Can you make a generator that produces electricity from salt water?

[stephenkohnle53]

I know very little about engineering and I would like to know if its possible to create a generator that uses salt water similarly to a salt water battery and generates electricity by simply being placed in salt water.

 

[anorlunda]

That is very interesting promising technology. I think the simple answer to your question is that sea water is not salty enough. In fact, the Wikipedia article below says that they may increase the salinity so far that it is not salty water, but closer to a bed of wet salt.

The less simple answer is that if that company could produce infinite cheap energy from the sea, they would be the richest people on earth, but they're not.

https://en.wikipedia.org/wiki/Salt_water_battery

 

[Vitro]

I know very little about engineering and I would like to know if its possible to create a generator that uses salt water similarly to a salt water battery and generates electricity by simply being placed in salt water.

The salt water is not the source of energy in such a battery, it is just the electrolyte. The energy is stored in the electrode (anode) material.

Take a magnesium rod and a graphite rod, stick them in salt water, or even in your back yard soil, hook up wires to them and you have a 1.8V battery. As you use this battery the magnesium rod will consume away, that's where the energy comes from. Once the magnesium is depleted the battery is dead. You can replace the magnesium rod and the battery works again, but keep in mind that the magnesium (or other material you could use) is not free so neither is the energy.

 

[anorlunda]

Take a magnesium rod and a graphite rod, stick them in salt water, or even in your back yard soil, hook up wires to them and you have a 1.8V battery. As you use this battery the magnesium rod will consume away, that's where the energy comes from. Once the magnesium is depleted the battery is dead. You can replace the magnesium rod and the battery works again, but keep in mind that the magnesium (or other material you could use) is not free so neither is the energy.

What you said is correct, but I think the salt water battery in this thread is not like that. Neither anone nor cathode are conserved. It is rechargeable.

SIBs store energy in chemical bonds of the anode. Charging the battery forces Na+ ions to de-intercalate from the cathode and migrate towards the anode. Charge balancing electrons pass from the cathode through the external circuitcontaining the charger and into the anode. During discharge the process reverses. Once a circuit is completed electrons pass back from the anode to the cathode and the Na+ ions travel back to the cathode.

 

[Vitro]

What you said is correct, but I think the salt water battery in this thread is not like that. Neither anone nor cathode are conserved. It is rechargeable.

Judging from the word "generator" in the title I think the OP is wondering about some method of extracting energy from sea water, not a (rechargeable) battery as an energy storage device. I'm pointing out to him that the energy in a galvanic cell is in the electrodes not in the electrolyte.

 

[DrZoidberg]

That is very interesting promising technology. I think the simple answer to your question is that sea water is not salty enough. In fact, the Wikipedia article below says that they may increase the salinity so far that it is not salty water, but closer to a bed of wet salt.

The less simple answer is that if that company could produce infinite cheap energy from the sea, they would be the richest people on earth, but they're not.

https://en.wikipedia.org/wiki/Salt_water_battery

That's not a real article, that's an ad. Someone should replace it with actually useful information.

 

[anorlunda]

That's not a real article, that's an ad. Someone should replace it with actually useful information.

You're right. Re-reading that article, it does sound more ad-like than science-like. However, the very first sentence on that page links to https://en.wikipedia.org/wiki/Sodium-ion_battery that I quoted in #4. That article seems to be more based on the peer reviewed papers referenced.

 

[stephenkohnle53]

My plan is preferably a generator that uses salt water or a battery that can store massive amounts of power (for a salt water battery that is). Either way it must be easy to use and not require say a forklift to lift if needed to be lifted out of the water. I would like it to be something that automatically creates or stores electricity while in salt water. Thanks for the info, as you can tell I have barely even touched engineering.

 

[anorlunda]

My plan is preferably a generator that uses salt water or a battery that can store massive amounts of power (for a salt water battery that is). Either way it must be easy to use and not require say a forklift to lift if needed to be lifted out of the water. I would like it to be something that automatically creates or stores electricity while in salt water. Thanks for the info, as you can tell I have barely even touched engineering.

Sorry, no such device exists, batteries don't create energy, they store it.

 

[rbelli1]

batteries don't create energy, they store it.

Even primary batteries. You extract energy put there in the manufacture of the materials comprising the battery. This is an enclosed version of @Vitro's rods in the ground.

At best you could design a battery that consumes waste materials. Then the stored energy is liberated from "garbage". It will still only give back energy previously stored.

BoB

 

[CWatters]

I know very little about engineering and I would like to know if its possible to create a generator that uses salt water similarly to a salt water battery and generates electricity by simply being placed in salt water.

Others have pointed out that a salt water battery works by consuming the materials it's made of not just the salt water. They are only practical for emergency life rafts and the like.

Perhaps read up on..
https://en.wikipedia.org/wiki/Osmotic_power

For that you need both fresh and salt water but both exist where rivers meet the sea. Has it's problems though.