The soletta is back…

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In the ’90s, Russia experimented with an orbital solar mirror (Znamya) for night-time illumination and Kim Stanley Robinson popularised the idea in his Mars trilogy where it was a part of terraforming Mars. It now appears that California has given the go-ahead to the construction of another for providing 200MW of electrical energy

I love the idea, but can’t help wondering:

  • What fraction of the total lifetime energy yield is represented by the launch into orbit.
  • How much energy collected in orbit can be beamed to the surface without exacerbating global warming. Granted, 200MW seems pretty innocuous, but so did the first 1000 automobiles.
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3 Responses to “The soletta is back…”

  1. j2 Says:

    Wow, given the cost of putting objects into orbit I can’t imagine this will be affordable for a long time + without a space elevator. I don’t think we have a lack of energy, we are inefficient at collecting that energy.

    I think you’re right about warming also. The prime purpose of the soletta in the Mars trilogy _was_ raising the surface temperature.

    I would further say this only makes sense on a large scale if you’ve burned up your petroleum reserves enough to develop technology to the point where you just need slightly more energy to develop a 100% replacement for petroleum, and are willing to risk/sacrifice surface viability. (or are areoforming, etc)

    And it still seems to me there are way cheaper ways to collect that energy.

  2. Ed Davies Says:

    Let’s wave some numbers around.

    Average European’s energy usage: 6 kW
    Population of the UK: 60e6
    Area of the UK: 240e3 km² = 240e9 m²
    Approximate human power density across the country: 6e3 * 60e6 / 240e9 = 1.5 W/m²

    However, 73% (I think it is) of the Earth’s surface is ocean so the country should get an area ocean share of 2.7 times its own area so the power density at UK levels planet wide would average out to 0.555 W/m². Actually most of the world will have lower power densities across their land: the US because it’s so big, most of the rest because of their low per capita power usage. Britain is one of the denser populated areas of Europe (I think England (not Britain) has now overtaken the Netherlands as the most densely populated) so the average even for the whole of Europe would probably be slightly lower. I’m guessing Japan would be the exception and on a par with or more power dense than Europe.

    Anyway, I’m not absolutely sure of the numbers but I think this is significantly less than the current AGW forcing though a bit more than the effect of the variation in solar input across the solar cycle.

    That’s even if all power comes from sources which would not otherwise get dissipated across the landscape anyway: e.g., from fossil, nuclear or space, rather than solar, wind, hydro, wave or tide.

  3. Roland Turner Says:

    J> And it still seems to me there are way cheaper ways to collect
    J> that energy.

    I’d have thought so, yes. Various industrial-scale solar systems (none photovoltaic) in experimental use in parts of Australia spring to mind.

    ed> this is significantly less than the current AGW

    Every individual source of AGW is significantly less than the total!

    My concern is that if you introduce more heat into the biosphere (assume an orbit wherein the collectors aren’t casting a corresponding shadow on the Earth) then, any way you cut it, there’s more heat trapped in the increasingly-CO2-saturated greenhouse in which we live.

    It is possible of course that any substitution of CO2-releasing energy generation 1:1 with this approach would leave the total heat the same, but in reducing CO2 emission would improve the atmosphere’s ability to dump heat, but it’s far from clear that _adding_ “clean” power sources will _reduce_ aggregate CO2 emission.

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