Power Generation General

[Scatty]

Thank you!

And it would pay for itself very quickly if you consider running power out there would be like ten grand at least. The sun is more places than powerlines are.

If you do start looking into 220kwh of batteries, just be prepared for a pretty big undertaking. I have 38kwh of lifepo4 batteries (2x 18kwh units), and combined they weigh around 1000 pounds. You also have to consider heat, humidity, inverter noise, and space.

I just poured a concrete slab and built a shed to house the monster batteries and the inverters. I used foam panels to insulate, and added a dehumidifier, air conditioner, and heater. By keeping the temperature in a fairly optimal range and keeping the humidity low, I hope to extend the life of the equipment. A similar setup might work for your situation, but obviously you'd need a bigger shed.

Note - I'm assuming that sperg rancher's numbers are correct, but I didn't doublecheck them. He seems to know what he's talking about.

 

[Cirrhosis_of_Liver]

I'm thinking I'll spend more money on buried pipe and do this irrigation scheme with direct well pressure. However, I definitely will be wanting to do a solar powered aerator in another place, and this has convince me that building a system for that much smaller motor (just enough to pump air to the bottom of a tank) set up with a solar system is doable for cheaper already than running power out there would be.

 

[DavidS877]

If you do start looking into 220kwh of batteries, just be prepared for a pretty big undertaking. I have 38kwh of lifepo4 batteries (2x 18kwh units), and combined they weigh around 1000 pounds. You also have to consider heat, humidity, inverter noise, and space.

My 220kWh battery pack weighs about 9000lbs.
But it came with a pickup included.

 

[Sargon's wife's son]

powering everything off steam engines those literally no downside all you need is wood

 

[NKVD qt]

powering everything off steam engines those literally no downside all you need is wood

Jokes aside steam is really cool but I think a small steam turbine would work better. If you use a tesla turbine it would also be relatively easy to service yourself assuming you can invest in a cheap laser cutter.

It's basically a stack of thin discs that you flow the steam through and using the "stickiness" of the fluid to the discs to spin the turbine.

They are pretty loud though

 

[Oxyjen]

Ok, super specific question time for all you true autists.

Say I want to pump 250 GPM of water for 24 hours out of a week (I do.) I don't need to be above 30-60 PSI, and it is downhill through roughly a quarter mile of 3 inch pipe.

How big of a solar array and battery bank would I need to achieve this if I used an electric pump? I am in the arid half of Texas. How much would this cost?

Down hill? What elevation change?
It sounds like you’d just want a way of starting a syphon and let gravity do the rest.
Or at least the pump will only be increasing the flow rate so its power requirement might not be too crazy.

What do you use for it at the moment, some kind of Honda engine driven pump?

 

[Cirrhosis_of_Liver]

I don't use anything at the moment. I was trying to determine whether it was nobler in the mind to invest in a shitload of 3" or bigger pipe to run all the way from the well to the hay meadow, or to use the existing scavenged pipe to refill the tank, and then pump a high volume to operate a sideroll.


I've come back around to my original plan, which was to shoot for more like 50 GPM directly from well down to hydrants to run a Vaughan style low pressure traveling gun.

Eventually I might invest in solar to run a well pump, but that's a lower priority as I already have grid power to the pump, so solar there is more of a prepper thing, and if I'm gonna go full prepper with solar, the house is a better place to start.

As per the house, I think I might be able to be clever and build a low shed for the panels instead of mounting them on my roof.

 

[Scatty]

As per the house, I think I might be able to be clever and build a low shed for the panels instead of mounting them on my roof.

This can be a good move if you pull it off right. I bought an adjustable ground mount for my setup since we have so much land. It takes a bit of time but we can turn handcranks to tilt the whole array to any angle we need.

Eventually I might invest in solar to run a well pump, but that's a lower priority as I already have grid power to the pump, so solar there is more of a prepper thing, and if I'm gonna go full prepper with solar, the house is a better place to start.

You know, it might be worth looking into some sort of water tower + solar. Instead of having thousands of pounds of batteries, have the pump fill up the tower during the day. Dunno if that's feasible for the quantities you're talking about but it's worth a thought. Keep in mind that you'd want some sort of deicer in the tower for the winter.

Another idea is to have solar without batteries to power the pump during the day when it's sunny, and then grid power during the night when there's no sun but grid power is cheaper. This kind of setup might actually save money in the long run. Lots of the new hybrid inverters can be set up to handle this transition automatically and they're not too expensive. You should be able to get electrical shed, ground mounts, panels, and inverters for less than 25k.

 

[Cirrhosis_of_Liver]

I don't think water towers are practical for irrigation, even at my small scale. I'm looking to put 0.5 to 1 inches on 14 acres per week. So that's at least an acre inch a day. An acre inch cylinder would be seven feet tall and eight feet across and when full would weigh 113 tons. That's a pretty serious construction, and I'm not sure what the advantage would be aside from keeping the water pressure more consistant.

 

[Sperg_rancher]

Instead of having thousands of pounds of batteries, have the pump fill up the tower during the day.

Wanna chime in here, battery conversion efficiency is ~ 80%, and volumetric storage tops out at around 64%- the easy calculation would be energy stored (kwh) = Cubic Feet * lift height (m) * 1.05*10^-5, which means to get the energy 220kwh needed in a water tower, you'd need to extract the energy from ~1.4 million gallons (5.84kt) in a standard 50 ft tower. You can verify yourself here: https://www.omnicalculator.com/physics/potential-energy

 

[Oxyjen]

As per the house, I think I might be able to be clever and build a low shed for the panels instead of mounting them on my roof.

Yeah I made a wooden frame for a load of panels, ended up putting sides on it for storage.. then added a floor.. now it’s quite a nice shed

Not sure I grasp all the ins and outs of your irrigation needs. But I’d agree with doing what you can with water storage (up the hill) and pump only during daylight if you can.

 

[Cirrhosis_of_Liver]

Oh, I wasn't understanding that the point of the water tower was to store energy.

Spoiler: in depth spergery

Water level in most of my wells is like 40 feet down, and it's been very dry lately. The energy to get the water out of the well and to the tank is almost negligible. I think I've been spending maybe 100 a month on the well I'm planning to replace. It's been giving me something like 16 acre inches a month. Now, with improves bermuda fertilized at the rate I'm using on that pasture you need about 6 acre inches per ton of dry matter. So reckon 6 months of 16 inches, 96 inches during the growing season, 16 extra tons of dry matter, call it 25 extra round bales, the water acquisition averaging to 24 dollars a bale. That's brilliant. Not that I wouldn't mind pushing it even lower, but the energy for a well pump with my groundwater situation is not bad at all.

What WOULD take a great deal of energy is the next leg, bringing a large volume of water all at once at reasonably high PSI (much higher than gravity would make, I think) to an old style side roll irrigator. And, for this and other reasons, I think I'll go with the roughly $25k start to finish direct well connection system I'm looking at, rather than the maybe $15k irrigation system and either $30k solar, very expensive powerline extension, or noisy and high operating cost gasoline or diesel pump. @Sperg_rancher 's post convinced me I'm best off buying more pipe and a bigger well, and then maybe using solar to lower operating costs in the future.

 

[DavidS877]

much higher than gravity would make, I think

1 PSI is 2.31 feet. So, figure out the PSI you need and do multiplication and that's how high the bottom of your tank needs to be above the point of use for gravity alone to give you your pressure.

 

[Sperg_rancher]

1 PSI is 2.31 feet. So, figure out the PSI you need and do multiplication and that's how high the bottom of your tank needs to be above the point of use for gravity alone to give you your pressure.

This is static- when flowing the pressure will drop depending on a few other things.. I'm not a plumber so I'm not sure what those are..

 

[DavidS877]

This is static- when flowing the pressure will drop depending on a few other things.. I'm not a plumber so I'm not sure what those are..

Mostly flow rate, pipe diameter and smoothness of pipe. Plenty of calculators on the Internet for estimates.

 

[Sperg_rancher]

Mostly flow rate, pipe diameter and smoothness of pipe

You're saying I need to polish my pipe so I can increase my flow rate?

 

[ToroidalBoat]

Sucks that portable fusion power from scifi is not a reality. And that "vacuum energy" is not really doable because there's no known way to make an energy difference in spacetime to extract useful energy from. Also home nuclear fission is not exactly entirely safe.

 

[Whoopsie Daisy]

There's discussion of solar, hydro and diesel generators but is wind not worth considering?
I know very little about wind other than wind turbines can charge your battery pack, even a trickle charge in light wind, and in heavy winds require a heat dump due to how much they produce.
Finland have done a fun test using sand batteries, where the heat from excess generation of wind turbines is dumped into a huge silo of sand, which get very bloody hot. This warms up pipes which transfer heat throughout the village, similar to the soviet steam pipes from power plants, if anyone is familiar with them.

Anyway. Wouldn't wind be the ideal generation if SHTF, as it's very low maintenance - a couple of bearings and a motor/generator wired to an (invertor?) then to the batteries.

 

[NKVD qt]

There's discussion of solar, hydro and diesel generators but is wind not worth considering?
I know very little about wind other than wind turbines can charge your battery pack, even a trickle charge in light wind, and in heavy winds require a heat dump due to how much they produce.
Finland have done a fun test using sand batteries, where the heat from excess generation of wind turbines is dumped into a huge silo of sand, which get very bloody hot. This warms up pipes which transfer heat throughout the village, similar to the soviet steam pipes from power plants, if anyone is familiar with them.

Anyway. Wouldn't wind be the ideal generation if SHTF, as it's very low maintenance - a couple of bearings and a motor/generator wired to an (invertor?) then to the batteries.

I think the biggest problem with wind is it's very location dependent and and assuming it's your only form of power generation it can be inconsistent. But if you have a battery bank, live in a good spot (like the top of a hill or by the shore of a lake or the sea), and are willing to conserve power. I don't see why it wouldn't work pretty well.

 

[Whoopsie Daisy]

I think the biggest problem with wind is it's very location dependent and and assuming it's your only form of power generation it can be inconsistent. But if you have a battery bank, live in a good spot (like the top of a hill or by the shore of a lake or the sea), and are willing to conserve power. I don't see why it wouldn't work pretty well.

Trees generate breeze. Could a small breeze with enough turbines generate enough power to charge the battery banks?
YMMV but I've never been to a part of the UK that isn't breezy and most days it's windy as fuck, even 100 miles inland.

To clarify, this is to just run the essentials of keeping fridges/freezers ticking over to keep food preserved in the event of a blackout. I wouldn't try and power my home off of it other than charging a laptop/tablet/torch, just low power utilities for necessity and entertainment. If/when I go off the grid, modern technology will be yeeted into the shitcan.