Solar energy

[learnin to learn]

who thinks that solar power would be a better form of energy compaired to nuclear power?

fell free to commit!!!!

[rockytriton]

you can get energy for your lightbulbs only during the day with solar power.

[Turtle]

who thinks that solar power would be a better form of energy compaired to nuclear power?

fell free to commit!!!!

 

It's all Solar ultimately as the Earth is a product of dead Suns. :cup: To your point, I think nuclear generators have by far a greater efficiency & new designs - pebble bed reactors - make it adequately safe. Let's see - what is the ratio of people last year killed in automobiles over those killed by nuclear power plants? :hihi:

___The night issue of solar is mediated with storage systems - batteries, flywheels, etc. :cup:

[C1ay]

Perhaps I should point out that solar energy is nuclear energy, it's just that the reactor is 93,000,000 miles away. It would be more efficient to use on we could connect to directly than to simply attempt to collect the byproduct of such a distant reactor.

[rockytriton]

maybe we should build our own nuclear reactor in space that's just a little closer and not as big as the sun?

[Rincewind]

I think that a realistic energy supply has to include several forms of energy generation. We should be setting up solar energy collectors and wind farms to supplement to the maximum extent possible the generation of power through non-renewable sources like nuclear.

 

There is also some very good research being done into wave power generation.

 

With these inconsistently available energy sources such as solar, wind and wave, there has to be a method of storing the power or using it straight away. In parts of Australia, many people have solar panels on their houses, and actually, during peak generation times, they sell the excess power that they're not currently using back into the grid, and get credits for it on their power biils.

 

A few people (like, single digit) have sometimes had negative electricity bills, so it is possible even today to produce more energy through natural sources than certain households may need. This can only get better as the technology improves.

 

Energy (the human type) must be put into the development of constantly available energy sources, as the non-renewable uranium, gas, coal and oil powered ones will just eventually run out of fuel. Solar, wind and wave power has to be made to work for society before this happens.

[Jay-qu]

although technically both forms of energy are equally as good - it really comes down to how we havest it and the efficency that we can obtain. Undoubtably the sun is a great source of energy and although our techniques of harnessing solar energy are becoming more advanced I think that nuclear is a bit more convinent. My only problem with nuclear is having all the waste...

[CraigD]

Which is better – nuclear (fission) power or solar power, depends on a lot of complicated factors.

 

Short term - ~ 2*10^13 W – ordinary 21st century human power needs

Using current commercial reactors and U-235 mining and extraction plants, which currently supply about 7% of the worlds energy, there’s only about a 70 year supply of fuel remaining. New designs are clearly required (allowing the use of nearly 200-times more naturally abundant U-238), as well as safe way to store fission wastes. Such designs appear achievable, and should be capable of supplying tens of thousands of years of terrestrial human energy needs. It’s reasonable to assume that nuclear fission power can ultimately be very, very safe, despite the danger inherent in the handling of its fuel.

 

Current solar power generation technology is certainly inadequate for it to supply even a substantial fraction of the world’s energy needs. It’s reasonable to assume that improved designs could make it as adequate as nuclear power.

 

Both solar and nuclear power are ill-suited to all power generation applications, in particular vehicles and other portable, power-consuming devices. So, for either technology to replace fossil fuels (oil, coal), effective, high-energy-density storage systems (battery/capacitor, flywheel, hydrogen, etc.) is needed.

 

So, short term, there appears to be no compelling technical reason to prefer solar power over nuclear, or nuclear over solar.

 

Politically, it is an unfortunate reality that nuclear power capability also confers the technology necessary for the manufacture of nuclear weapon. Since it appears likely that political instability and war will persist into at least the near future, when considering the safety of nuclear power, it’s necessary to factor in the possibility of it being used to produce weapons that kill many millions of human beings.

 

So, short term, there appear to be compelling social and political reasons to prefer solar power over nuclear.

 

Long term - 10^17+ W – Ability to accelerate 100+ metric tons to .75 c each year

For this need, neither nuclear (fission or fusion) nor Earth-based solar power will be adequate. The only source of power currently envisioned that could satisfy these power requirements is space-based (eg: closely orbiting the Sun) solar power.

 

So, in the long term, solar power appear best, although of such an advanced nature that it bears little resemblance to current solar power technology.

[UncleAl]

Area necessary to generate 1 GW electrical, theoretical minimum

 

mi^2

Area, Modality

==============

1000 biomass

300 wind

60 solar

0.3 nuclear

[alexander]

we could always just send 2 satellites up in space and connect them with a wire and harness the power of the earth's magnetic field...

[Jay-qu]

we could always just send 2 satellites up in space and connect them with a wire and harness the power of the earth's magnetic field...

 

which isnt much power... The field is weak and its fading - it is at most 60microTesla on the surface, Im not sure if its stronger or weaker in space...

[CraigD]

we could always just send 2 satellites up in space and connect them with a wire and harness the power of the earth's magnetic field...

There’s a problem with the basic Physics of a “power tether” schemes like alexander describes. Such a system is essentially just a DC electric generator – it’s not extracting energy from the Earth’s magnetic field, but from the kinetic energy of its armature – the satellites and tether. To maintain the satellites in orbit requires that they be boosted, presumably with the usual hydrazine or combustible rocket propellants, which, unless the satellites are launched with huge masses of fuel, must be periodically refueled via supply rockets. However it’s done, the mechanical parts of the system and all the fuel it uses must be boosted into orbit, which requires a lot of propellant and other pricey stuff, not to mention safety and pollution concerns. In addition to its generating and orbit-maintaining parts, it needs parts to “beam” the energy back down to the ground.

 

:friday: All the system is, in essence, is an inefficient, expensive rocket-powered electric generator, not much good for generating power to be used on the Earth’s surface.

 

:hihi: For generating electricity to be used by the orbiter, power tethers appear to be promising – they can generate a lot of it, and might be mechanically simpler than other generators, such as solar cells, fuel cells, or conventional generators. They’re also potentially very versatile – like any electric generator, they can be “run backwards” to be a motor, allowing an orbiting spacecraft to be maneuvered, even de-orbited into atmospheric reentry, using nothing but electricity. In fact, most interest in orbital tethers is currently focused on their tether propulsion potential.

 

Actual experiments with tethers in orbit have proven them tricky to keep from power surging, shaking, and breaking, but who doesn’t like an engineering challenge :eek:

[alexander]

i never said it was supposed to be easy, but then what in this world is easy?

[CraigD]

i never said it was supposed to be easy, but then what in this world is easy?

Please allow me to clarify post #12.

 

Generating power using 2 orbiting satellites connected by a wire is innately not a good way to generate electric power to be used on the ground – you’d do better to burn the fuel you’d use to launch them and maintain their orbit in a conventional powerplant generator.

 

It’s potentially a good way to generate electric power to be used on the satellites, and an even better way to use electric power on them. To realize this potential, several seemingly tricky – and rewarding - engineering challenges must be met.

 

The payoff of working out the problems of tether propulsion is big. Imagine …

• a solar powered satellite with limitless maneuvering energy, able to change orbits at will. As long as it doesn’t mechanically wear out, such a satellite would last forever, never falling to Earth because of a decayed of orbit.
  
• a vessel able to quickly rendezvous with satellites in many orbit, carrying people, performing maintenance, etc., but requiring no expendable reaction mass.

Tether power is less promising as a generator of power than as a consumer of the ample solar power available in earth orbit.

[alexander]

what if there was a possibility of wirelessly transmitting electrical current without loss, say through a controlled wormhole...

[CraigD]

what if there was a possibility of wirelessly transmitting electrical current without loss, say through a controlled wormhole...

It matters not. The system is still an electric generator that requires a lot of energy (a launch into orbit) before it can begin requiring energy to maintain its orbit, which is converted into electricity.

 

The only way to get “free energy” via the Earth’s magnetic field, as near as I can tell, is to erect a rigid, conductive, 300 km pole from its surface to the ionosphere. This would then allow electricity to be generated by slightly reducing the Earth’s rate of rotation (so it’s not really “free”, just abundant – the earth has about 2*10^29 joules of kinetic energy – enough for 10^16 seconds (300 million years) of power at current world power demands. The material engineering challenges of erecting a 300 km tall rigid tower capable of withstanding the force of generating a substantial fraction of the worlds total power demands, however, are daunting! :friday:

[Erasmus00]

what if there was a possibility of wirelessly transmitting electrical current without loss, say through a controlled wormhole...

 

Regardless, magnetic fields don't do work, so any power you gain comes from power you put in. Sattelites would generate electricity by slowing down (or using fuel to increase their thrust). Its not extracting energy from a magnetic field, its extracting energy from sattelite fuel, which we can burn on the ground.

-Will