Excess energy?

Background:  I have been interested in alternative forms of energy since I read Mother Earth's "Homemade Energy Handbook" (or something like that.  It doesn't seem to be published any more) in 1977.  As I have "grown up" with it and think about living off grid, I become less and less enamored with the idea of having massive piles of batteries around to store energy.  What are other ways that electricity from pv panels, wind turbines; and excess heat from combustion or exothermic reactions be stored or used?

Tom Connolly wrote:Background:  I have been interested in alternative forms of energy since I read Mother Earth's "Homemade Energy Handbook" (or something like that.  It doesn't seem to be published any more) in 1977.  As I have "grown up" with it and think about living off grid, I become less and less enamored with the idea of having massive piles of batteries around to store energy.  What are other ways that electricity from pv panels, wind turbines; and excess heat from combustion or exothermic reactions be stored or used?

I always loved the gravity dam, where during times of over production, water is pumped from a reservoir on the bottom, to a reservoir on the top. At times of low production, or when demand is high, water is released and the micro-hydro set up provides a buffer to the over all system.

Along the same lines, but slightly different, an inclines railroad is made, and as excess power is produced, it is pulled up the inclined plane. At times of low production, or when demand is high, it would be released and through dynamic braking, power is produced. (This could be done as well with animal power toting the weight on an inclined railroad)

Tides of the ocean, rising and falling, captured and sent through a turbine would make the greatest "battery" as there is no cost in causing the water to rise.

Wind up old school technology could be used. A lifted weight in times of over production, dropping from a tower in a series of sheaves that power a generator as it falls when additional power is needed. (animal power could be used)

Here is a doodling of the latter example.

As far as storing energy using gravity, I really like this version: https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/


On a homestead level, for storage, I feel like thermal batteries have the most potential. Ice battery for food storage... heated thermal mass for heating water/dwelling/greenhouse... several options for the latter.


As far as using excess PV goes, I will be installing a ductless minisplit heatpump to use 'excess' solar power for 'free' heat in parts of shoulder seasons, and AC in the summer. The array and batteries being sized for short cloudy winter days, there should be substantial excess power much of the year. My situation is a tinyhouse, but the same idea could work with a full house with a bigger array, or simply focus on 1-2 rooms..

I also plan to have a medium sized reservoir located near the center of where I am likely to want water, on the highest practical point. My place is pretty flat, so its not enough to gravity flow anywhere... but I will be able to use a direct solar pump to refill this reservoir from a larger one downhill and several hundred metres away. On demand pumping from the closer, higher site will be more efficient, and by keeping the big pumps close I can run them off my main solar array or off a generator, without needing to run pricey wires to the far reservoir, or install a separate generator/combustion powered pump... This one isn't strictly speaking 'excess' PV though... for that, I'd need my house site to be down in the marsh!

I suppose I could eventually experiment with a system like Travis describes, allowing the water back to the lower reservoir through a turbine... but as mentioned the lower reservoir is pretty far from my house... hm.

If you've got a big hill and a sizable reservoir at the top, pumped hydro could make all kinds of sense. I'm not as sold on the stacking of blocks and did the math on a lifted deadweight system a couple of years back...the engineering required to build the supporting frame to lift enough mass to a sufficient height to store 10 kWh was ridiculous when compared to a stack of batteries.

A 1kW motor can winch a 1T mass up 10 m in just over 1.5 minutes (use a block and tackle, please). So you would need 40 tons of mass at a 10 m height to store 1 kWh of energy. A pretty frugal household (way better than mine) might use 10 kWh a day on average. So this means you would need 400 tons of mass lifted to 10 m to store that on a regular basis. Have a think about the sort of structure that you'd need to build to reliably lift and drop that amount of weight. That's where I bailed out.

Phil Stevens wrote:If you've got a big hill and a sizable reservoir at the top, pumped hydro could make all kinds of sense. I'm not as sold on the stacking of blocks and did the math on a lifted deadweight system a couple of years back...the engineering required to build the supporting frame to lift enough mass to a sufficient height to store 10 kWh was ridiculous when compared to a stack of batteries.

A 1kW motor can winch a 1T mass up 10 m in just over 1.5 minutes (use a block and tackle, please). So you would need 40 tons of mass at a 10 m height to store 1 kWh of energy. A pretty frugal household (way better than mine) might use 10 kWh a day on average. So this means you would need 400 tons of mass lifted to 10 m to store that on a regular basis. Have a think about the sort of structure that you'd need to build to reliably lift and drop that amount of weight. That's where I bailed out.

I am not sure your calculations are right, or at least someone (a long time ago) has found a way to overcome the problems you envision.

I say that because near me there is a lighthouse, and adjacent to it is the fog horn tower. But back in the day it had a bell, and it had a mechanism, perhaps 25 feet tall, that was "wound", and as the weight dropped, it struck the bell in repeated blows. The hammer was several hundred pounds. It would seem to me, that if dropped weight had enough power the lift a several hundred pound hammer for repetitive blows over the course of several hours, there would be a way to harness that potential energy to drive a generator.

Equally, back in the 1890's when paper was starting to be derived from wood, and wood needed to be bucked into 4 foot long lengths instead of 52 foot logs, a weight activated pendulum device was devised to mechanize the bucking of trees. That was a device able to be hand carried to a fell logged, yet despite its smallish size (comparatively speaking), it had enough power to cross cut a log. It would seem to me that electricity could be generated from a spinning jenny.

Even the overshot waterwheel; that is nothing more than 5 gallon buckets held out on sticks by ten feet or so. That generates tremedous leverage...and there is ten of those buckets hanging out there. Turning a train of gears, those powered sawmills.

It would just seem to me, that if (3) weigh-dropping devices were put into production, and did an appreciable amount of work, and there is a HUGE discrepancy in the amount of weight utilized, your figures or means to achieve work, were off. 400 tons is a lot of weight.

Unfortunately the numbers are not far off. In the two examples you mentioned neither one was using much power. The bell in the single digits of watts the crosscut saw  probably approx 100watts per hour of work. So if you can live with that level of storage then you are good. Again It's not that they won't work it's the sheer energy density of batteries for the cost. A 2 l16 battery bank measuring 24x24x18 inches total store 4.8 kWh for $700 and last for 10 years plus if treated well and are recyclable at end of life. I think your idea of storing energy as heat and cold is the better one with a very modest battery to fill in the blanks. I wish you well either way
David

I don't think there's necessarily a problem with the math, the blocks described in the article are damned heavy.

I wouldn't personally want to build a 140ft crane, but I don't find it shocking that they claim a reasonably cheap cost per kw stored: that one crane can reach an awful lot of blocks, and the blocks are very heavy.

A scaled up version would be cool. Take the crane facility, put it atop a mountain. Build another one at the bottom, and a pair of shafts or chutes connecting them.. a few teething problems would no doubt pop up.

I'd think a 140 ft crane is pretty much outside the scope of anything you'd want to build on a typical homestead. And I wouldn't want to use concrete for the mass unless it was salvage or urbanite...the carbon footprint (as well as embodied energy) of portland cement is horrific.

When it comes to both bang for the buck and ease of deployment, unless you've got a nice hill and a way to store a lot of water at the top, you're just not going to find many ways to beat a properly sized battery array. Maybe a funicular railway on a hill if you don't have the supply of water or reservoir site.

Thanks!  Very innovative and creative ideas.  I like the idea of the weight and ratchet release idea, though some people might think you were Cuckoo ;)  What about compressed air and hydrogen?  20 years ago, I saw very little on the web about hydrogen generation/electricity generation...but now I am starting to see more and more people playing around with it.  The Japaneses government seems to be investing heavily in it and viewing it as a significant part of their future...but I guess, if you are an island nation, that makes sense.

I think the crane idea was a great one, I just think they did not realize how to fully get the most use out of their idea.

I would not use a 140 foot crane, nor concrete blocks, but set my crane up over an abandoned quarry. Here they are several hundred feet deep, so a short crane could drop weight a long distance. In short, instead of building a crane UP, drop the weight into a hole, but in this case, the hole was already dug for you, and paid for by people in the 1800's.

And so I would not use concrete. Again, being a quarry, I would use the granite itself as weight. It would cost money to slab out blocks of consistently sized granite, but that would be about the same cost as paying for concrete blocks.

Tom, I realize you are looking for off-grid storage ideas, but a net- metered grid-tie gives you the option to store the excess in dollars. Your excess also allows the power station to burn less fuel to fill your neighbor’s needs.

Dollars don’t discharge or leak, and could also be used to buy fuel for a reliable propane generator which could run during an extended outage.

Kenneth Elwell wrote:Tom, I realize you are looking for off-grid storage ideas, but a net- metered grid-tie gives you the option to store the excess in dollars. Your excess also allows the power station to burn less fuel to fill your neighbor’s needs.

Dollars don’t discharge or leak, and could also be used to buy fuel for a reliable propane generator which could run during an extended outage.

Yep!  No problem with your thinking other than being off-grid is not a choice for me.  Estimates of running electricity to the property [b]start[/b] at about $30K!

Battary tech has come a long way  lithium battarys are fffaaarrrr better then the huge banks of lead acid   it also depends on how far your willing to go with off grid everyone seems to think off grid meens a mud house or as i like to call it going full caveman lol but depending on your budget you can go off grid and live  with next to no change from on grid liveing that your use to

The 2 extreems are a 12v set up witch can be done for 500$ to 1000$ and that will power most everything you "need" most 12v are a car batt or 2 but I find that overcomplicates it for about 350 bucks you can get a 500 watt lithium battery with built-in inverters and everything it's practically Plug and Play it will last longer and is more reliable than let acid

On the other extreem you have large-scale lithium home batteries they cost a small fortune take mine for example a 5kw lithium battery runs about $8,000 after shipping if you would include installation you can add another thousand or so but they will run just about everything just like a normal home the smaller ones might need you just switch things like electric stoves and electric dryers to gas but for the most part your house will operate like normal however there is a bit of a learning curve to figuring out how it all works but the size is not an issue for example my 5 kilowatt battery is the equivalent of about 10 to 12 car batteries however it's actually quite small heavy at 270 pounds with the inverter and solar controller built in and it Bluetooth to my phone but it's quite small I'll even share a picture for you

I like some of the new combo solar panels that also condense moisture out of the air. Their usefulness is relative, but anywhere the water quality is suspect, it would represent saved time and effort, and in some cases increased odds of thriving rather than merely surviving.

An argument could easily be made that situating such panels strategically on a homestead could not only provide power in excess of what is strictly necessary, but also irrigate the areas surrounding them, which represents another type of energy savings.

I think that if you happen to have a workshop that uses compressed air, having excess storage tanks that get pumped full in times of excess is a terrific idea. It's like pumped hydraulic storage, only less dependent on convenient landforms. At that point, I think conversion losses would dictate that the stored energy be used as compressed air rather than run through a generator to generate electricity, but you are still capturing energy that can do useful work that would otherwise be lost.

In some parts of the world, there exist compressed air-driven vehicles, so it's not impossible to think that one could power a tractor or other mobile equipment. I could see having a trailer kitted out with the largest air pig it could carry and a full compressed air toolshop for use around a larger homestead.

I think the future of energy storage in times of overproduction lies with hydrogen. I think that repurposing petroleum pipelines to ship hydrogen split from water (condensed out of the air) using excess electricity generated by wind and solar is the best idea going that takes into account current needs and existing infrastructure and societal expectation. Even if that hydrogen was only fed to electric generation plants in times of increased demand for the generation of grid power in huge hydrogen fuel cells, rather than using hydrogen directly to power such cells in homes and vehicles, it would provide all the power we need.

Taking that one step further, if all above-grade pipelines in acceptable locations had solar panels installed along their run, with periodic electrolysis stations on the line, we would generate more renewable energy than we could reasonably expect to use, even if internal combustion engines were phased out in favour of battery-electric or hydrogen fuel cell cars.

I think it boils down to the power systems we wish to use, and what's commercially available. I, for one, think that having a central steam generator and steam-powered stationary infrastructure would be really cool. I could have steam-powered elevators, cranes, automatic doors, a workshop, even engines that generate electricity for when I need it. It wouldn't be too different from compressed air-powered systems, and in a climate where you're heating for at least six, but more likely eight, months of the year, it might make sense, in a function-stacking sort of way.

But I doubt that steam-friendly tools and mechanisms exist to the same extent that compressed air doodads do, which would mean either making existing compressed air gear work with steam, or making stuff from scratch.

But I digress. I agree with Travis in that the appropriate choice depends on the situation. If you have an old quarry, raising and dropping granite slabs might make all the sense in the world. If you have a large pond at your height of land, or an empty spot where you can build one, and a large pond somewhere at the bottom, you can have pumped hydroelectric storage. If you don't use any compressed air tools at all, then perhaps compressed air energy storage isn't the best choice.

Good thread. Great input.

-CK

The problem I have with lithium-anything is the lithium. It's expensive because it's rare, so much so that there are places in the world where "conflict lithium" is being mined, destroying the land and the livelihoods of people living there.

It's also unnecessary in a stationary application. One of the major benefits to lithium in batteries is how lightweight the battery remains. This is only relevant if you're talking about a mobile device or vehicle.

As low-tech as lead-acid batteries are, they are infinitely more easily recyclable, and the infrastructure to do so exists today, and has for some time. There are also other stationary battery technologies that will wear longer and be more environmentally friendly than lithium-based technology.

In the context of storing energy, in a conversation that started with hauling many-tonne cement blocks up a cliff with a crane, the benefit of small size and weight matters not at all.

-CK

Ryan Sleep wrote:Battary tech has come a long way  lithium batteries are fffaaarrrr better then the huge banks of lead acid   it also depends on how far your willing to go with off grid everyone seems to think off grid meens a mud house or as i like to call it going full caveman lol but depending on your budget you can go off grid and live  with next to no change from on grid living that your use to

The 2 extremes are a 12v set up witch can be done for 500$ to 1000$ and that will power most everything you "need" most 12v are a car batt or 2 but I find that over complicates it for about 350 bucks you can get a 500 watt lithium battery with built-in inverters and everything it's practically Plug and Play it will last longer and is more reliable than let acid

On the other extreem you have large-scale lithium home batteries they cost a small fortune take mine for example a 5kw lithium battery runs about $8,000 after shipping if you would include installation you can add another thousand or so but they will run just about everything just like a normal home the smaller ones might need you just switch things like electric stoves and electric dryers to gas but for the most part your house will operate like normal however there is a bit of a learning curve to figuring out how it all works but the size is not an issue for example my 5 kilowatt battery is the equivalent of about 10 to 12 car batteries however it's actually quite small heavy at 270 pounds with the inverter and solar controller built in and it Bluetooth to my phone but it's quite small I'll even share a picture for you

Thanks for a nicely detailed answer.  I think every building project - every lifestyle - has to begin with conservation, whether online or off-grid.  I have been thinking about all aspects of energy usage: cooking, heating, cleaning, entertainment, working, etc  Looking at each aspect to see how it can be done in as efficient way possible and what kind of energy should be used.  House lighting, for example, I think should be left as LED's built into the ceiling (or whatever) as the native voltage, rather than upgrading the electricity to 110v after the source and then having the light panel reduce the 110 to 12v (or whatever) to make light.  If there are voltage choices for tools, what are they?  What is/are the best common denominator for all of this stuff?  Is one voltage ok?  or maybe 2 or 3?Since I don't have a house yet it will be relatively easy to build this kind of thinking into the house.  

Well chris can understand your concerns with conflict lithium but if you want to work your way down production chain of every item imaginable and then check the morality of each item during said process you'll find that you can't buy much of anything without some kind of morally concerning issue  personally I don't take my permaculture lifestyle two quite that much of an extreme that said to each their own and secondly yes lithium is more useful in a mobile setup but it's also better better stationary as it takes up about one-tenth of the space the batteries last considerably longer and you don't have to worry about ventilating it I could go on all day but in a nutshell in no shape way or form Is lead acid better than lithium aside from perhaps cost and even that is arguable in some cases

Back to the original topic if you don't mind my asking what kind of budget are you looking and to what level of permaculture or off-grid living are you looking to attain in other words do you want a fairly normal house that happens to be off grid or are you looking more for the full caveman look I've known people and seen setups both ways but I can better advise you if I had a better idea of what you are hoping to accomplish and on what budget

As far as the more minimal 12-volt setup goes it will run all of your lights charge all your small devices including laptops it will even run some medium-scale things like small monitors and 12 volt water pumps where the 12 volt system begins to run short at least on the small scale is it has a hard time running things like small freezers or refrigerators that run on 12 volts also if your off grid and you are running say well water the well pump might require 110 at least I'm on a hill so my pump is a 220 as it has to pump water 270 feet up also 12 volt will Run short when you're trying to run things like a toaster or microwave maybe a good-sized TV 12-volt setup scan have 110 inverters on them but they don't pull the same amperage in most applications so when you say a house I'm thinking a fairly normal home simply wired differently if you're thinking something more along the lines of a tiny home with say a rain collection system 10 12-volt might be a bit more doable


For the small-scale something like this is probably best

https://www.amazon.com/gp/aw/d/B01M260BAN/ref=sspa_mw_detail_4?ie=UTF8&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEySFU1VlM4NlUwODFLJmVuY3J5cHRlZElkPUEwOTcyNzAzU01SRjA1STBSR1hFJmVuY3J5cHRlZEFkSWQ9QTA0NzE4MjMzNUU3MFdCSUVFSEtKJndpZGdldE5hbWU9c3BfcGhvbmVfZGV0YWlsJmFjdGlvbj1jbGlja1JlZGlyZWN0

So if space isn't an issue, and it's in a stationary application, the added costs, environmental, social and financial, are unsupportable, in my view.

It doesn't matter what level of permaculture you're after. Permaculture is largely about whole systems design and accounting. There is no waste. If something is produced that needs disposal of, chances are it's not a very permacultural way of dealing with whatever problem you're trying to solve.

If your system produces a waste, its scope is insufficiently large.

The reason lead-acid batteries are preferable for the vast majority of stationary homestead applications is the fact that it's not only proven technology, but is also cheaply available off-the-shelf, and almost completely recyclable, as in, the spent batteries are broken down and used to make new batteries.

And whataboutism isn't very useful. I don't care that every product marketed to us has a waste stream attributable to it, and that there are ethical concerns with just about everything. To say that nothing matters because everything is flawed is defeatist nonsense. The problems that exist in the system are precisely why we're into permaculture.

-CK

Money is always where the rubber meets the road.  I have 3 goals with power generation right now  The first is to devise a model showing the needs and how they can be met so that the need for electricity an be minimized.  This will feed into the actual design of the house - materials, used, shape, location, etc.  The second is to determine if some counter cyclical means of electricity generation can be used - counter cyclical  to the use of PV cells (which can only be used in the daytime) meaning that electricity an be generated during the non-daytime hours, i.e. dusk to dawn; and the third is to minimize the cost of storing electricity to fill in the gap. I am hoping to be able to procure the solar panels and mgmt parts for under $5K (2kw), the wind part for about the same price (intial questions seem to indicate the property that I have has enough wind to make this feasible) and $3K for batteries.  I am hoping that the same batteries and charging system can be used for both the solar pv cells and the wind.  If I find that an alternative means of power storage can be used and partially replace some of the batteries, it does not have to be directly cost effective. For example, if I can use compressed air to replace 1/3 of the batteries I would be willing to pay $1.5K for them (vs  $1K for the batteries）。  I am also concerned about  the effect that lithium mining is having on our planet, but I also don't want to have all of my eggs in one basket, so having batteries, having compressed air storage and having a generator gives me 3 options - 2 forms of backup.  If it turns out that I will need air conditioning, I would consider giving it a battery of it's own to manage the power surge created when the compressor first kicks in...but that is related to goal #1.

Tom Connolly wrote:I think every building project - every lifestyle - has to begin with conservation, whether online or off-grid. I don't have a house yet it will be relatively easy to build this kind of thinking into the house.

A few months ago I started work on this Tiny House, which belonged to my Grandmother and sat vacant for 11 years. It is grid-tied, but only had (6) outlets because the house is 88 years old; before electricity came here. It is a long story, but we gutted this house and started over, studs, sheathing, insulation, siding, and yes wiring too. Because I started over, I did (2) things that have since paid for themselves in only 3 months of living here.

1. I installed a Green Switch. Right beside my front door is a load box, and before we leave the house unattended, we hit the main switch. This cuts 90% of the power to the house. This eleminates phantom loads, but also resistence to wiring losses running through the house. The other 10% that does not get shut off though, powers the essential stuff like the heater, the refrigerator, and every bedroom has (1) forever switch in it. In short it is a very safe switch because I cannot leave my oven on, or if a pipe bursts the water pump won't keep running and flood the house, and 90% of the power is shut of if a rat was to chew through a wire.

2. I up-sized up all my wire. Forget AWS #14 wire, all my wire is AWS #12, or if it called for #10 wire, it got #8 wire. You get the idea. By doing so, despite the added cost of wire, the electrical resistance losses (or lack therof) pay for the additional wire in only a few months time!

So all this is theory, how has it worked out?

Our power company called and asked why our power consumption was cut by over half! We still own both houses, and the power bill is on the same bill. That is how much of a difference these two simple changes made, all other things being equal. I know it has nothing to do with being off-grid and all that, and I respect everyone's conversations on that, I just thought I would suggest these two wiring improvements since they really cannot be retrofitted into a home. (My current Tiny House was already built, but we opened up all the walls so it was like wiring a new house. That is why I wired it as I did).

Note:
We are a family of 6; (2) adults, and (4) young daughters. We were spending $130 a month and now are spending about $60 a month in electricity. Once we shut the other house off completely, our power bill will go down even more.

Tom Connolly wrote:Thanks for a nicely detailed answer.  I think every building project - every lifestyle - has to begin with conservation, whether online or off-grid.  I have been thinking about all aspects of energy usage: cooking, heating, cleaning, entertainment, working, etc  Looking at each aspect to see how it can be done in as efficient way possible and what kind of energy should be used.  House lighting, for example, I think should be left as LED's built into the ceiling (or whatever) as the native voltage, rather than upgrading the electricity to 110v after the source and then having the light panel reduce the 110 to 12v (or whatever) to make light.  If there are voltage choices for tools, what are they?  What is/are the best common denominator for all of this stuff?  Is one voltage ok?  or maybe 2 or 3?Since I don't have a house yet it will be relatively easy to build this kind of thinking into the house.  

Tom, for tools are you asking about battery or corded/wired tools? I just invested in some 18v Milwaukee tools with 12Ah high capacity batteries (chainsaw, blower, circular saw) and they are great! The circular saw is more powerful than a corded saw due to the high discharge capacity of the new battery, also compatible with the other tools/batteries in the line. The flexibility to charge a laptop/phone, cut a tree, build a shed, work on your car, run some lights, go off to work and carry some electrons home... seems like a plus.

Along the lines of keeping storage and usage voltages the same rather than converting...using thermal collection and storage to fill thermal needs is better, since the collection is 5x more efficient, and storage can be arranged so that losses are recaptured (like tanks below living spaces), and no conversion losses.
Are you planning to use electric for cooking/heat? At Tamera in Portugal, they have a solar stirling generator (for electricity and pumping simultaneously) which uses hot (200*C?) vegetable oil as a storage medium (heated by evacuated tube collector) which can also be used as a means of boiling water for cooking. The system can also be run in reverse (I'm assuming like a heat pump) to provide cooling for food storage...

Chris Kott wrote:So if space isn't an issue, and it's in a stationary application, the added costs, environmental, social and financial, are unsupportable, in my view.

It doesn't matter what level of permaculture you're after. Permaculture is largely about whole systems design and accounting. There is no waste. If something is produced that needs disposal of, chances are it's not a very permacultural way of dealing with whatever problem you're trying to solve.

If your system produces a waste, its scope is insufficiently large.

This sounds to me kind of like saying 'full caveman' is the only ethical option? I can't see any system involving any electricity being produced with no waste, unless you're gowing to scrounge every single piece and call that 'zero-waste'.

That last line is a great quote, and a great goal.

Unfortunately until a much bigger chunk of the general populace is on board with this idea, there will be waste. The solar panels will have major disposal ramifications, they're full of nasty shit and funds should be getting earmarked for dealing with it at point of sale... Some stuff will arrive in awful nonbiodegradable packaging. Devices will fail, and even if in theory they could be recycled... you've seen the videos of people burning piles of circuitboards, right?

I can't speak for the others in the thread, but my permaculture is full of messy, unfortunate compromise. There are a lot of things I'd like to do with the help of 200 hard working people with hand tools, that I instead do with a tractor or excavator. Damn near everything I buy has strings of awfulness trailing behind it, even if it's the least awful option.

My LiFePo4 battery is waaay down the list of things I would lose sleep over. I don't know what lead acid systems you have, but the ones I've used haven't been as nice as you describe.

One thing a LiFePo4 system will do is allow me to run a very serious load for short periods, far beyond lead acid for a similarly sized bank. This will let me skip running a generator for some uses. It can also be charged much quicker, very helpful if I get a 2 hour burst of sun in 3 weeks of heavy cloud.

Travis, I like your quarry refinement of the crane.. with the right shape of quarry one might be able to use a 3-beam gantry crane over top, accessing a pretty large area...

The blocks in the linked article where mostly recycled material held together with concrete; I imagine that the cost in dollars and ecological terms would be closely related to the location as transport of so much weight would be unfortunate...

Of course compromises have to be made. I just contend that to do so at this point in the planning is not the best way to start.

I think that the option that can be both manufactured and recycled closest to point of use makes the most sense from a planning standpoint. Not only can you have some amount of control and oversight of the processes that produce your storage medium, it travels a shorter distance to get to you.

I agree that the most pragmatic solution is often to buy stuff from overseas. It's cheaper, and usually as good. And you don't have to worry about what went into making it, or the consequences of its manufacture.

Of course, that only remains true if the scope of the system is kept sufficiently small.

-CK

I am not sure if full-caveman is going to work or not. Here is why...

Right now the electric industry is in a death spiral. Technology is making electrical consumption less and less per household. However the way electricity is paid for, is by a per KW basis. Because power companies are experiencing higher costs due to materials, labor, etc; they are getting higher and higher per KW rates. This causes the consumer to invest even more in energy efficient appliances...

As you can see; it is a death spiral that cannot continue. Already Maine is considering a Flat Electrical fee to stop this nonsense. It does not matter how much power you use, it is going to cost you x amount of dollars...read X as A LOT!

Full Caveman MIGHT be part of the answer: no electric umbellical cord means a person is isolated from the Flat Electrical Fee.

BUT...I think they would just change the rules. If a person had the power connected to their house, or reasonably close by, they would just be assigned a fee anyway. That is what I suspect would happen. I could be wrong on that, and I hope so. If someone goes full caveman, they should be rewarded fiscally. However, I KNOW the industry is in a death spiral.

Tom, I would definitely second the recommendation of the Milwaukee tools, mine have proved far superior to my Dewalt stuff.


I am running a primarily 24V system, with a step-down to 12V for a variety of small loads, things that are unavailable or unreasonably expensive on 24V.

I think if you go beyond 3kw of solar, 48v battery systems start to get compelling, but it sounds like you're probably somewhere in the same range as me where 24V isn't a big compromise. While less stuff is native 24v compared to 12v, there's still a *lot* more available than for 48V.

That's an interesting problem, Travis. We've disincentivised waste by charging for the amount used, and so we've created the drive for efficiency that kills the business.

And yet we rely on electricity. Apart from everyone generating their own, what do we do? State-run, taxpayer-funded public power generation and transmission?

-CK

@Travis - The quarry makes the proposition viable in your case. How deep is the pit?

@Chris - Lithium is the 25th most abundant element on earth. Seawater has a lot of it as dissolved salts. The problem is there aren't a lot of concentrated deposits of ores like we get with most metals, so the usual extraction method is to target brines and evaporation pans like the Salar de Uyuni in Bolivia. It's still pretty easy and cheap to get compared to rare earth elements which figure in modern magnets for motors and generators, or cobalt (which is used in some lithium battery formulations).

There are going to be tradeoffs with any storage technology. All I'm pointing out is that for most household applications batteries are going to be the killer app in terms of energy density per unit cost and flexibility for multimodal loads.

Chris Kott wrote:The problem I have with lithium-anything is the lithium. It's expensive because it's rare, so much so that there are places in the world where "conflict lithium" is being mined, destroying the land and the livelihoods of people living there.

It's also unnecessary in a stationary application. One of the major benefits to lithium in batteries is how lightweight the battery remains. This is only relevant if you're talking about a mobile device or vehicle.

As low-tech as lead-acid batteries are, they are infinitely more easily recyclable, and the infrastructure to do so exists today, and has for some time. There are also other stationary battery technologies that will wear longer and be more environmentally friendly than lithium-based technology.

In the context of storing energy, in a conversation that started with hauling many-tonne cement blocks up a cliff with a crane, the benefit of small size and weight matters not at all.

-CK

Actually Chris as someone with a mining background and a masters degree in Electrical ENgineering, lithium is not the limiting factor for lithium batteries as strange as that may sound.  The limiting factor is cobalt and you are right that much of it is mined in the deepest Africa although to characterize in a similar vein as the lithium  as "conflict lithium" may be a stretch.

Cobalt is needed to make the lithium work efficiently in the battery and whiie the amount of cobalt is slightly less than the amount of lithium, the cobalt is the rate determining element.  There is lots and lots of lithium around even in Nevada and other non-conlfict areas albeit at lower concentrations.  The cobalt not so much.  it has already gone up in price but will likely go a lot higher if the trend for electric vehicles continues.

Sincerely,

Ralph

Chris Kott wrote:That's an interesting problem, Travis. We've disincentivised waste by charging for the amount used, and so we've created the drive for efficiency that kills the business.

And yet we rely on electricity. Apart from everyone generating their own, what do we do? State-run, taxpayer-funded public power generation and transmission?

-CK

I do not have the answer, and I am not causing problems here, it is just a death-spiral that most people do not think about. I mean paying for electricity on a per use basis has been that way for over 100 years right? But as of right now, going Caveman is the best answer. There is not enough Caveman out there to be a problem...yet.

Phil Stevens wrote:@Travis - The quarry makes the proposition viable in your case. How deep is the pit?

My quarry is a surface pit so it would not work here, but most granite quaries are several hundred feet deep.

Tom, for tools are you asking about battery or corded/wired tools? I just invested in some 18v Milwaukee tools with 12Ah high capacity batteries (chainsaw, blower, circular saw) and they are great! The circular saw is more powerful than a corded saw due to the high discharge capacity of the new battery, also compatible with the other tools/batteries in the line. The flexibility to charge a laptop/phone, cut a tree, build a shed, work on your car, run some lights, go off to work and carry some electrons home... seems like a plus.

Along the lines of keeping storage and usage voltages the same rather than converting...using thermal collection and storage to fill thermal needs is better, since the collection is 5x more efficient, and storage can be arranged so that losses are recaptured (like tanks below living spaces), and no conversion losses.
Are you planning to use electric for cooking/heat? At Tamera in Portugal, they have a solar stirling generator (for electricity and pumping simultaneously) which uses hot (200*C?) vegetable oil as a storage medium (heated by evacuated tube collector) which can also be used as a means of boiling water for cooking. The system can also be run in reverse (I'm assuming like a heat pump) to provide cooling for food storage...

 Yes, battery operated tools solve two problems - the first being the storage of energy, the second being the distribution of energy: battery powered tools need no cords :)  Yes, electricity should not be used for heating - that is a waste of resources.  Thanks for the connection to the stirling engine - I have been looking for those.  It is interesting that you mention using evacuated tubes to heat oil and then cook with it  I have been toying with the idea of an oven that uses oil heated by the sun instead of electric heating elements or gas jets....small world :)  It would not be movable, but most people's ovens aren't.

Someone hinted at this above...I think it is in Arizona somewhere..the electrical utility company raised their rates a blanket $45.  Turns out, that is what the expected savings from using solar cells is for the average household. In the past I have read of municipalities discussing the legality/feasibility of installing meters on private wells, which, we all know will end up in the government trying to collect $$$. Our country has a huge amount of money invested in utility infrastructure and there are probably trillions of dollars still outstanding in bonds that were sold to pay for much of it.  We can dream and scheme as much as we want and assume that the payback period for our investments to make a greener world will be based only on the "typical" forces but the reality is that someone still has to pay for the bonds and the salaries of the "unenlightened" folk that we put in office.

In addition, even if everyone had PV cells on their homes, the utilities would still have to keep the plants running at 10-20% (or something like that)  so that they could quickly be put online again, if needed.  You cant just flip a switch and turn those puppies on and off like you would a light bulb.  Most of the home setups I have seen look like they were designed for working at full power during the summer months plus or minus months in spring and fall...ideas come and go. but governments will still demand their money and we, the taxpayer/consumer must shoulder the burden.

Tom Connolly wrote:Someone hinted at this above...I think it is in Arizona somewhere..the electrical utility company raised their rates a blanket $45.  Turns out, that is what the expected savings from using solar cells is for the average household. In the past I have read of municipalities discussing the legality/feasibility of installing meters on private wells, which, we all know will end up in the government trying to collect $$$. Our country has a huge amount of money invested in utility infrastructure and there are probably trillions of dollars still outstanding in bonds that were sold to pay for much of it.  We can dream and scheme as much as we want and assume that the payback period for our investments to make a greener world will be based only on the "typical" forces but the reality is that someone still has to pay for the bonds and the salaries of the "unenlightened" folk that we put in office.

In addition, even if everyone had PV cells on their homes, the utilities would still have to keep the plants running at 10-20% (or something like that)  so that they could quickly be put online again, if needed.  You cant just flip a switch and turn those puppies on and off like you would a light bulb.  Most of the home setups I have seen look like they were designed for working at full power during the summer months plus or minus months in spring and fall...ideas come and go. but governments will still demand their money and we, the taxpayer/consumer must shoulder the burden.

That is just it; no one can predict the future, but I do think it is prudent to do for us much for ourselves (and families) as we can. But that is not a power generational thing, but all across the homesteading spectrum.

First off I am tired of people basically accusing the utilities of stealing.  They are not.  Net metering was silly from day one.  When it was a few percentage points of the total it was fine as the added cost to everyone else was spread out.  What net metering forgot was stranded costs beyond the cost of power and transmission losses.  Every grid tie home is getting multiple benefits from being grid tie and the people with solar forget those benefits.  If they don't like the cost they simply need to go off grid and eliminate them.  But they will then have the battery costs, backup generation costs, loss of reliability costs etc to bear.

Now back to the question of the post storage.

I will touch on several.

1.  Lets start with one already mentioned.  Compressed air.  It has value in the shop.  You can get power hand tools for it cheaper in most cases than electric and in many cases they are more durable as well.  How might this fit with permies?  One of my customers bought a skid with two large air tanks on it military surplus cheap.  It was something like 600 gallons capacity with a working pressure rating of something like 300.  He has special trusses made building a shop so those tanks are literally built into the attic of the shop now.  Now my worst air tools will cycle my 60 gallon air compressor after about 4 minutes of operation and if I stop it takes about another 4 or 5 to refill the tank.  So in essence what I get is 4 minutes of 5 Hp from it.  Now his tank is 10X the size of mine and holds more than twice the pressure so he could easily store 80 minutes of 5 hp.  It isn't huge but it is very low loss designed properly and power in the final form it will be used in.  So if you can find the right stuff to re-purpose this is very much in keeping with permies principles if you need air power.  So any time I have excess power I can dump it to a small DC high pressure compressor.  It also might give me the ability to put in a smaller inverter power system because I didn't need to support this high power motor.  A small portable gasoline or diesel compressor could be used to make up the short fall on days when the stored air wasn't enough.  If the system is built right I can add systems for cooling, heating, nitrogen, oxygen and CO2 storage to it fairly easily too.  And these systems could likely be made from salvage stuff too also in keeping with permies principles.  Nitrogen might give me better tire life & low oxygen storage for things like apples.  Oxygen storage might run my torch.  CO2 storage might let me improve growth rates in a greenhouse.  If you were going to build such a system with all new materials it would be expensive and definitely not in keeping with permies principles most likely.  So don't.  Salvage ans work smart.

2.  Hydrogen storage of power was not mentioned.  Done on the cheap efficiency sucks.  An electrolyser  is 50% to 80% efficient  Cheap buildable ones are down in the 50%-60% range.  So you have lost nearly half your power before you ever store it.  For storage use hydride tanks.  This allows the hydrogen to basically stored in a low pressure metal sponge. Semi expensive but the big advantage is the ability to store nearly lossless for decades if needed.  Then go back thru a fuel cell to get the power back.   There again losses amount to another 25% of the power.  So roughly 33% return on power if done with affordable storage systems.(even with expensive equipment this one only runs about 60%)  Not good.  But if you can capitalize on any of the hidden gains here you have more to gain.  The electrolyizer produces pure oxyben so there is a possible gain.  It also produces heat.   At full power output the fuel cell produce high humidity hot air and if it is idling only producing a little power it is endothermic and actually cooling for some types of fuel cells.  So can any of these others be economically capitalized on?

3.  Now for the big one that was not mentioned.  Thermal storage systems.  They have the ability to greatly reduced the number of needed photovoltic panels while adding solar thermal panels that will run in lower light levels and in cloudy areas.  In its simplest form it is simply a large heavily insulated storage tank in which stratification is encourage.(the one out of the alaska house example was something like 5000 gallons and insulated to R70.  in this case he figured he had 2 months of hot water and household heating stored)  In a more complicated version you do the chiller system out of Europe.  This involves both hot and cold tanks and a small heat pump running between them.  Any time you have excess power you heat one and cool the other.  The hot tank does the domestic hot water and household heating needs,  The cold tank serves for refrigeration primary, in some cases freezer primary and AC.  After having read about these systems I think they are still missing bets.  The hot side could be also be preheating the oven to say 140 degrees, providing heat for a clothes drier,  providing heat for a closet that in various season did different things.  In summer and early fall it is a food dehydrator, fall just after hunting season it becomes a smoker and then it spends the winter warming and drying cold weather gear.  In my thinking 2 different solar thermal systems, 1 hot and 2 cold tanks.  Still trying to figure out how to get all the dream functions in one affordable system.

There's been a lot of news recently about gravity based systems where huge concrete blocks are raised to store the power as potential energy.

We have cities of skyscrapers, and at least here in NZ, we have base isolation as a way of protecting against earthquakes.
I wonder if it's feasible to use your above ground house or skyscraper as the energy store.  Use jacks powered by spare electricity to raise the buildings, and then lower them to recover the power.

Thermal batteries. Now we're talking. That is something we can implement with low tech requirements. Add in gradient effects and it gets super interesting.

Phil Stevens wrote:Thermal batteries. Now we're talking. That is something we can implement with low tech requirements. Add in gradient effects and it gets super interesting.

Yeah exactly!!! This is the right way to implement with low tech requirement.

Here is the alaska house video that I first learned about heat storage tanks from  The tank information start 1 hour and 18 minutes in.

Here is the a commercial home build for home chillers.  

The neat thing is most of this is well within what we can do thru salvage and reuse.  If you went full chiller type the heat pump itself likely isn't but all the rest is just plumbing which most of us can do.