Is there a way to generate electricity that doesn't involve a turbine?

[Will_Repair]

Can’t think of a practical method but collapse the magnetic field around the wires.
(Reason for diodes across solenoids to prevent this opposite current.)

[CalMeacham]

I’m pretty sure that the energy cost of removing and disposing of the all the cat poop would offset any energy actually generated in this fashion.

Yeah, but you can put that in a digester and make methane. It’s a win-win situation!

[Bobotheoptimist]

I came to mention Seebeck Effect, but I see it’s been covered. IIRC this is used on a number of deep space probes, the ones that aren’t going to be hanging around close to the sun so can’t use solar power. Environmentalists freak out the launch because they use radioactive decay to provide the heat, even though they know how expensive it would be to send up a cat and someone to pet it.

[Mycroft_H]

@UncleRojelio

I’m pretty sure that the energy cost of removing and disposing of the all the cat poop would offset any energy actually generated in this fashion.

Good point. If CalMeacham’s option didn’t work, all the cat poop would need to be disposed of in Yuck-a mountain, and we all know what a pile of crap that process has been.

[Ludovic]

@Mycroft H.

Good point. If CalMeacham’s option didn’t work, all the cat poop would need to be disposed of in Yuck-a mountain, and we all know what a pile of crap that process has been.

Hey, one man’s Yuck-a mountain is another dog’s Big Rock Candy Mountain.

[Napier]

>IIRC this is used on a number of deep space probes, the ones that aren’t going to be hanging around close to the sun so can’t use solar power.

I had reason to research these radioisotopic thermopile generators recently. IIRC there have been 23 made in the United States, used on 17 different missions. They typically use Plutonium heat sources and lead telluride thermopiles. I think the cost is around $20,000 per watt.

When one particular space probe was sent off - I think it was Gallileo, or possibly Cassini - it took with it almost the entire US stock of Plutonium.

[Baron_Greenback]

@Mycroft H.

To make it feasible as a national energy policy option, would we all need to pet cats while hooked into the grid, or would we need to develop giant mutant cats that would be used as power plants?

Or we could all spend an hour or so each day petting a cat whilst walking up and down on a nylon carpet. At the end of this we all touch a door handle and then somehow the energy can be transferred to the national grid. I’m filing highly speculative patents as we speak.

[Fear_Itself]

@Napier

>When one particular space probe was sent off - I think it was Gallileo, or possibly Cassini - it took with it almost the entire US stock of Plutonium.

Unlikely. In 1996 (the year before the Cassini launch), the US inventory of plutonium was 99 metric tons.In contrast, Cassini used only 72 pounds, and Galileo used a mere 48 pounds.

[matt]

@Fear Itself

Unlikely. In 1996 (the year before the Cassini launch), the US inventory of plutonium was 99 metric tons.In contrast, Cassini used only 72 pounds, and Galileo used a mere 48 pounds.

Ah, but the thermoelectric generators use Plutonium 238, which is hard to produce and is only synthesised in very small amounts for this specific application. Whereas fissile Plutonium 239 is far easier to produce and is synthesised in large amounts to make pits for fission bombs. So if we’re talking about Pu 238, it is very possible that an entire current inventory was blown on one satellite.

[Bobotheoptimist]

Yeah, change that to Pu 238, and I’d believe it. I think we imported much of the 238 we use from Russia, under the agreement that it wouldn’t be used for military purposes. The best cite I can find at the moment is this, which is primarily about the government trying to build a facility near Yellowstone to make more of the stuff. It says known missions will require 55 pounds of plutonium by the end of the decade, and since the Yellowstone plant won’t be online for a few years (if ever, I’ve not followed this so I know nothing about its current status), those 55 pounds probably will be bought from [DEL]the Soviet Union[/DEL] Russia as needed, rather than have stockpiles laying around.

still seems weird to call it “Russia” rather than “The USSR”. I guess I’m showing my age again.

[Santo_Rugger]

@Napier

<snip>

When one particular space probe was sent off - I think it was Gallileo, or possibly Cassini - it took with it almost the entire US stock of Plutonium.

Cite?

[Strain_of_Thought]

@Mycroft H.

…would we need to develop giant mutant cats that would be used as power plants?

I think the real energy hole would be the motors in the giant robotic hand needed to do the petting.

[Kevbo]

One class of electrical generator uses only electric fields rather than magnetic fields. These tend to generate quite high voltage, but minuscule current. Wimhurst machines and Van deGraf generators are the most common examples.

[Napier]

>So if we’re talking about Pu 238, it is very possible that an entire current inventory was blown on one satellite.

I think I remembered incorrectly and should have said specifically Pu 238, as you guessed. I hunted around unsuccessfully for my original cites - I’m at home now and my record of them is at work - but I did find many that discuss the dwindling US stockpile of Pu 238 and growing need for it in RTGs.

Thanks for straightening me out!

[USCDiver]

@Napier

Like others point out, the Earth’s magnetic field isn’t typically used in power generation. In fact as far as I know it has never been used to generate useful power, though I am not certain.

In the late 1990’s NASA ran a series of experiments from the Space Shuttle using a thin (shoestring sized) conductive wire wrapped in insulation and deploying it slowly. The conductive wire moving through the Earth’s magnetic field generated a current.

I googled “Tethered Satellite System” to find this link

The motion of the conducting tether across the earth’s magnetic field generates an electric field along the tether which becomes in fact an unipolar generator. With a 20 km tether, moving perpendicular to the magnetic field, one obtains a maximum potential difference between the two terminations of 5 kV.