Extremely long lasting energy storage solution

[tautech]

a mass, and a heavily geared motor for the generator, as long as the motor and gearing is sealed, and the grease / components do not break down over time, it will be ready to give unregulated power for a few minutes, by varying the mass and the gearing you can control the time and the wattage.

Lifting this principle a notch or two to minimise losses.
Mass = very high speed flywheel.
Bearings = magnetic levitation.
All sealed in a vacuum.

[janekm]

LiSoCl2 batteries, specifically the ones made by Tadiran: http://www.tadiranbat.com (unless you meant rechargeable? but they do make a rechargeable range too now...)
They've actually had batteries coming back after more than 30 years in the field still with capacity to spare. So now you just need to worry about the rest of your circuit and the idle current 

[coppice]

LiSoCl2 batteries, specifically the ones made by Tadiran: http://www.tadiranbat.com (unless you meant rechargeable? but they do make a rechargeable range too now...)
They've actually had batteries coming back after more than 30 years in the field still with capacity to spare. So now you just need to worry about the rest of your circuit and the idle current 

You need to very specifically use the Tadiran ones. LiSoCl2 cells don't, in general, have fantastic lives. Tadiran make some which are rated for high life and seem to have a very special construction, using low corrosion materials. They won't get the 80 year life the OP wants, though, and they aren't cheap.

[Gyro]

I'm sure some batteries are manufactured dry, with fully charged plates - I think that's the case with Lead Acid, probably other wet cells too. It certainly used to be the case with water activated batteries used on Radiosonds.

Just keep the battery hermetically sealed, with a dessicator to be on the safe side. When needed, just add water / electrolyte, also stored in hermetically sealed containers if they will not be available at the time. That should do you a couple of Centuries

[Don Hills]

A long storage life isn't the main problem.
According to the OP, it's going to be used regularly.
"... a 1 watt LED turned on for 30 minutes every 2 or 3 days for 80 years."
That's about 7300 watt-hours... a big battery, regardless of technology.
In theory, an RTG would do the job. More practically, over-specified NiFe cells and solar panels.

I don't think it's is worth spending any more time on this unless the OP gives a plausible scenario.

[Mr. Scram]

I was surprised to see capacitors mentioned.  So you can place a charge on, say, a ceramic capacitor, then set it aside for 80 years, and when your decendents measure it, most of the charge will still be there???  I had no idea.

I think the idea is that your decendant will be able to charge that capacitor, rather than it keeping the charge for that long.

[SiliconWizard]

The OP has not clarified whether he/she is looking for

1)  a way to store X joules of energy for 80 years, i.e. deposit X joules now, wait 80 years, then get >= 0.5X joules out, or

2)  an energy storage mechanism which you can build today, and still come back and use 80 years in the future.

That was the gist of my somewhat tongue-in-cheek comment above, which no one seems to have picked up on.  Must be my odd sense of humor

Sorry, I actually just read your comment and was about to reply in the same vein.

Personally I find scenario 1 more interesting, although any potential application sounds like a Hollywood movie plot.

Whether 1 or 2 is more interesting is largely up to debate and entireley depends on the application.

If you look for ways to repeatedly store energy and release it, then scenario 2 is more interesting. And it would probably have a lot more use because that's really what is needed at the moment if we are to deploy many renewable forms of energy on a large scale. It's also what is needed for anything "mobile", including vehicles. I'd guess that scenario 1 would be useful but more for niche applications.

[Safar]

Thought it is good idea to use dry rechargeable batteries and use special device that will fill electrolyte to dry cells in the right moment. Similar technique used in some military devices but with one time cell.

You can use several (or several decades) batteries that can be activated one by one in reason of lost capacity or lasting some time.

Hope it is possible to make hermetically sealed box with dry cells, electrolyte capsule and some activation device, e.g. elecromagnetic driving needle that can crack glass capsule.

But absolutely not sure about chemical choices. Know that Pb Acic batteries can be store in dry charged state not more than 5 years, but it general info for not hermetically sealed batteries.

[suicidaleggroll]

I was surprised to see capacitors mentioned.  So you can place a charge on, say, a ceramic capacitor, then set it aside for 80 years, and when your decendents measure it, most of the charge will still be there???  I had no idea.

The OP has not clarified whether he/she is looking for

1)  a way to store X joules of energy for 80 years, i.e. deposit X joules now, wait 80 years, then get >= 0.5X joules out, or

2)  an energy storage mechanism which you can build today, and still come back and use 80 years in the future.

He pretty clearly said at the beginning that there would be a solar panel to regularly recharge the system.  Many posters even commented on the fact that a solar panel won't last that long either.

[RES]

In an application operating at 50°C, 24 hours per day, 7 days per week, the data retention time (specified in Understanding MSP430 Flash Data Retention (SLAA392) [6]) is reduced from 1324 years to 1324/6 ? 220 years.

If the application is running 5 hours per day at 50°C and the rest of the day at 25°C, the data retention is calculated as shown here: 5 hours/day at 50°C is equivalent data aging at 25°C: 5 hours × 6 = 30 hours 19 hours/day at 25°C is equivalent data aging at 25°C: 19 hours Total data aging per day is 30 hours + 19 hours = 49 hours ? 2 days at 25°C. In this scenario, data retention is 662 years.

http://www.ti.com/lit/an/slaa334a/slaa334a.pdf

[David Hess]

This is something I don't understand, why do the wet batteries have to be open and can't be hermetically sealed?

I know this is an incredibly stupid question but I just can't find answers.
Is it for when the batteries are overcharged and there is excess gas?
Coudn't I just build a NiCd/NiFe wet battery and hermetically seal it?

It is not a dumb question unless you have experience with them which is very rare now.  Flooded cell NiCd and NiFe operate at low pressures and lack the ability to recombine oxygen and hydrogen produced during charging so the vent operates at a very low pressure.  The same vent is used to add water periodically.

As far as supercapacitors, raising their charge voltage by 0.2 volts decreases their operating life by 10 times so operating them at a lower voltage and using charge balancing will extend their operating life significantly.  Some are rated to 20 years.

[mubes]

Flywheels are interesting for this kind of application. Magnetic bearings in a vacuum lead to very low maintenance requirements - bury it 6ft underground in the back garden and forget about it. I don't know what the frictional losses will be but last I looked they were amazingly small....but my gut tells me they will probably be too high for you unless you can poke a bit of power in from time to time.  Williams did a lot of work on them (originally for F1 KERS) but they've sold it on to GKN now. They're reasonably common for fast-online backup PSUs for things like data centre applications. Main risk seems to be catastrophic failure of the flywheel mass ... I've seen the inside of a workshop where one of those had a sense of humour failure and the damage was _very_ significant. Apparently in that case no one was hurt but it was enough to stop the company doing more research in that direction .... The 6ft underground bit is a sensible precaution.

[tautech]

Flywheels are interesting for this kind of application. Magnetic bearings in a vacuum lead to very low maintenance requirements - bury it 6ft underground in the back garden and forget about it. I don't know what the frictional losses will be but last I looked they were amazingly small....but my gut tells me they will probably be too high for you unless you can poke a bit of power in from time to time.  Williams did a lot of work on them (originally for F1 KERS) but they've sold it on to GKN now. They're reasonably common for fast-online backup PSUs for things like data centre applications. Main risk seems to be catastrophic failure of the flywheel mass ... I've seen the inside of a workshop where one of those had a sense of humour failure and the damage was _very_ significant. Apparently in that case no one was hurt but it was enough to stop the company doing more research in that direction .... The 6ft underground bit is a sensible precaution.

Yep.
But we have a wider range of materials at much lower cost today that can enhance reliability and safety.
Kevlar springs to mind.

[amspire]

Aluminium metal stores a very high amount of energy and can be stored indefinitely. It is also one of the most common elements in the earth's crust. Storing 10 years of energy for a house in a basement is very possible. You wouldn't need a huge space. I have forgotten the number, but it is a few cubic meters of space would be needed for a 10 year supply at 24KWH/day usage. The problem is just coming up with a good way to extract the energy. Making a charge-discharge cycle is particularly hard. Other metals store a fair amount of energy, but in most cases, a lot less the Aluminium.

The metal would have to be stored in solid ingots and not powder  - power form is a very dangerous fire risk, and also more of the metal oxidises which you do not want.

[BrianHG]

Aluminium metal stores a very high amount of energy and can be stored indefinitely. It is also one of the most common elements in the earth's crust. Storing 10 years of energy for a house in a basement is very possible. You wouldn't need a huge space. I have forgotten the number, but it is a few cubic meters of space would be needed for a 10 year supply at 24KWH/day usage. The problem is just coming up with a good way to extract the energy. Making a charge-discharge cycle is particularly hard. Other metals store a fair amount of energy, but in most cases, a lot less the Aluminium.

The metal would have to be stored in solid ingots and not powder  - power form is a very dangerous fire risk, and also more of the metal oxidises which you do not want.

Here, rechargeable Aluminum Air battery...
http://www.phinergy.com/product/

They aren't the only ones, google 'Aluminum car battery' and you'll see others...

[amspire]

Aluminium metal stores a very high amount of energy and can be stored indefinitely. It is also one of the most common elements in the earth's crust. Storing 10 years of energy for a house in a basement is very possible. You wouldn't need a huge space. I have forgotten the number, but it is a few cubic meters of space would be needed for a 10 year supply at 24KWH/day usage. The problem is just coming up with a good way to extract the energy. Making a charge-discharge cycle is particularly hard. Other metals store a fair amount of energy, but in most cases, a lot less the Aluminium.

The metal would have to be stored in solid ingots and not powder  - power form is a very dangerous fire risk, and also more of the metal oxidises which you do not want.

Here, rechargeable Aluminum Air battery...
http://www.phinergy.com/product/

They aren't the only ones, google 'Aluminum car battery' and you'll see others...

I am aware that several companies are developing Aluminium batteries, but they have the disadvantages of batteries - relatively low energy storage density and self discharge. Storing energy as pure Al gives a much higher energy density and zero self discharge. It needs someone to invent a way to make it work. Batteries are not a good solution for long term storage.

[mrpackethead]

Take a block of concrete up a mountain. Put it somewhere. It will stay there a long time.  Potential energy stored wont' go far.

[LaserSteve]

Old school Acetylene lighthouse lamp and a lot of tanks.  Think I'm joking?  I'm not.

 Our gas furnace here is 48 years old and is still on its original valve system.

Our pilot flames have burned for decades at a time on both the gas furnace and the gas water heater.

Old gas based lighthouses were known to run for a year Or two  unattended. 

Steve

[janekm]

Old school Acetylene lighthouse lamp and a lot of tanks.  Think I'm joking?  I'm not.

 Our gas furnace here is 48 years old and is still on its original valve system.

Our pilot flames have burned for decades at a time on both the gas furnace and the gas water heater.

Old gas based lighthouses were known to run for a year Or two  unattended. 

Steve

Indeed, I was visiting the "Deutsches Museum" in Munich which had exhibits of steam engines which had been operated for more than 100 years (though presumably with some degree of maintenance).

[texaspyro]

Nickel or silver / gaseous hydrogen batteries.  Good for 20,000+ charge/discharge cycles.  Can't be overcharged.  Typically quoted as 15-20 year lifetime... in this application they might make 80 years.  I had some in a remote solar application that were still going strong after 17 years when the project ended.