The Moon: Solving Earth's Energy Crisis

[VedekPako]

I watched a show on the NGC about colonizing the Moon last night. Then I realized before the mentioned it, if you networked solar power stations in a circle around the Moon, you could have a power grid that's always receiving solar energy and can be beamed back to Earth. The Moon does have the raw materials to construct solar panels.

 

Now, do we currently have the technology to do this and can anyone guestimate cost vs. other energies?

[Moontanman]

The first thing that comes to my mind is that it's a long way to beam energy, losses from the beams would be enormous.

[Cap'n Refsmmat]

There's a few ways to beam power. Microwaves work, but from geostationary orbit the beams diverge enough to require a 10km-wide antenna. From the Moon you'd be looking at one very large antenna. Lasers also work, but you'd still need a very large collection area and far better laser power technology. (Current lasers are not particularly efficient and would melt at the power needed for massive energy transfer.)

 

So it'd be a challenge. Building a large enough antenna for microwaves and not frying half a continent may be a challenge.

[Mr Skeptic]

If I recall, the plans for an orbital solar power plant with microwave beaming, involved a fairly large collector area on the planet, and weak enough microwaves that people could walk in that area without getting fried or particularly damaged.

[Tau Meson]

Would it be possible to somehow store that energy, rather than beam it all the way from the Moon back to Earth? This way the only logistics that need to be worked out would be transportation, rather than figuring out how not to fry the Earth.

[Cap'n Refsmmat]

If I recall, the plans for an orbital solar power plant with microwave beaming, involved a fairly large collector area on the planet, and weak enough microwaves that people could walk in that area without getting fried or particularly damaged.

 

Yes indeed. They suggest a sort of mesh antenna about 10km wide that you could even plant crops under. The microwave exposure around the edges would not be above any safety levels, and efficiency would be around 80% for transfer. But if you beam all the way from the moon, that antenna will have to be several times larger. (And the costs of a 10km diameter giant metal antenna are already substantial.)

[Mr Skeptic]

You can't store a constant stream of energy; eventually you will run out of storage. Besides, we badly need the energy here on earth, where we are still burning fossil fuels to supply a large portion of it... and we can't just keep doing that.

[Tau Meson]

I understand that, but whats to stop them from just simply supplying only what is in demand, rather than just taking it all in constantly? For one, you can only make solar panels so big, so there is a physical limit to how much energy you can collect. Even fossil fuel power plants don't just keep generating large amounts of electricity when very little of it is in demand.

[Moontanman]

I would think that beaming large amounts of power to the earth would have negative consequences, beams from the moon would not be focused very small and would no doubt be spread all over the entire earth. To make them concentrated enough to be useful would require beaming many times the power needed to make up for beam loss. I honestly cannot see this being a viable alternative.

[Mr Skeptic]

Solar energy is essentially limitless, at least compared to the absolutely minuscule quantities of energy we use.

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I would think that beaming large amounts of power to the earth would have negative consequences, beams from the moon would not be focused very small and would no doubt be spread all over the entire earth. To make them concentrated enough to be useful would require beaming many times the power needed to make up for beam loss. I honestly cannot see this being a viable alternative.

 

In space the sun always shines, and shines good and bright. Constant, high power energy.

 

On earth, it shines less than half the time. The atmosphere eats all the highly energetic UV rays, and the intensity varies as the time of day. And then there's night. Even with significant losses, space solar has a big advantage in overall power, and then add to that the fact that you don't need to store it for night time. Storing a night's worth of energy will cause significant losses and even more significant costs.

[Moontanman]

Solar energy is essentially limitless, at least compared to the absolutely minuscule quantities of energy we use.

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Consecutive posts merged

 

 

In space the sun always shines, and shines good and bright. Constant, high power energy.

 

On earth, it shines less than half the time. The atmosphere eats all the highly energetic UV rays, and the intensity varies as the time of day. And then there's night. Even with significant losses, space solar has a big advantage in overall power, and then add to that the fact that you don't need to store it for night time. Storing a night's worth of energy will cause significant losses and even more significant costs.

 

Skeptic, what does this have to do with beaming power from the moon? i know it could be done, it's the doing of out that will be difficult. beaming power from the moon is considerably different than beaming power from geo orbit .

[Tau Meson]

I would also like to add that I looked up space based solar power all over the net, and from what I'm reading these systems would have to be pretty huge. And this is only from orbit. Does anyone know how much power is lost through a beam? We might be able to come up with a quick calculation for how strong the beam from the moon would have to be in order to power the Earth, and thus how large the solar power plants on the moon would have to be.

[Cap'n Refsmmat]

The very best microwave systems from geosynchronous orbit could get perhaps 85% efficiency in transfer. There would likely be more losses in transformers and transmission on the ground, of course -- this is just DC power in to DC power out on the ground.

 

(I wrote a research proposal on this last semester)

[VedekPako]

Well look at the bright side. The Microwave Beam could also be used as a weapon; so any nation that operated it, would have more political weight along with energy...!!!

 

 

Ok, I want to move past science fiction and concept, to reality. I've been thinking of starting a solar power company, but what if, what if I could actually build solar power plants on the Moon?

 

I'm sure the costs are astronomical*, but, if the technology's there, or may be available at a time when I have the proper funding, this might be possible.

 

 

*Literally

[Mr Skeptic]

Actually, its military potential is a huge drawback. Anyone can legitimately attack it, claiming it is a weapon, and likewise legitimately have a system designed to kill it. Therefore it should be designed to be inherently safe, or at least trackable.

[dragonstar57]

a solar power stations could be used to charge giant batteries and then fired at the earth on a rail gun

i don't think it would be very efficient tho

but the energy is badly needed for a solar colony EM radiation shield

[Moontanman]

I think the best way for the moon to solve Earth's energy crisis is by providing Helium3 for aneutronic fusion. Yes Solar power can be used to extract the helium3 from the moon, helium3 is energy dense enough make it worth while to bring it to the Earth and aneutronic fusion creates no radioactive waste and can be turned directly into electricity without steam and other inefficient means of generation.

[Airbrush]

I think the best way for the moon to solve Earth's energy crisis is by providing Helium3 for aneutronic fusion. Yes Solar power can be used to extract the helium3 from the moon, helium3 is energy dense enough make it worth while to bring it to the Earth and aneutronic fusion creates no radioactive waste and can be turned directly into electricity without steam and other inefficient means of generation.

 

That sounds great. Can you go into more detail how this is done? Have robotic factories on the Moon extracting helium3. How is it extracted? Then fill space shuttles with He3 to fly back to Earth and re-enter like the space shuttle with a few tons of He3?

 

.....if you networked solar power stations in a circle around the Moon, you could have a power grid that's always receiving solar energy and can be beamed back to Earth. The Moon does have the raw materials to construct solar panels.

 

The question is why try to beam energy from so far away when you could accomplish the same more efficiently by solar power stations gathering energy in Earth orbit?

[Ophiolite]

The question is why try to beam energy from so far away when you could accomplish the same more efficiently by solar power stations gathering energy in Earth orbit?

Because the solar panels could be produced in situ from lunar materials, not flown to Earth orbit at large energy cost. You would only need to launch the initial robotic factories.

[CaptainPanic]

Because the solar panels could be produced in situ from lunar materials, not flown to Earth orbit at large energy cost. You would only need to launch the initial robotic factories.

 

We can build solar panels in situ on earth as well... and use them here, right where we need the energy. Seems easier to me?

 

Some advantages that come to mind:

- We have a large industrial infrastructure here on earth.

- The energy is required here as well.

- Maintenance is cheaper here (although admittedly, they get dirtier here as well, because of rain, wind, birds and dust).

- Earth based solar panels receive free air-cooling, while lunar solar panels will just get toasted in the sun. Silicon based solar cells decrease in efficiency at higher temperatures.

- There is plenty of space available to place solar cells on earth. The area required to substitute all our electricity by solar electricity is still not much more than all the space on the roofs of all buildings.

[swansont]

We can build solar panels in situ on earth as well... and use them here, right where we need the energy. Seems easier to me?

 

- Maintenance is cheaper here (although admittedly, they get dirtier here as well, because of rain, wind, birds and dust).

 

 

Not necessarily dirtier. Lunar dirt/dust is quite nasty; it adheres really well and is notorious for the difficulties it caused for mechanical systems on the Apollo missions.

 

[E]ven the vacuum cleaner that was designed to clean off the dust clogged down and jammed.

 

http://www.space.com/scienceastronomy/061007_moon_dust.html

[Airbrush]

We can build solar panels in situ on earth as well... and use them here, right where we need the energy. Seems easier to me?

 

Some advantages that come to mind:

- We have a large industrial infrastructure here on earth.

- The energy is required here as well.

- Maintenance is cheaper here (although admittedly, they get dirtier here as well, because of rain, wind, birds and dust).

- Earth based solar panels receive free air-cooling, while lunar solar panels will just get toasted in the sun. Silicon based solar cells decrease in efficiency at higher temperatures.

- There is plenty of space available to place solar cells on earth. The area required to substitute all our electricity by solar electricity is still not much more than all the space on the roofs of all buildings.

 

Solar farms are generally planned for desert areas that get very little rain (but rain would clean the panels), little wind, no birds (in fact birds should be afraid of shiny reflecting surfaces), but dust may accumulate slowly. If they are positioned at a steep angle dust will not settle as much.

 

Would solar panels in space get "toasted in the sun"? I don't think so. Otherwise they would be replacing the space station solar panels regularly. Do they?

 

Interesting info about roofs of all buildings would be more than enough solar panel surface area for all energy needs. Where did you find that?

 

"Solving Earth's Energy Crisis" will more likely be thru diverse energy means, including solar, wind, nuclear, geothermal, hydro-electric, fuel from corn, switch grass, garbage, and what's left of "dirty energy" coal and oil. I believe also algae can be a source of energy generation.

 

How about tidal power? Build dam-like structures along coastlines that have significant tidal action. Maybe Bay of Fundy? As water flows thru the dam, turbines generate power. Any others? How about tapping into volcanos, especially supervolcanos like Yellowstone?

Edited August 25, 2010 by Airbrush

[CaptainPanic]

Not necessarily dirtier. Lunar dirt/dust is quite nasty; it adheres really well and is notorious for the difficulties it caused for mechanical systems on the Apollo missions.

 

[E]ven the vacuum cleaner that was designed to clean off the dust clogged down and jammed.

 

http://www.space.com/scienceastronomy/061007_moon_dust.html

 

yes, if the solar panels get covered in dust during construction, then that's a problem. But after construction is complete, they will remain clean... there is no wind to carry the dust to the panels.

 

I believe I heard a story that the the Russians (or rather the Soviets) placed some mirrors on the moon. Those are still reflective 30 or 40 years after. Try that with an earth based piece of glass.

 

Solar farms are generally planned for desert areas that get very little rain (but rain would clean the panels), little wind, no birds (in fact birds should be afraid of shiny reflecting surfaces), but dust may accumulate slowly. If they are positioned at a steep angle dust will not settle as much.

The angle of the solar panel is governed by the position of the sun, (or perhaps by the whims of the architect if they're placed on buildings... but let's assume that we just make a farm, so those things follow the sun).

Rain is actually quite dirty at times. Most raindrops form around an aerosol. Fact is that solar panels need to be cleaned. Deserts can have dust storms.

 

Would solar panels in space get "toasted in the sun"? I don't think so. Otherwise they would be replacing the space station solar panels regularly. Do they?

Ok, I chose my words a bit too strong. Fact is though that the regular silicon based solar cells (the ones we talk about here, the ones for which the materials are available on the moon) are less efficient at higher temperatures.

Space based solar panels aren't the regular solar panels that are placed on roofs... I know quite little about those.

Interesting info about roofs of all buildings would be more than enough solar panel surface area for all energy needs. Where did you find that?

You can calculate it yourself. I checked some internet sources for the Netherlands (the total built area, the total area for housing, the total electricity demand, the insolation (amount of sun received per day on average) and the average efficiency of solar cells). With those numbers, I arrived at the conclusion that we just need to fill 65% of the roofs of houses (offices and industry therefore not included) with solar panels to replace all electricity.

If specifically asked for, I'll post the calculation in a separate thread.

 

"Solving Earth's Energy Crisis" will more likely be thru diverse energy means, including solar, wind, nuclear, geothermal, hydro-electric, fuel from corn, switch grass, garbage, and what's left of "dirty energy" coal and oil. I believe also algae can be a source of energy generation.

I don't believe in algae (yet). Most of the media attention focusses on the ridiculously high yields obtained in labs... 10% of the sun's energy converted into biomass or something. That will never be achieved in reality, simply because there are some limiting factors: oxygen is toxic at some point (needs to be removed). CO2 must be pumped into the water (using energy intensive turbines). The algae must be harvested, separated from water, dried. That all requires energy too. I saw many designs for closed systems (with transparent pipes) and I think they're all mad.

 

The only algae technology I believe in are the open systems - bassins where CO2 comes from the air, and oxygen can go into the atmosphere. During growth, little or no energy is needed.

 

How about tidal power? Build dam-like structures along coastlines that have significant tidal action. Maybe Bay of Fundy? As water flows thru the dam, turbines generate power. Any others? How about tapping into volcanos, especially supervolcanos like Yellowstone?

No idea about those... but I have little against it.

Personally, I am quite a big fan of the wind turbines. By now, I consider them proven technology. Biofuels can be an intermediate solution for the next 10 years (especially if we can put an end to the use of corn).

 

... but in the end, the energy crisis will only be solved if we stop population growth. That's the nasty conclusion... It's so nasty, because technology can do nothing about it.

[swansont]

yes, if the solar panels get covered in dust during construction, then that's a problem. But after construction is complete, they will remain clean... there is no wind to carry the dust to the panels.

 

I believe I heard a story that the the Russians (or rather the Soviets) placed some mirrors on the moon. Those are still reflective 30 or 40 years after. Try that with an earth based piece of glass.

 

 

 

You're going to have this problem present with robotic fabrication though. And the corner reflectors have gotten worse over the years, presumably from dust. Any impact (e.g. meteor) with the moon will kick up dust, which will be widely dispersed because gravity is weaker.

[Mr Skeptic]

Well there are plans to have some cleaning done too (eg on the panels for our next Mars rovers). If we're making solar panels on the moon I'd think we'd be able to scrub them down every decade or so. On earth washing will be easier but will need to be done more often for efficiency. Another factor is wear and tear. Dust storms or hailstorms will do nasty things to your solar panels, for example. On the moon there's none of that, but micrometeorites might be a problem instead.