I bought an old marine generator engine I can take the generator off and power with windmill or watermill produces 120 volts 36 amps @ 1700 rpm can also charge 12v battery, the engine is junk paid 100 bucks for it
still be more efficient than compressed air power, can also rig up a car alternator to a wind or water mill for 12 volt applications. air compressors are noisy require more maintenance.
now I did see a guy who was going to use 2 large air bags under water and transfer air back and forth producing electrical power, there's a cost factor in designing for water. and you could the same thing with a water mill and generator of using a 12v pump to pump the water back up over the water wheel and produce 120v or a combination wind and water mills. You might be able to pick up a used generator with a blown motor quite cheap that will have more function for more things.

Personal home Off grid electrical systems work extremely well and save a lot of money to people who:
1 Can gain access to reasonably priced equipment
2 Reduce there electrical demand to meet there supply
3 Are willing and capable to maintain and service there own installation

I speak from personal experience with my system costing less then 5 years worth of electrical companies service charging alone

Off grid systems wont save you money but will give you independence to people who:
1 Size there system to match modern day luxury living
2 Buy complex and/or expensive equipment

Obviously businesses and trades and even locations are all different

I had looked at this hard and am still mentally playing with it. I can run the big 1" air gun for about 4 minutes on the 60 gallon tank of air before it gets to low to run the airgun effectively. The die grinder is the other big air use one and it will run about 7 minutes on the same tank of air before the tank gets to low for it to work. Since I only probably use the air gun or the die grinder 4 hours at the most in a typical work day that would mean max storage of 3600 gallons should let me run the worst days I commonly see.(and that is a fairly rare day) But since I am starting with a single stage compressor max pressure is 120 psi. If instead I get storage pressure to 200 psi that would bring the needed tanks size down to about 2000 gallons. Now usually I know on those days that I expect to be using that kind of volumes of air. So if the first thing I did in the morning was plug a smaller air compressor in and just let it work away all day I probably might need that much air storage. But by the same token though the wind doesn't blow every day so storage for multiple days would be nice.

Now the thing everyone seems to be missing in compressor design for wind mills is that the load can easily be designed to be practically infinitely variable. By stair stepping the sizes of the pistons in a binary fashion where each one doubles the power needs of next one down and giving them speed controlled unloader valves the load can be varied from next to nothing clear up through max wind speed power. Beyond a certain point likely you will want the valves also set up to change from single stage to 2 stage operation for greater pressure. By having a number of pistons the load should be scalable for the max ever observed wind speeds in an area meaning instead of shutting down in high winds the tower just keeps increasing its power output.

Couldn't a commercial type, 'engine driven' style AC compressor be used to compress freon in this same way? Such as one off of an older car? If you don't want to use freon, what about propane? For extracting useful energy, the freon/propane could be used to supercool a peilter junction array, or used to directly chill a refrigerator, or drive another compressor backwards as an air-motor. It would require a large pressure vessel capable of holding the propane as a gas, but perhaps a simple bladder bag would suffice for this purpose.

I am really glad that joined this forum because every time I come here, I find that someone has posted a question that is on my mind. I have been thinking about the topic "alternative means of storing excess energy" for a long time. Energy creation means could be wind, solar panels, solar heat (as in produced by a sterling engine) or whatever other means that produces energy that is not readily available 24/7. I have considered the use of compressed air, pressurized hydraulic oil, hydrogen (produced by breaking down water), and even the use of water (pumped from a lower elevation to a higher elevation, and then allowed to fall to the original elevation and turn turbines in the process. In any of these scenarios, I have not considered replace the appliances that I want to use with pneumatic, hydraulic, etc. I assumed that I was going to use the standard 110/220, etc volt applies that are common to the area. There are a few exceptions - I have heard of refrigeration systems that were partly operated by solar (heat) energy. I think LED lighting might be a subject worth considering installing on a separate circuit, that can operate on lower voltages.

In my mind, the system (no matter which technology was used to generate electricity) would be a hybrid system and would still require the use of a battery pack, but a much smaller pack then is normally used. Secondly, electricity needs should be mapped out carefully and life habits should be changed accordingly. If a house uses electricity to dry clothes (why, but why??) it does not make sense to have someone drying clothes at 10 pm if maximum energy generation from the windmill is from 3 a.m.to 8 a.m. (I am just using this as an example) If the clothes are dried during this time, that is electricity that does not need to be stored in a battery but can be utilized directly from the windturbine/generator. Clothes should be washed/dried; fruit should be dried; batteries charged (notebook and tablet pc) water pumps should be operated all during this optimal energy production time. By effectively planning energy needs this way it might be possible to reduce the amount of hardware needed to generate/store energy. Once these strategies have been implemented, a sensor should be connected to the battery pack. The size of the battery pack should be equal to, for example, ten minutes of electricity usage in the non peak times (the times that you are not drying your clothes, pumping water, etc). When the sensor realizes that the battery is at (for example) 40% of storage capacity, the compressed air generator (or whatever) can kick in and start generating more electricity. This electricity can be used to both recharge the battery pack and also meet the needs of the current drain.

Maybe this is as clear as mud....

Tom Connolly wrote:Maybe this is as clear as mud....

No, it's quite clear. Thanks for taking the time.

I've also done thinking along these lines. However, try as I might, I can't quite figure a practical micro off grid energy system that can completely do away with a battery system ("practical" is the key word). Minimizing this system is the best I've considered. A combination of opportunity loading (as you described), minimizing electricity use (frugality, conservation, efficiency), and keeping a backup generator (as opposed to maintaining a massive battery for several days of inclement weather) - these seem the most practical solutions.

I have made posts elsewhere that might interest you. For example, one way to achieve opportunity loading of a freezer can be done by adding a phase change material as a thermal mass. For example, bottles of salt water (not necessarily NaCl) can lower the freezing point. This can carry the freezer through a day or more after they're frozen. As a side benefit, it would eliminate cycling the compressor which could extend the life of the unit. I considered this for use with a solar array, or for use with a wood gas engine system operated several hours each day. On that last note, I have made posts about powering a modest off grid home solely with a wood gas engine system plus modest battery. I consider this prospect to be fascinating mainly for its low tech approach even though it's hard to justify not using photovoltaics in most settings. The engine system operated a few hours daily can (1) charge a battery, (2) use the heat from the engine to regenerate a desiccant (for space cooling or space heating), (3) heat water with the steam driven off the desiccant, and (4) power a refrigerant compressor to freeze a salt water thermal mass in a freezer. The battery is required to power the few electric/electronic systems required, and these would be minimized (i.e. laptop computer, LED Lights, small fans). One of the major consumers would be air moving equipment (fans) for ventilation and heating/cooling, but these can be fairly small and DC (more efficient than small AC motors, and no inverter losses). One problem is getting a full charge cycle on the battery. The most practical solution here is probably to take advantage of newer lithium based batteries that do not require absorption (in particular, consider lithium iron phosphate batteries).

Reality Check: A note on the original topic of this thread. I do not believe that storing energy in the form of compressed air can be practical in the micro scale (especially if one considers using this energy for electricity generation). Quite simply, the energy density is too low. However, there are also many losses involved. I can go through the physics, but I also have experience as I used to operate and maintain very large compressed air systems (3000 psig, and 10,000+ gallons). This air was used to pressurize a hydraulic fluid used operate a very large hydraulic motor. In that case it made sense because the motor had to generate over 2000 hp for 15 seconds. However, while this is a high power application, the actual quantity of mechanical energy is fairly modest. I won't bother with a lot of math, but note that 2000 hp for 15 seconds provides the same energy as 500 hp for 60 seconds, 8.33 hp for one hour, or 0.350 hp for 24 hours. So, it would provide roughly 250 watts continuous over a 24 hour period, and much less after alternator losses are considered. A 500 pound lead acid battery could do the same with a helluvalot less complication, expense, weight, and bulk. If someone lives in a region with a good wind resource, is off grid, can position a large wind turbine near a shop that relies on compressed air, then perhaps it can be practical. However, please don't consider this viable in general.

Thanks. Reality checks are good, especially when they come from really smart people who can do math - I have trouble after I run out of fingers and toes If I can take one step back first...in the 1800's, in the U.S., when pioneers settled mostly remote areas they would often find a piece of common ground, say one corner of each person's property and each of the four, five or six family would build their house within shouting distance of each other. I think this philosophy would go a long way to people who are living off the grid, but alas, we modern pioneers seem to be more intent on "getting away from it all" than we are in finding a practical way to "stay away from it all" and enjoy the process. individualism, at some point, becomes too expensive a lifestyle to successfully maintain.

LiFe (Lithium Iron) batteries are the most resilient of batteries, as far as I know, but far more expensive than the standard Iron batteries. As I understand it, the technology to rebuild LiFe batteries is much more complicated and expensive than the standard "old faithfuls" that we have used in electric vehicles for years. Both batteries produce toxic waste when their useful life is up, whether it is by destroying them or rebuilding them. Each presents its own challenges - the old batteries being very heavy and requiring quite a lot of them to do the job, while the LiFe require much fewer batteries but at a higher cost.

If I expand the scenario to one degree greater, I was also thinking about ways to simplify the total process of obtaining energy. I would like the common denominator of energy storage to be something that, when calculating the total needs/costs of a homestead, will be practical, safe, inexpensive (investment vs. return) and as un-complex as possible. If we use batteries (electricity) as the common denominator, I can buy a 2 wheel tractor that runs on electricity. I can buy an electric car. Almost everything in the home runs on electricity as it is, with the exception of perhaps cooking and heating. The problem here - what if I encounter an exceptional need - blizzard, flood, heatwave, whatever, that requires much more electricity than my trusty little solar panels can put out and my batteries can store? A backup generator is required, probably running on some kind of fossil fuel.

Even if it were possible to do the same with compressed air or hydraulic fluid, the same weakness still exists - the need for a backup generator, as well as for some size battery pack to act as a buffering agent.

Now, what if the excess energy produced by solar cells, wind turbine (or sterling engine, etc) was used to produce hydrogen? I have never done a conversion but I have been told that most gasoline powered engines can be converted to use hydrogen. The tractor engine can use hydrogen. The chainsaw motor (sorry folks, but I have never used an electric chainsaw that could even get close to doing the same things that a gas one could) the rototiller, the car, maybe even the heater for the house or the oven - and if you must, your clothes dryer. Bright sunny days can produce an excess of hydrogen that can be stored in relatively inexpensive bottles - car hydrogen systems use a different means of storing it to make it more stable....and, of course, a generator can be retrofitted to use hydrogen as well. Hydrogen becomes the common denominator and can more easily be stored and used than any of the other options - even easily sold or shared with neighbors (heaven forbid!). The energy generating source can still pipe electricity directly into the house, shop, etc, but excess would be converted into hydrogen. Yes, some kind of battery system will have to be in place, but given the ability for a generator to kick on in a few seconds, maybe the battery need be sized to 15 minutes demand. With a total battery system, excess energy cannot easily be stored - I would have to run out to my nearest battery store, pick up a few hundred pounds of batteries, bring them back, wire them in and let them work. In the mean time, the sun has gone down. Yes, there are dangers associated with working with hydrogen (but it is not nearly as unstable a substances as people think it is) but there are also dangers in working with compressed air, electricity, etc.

I have read quite a number of very promising articles on solar powered sterling engines that describe them as being the most efficient means so far of using solar energy. In addition to producing mechanical energy they also produce a lot of heat. Turbines, of course, are established technology, as well as are solar cells. Lots of options to produce the energy...problem is how to store it. I am not in a position yet to implement - I am now shopping for my land, but if I were to put in the system tomorrow I would most likely use hydrogen.

Tom, you provided lots of things to consider. I like to consider all kinds of possibilities. However, there really are very few practical ways to power a modern and modest off grid home. Really, the lowly battery is the most practical and cost effective way to store energy for electricity. A backup generator is required, but it need not be used often. In particular, consider that the cost for PV panels is very low today and likely to drop in price further. A combination of a large PV array and modest battery is a good strategy to minimize battery costs and also minimize generator run time. There will be days of effectively zero solar flux on the panels, and a backup generator is required. However, a large array will get that battery charged or nearly so even when solar is low. Plus, the large array is available for opportunity loading.

I don't have confidence in hydrogen as a means to store energy. It's complicated and inefficient. Consider the losses involved in each step. It's also not easy to store as the energy density is low. There are ways around this, but not without complications. Now, if one desires to use hydrogen in an internal combustion engine, then that's very inefficient (you lose at least a third in making hydrogen, then you lose another 3/4 in the engine)! A fuel cell would be necessary to see an acceptable overall efficiency, but even here the losses are overwhelming (you lose the third in making hydrogen, then half in the fuel cell). By contrast, a battery is about 80% efficient and inverter about 85% efficient, so only a third is lost (and efficiency is better when opportunity loading is used as this avoids a lot of battery losses).

I'm sour on solar Stirling engines also, at least for residential use. There might be some potential for small scale solar Rankine cycle engines with thermal storage and CHP (and fuel assisted), but more development is certainly required.

If you were to set up a system today, then you would certainly use a conventional battery. There really is no other rational alternative. The most cost effective technology is flooded lead acid (but a lithium iron phosphate battery is not unreasonable). A combination of large PV array and intelligent opportunity loading will go a long way to minimize the size (and cost) of the battery, and opportunity loading will increase overall efficiency. For example, get yourself a very well insulated home with some thermal mass, then a heat pump can be powered as an opportunity load during the day for air conditioning or space heating as required.

Marcos, do you have a very rough figure on what % loss is typical when a given amount of power is converted to compressed air. Suppose a one hp motor is used to run a compressor. Would we be able to operate a 1/2 hp table saw ? I get some pretty good wind on occasion, which is why this idea arose. But, I'm sure there ore other places where this makes more sense. My 3/4 hp compressor produced a lot of heat, especially on humid days when lots of water was condensed. In certain locations, the ability to take water from the air might be quite valuable.

Here's an industrial site where they talk about heat reclamation from compressors. We'd want to go closed loop with rust inhibitors. Some systems use city water and then run it down the drain. Better systems use it to heat the factory and/or to heat water. None of the industrial sites consider condensed water as anything useful.

http://www.airbestpractices.com/sustainability-projects/boilers/heat-reclaim-economics-air-and-water-cooled-air-compressors

Dale Hodgins wrote:Marcos, do you have a very rough figure on what % loss is typical when a given amount of power is converted to compressed air. Suppose a one hp motor is used to run a compressor. Would we be able to operate a 1/2 hp table saw ? I get some pretty good wind on occasion, which is why this idea arose. But, I'm sure there ore other places where this makes more sense. My 3/4 hp compressor produced a lot of heat, especially on humid days when lots of water was condensed. In certain locations, the ability to take water from the air might be quite valuable.

Here's an industrial site where they talk about heat reclamation from compressors. We'd want to go closed loop with rust inhibitors. Some systems use city water and then run it down the drain. Better systems use it to heat the factory and/or to heat water. None of the industrial sites consider condensed water as anything useful.

http://www.airbestpractices.com/sustainability-projects/boilers/heat-reclaim-economics-air-and-water-cooled-air-compressors

Hi Dale. Conversion efficiency varies widely. It's similar to engines, motors, and generators where the largest, most sophisticated, and most expensive units see the best efficiency. This is a reason why I generally poo poo the idea of using compressed air for energy storage in the off grid setting as it's not practical for an individual to access the required hardware (I tend to restrict my considerations to a residential/individual scale unless I note otherwise). I don't have actual figures, but I speculate there to be about a 20% loss in even a very good small compressor, and I expect the losses in the expander to be even greater. I don't expect anything but a very sophisticated system to see overall losses under 50%. Still, I don't consider the efficiency to be the main obstacle which I see as the limitations in energy storage. I know it can be made to work, but I see it as vastly inferior to using electricity. A small alternator and small motor with battery will still see a 50% loss. However, transferring energy in the form of electricity with conducting wires is a lot easier than transferring compressed air in piping, and a battery will store a great deal more energy than a tank of compressed air unless one disregards bulk, weight, cost, safety, etc. It's fun to consider alternative possibilities, and it's educational, but we should keep all serious considerations tethered to Earth.

I don't discount the possibility of using compressed air in some settings. For example, the trompe systems mentioned in other posts make sense in the right setting. A large scale system that makes use of this compressed air can be very efficient. I mentioned in another post the prospect of heating compressed air in a biomass furnace or solar concentrators for use in heat engines. That could leverage compressed air a long way and allow literally most of the heat input to be converted to electricity since the compression work is performed elsewhere. It's possible to input a great deal of heat with a good system and extend the work by two or even three fold, and there remains heat available at the exhaust for heating applications. Something like this might be practical, but what a nightmare to build! When the drawing board meets the check book, then solar PV and battery storage starts looking really good.

Air is very inefficient. Compare a 6.5 amp drill(works out to just under 1 hp.) and a similiar air drill of slightly lower power. The air drill is being powered by a 5 hp single stage compressor. Yet the compressor is not big enough to run the air drill constantly. Duty cycle is about 50% So you are looking at about a 10% efficiency for the system vs electric. A 2 stage compressor would improve that some to about a 15 to 18% efficiency. But it still isn't good.

Even with the inefficiency though I think it could be made to be economical if you can get components cheaply enough for either a wind or trump system to work. The big one is being able to purchase the storage tanks cheaply enough. The neighbor got a trailer with 2 air tanks mounted on it through military surplus for about $50. This was 2 tanks about 3 ft in diameter and 12 feet long. It cost him more to pull it home than he payed for it. So I know there are possibles out there and I will have to keep looking.

The big advantage to air storage is your stored power won't see much loss over time if you build right.

Looks like this dude's been doing it:

http://www.fieldlines.com/index.php?topic=138951.0

Is fully off grid energy likewater catchment in a isolated desert environment?
You would use large,leak proof tanks to be certain to catch and keep every drop.You would make sure you could fix /make them yourself, since there will be no easy resupply.
The cost/complication/Inefficiency of the catchment tanks wouldn't matter as all other options for getting water are either more complex/expensive or simply impossible.
Of course you would minimize water usage but that only goes so far.


In a civilized rainy enviroment one wouldnt care if your barrel was leaky (batteries) because there is plenty of rain, plus city water (grid tie) or a well(fossil fueled generator).

So it sounds like compressed air is good at holding onto power, but is more complicated and more expensive.
Is it any easier to maintain without outside inputs? Doesn't seem so.
Adding in that variable might make muscle power king, despite inefficiencies and complications in converting wind power into muscle fuel...
This brings me to mills, water, wind and muscle powered.
Seems like one of the best ways to store wind energy might be to use it to pump water, and use the water to generate electricity.
The losses would be huge but the system would be robust.
I think it would be easier to maintain without outside inputs than anything but muscle.
So how about a set up like an old style mill, one spining pto shaft that could be powered by wind, water, muscles or even a wood gas generator. Water is the energy storage medium, withdrawals of said energy are made in as few steps as possible, so yes you could charge a battery from the generator, but grain would ideally be ground strait from the wind turning the pto shaft.

Crazy? Yeah, I got a little off topic, trying to find my point.

Which is...
Well maybe if you are going for energy independence, the ability to make/repair/maintain your system is as important as efficiency/cost.
The energy itself is like the land. Sun and wind will persist. Losing half of a crop every year could be pretty good if you have not had to use any inputs for a decade.
If you lose nutrients by canning that crop, should you freeze It instead, knowing that a loss power could mean losing the years crop?
Should you just buy organic foods from the co-op?
Well if food independence is your goal, I think you should grow your own and preserve it with care, depsite the inefficiencies involved.

Same goes for power.
There I am done, I hope I added something useful,sorry for utter llack of clarity, lack of sleep blah blah blah...

I remember that a guy looked into air as energy storage and found that the air motors couldn't be more than about 10% efficient (at converting air pressure to motion) or the air motors would ice up in operation. It was reportedly very hard to get enough water out of the compressed air to stop icing up in efficient motors. Inefficient motors form heat with the wasted energy, preventing icing. At least that's what I remember him telling me.

Use a hydraulic motor to convert air pressure to motion. That is how a hydraulic hybrid vehicle works.

Electric batteries and air batteries are not mutually exclusive. They can compliment each other.

You could integrate wind, solar and a stationary engine with a generator, hydraulic pump/motor, air storage and conventional batteries.

Oh wow! I had no idea this topic was already generated!! I have some catching up to do to learn what has been discussed so far but I just HAD to make a post to get the ball rolling again. I have LOTS of ideas for overcoming the issue of pressure slowing the windmill rotation and the most interesting one involved using a VERTICAL BLADE wind turbine built from like a playground carousel but install air tanks ON THE PERIMETER so that they gain weight as they pressurize. Rig some wind blades and a compressor head close to the axle underneath and pipe the output of the compressor up through the axle with a swivelling coupler and pipe the air to the tanks on the carousel. Another idea I am working on is a PENDULUM swing with the air tank as the pendulum weight and a simple sail on top. I have a prototype video started here: https://www.youtube.com/watch?v=rOhBQDYTVuQ

THANK YOU for raising this idea, I look forward to catching up and contributing some more, I have even begun to covert a gas powered generator to compressed air with the aid of a flywheel.

Brian Cady wrote:I remember that a guy looked into air as energy storage and found that the air motors couldn't be more than about 10% efficient (at converting air pressure to motion) or the air motors would ice up in operation. It was reportedly very hard to get enough water out of the compressed air to stop icing up in efficient motors. Inefficient motors form heat with the wasted energy, preventing icing. At least that's what I remember him telling me.

Check out this Australian rotary air motor, absolutely shatters the old "ass"umption that compressed air is too inefficient for a viable off grid system. https://www.youtube.com/watch?v=-X6oWZe0QTc

The company is called Engineair and the inventor's name is Angelo Di Pietro. Here are some better details: https://www.youtube.com/watch?v=ZGiviT-C_oY

Why this is not in widespread use today is nothing less than criminal IMO.

I began a new forum topic about some specific design ideas for overcoming some of the air collection process limitations, perhaps we could start anew without all the diversions and detractions from this extremely relevant and viable topic now?

I just can't seem to get past the notion that compressed air technologies have been in use for the "upper echelon" for centuries and just kept under wraps from the "unwashed masses" in favor of "consumables" that profits can be gleaned from. We see all sorts of "Hollywood" castles and catacombs and whatnot with "secret levers" and triggers of all sorts that sit and wait for a simple movement to cause HUGE WALLS to move or passages to open up and all sorts of gizmos in operation with no explanation of the power source, but what if it has ALWAYS BEEN KNOWN that compressed air could be harnessed so easily and it is just one of the "sacred" secrets from Masons (not necessarily "the order", just the trade itself) gleaned from metallurgical use of BELLOWS to super-heat things and have just been adopted into all kinds of INDUSTRIAL applications that just aren't taught at "basic" levels?

It seems at every turn the "experts" vehemently express how "inefficient" air power is and always has been and is why we don't use it "at the consumer level" and yet it IS used industrially all over the place because of it's on-demand convenience and versatility... but why not in the home? Why are we coaxed into using high voltage, highly combustible "alternatives" for energy when there are simple pneumatic devices that people could EASILY charge themselves, even through methods that could be construed as actual FUN like children's carousels, swing sets, even freaking retractable dog leashes with small compressed air tanks replacing the coil springs? Walk the dog, come home and use the dog's energy to run the dishwasher? =/? (although I do already use the dogs to "prewash" dishes already occasionally, LOL)

Just seems like a very underutilized natural resource, but ONLY when it comes to "consumer level" apparatuses.

I'm considering building a trompe on my seasonal stream. First, I have to come up with something that the energy could be used for.

With a suitable air motor, a sawmill, hammermill or gravel trommel could run virtually free.

I guess the manner in which I expressed my distrust for the systems of "intellectual property laws" and land ownership in general did not meet a moderator's approval, so I'll try a different message entirely that relates to water since it has been mentioned for building a "tromp" configuration to create compressed air. The designs I have seen appear to require some sort of structure built 300 feet below the initial flow height, which seems pretty darned unattainable by the "common man", and even one built at a more shallow depth for lower pressures and/or volumes seems pretty elaborate and wrought with pretty much guaranteed need for periodic maintenance of some sort, especially in a dome structure that has been buried.

But the real reason I'm interested in energy from water in motion is from this recently discovered "4th state" of water that has been labelled "E-Z Water" which is apparently a state that exists between liquid and solid forms? When I heard about it, it "sounded" as if vessels of water were to become merely PRESSURIZED that it had the ability to hold some sort of never-before realized "potential" energy and has been linked to the reason why plant matter yields the most energy at the point when it is first harvested. Apparently the cell walls enable the water to be at a pressurized state and the longer it has been removed from the "source", the more pressure becomes equalized to ambient surroundings and the energy levels rapidly begin to decay.

Using this understanding, I thought of a way to incorporate my concept of a "fluidic flywheel" built from ordinary tires filled with WATER instead of air which would theoretically enable easy-start and prolonged inertia into an idea for using centripetal forces to pressurize water and perhaps force electrons from it? If one were to fabricate an insulated housing (like a rubber tire) but embed a conductive band around the perimeter that can make contact with the water on the inside and electrically pass properties to the exterior, then perhaps a plate could be placed in close proximity to the band on the exterior and CAPACITIVELY couple stray electrons from the water as it is pressurized from spinning the flywheel?

Or even test the theory out using a simple piston to pressurize the water in a non-conductive vessel with a singular conductive pathway to see if electric potential is created similar to the piezoelectric effect? After all, water does indeed form crystals when frozen and crystals are a source of electrical energy when pressurized, so perhaps this "4th state" of water is what needs to be created in order to convert it to electricity directly? I'm not sure whether electrons can be "manufactured" in this manner or whether the water would merely become a conduit for them from an external source somehow, it would be an interesting set of experiments to "dabble" in. Not exactly on topic I suppose, but it seemed like a convenient spot to spur some interesting discussion about it (hopefully).

Trompes are a Roman invention. No one is trying to control intellectual rights concerning them.

A small trompe for aerating a fish pond can be accomplished for as little as $20.00. I may spend a few hundred capturing the power of the stream.

The problems with compressed air are technical, not legal. It is a very low density energy storage medium and thus requires very large storage tanks or very high pressure.

There is nothing elitist about everyone using whatever resource they have to the best advantage. I have a waterfall, and it make sense to use it. I paid $58,000 for the land, 12 years ago. I live mostly at various jobsites.  Not very opulent.

Stationary storage tanks will indeed perpetuate the myths of pneumatic power "inefficiencies", but begin including their dynamic mass accumulation into the power collection process and these "assertions" diminish if not completely become irrelevant. Compressed air is the ONLY power source that can be used in this regard and is completely being overlooked IMO. I attempted to explain this concept to a propane delivery dude and he attempted to INSIST that since atmospheric gases don't "start" as a liquid, that they do not gain weight under pressure.

However, I feel compelled to mention (because it dawned on me that I never have mentioned it yet) that the beauty of almost all my designs is that they operate from SURFACE winds and don't require towers, especially the pendulum and vertical axis wind turbine concepts with air storage tanks in motion along with the outer perimeter that gain weight as the rotation increases their pressure. Combine this with liquid-filled flywheel enhancements that start easily and slow resistively and BAM we got windbottlin' goin ohn... hell, turn it into a kid's carousel with sails and let the kids playtime generate shared pressure throughout entire communities in an "on demand" consumption and maintenance self-provision network.

Every house has the option of either self-providing or tapping into the "air grid" to either download extra unused pressure from the household, or borrowing some of other people's excess, or using credit from previous times of excess. We could even use existing gas and/or water lines depending on how we decide to PROPERLY dispose of our waste without using the "power" of our own fresh water supplies.

Note to consider: Compressing air results in WATER ACCUMULATION right out of the atmosphere that can be consumed or used in place of well or municipal water sources.