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Building solar farms above the clouds

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Re: Building solar farms above the clouds

#31

Post by eric_h »

viacoffee wrote: post #28

Although it has always been a good idea for something like this. I'd be surprised if the FAA allowed such a thing to happen. It would have to be a permanent NOTAM, and in an already existing no-fly zone for personal aircraft.

Save you folks a google:

A Notice to Airmen (NOTAM or NoTAM) is a notice filed with an aviation authority to alert aircraft pilots of potential hazards along a flight route or at a location that could affect the safety of the flight.

NOTAM - Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/NOTAMWikipedia

Re: Building solar farms above the clouds

#32

Post by Htsthbjig »

Oh, yeah, and give me shadows in the land.

I hate the idea because it has the potential for abuse: If it works it means blocking the sky for those under. Like making clouds to artificially rain on your land, while not raining where it used to rain.

Sun is one of those fantastic things that is free. Free until someone has the idea to appropriate it.

Problems to aircraft makes this idea non practical near population centers, where energy is consumed. It is possible in the ocean.

Re: Building solar farms above the clouds

#33

Post by bigiain »

Findeton wrote: post #27

What kind of danger would this kind of thing pose to airplanes?

I was making this argument in another thread yesterday.

The fact that aviation currently assumes it has exclusive right to all airspace does not mean things have to be (or even should be) that way.

The vast majority of commercial air traffic file flight plans and flys along well know routes.

There's currently outcry about drone pilots "flying in dangerous manner for airplanes/helicopters", but it seems to me that nobody ever agreed that the occasional police or news helicopter flying over my local park was automatically reason to ban flying drones/kites/rc-aircraft there _ever_.

Same here, just because general aviation has had un-contested access to the sky and the freedom to assume they're entitled to unimpeded safety _everywhere_, is not something we've ever chosen - it's just "the way things have always been", which isn't necessarily "the way things should stay".

If someone comes up with a technical way to make tethered balloons work as a reliable and cost-effective renewable energy source - I personally don't think that "but it might impose a safety risk to airplanes who want to fly there" is a good enough reason to not allow them to try.

There's is (I suspect) a great "safety risk" to flying your Cessna or gyrocopter over, say, Area 51 or Groom Lake or The Whitehouse, why shouldn't pilots have the responsibility to avoid tethered-balloon electricity plants as well? Surely the net benefit to society of a few GW of renewable energy is way more than the ability of civilian pilots or news choppers to have unlimited access to all airspace at all times for no reason?

Re: Building solar farms above the clouds

#34

Post by gozur88 »

The fuel cell part is a bit dodgy. It would make more sense to include a little hydrogen bottle on the tether if extra H2 is needed to top of the balloon.

And there's no point to storing power in the air like that - it's better fed to the grid when the sun is shining to be stored at the grid level. Generating hydrogen just isn't a very efficient way to store power.

Re: Building solar farms above the clouds

#35

Post by kijin »

sevensor wrote: post #15
undersuit wrote: post #12

Earlier quoted context omitted.

They are energy collectors, I would assume you use some of that energy to heat the air in their balloons. I'm more interested in how you optimally position the solar cells, would a sphere really be the best or would a pontoon dragging in the wind give a better chance for the solar panels to receive optimal light? You probably don't want that 20km tether to be twisted too many times either.

Interesting point about placement --- seems like a dense array of these would be at risk of getting tangled. And then there's the risk of the tether / cabling becoming a conduit for electrostatic discharge. Of all the engineering issues here, I think tethering is the most problematic.

Put some propellers on the balloons, and a computer to control them.

If we can get drones to avoid trees while flying through a forest at high speed, we can make balloons maintain a safe distance from one another at an altitude way above most storms.

Re: Building solar farms above the clouds

#36

Post by oska »

Htsthbjig wrote: post #32

Oh, yeah, and give me shadows in the land. I hate the idea because it has the potential for abuse: If it works it means blocking the sky for those under. Like making clouds to artificially rain on your land, while not raining where it used to rain. Sun is one of those fantastic things that is free. Free until someone has the idea to appropriate it. Problems to aircraft makes this idea non practical near population ce…

The shadow from a balloon six kilometres up is basically non-existent. When was the last time you noticed a shadow from an overflying jetliner cruising at that height?

Re: Building solar farms above the clouds

#37

Post by dogma1138 »

CapitalistCartr wrote: post #23
notahacker wrote: post #21

Earlier quoted context omitted.

It gets dark in the stratosphere too, and the UK already has a power grid connecting it with the Spanish power grid which doesn't rely on 20km cables into the sky...

The parent post was about outer space, not the stratosphere. And that method uses microwave transmission, not cables.

Outer space gets dark too you not sure which orbit will get you 100 sun time solar synced orbits still get 50% night time. Maybe some geosync high polar orbit but then you have issues with transmition. Space solar makes very little sense you only get twice the solar power at 50% efficiency rate at best.

Re: Building solar farms above the clouds

#38

Post by kaybe »

sevensor wrote: post #10

How are these things supposed to stay aloft? They need to lift: 1) Themselves 2) The solar panels 3) Fuel cells 4) 20km of tether and cable The idea seems really neat, but I'm an engineer and I want to see the math. Edit: And how about that tether? What's the wind load going to be like? How is it moored? What is it made of?

An idea is to use rotating cylinders as balloons which generate lift (Magnus effect). It helps a little.

Re: Building solar farms above the clouds

#39

Post by shkkmo »

djKianoosh wrote: post #20
sevensor wrote: post #10

How are these things supposed to stay aloft? They need to lift: 1) Themselves 2) The solar panels 3) Fuel cells 4) 20km of tether and cable The idea seems really neat, but I'm an engineer and I want to see the math. Edit: And how about that tether? What's the wind load going to be like? How is it moored? What is it made of?

why tether? why not let the balloon charge a battery, and have drones carry the battery back to earth when full, and vice versa...

Batteries are heavy, lifting them with aircraft is significantly inefficient.

Re: Building solar farms above the clouds

#40

Post by aaron695 »

More junk science designed by artists?

Wind I can see making sense since at high altitudes, it's more constant.

Creating and storing the hydrogen in the balloon triggers a strong, this is just fluff. We can't really even do this on the ground.

They are inventing two new technologies we yet don't have?

I going to go with, it'll be better covering the other 98% of roof space with solar first. And get wind powered balloons going for night time use if you're going down this route.

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