Extremely long lasting energy storage solution - Page 1
Forum section: electronics / projects

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 12:38:14 pm
content: I am looking for an energy storage solution that lasts a very long time, something that basically has no real way of degrading.I first thought super capacitors would suffice but I learned that they degrade over 10-20 years so I can't use those.thanks

author: danadak
author_rank: Super Contributor
timestamp: December 21, 2017, 12:50:33 pm
content: A few more specifics in order -1) V and I demands on the battery2) Environment, temp, humidity, altitude3) Size, weight.....4) Application, what is battery powering5) Load been optimized for power consumptionRegards, Dana.

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 12:53:36 pm
content: I don't really have all of the specifics about the final project, I knew this would come up.I am just hoping to have some suggestions and then I'll look into how well they might work.As long as it's not crazy like thousands of volts or gigantic batteries.

author: Zbig
author_rank: Frequent Contributor
timestamp: December 21, 2017, 01:01:35 pm
content: A bucketload of stones suspended on a string. An old car filled with bricks, sitting on the edge of a cliff. Don't expect anyone to waste their time throwing ideas around without having a slightest clue what the goal is, only for you to judge whether the solution is adequate for your undisclosed mystery problem. That's not how problem solving or asking for help works.

author: coppice
author_rank: Super Contributor
timestamp: December 21, 2017, 01:02:28 pm
content: Nothing last forever. If you don't think 20 years is a long time, then what is your idea of a long time?

author: jolshefsky
author_rank: Regular Contributor
timestamp: December 21, 2017, 01:03:00 pm
content: Lift heavy things then recoup the energy during descent. Pumped hydro works, orhydraulics under pressure, or evenweights dropping on a line.As for chemical batteries, I think NiCd batteries, if well-tended, can last up to 10 years (vented cells, 20 years). Maybe modern NiMH ...Wikipedia says nickel-iron.

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 01:06:01 pm
content: Sorry I don't have many specifics I was just looking to see if anyone knew of some technologies.The batteries will be charged by a solar panel at 12V and I am looking to run a 1W light at 12v for 30 minutes.Operating temperatures will probably go from 10C to 30CI am sorry I don't have many more specifics.

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 01:07:26 pm
content: 80 years without loosing more than 50% of capacity. Sorry should have been more specific

author: PartialDischarge
author_rank: Super Contributor
timestamp: December 21, 2017, 01:10:26 pm
content: What you need is a thermal battery. Will last for decades, don't need to be recharged, and will generate lots of energy once.They are used in nearly all missiles, only problem its a military item and they are not available to the public

author: daqq
author_rank: Super Contributor
timestamp: December 21, 2017, 01:13:11 pm
content: QuoteWell, the nuclear option is a RTG (https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator), but more within the realms of sanity I guess ceramic caps should have a pretty much unlimited shelf life. That said, you'd probably need LOTs of them.

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 01:14:51 pm
content: Thanks for the info the wiki page states that Nickel Iron batteries can last a very long timehttps://en.wikipedia.org/wiki/Nickel%E2%80%93iron_batteryI have previously come across this information but several people told me this is false and they don't last a very long time at all

author: mariush
author_rank: Super Contributor
timestamp: December 21, 2017, 01:21:11 pm
content: Maybe get some lead crystal batteries (up to 12 years of life) , bury them in a box a meter or so underground to have them at constant temperature throughout the yearimho you should be more worried about that solar panel ... weather and birds and other stuff could easily damage it in 10 years

author: max_torque
author_rank: Super Contributor
timestamp: December 21, 2017, 01:22:09 pm
content: What's the ageing like on that solar panel?

author: seanspotatobusiness
author_rank: Regular Contributor
timestamp: December 21, 2017, 01:36:05 pm
content: A "gravity light" uses a weight on a cord which illuminates. I don't know how long it would last but it might work for your application:https://www.amazon.co.uk/GravityLight-GL02-System-Portable-Powered/dp/B01M7SM0KEThe finished product is expensive but maybe it would be feasible to DIY. Edit: the commercial one is only 0.085 W so you would have to make your own to get more power.

author: mariush
author_rank: Super Contributor
timestamp: December 21, 2017, 02:06:39 pm
content: May be worth investigating if you could use the solar power to compress air in a tank throughout the day and then release the air to generate power. Of course you add complexity of pump, moving parts, dynamo or something to generate power at release of gas etc.There's spring options, wind up spring like clock mechanism then release it when needed.. but again, it's mechanical parts, metal, risk of oxydizing, rusting etc

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 21, 2017, 02:07:33 pm
content: What about regular solid state capacitors?

author: wraper
author_rank: Unknown
timestamp: December 21, 2017, 02:09:21 pm
content: Quote from: Mr. Scram on December 21, 2017, 02:07:33 pmTo supply 1W of power for 30 minutes?

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 21, 2017, 02:10:22 pm
content: Quote from: wraper on December 21, 2017, 02:09:21 pmSorry, I missed that. I was thinking about much lower energy requirements. Or you'd need an absolutely huge bank of capacitors.

author: alanb
author_rank: Frequent Contributor
timestamp: December 21, 2017, 02:10:57 pm
content: Coal --- already about 250 Million years old and hasn't lost energy!

author: mariush
author_rank: Super Contributor
timestamp: December 21, 2017, 02:12:01 pm
content: Would be a lot of capacitors but if i remember correctly, even with polymer capacitors they estimate their lifetime to around 17 years (or a value around that, again saying from memory), as that's the maximum life they guarantee the rubber seal for.

author: mac.6
author_rank: Regular Contributor
timestamp: December 21, 2017, 02:36:43 pm
content: You will need a very tough solar panel (glass, no plastic) that will need periodic cleaning though the next 80 years.For the battery cycling, I guess niFe is probably the way to go.Anyway nobody will witness the 80y+ life, everybody will forget about it in 10/20y+ or so...

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 21, 2017, 02:39:13 pm
content: Capacitors certainly don't last forever, although they will last much longer and with many more cycles than any rechargeable battery at the moment. Ceramic capacitors are probably your best option, but their energy density is fairly low. They are also prone to cracking under mechanical stress.alanb has suggested coal, which is indeed very long lasting. Thing is, on top of not being very practical to use in an electronic deviceit's not exactly an energy storage solution. It contains energy, like a primary source, but can't store generated energy for later use. Along the same line, uranium is also a very long lasting solution.

author: capt bullshot
author_rank: Super Contributor
timestamp: December 21, 2017, 03:16:48 pm
content: A metal canister of fuel oil should provide you long lasting energy storage.If you think of ages, think stone coal or brown coal. Mother Nature uses coal to accumulate and store energy for ages.

author: RES
author_rank: Regular Contributor
timestamp: December 21, 2017, 03:46:31 pm
content: What about creating a special battery by series/paralleling tantalum polymer capacitors with extremely low DCL? Likehttp://datasheets.avx.com/TMJ_S1gma.pdf(DCL of 0.001CV)

author: wraper
author_rank: Unknown
timestamp: December 21, 2017, 03:55:16 pm
content: Quote from: capt bullshot on December 21, 2017, 03:16:48 pmAnd what are you supposed to do with this oil? It's not like device which is able to use this oil will start reliably after 80 years. Not to say this is completely impractical. And you will still need some sort battery storage to start that oil burning device.

author: jonovid
author_rank: Super Contributor
timestamp: December 21, 2017, 04:11:18 pm
content: atomic battery or radioisotope generator10 to 20 yrshttps://youtu.be/yNQCaSNIrEMstop video at 16:18 tritium battery

author: suicidaleggroll
author_rank: Super Contributor
timestamp: December 21, 2017, 04:22:45 pm
content: Quote from: adjustttt on December 21, 2017, 01:07:26 pmWhy does 50% capacity matter? That's a way of rating the lifetime of a battery, not the lifetime of an application. Use a battery that's twice as big and now when it's at 50%, it's the same as a brand new half-size battery. In that case wouldn't it be the 25% mark you care about? Or you could go with one 10x larger, then it's only a problem when it gets to 5%. That's a common way of increasing application lifetime with chemical batteries, just oversize so you're less impacted by the drop in capacity with time.

author: tggzzz
author_rank: Super Contributor
timestamp: December 21, 2017, 04:25:17 pm
content: NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.If you believe this to be in error, please contact the moderator involved.An optional additional explanation is:

author: wraper
author_rank: Unknown
timestamp: December 21, 2017, 04:42:29 pm
content: Quote from: jonovid on December 21, 2017, 04:11:18 pmYeah, and you would need thousand times of that to generate 1W (when new). Not to say Tritium half life is 12.3 years, so you would need to multiply that by around 100 after 80 years. So around 100 000 times of that to work after 80 years.EDIT: actually multiply the figures I wrote above by 1000. Because in the video he got 1uW but I was thinking about mW when calculating them. So you would need 1 million when new and 100 million of those tritium "batteries" to get 1w after 80 years.

author: duak
author_rank: Super Contributor
timestamp: December 21, 2017, 07:56:09 pm
content: Years ago, many emergency lighting batteries were wet cell NiCad that were good for far longer than the typical 5 years of a sealed NiCad or Lead acid. I looked up wet cell NiCad and see that they are used for high reliability in things like railroad signalling. I see that Saft still makes these things and they talk about a 20 year lifetime:https://www.saftbatteries.com/products-solutions/products/spl?text=&tech=&market=342&sort=newest&submit=SearchThey probably require periodic maintenance like cleaning and adding water. I see that they also talk about oil which I suspect is a layer on top of the electrolyte and minimizes evaporation. I have a 10 amp-hour wet cell NiCad from the 70's and the last time I tried it out it still held a charge and had pretty much all its electrolyte.On a whimsical note, I'm old enough to remember when cars had clocks with mechanical movements where the mainspring was wound up every few minutes or so by an electric motor. These worked for years although their timekeeping wasn't all that good. I wonder something like this couldn't be useable. The only thing is to figure out how to extract the stored energy incrementally. A simple generator would extract it whether you needed it or not.Cheers,

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 09:44:56 pm
content: 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?Thanks

author: Damianos
author_rank: Frequent Contributor
timestamp: December 21, 2017, 09:48:39 pm
content: Quote from: adjustttt on December 21, 2017, 01:06:01 pmQuote from: adjustttt on December 21, 2017, 01:07:26 pmSo, there is a light that will turned on for thirty minutes at a moment in the next eighty years!Do the rest of the system also "dies" when this happens?In any case, you don't need a solar panel or sophisticated batteries. Use alkaline batteries and a reminder to the user to replace them when needed. I have some alkaline batteries that after ten years are in a "top of health" state.I think that the big problem is not the batteries but all the other things (including the user) that may need maintenance or replacement!

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 09:51:25 pm
content: I wasn't specific enough again sorry about that it seems that is not really my strong suitIt is going to be turned on every 2/3 days or so for 30 minutes for 80 yearsAt his point in time the most feasable solution seems to build 2 or 3 NiFe batteries, that are hermetically sealed.When one gets below a certain capacity one of the others takes over.

author: Gip-Gip
author_rank: Contributor
timestamp: December 21, 2017, 09:54:23 pm
content: If anything I'd think an Iron/Nickle Battery would last a long time.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: December 21, 2017, 10:13:08 pm
content: Dear adjusttt, what the heck is "it"? just say it so that there could be some useful answers. right now it is just wild guessing... Different applications require vastly different power sources...

author: mark03
author_rank: Frequent Contributor
timestamp: December 21, 2017, 10:40:53 pm
content: 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.

author: kubeek
author_rank: Contributor
timestamp: December 21, 2017, 11:01:37 pm
content: If you want long lasting then I´d use an enormous watch spring (1200J stored mechanicaly is a LOT) for the energy storage and a generator to dispense it.

author: adjustttt
author_rank: Contributor
timestamp: December 21, 2017, 11:05:00 pm
content: A 1 watt led light, there are multiple for redundancy

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 21, 2017, 11:05:53 pm
content: So why does it need to last 80 years? In what environment (indoor, outdoor, post global climate catastrophe..?)A solar cell, if outdoors is probably not going to last due to UV damage.How about a hand-cranked generator, with a very under-run incandescent bulb - that's probably the only tech that has a comparable track record.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 21, 2017, 11:06:59 pm
content: Quote from: adjustttt on December 21, 2017, 11:05:00 pmHow do you know that LED isn't going to degrade, e.g. due to moisture getting at it ? You'd at least want to hermetically seal it in glass, and keep it away from daylight.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 22, 2017, 02:21:10 am
content: https://en.wikipedia.org/wiki/Oxford_Electric_Bell

author: BrianHG
author_rank: Super Contributor
timestamp: December 22, 2017, 02:33:27 am
content: Hand cranked generator with a low leakage long shelf life supercap. You can generate 60 watts by hand for 30 seconds, or make things a bit easier generating 30 watts for 1 minute, then your 1 watt lamp will last for 30 minutes.Note that I can pedal on my generator connected bike going all out delivering 600 watts for 1 minute, then I'm dead... But, charging a sufficient sized super-cap, your 1 watt light will run for 10 hours after 1 minute of effort.Super large wound up spring loaded generators will also do it without the capacitor, but, keeping the spring tightly wound will leave the spring with some memory after 20 years. If you leave the system un-wound, then wind it up at use, you can do it. Note that a 30 watt potential spring will be pretty big and heavy, but, doable.Ohhh and by the way, pedaling 30 watts on my bike for 1 minute, well, It's so easy, I can do it by hand on the pedals. Using my legs, it's like pedaling on air, or, no load whatsoever.

author: cdev
author_rank: Super Contributor
timestamp: December 22, 2017, 02:35:11 am
content: Compressed air.

author: Gip-Gip
author_rank: Contributor
timestamp: December 22, 2017, 02:53:11 am
content: Quote from: cdev on December 22, 2017, 02:35:11 amThe stuff has some of the lowest energy densities tho. last time I checked liquid nitrogen at ~2,000 atm is like 2 MJ/L, compared to lithium at 4

author: Gip-Gip
author_rank: Contributor
timestamp: December 22, 2017, 05:05:50 am
content: I'm not sure how well a hermetically sealed battery would work. The stuff essentially performs electrolysis if overcharged, releasing hydrogen/oxygen...I'd get a non-sealed system and set up a device that measures the water level and automatically refills the thing if it gets too low.

author: Rerouter
author_rank: Super Contributor
timestamp: December 22, 2017, 05:14:57 am
content: 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.

author: mark03
author_rank: Frequent Contributor
timestamp: December 22, 2017, 05:25:48 am
content: The OP has not clarified whether he/she is looking for1) 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, or2) 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 humorPersonally I find scenario 1 more interesting, although any potential application sounds like a Hollywood movie plot.

author: jonovid
author_rank: Super Contributor
timestamp: December 22, 2017, 05:30:34 am
content: take the nuclear option.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 22, 2017, 05:45:26 am
content: Repeating the chorus. Really carefully define the application. Installation on a sea coast could make this impossible while installation in a carefully controlled environment may make it a somewhat achievable goal.Over eighty years with no maintenance you will have many problems beyond the batteries. Thermal cycles, moisture, slow oxidation reactions, oil evaporation, plastic outgassing, UV depolymerization and any number of other effects will degrade everything. Wire insulation. LED encapsulation. Solar cells. Switch contacts and springs. Lubrication in switches. Metalization on ICs. And a long list of other things. This duration is far beyond what is required by any existing military or space equipment, and achieving a quarter of this is fairly challenging. Those who work on eighty year old equipment understand that while not everything fails after this time interval, much deterioration occurs and the likelihood of turn on success is well below unity.If maintenance is allowed you need to start defining allowed maintenance interval, and designing for maintainability. Also need to plan for component availability. Think about how many components available in 1940 are still available off the shelf today. This means making provision for using similar but not identical parts for replacement and/or stockpiling large numbers of replacement parts which will need to be tested before use since they will surely have reduced reliability no matter how carefully they are stored.

author: BrianHG
author_rank: Super Contributor
timestamp: December 22, 2017, 06:02:17 am
content: Yup, it will need to be cleverly built like a tank and kept in controlled conditions. Though not impossible. I know my audio amp has been in use for 25 years now, without fail and I don't expect it to fail, but, it's a 5k$ device built with premium components and wiring not found in run of the mill 250$ consumer devices which would have died by now the way I use it...

author: tautech
author_rank: Super Contributor
timestamp: December 22, 2017, 06:43:21 am
content: Quote from: Rerouter on December 22, 2017, 05:14:57 amLifting this principle a notch or two to minimise losses.Mass = very high speed flywheel.Bearings = magnetic levitation.All sealed in a vacuum.

author: janekm
author_rank: Unknown
timestamp: December 22, 2017, 06:48:26 am
content: 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

author: coppice
author_rank: Super Contributor
timestamp: December 22, 2017, 09:47:39 am
content: Quote from: janekm on December 22, 2017, 06:48:26 amYou 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.

author: Gyro
author_rank: Super Contributor
timestamp: December 22, 2017, 10:34:47 am
content: 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

author: Don Hills
author_rank: Regular Contributor
timestamp: December 22, 2017, 11:15:02 am
content: 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.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 22, 2017, 11:53:41 am
content: Quote from: mark03 on December 21, 2017, 10:40:53 pmI think the idea is that your decendant will be able to charge that capacitor, rather than it keeping the charge for that long.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 22, 2017, 01:29:41 pm
content: Quote from: mark03 on December 22, 2017, 05:25:48 amSorry, I actually just read your comment and was about to reply in the same vein.Quote from: mark03 on December 22, 2017, 05:25:48 amWhether 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.

author: Safar
author_rank: Regular Contributor
timestamp: December 22, 2017, 02:01:35 pm
content: 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.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: December 22, 2017, 02:20:34 pm
content: Quote from: mark03 on December 21, 2017, 10:40:53 pmQuote from: mark03 on December 22, 2017, 05:25:48 amHe 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.

author: RES
author_rank: Regular Contributor
timestamp: December 22, 2017, 04:03:04 pm
content: 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) ) 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

author: David Hess
author_rank: Super Contributor
timestamp: December 22, 2017, 04:51:52 pm
content: Quote from: adjustttt on December 21, 2017, 09:44:56 pmIt 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.

author: mubes
author_rank: Regular Contributor
timestamp: December 23, 2017, 12:48:38 am
content: 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.

author: tautech
author_rank: Super Contributor
timestamp: December 23, 2017, 01:16:27 am
content: Quote from: mubes on December 23, 2017, 12:48:38 amYep.But we have a wider range of materials at much lower cost today that can enhance reliability and safety.Kevlar springs to mind.

author: amspire
author_rank: Super Contributor
timestamp: December 23, 2017, 02:02:53 am
content: 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.

author: BrianHG
author_rank: Super Contributor
timestamp: December 23, 2017, 04:13:43 am
content: Quote from: amspire on December 23, 2017, 02:02:53 amHere, rechargeable Aluminum Air battery...http://www.phinergy.com/product/They aren't the only ones, google 'Aluminum car battery' and you'll see others...

author: amspire
author_rank: Super Contributor
timestamp: December 23, 2017, 04:54:19 am
content: Quote from: BrianHG on December 23, 2017, 04:13:43 amI 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.

author: mrpackethead
author_rank: Super Contributor
timestamp: December 23, 2017, 05:49:04 am
content: Take a block of concrete up a mountain. Put it somewhere. It will stay there a long time. Potential energy stored wont' go far.

author: LaserSteve
author_rank: Super Contributor
timestamp: December 23, 2017, 06:37:05 am
content: 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

author: janekm
author_rank: Unknown
timestamp: December 23, 2017, 07:14:41 am
content: Quote from: LaserSteve on December 23, 2017, 06:37:05 amIndeed, 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).

author: texaspyro
author_rank: Super Contributor
timestamp: December 24, 2017, 03:11:01 am
content: 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.