060586)
            which means the array will be in the earth's shadow just less than half the time.

            Not really. A Geostationary orbit (over the same point) would cut through Earth's shadow for about 45 minutes on orbits where the orbital inclination lines up with the sun... generally in the spring and fall. Other times, the orbit is up to 23 degress off the Earth-Sun plane, and not in the shade at all. Since this power interruption would occur at "midnight", it probably won't affect peak power usage at all. And if you pu

        • Re: (Score:3, Insightful)

          This _strongly_ depends on your orbit and your technology. Unless your collector is a sphere of solar cells, your collector or reflector arrangement will get different efficiencies depending on where it is pointing relative to the Sun. And for many geosynchronous orbits, the Earth will occlude the sunlight in the middle of the night.

          Now, the currently available geosynchronous orbital space is dangerously cluttered. Big mirrors there are begging to get hit by satellite debris. A reasonably large solar mirror

      • by Ihlosi (895663) on Tuesday April 14, 2009 @07:39AM (#27568699)
        Nope. The amount of sunlight per m2 in space is several factors higher than on earth.

        The solar constant is about 1.4 kW/m^2 in Earths orbit. I fail to see how they want to produce 200 MW with significantly less than 0.2 km^2 of collector area. Care to explain it to me?

        • by baffled (1034554)
          Smoke and mirrors. Minus the smoke.
        • by Doc Ruby (173196) on Tuesday April 14, 2009 @08:54AM (#27569711) Homepage Journal

          How about I convince you they're planning to deliver only 2MW, not 200MW.

          They say they'll reach a 17GWh:y delivery once the platform is stable. There's 8765.81277 hours in a year, so that's 17 billionWh / 8765.81277h = 1.9393524 million watts.

          The solar "constant" [wikipedia.org] in geosync Earth orbit (about 35Km elevation) is 1366W:m^2. That's 1419.73089m^2, or 0.00141973089Km^2, significantly less (0.709865445%) than 0.2Km^2.

    • It doesn't have to be thick: the old, classic scheme is to use a reflector of extremely thin foil to concentrate the energy on a central collector, and use that to transform and beam the microwave more tightly to a target. The big, big concern is weaponry uses, followed by security: the more efficient and effective the system, the more potentially dangerous for aiming at a neighborhood or a building. I'd be extremely concerned about the security of the control system for such collectors, although I see this
      • Re: (Score:3, Insightful)

        by tygerstripes (832644)
        Another advantage is the potential mobility of energy infrastructure that this provides. If production and distribution of electricity no longer need to be physically connected by heavy infrastructure, it becomes much easier to move and distribute the energy to where it's most needed. Mobile power-generation could be operated without constant fuel supply. More significantly, the daily and seasonal fluctuations in energy requirements throughout the world could be mitigated by redirecting collected solar ener
      • Re: (Score:3, Informative)

        1. Orbital solar platforms cannot be used as weapons unless you are trying to drop them on someone (which is true of anything in orbit). The energy they put out is the wrong frequency; it doesn't interact with human biology at all.

        2. If you can build 25 ton to LEO heavy lifters, James Bondesque schemes are a waste of time. Better to lob nukes. Heck, even throwing a 25 ton block of concrete on a ballistic course would be more far, far more dangerous than 100 years of orbital solar power transmissions.

        • by Ihlosi (895663)
          1. Orbital solar platforms cannot be used as weapons unless you are trying to drop them on someone (which is true of anything in orbit). The energy they put out is the wrong frequency; it doesn't interact with human biology at all.

          Well, does it interact with anything else? Communications, airplanes, missiles, buildings? Who says that a weapon needs to be able to kill people?

    • Maybe a bunch of these could be used to block out the sun, and thus, reverse Global Warming?

      • 1. Very expensive way to perform geoengineering. There are cheaper proposals (iron seeding, spray boats, atmospheric particles etc) around.

        2. Sunlight exerts pressure, so if it's not in an orbit, it will soon be on its way out of the solar system. There was a proposal to build fresnel lenses instead.

    • maybe they are thinking to reuse all those progress solar panels instead of burning them together with the spaceship.

  • by Big Nothing (229456) <big.nothing@bigger.com> on Tuesday April 14, 2009 @07:29AM (#27568625)

    "PG&E Makes Deal For Solar Power From Space"

    Is there any other kind?

  • This is an excellent use for Fresno. I approve.

  • by muffen (321442) on Tuesday April 14, 2009 @07:41AM (#27568725)
    I saw a documentary [wordpress.com] on Discovery a few months ago, it was an episode part of "Discovery Project Earth".
    I found it extremely fascinating and was wondering if it would just die or if there would be some actual results from the project, seems like we are getting somewhere now!

    I remember from the documentary that the biggest problem was the beam being split in two, rather than one focused beam. Hopefully they found a solution to this problem.
    Anyways, I strongly suggest watching the documentary if you are interested in this, it really shows how the idea was born and all the small advancements they made which resulted in a successful test.
  • "space satellites could generate power 24 hours a day, unaffected by cloudy weather or Earth's day-night cycle."

    That might be true depending on the orbit. If it's in an expensive synchronous orbit it will still be in earth's shadow once a day but I would expect that the beam would have a pretty large diameter at Fresno. If it's in any other orbit Fresno will be in line of sight for only part of the time. So how do they generate and transfer power over 90% of the time?

  • ok, wait a second (Score:3, Insightful)

    by blind biker (1066130) on Tuesday April 14, 2009 @07:51AM (#27568809) Journal

    I am really a supporter of solar energy - I even have invested some of my money in it - but THIS to me seems like technological masturbation. I do not believe it's cost-effective, and the debris in orbit is only going to increase, so it's a risky investment in any case.

  • I had a lunatic prof in college who advocated this stuff, along with laser powered lightcraft. The technology really works - as he put it, if we can hit an ICBM at Mach 20 with a laser, we can hit a spot on the (relatively) unmoving Earth with a laser.

  • This reminds me a lot of the Microwave power from Sim City 2000... Anyone remember the disaster that happened with the beam would occasionally miss?
  • These guys made this deal so that they can get investors and loans to build the thing. It's no risk to PG&E, and now these guys have to execute.

  • ...Solaren was purchased by the Mikado Group, whose chairman, Dauragon C. Mikado, says that the satellite plan will bring ultimate power...

    listens to the crickets

    Yeah...didn't expect many people to get that reference.

    Dan Aris

  • by LabRat (8054)

    ...otherwise kiss radio astronomy in North America goodbye. Those guys thought they were getting interference from the Iridium constellation? Heh..wait until they get 200MW of broadband RF interference coming down on them from this monstrosity.

    Not to mention, this seems to be a complete waste of resources. I'd wager that at least as much land (if not more) will need to be dedicated to the antenna array as a 400MW (put in twice the power to make up for day-only operations) solar concentrator plant if they

  • SPSS (Score:4, Interesting)

    by Orgasmatron (8103) on Tuesday April 14, 2009 @08:43AM (#27569535)

    This really is very safe, and all the technology is known (not at this scale maybe, but known). The only thing that has stopped us from doing it already has been a lack of willpower.

    If you are sending microwaves from a smallish antenna (small enough that you can boost it into GEO, for example) all the way back to earth, the receiver needs to be huge, like many acres. Basically you find a good pasture, put posts in the ground every few dozen feet in a grid, run wires and diodes between the poles, and you now have a high efficiency rectenna and the cows grazing underneath won't even notice.

    Even if the beam wandered, the power per square meter isn't that high, and to get through the atmosphere with minimal losses, it won't be at a frequency that is easily absorbed by water, which means that it won't be at a frequency that is easily absorbed by you or me.

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