Manufacturing as energy storage - help me brainstorm

I was recently watching a video where Curtis Stone was giving the specs of his off-grid solar arrangement.  He mentioned the output difference between a good day in the summer (where he is desperately scrounging for ways to use the power) and the worst day in winter (when he has to run diesel backup) is roughly 100x the power!

I guess I always expected some seasonal fluctuations, but, wow!

For the excess, there's the obvious and expensive solution of throwing more batteries at it, and some of the alternatives like pumping water uphill (which he discusses).

I remember reading an article one time (can't find it again, and google is no help) that proposed a different way of looking at excess electricity.  They proposed the idea of looking at manufacturing as an embodied store of energy.
For example, whenever the sun is shining and the batteries are full, you use the power to run a CNC and have it a make bunch of cutting boards.

There are other things, too, like you could make hydrogen or some other fuel gas...  maybe figure out a way to automatically feed a chipper to make bark chips... Ooh! Or some kind of auto-fed log splitter that splits all your firewood for you!!
(Of course, the best options are the ones that run on their own with the least possible babysitting.)

I think there are a lot of possibilities looking at things this way.  What other ideas you can think of?

Good idea.  So you aren't storing it for later use, you're making use of the energy when you have it for a non-traditional purpose.  You'd still be screwed in the cloudy wintertime.

The opportunities could come around a common waste product that can be melted or crushed slowly into something better.  

So sawdust, wood chips, plastic, glass, aluminum cans, etc as a feed product that you put in a big hopper.

Turned into glass tiles, aluminum ingots, etc

Maybe run a pellet mill for making wood burning pellets?

An annoying one that I don't like is bitcoin mining.

Off grid over 20 years now with solar and wind power.

The problem most off grid people have is they are trying to live off grid like they would on grid and using appliances that are not efficient and not designed for off grid living and many homes are not energy efficient and waste energy needed for heating and cooling.

The 2 main power consumers in any house is heating and cooling. with water heating next.

So focus on taking those off your system or reducing their use before you ever consider solar power.

Start with passive ways to reduce your need for heat and cooling.

Increase your insulation in the attic, seal leaks around doors and windows, install a roof turbine to expel excess heat, build on a shade porch to cover sunny windows and grow trees to shade the house but don't block the sun on your solar panels. White metal or shingle roofing reflects heat and can greatly reduce the need for cooling. Thermal blinds and window quilts hold in heat loss from windows in winter and don't build lots of windows in to your homes. That is like having an open hole where you throw the money out.

Wood stoves can be used for  heating but you need a reliable wood source and wood can be expensive if you have to buy it and you will likely need a truck and chainsaw and gas if you are cutting your own,  Wood stoves require maintenance and can be a serious fire hazard and if you have to leave your home for an extended time your pipes can freeze. They can be used for cooking and heating water but in summer they will over heat your homes for those purposes. We need live trees left standing to capture carbon so only dead trees and scrap wood should be collected.

Propane is a green fuel that burns very efficiently at about 99.7% and can be used for heating, cooking and water heating. It is cheaper than buying wood or grid electricity most places. You can get propane heaters that require no power at all or have a small fan and propane OD water heaters work great and require no power and just a battery for the ignitor.  Cooking with propane is cheap and just like NG but use a range hood vented outside.

Heat pumps are all the rage now but they are better at cooling than heating and below 40F they start losing efficiency and they require a much larger solar power system and batteries to operate and if you have very low sun in winter you may need a backup heat source.

My energy system for full time off grid living is 400 watts of solar with two 200 watt recharging stations and a 400 watt wind turbine. Wind is fickle so I don't rely on that for much power.  My cabin is built like a self contained RV and that system powers my 12 volt water pump, laptop/tv, LED lights, microwave and micro washer/dryer, and recharges lots of gadgets and tools.

In summer I have excess solar power which I use to run an 85 watt evap cooler, recharge my ebike and electric lawnmower batteries and I use electric cooking appliances more to reduce the use of propane.

I have a 12k BTU propane heater, cookstove and OD water heater that uses about a gallon a week in winter and almost nothing in summer. Propane is fairly cheap here but I also have a wood cookstove with hot water tank in the event I can't get propane. I have many small electric cook appliances that will run off my  solar and batteries and I do have a gas generator for backup but rarely needed.

Over the years I have found the balance of having a system sized right for my needs and with the right appliances so I use any  excess power in summer and have enough for 5 long days of low sunshine in winter and I have greatly reduced my reliance on propane and gas generators with passive heating, cooling and having my cabin super insulated and sealed.

Hope that helps and here are some vids of my system for ideas and I have many vids of my passive systems, heating, cooling and ebike recharging on my channel: http://www.youtube.com/solarcabin

I think separating and storing atmospheric gasses makes a lot of sense.
There are a lot of uses for the liquid and solid versions of these gasses even at a homestead level.
While other manufacturing requires the gathering of some kind of raw material, atmospheric gasses are always at hand.
A lot of manufacturing that uses readily available materials, like distilling water or kilning bricks, would involve turning the electricity into heat.  
This seems kinda of a waste, especially at the times of year that photovoltaic are most productive.

If I was anywhere near water I would just go with pumped storage. You could possibly get a green credit, but also do usable work when the sun shines. It need not be oversized as you can get swimming pools pretty cheap now. Plumb a few Kaplan turbines out of the bottom of one during peak hours and save a boatload of money.

We have got automated water moving down pretty good on the DIY scale with heating systems so it would be simple and off the shelf.

At the homestead level pressure canning with an instant pot comes to mind. I could see an argument for hydrogen generation but storage is a pain. Making concrete clinkers, melting down aluminum scraps has been mentioned, electric chainsaw and splitting. Lumber milling, extra battery banks for electric tractor work concentrated in the summer.

David Baillie wrote:At the homestead level pressure canning with an instant pot comes to mind.

Good thinking.  Or similarly, run a freeze-dryer.

I have read about a plan to use excess electricity in the far north during the summer, to change biomass which can grow quickly in the long days of summer, into biofuel to replace diesel in the winter. So if you're specifically trying to "manufacture" storable energy, this would fit the description.

However, it seems to me that what K  Eilander is referring to is quite different.  

I remember reading an article one time (can't find it again, and google is no help) that proposed a different way of looking at excess electricity.  They proposed the idea of looking at manufacturing as an embodied store of energy.
For example, whenever the sun is shining and the batteries are full, you use the power to run a CNC and have it a make bunch of cutting boards.

To me this question is asking, "what useful products can be made seasonally either because they can be stockpiled for winter (like home canning which was suggested) or in a quantity which represents a year's supply?"

At the moment, fabric and clothing is ridiculously cheap compared to the embodied energy it represents. If that were to change, I could see using excess electrical in the summer to do small scale automation of fabric and sewing sub-steps.  The problem with that theory, is that frequently the same people who would be doing such things, would be busy managing their homestead during the summer weather. I did almost no sewing all summer and have done a pile of sewing in the last 2 months.

My friend's wood mill uses fossil fuels. I don't know if it could be run on an electric motor. Stock piling dimensional lumber so that it can dry slowly under cover until the next building season might make sense.

Our "modern industrial attitude" is that if you invest in equipment, that investment needs to earn its keep every day of the year. What this quandary is suggesting is that we need to go back to seasonal approaches to manufacturing.

In my more mad scientist days I thought the manufacture of nitric acid would be a good use for "extra" electricity. Before they cracked natural gas to manufacture nitrogen fertilizer they used this very electric intensive method to duplicate how lightning creates nitrogen...

There are a number of large scale answers but most don't translate well into the small scale.

My personal favorite is burning powdered iron for fuel.   The result is rust in slag form.  Apply electricity in the proper solution dissolving the iron as you go and electroplate the iron back out.  Grind it back to powder and burn it again.  Roughly 60% closed cycle efficiency and lower cost on scale than most system.   Long term lossless safe storage.  Easy conversion of EXISTING coal and natural gas fired plants.  Could provide storage for renewables and for nuclear when over producing

Second choice large scale is burning ammonia.  More complicated to implement, more dangerous but also can be used to cycle renewables into fertilizer production

Third choice that may be smaller scale shortly is flow batteries.  There are a couple of promising looking answers.  Right now proof concept running by 2 manufacturers in the US.  Good long term storage.  Fairly safe storage but still a bit dangerous.  Lower energy density  Since the battery's energy is stored outside of the battery, battery size is no longer tied to storage size.  Now you can have large storage and a small battery(ideal) or vice versa

Now looking at the video he is mostly right on things that won't work.  But he is missing a couple good possibles.  Solar thermal using a big well insulated tank and stratification I would say is the first piece of the puzzle.  The outfit out of Alaska that stores 2 months of hot water and house heating would solve his one month gray period.  The other piece I would be looking at is if he has any of those outbuilding that don't need to stay room temperature looking at simple ground loop heating and cooling(No Heat pump).  I want to see his numbers after he has the new house running.  If it is well designed it should solve a bunch of the problems.

Now I have loved the idea of hydrogen for nearly 40 years.  That said except for a few niche markets I don't expect to see it at a scale.  Big agricultural tractors and harvest machinery is one of the place I expect to see it.  But general use there are simply better and more cost efficient answers in most cases.

David Baillie wrote:In my more mad scientist days I thought the manufacture of nitric acid would be a good use for "extra" electricity. Before they cracked natural gas to manufacture nitrogen fertilizer they used this very electric intensive method to duplicate how lightning creates nitrogen..

Haha, that's brilliant! Very cool stuff, David. Also possibly a way to utilize excess energy from an electric fencer (say, a 7 mile cattle fencer that only needs to run half a mile). Thanks!

I think to some degree companies are already doing manufacturing as energy...

Consider the modern sawmill. One by me saws a million board feet of white pine logs per week. They waste almost nothing! The bulk of their production is boards, but the bark is ground up and sold as bark mulch to consumers, the sawdust is sold to farmers for bedding, off-cuts that are thick enough are made into childrens blocks, and any production that exceeds sales, going into a grinder and put into silos that later burns the wood waste. That makes steam and it powers the sawmill. Any excess power, like on the weekends and late nights, goes to the grid.

Even at my own job where I work in hydro power, yes we make electricity from the damned up river, but our head pond is not just for that. Just upriver is a paper mill that makes paper plates and cups. They also have a boiler that makes electricity for their mill, with excess going to the grid. Thy need our dam to get the water that they need.

The dam above ours, their head pond is used by another paper mill in New England, where they make paper for medical uses, and of course make power for their mill and sell excess power to the grid. The dam above that... well you see the trend I am sure.

I might be wrong but I think the OP is talking about ways to use excessive summer solar energy to run a small-scale, unattended manufacturing process.  Possibly for a homestead.

Perhaps you put in enough solar to get you through the winter.  Then you have 10x the needed energy in the summer.  Can it be used to make something for those months without babysitting it?  

- storing heat in the ground below the house for winter
- electric kiln for pottery
- seawater desalination (if you are near the sea and don't have much water)
- blacksmithing using induction heaters instead of a forge

I got around to watching the whole video mentioned by the OP. It was refreshing to see someone posting to youtube about solar who had a pragmatic view on the seasonality of solar. I believe his plan is to run his heatpump for AC off of solar in the summer and switch to propane cooking in the winter as his main dumps. He mentioned a boiler which I assume is gas fired. I believe he mentioned electric hot water as well so there is another dump.  They spent a boatload of money on their system though. Damn, I would of loved to have him as a client!
I'm planning our new array and my strategy for summer excess will be to move the heat pump load, the washing machine, the HRV, the freezer, and maybe the dishwasher over to the solar panel in summertime... I've been monitoring quite closely https://permies.com/t/204629/Energy-Monitoring
so have a really good idea how much I will need. My inverter is not set up to naturally do self consumption so I'll have to improvise. As a 20 year solar person let me tell you too much power is a nice problem to have!

You could look into  flywheel storage system. I heard they are almost as good as a battery based back up system.
I'm not sure of the cost but they are commercially available.
https://www.activepower.com/en-GB

J McKravits wrote:You could look into  flywheel storage system. I heard they are almost as good as a battery based back up system.
I'm not sure of the cost but they are commercially available.
https://www.activepower.com/en-GB

Unless I'm very much mistaken flywheels would be more suitable for minutes or hours of storage for large loads not days. In that way they become another battery so not really suitable for balancing out the seasons.

" Unless I'm very much mistaken flywheels would be more suitable for minutes or hours of storage for large loads not days. In that way they become another battery so not really suitable for balancing out the seasons. "

If the fly wheel is on magnetic bearings and in a vacuum it can last up to 20 years according to a few sources.
https://www.sciencedirect.com/topics/engineering/flywheel-energy-storage

I've been meaning to chime in on this thread for a while now.  I have tentative plans for a large solar array to be placed on the roof of a future pole barn/workshop.  There would be enough electricity produced to cover all of my needs plus some extra.  The problem with the extra is that Ohio Utilities don't pay squat for surplus energy credits.  My thinking was that I could use up my excess capacity by running a small welding shop.  

Thomas Tipton wrote:I've been meaning to chime in on this thread for a while now.  I have tentative plans for a large solar array to be placed on the roof of a future pole barn/workshop.  There would be enough electricity produced to cover all of my needs plus some extra.  The problem with the extra is that Ohio Utilities don't pay squat for surplus energy credits.  My thinking was that I could use up my excess capacity by running a small welding shop.  

Hi Thomas, a few thoughts. If you have the land for it I would strongly suggest putting it on the ground. Snow on a grid connected systems does not impact you except revenue but on a stand alone it can really cut into the energy you need day to day. Also if the pole barn is finished you would probably be required to follow the rapid shut down requirements which add cost and complexity. Think of the existing grid connection as the quietest back up generator you could buy at a very reasonable monthly payment. Your type of setup would be called "grid zero" or "self consumption" depending on the manufacturer
Cheers,. David

Most of the suggestions I have are already in the list above - I guess Permies minds work alike: food and wood processing. The others involve too much investment in equipment to be worth using an intermittent energy source. I think simple plastic recycling might be quite practical though. You collect up your (or your community's) bottle tops or milk jugs over the year and then process them into something useful. This mainly involves heat and pressure in the simplest form, although some care would be needed to ensure that the temperature didn't burn the plastic and degrade it. I found this old 'blog post that seems to succeed in simple processing to make flat sheets and containers:


Source - Atomic Shrimp

If you didn't fancy the non-natural materials, I remember a thread about dishes from leaves.....here it is!, I'm pretty sure heat and pressure were part of that process too.

Nancy Reading wrote: I think simple plastic recycling might be quite practical though. You collect up your (or your community's) bottle tops or milk jugs over the year and then process them into something useful.

Good thinking. I like that you could stockpile plastic throughout the year and have the material ready to run the batches any time that it's convenient.
Also, Precious Plastics has come up with some other great machines that could work as well.

Nancy Reading wrote:Most of the suggestions I have are already in the list above - I guess Permies minds work alike: food and wood processing. The others involve too much investment in equipment to be worth using an intermittent energy source. I think simple plastic recycling might be quite practical though. You collect up your (or your community's) bottle tops or milk jugs over the year and then process them into something useful. This mainly involves heat and pressure in the simplest form, although some care would be needed to ensure that the temperature didn't burn the plastic and degrade it. I found this old 'blog post that seems to succeed in simple processing to make flat sheets and containers:

Source - Atomic Shrimp

If you didn't fancy the non-natural materials, I remember a thread about dishes from leaves.....here it is!, I'm pretty sure heat and pressure were part of that process too.

3d printing comes to mind as well. I know there are open source designs out there for recycling plastic into printer wire. The printers are electric heat intensive so maybe a good seasonal dump load.

I also found this:
Solar distillation of ethanol alcohol for fuel
(Run a still?  Granny Clampett goes green!  LOL!)

Their design is not electric, but direct solar.  I suppose you could either do it their way and/or power an electric heating element to do the same thing.

Using excess power to manufacture a product which can be sold at a higher profit per kW than selling the excess power to the utility company... or better yet, at an equal or higher rate per kW than buying that electricity back come Winter.

Skills, equipment, materials, labor, watching, and don't forget sales and marketing...

Of all the ideas mentioned, electric ceramics kiln might be the best for Watts/time to watch it. But then, ceramicist has to be in your skill set... (same goes for blacksmith, welder, machinist, woodworker...)
3D printing might be the best "lights out" option, and quick to learn. You'd have to identify a widget to print, or run a print on demand site, but then you'd be at it year round to keep customers happy.

So what if you "eat your profits"?!
Canning seems like the best personal/homestead scale option, since it could be some or all of your own food, or sold at a market. Syncing excess solar production and harvests might be tricky?
Baking is another homestead option, for personal use, or markets, or even frozen for sale later.

Ice maker? selling bagged ice to the public? stores? fishermen?
Ice cream stand? might be the best match for the seasonal over-production!!

Rock tumbling/polishing, especially if you are in an area where semi-precious stones are found, or in a tourist location, but also you could just buy rough stones, then ship polished ones to gift shops.
Lapidary would be the next step up, cutting and polishing for jewelry, but way more hands-on.
Maybe sawing and polishing stone slabs for cheese/charcuterie "boards"?

Running some sort of pellet mill? for fuel or for feed? Materials could be fed from a silo.

Another idea: Rust removal by electrolysis. Refurbishing all sorts of steel/iron things: cookware, farm equipment, car/truck/trailer frames, wrought iron patio furniture, old tools...
Some of the larger stuff, you'd do outdoors, summertime would be a perfect time to do so.

I was just watching the most recent video by NighthawkInLight where he came across an old oxygen concentrator, which he uses to make things like an oxy-propane torch, etc.

You could excess electricity to separate air into oxygen and nitrogen gas.  The nitrogen could be used to fill insulated glass panes and the oxygen could be used for medical needs, or forging, metal melting, and various other things you'd want a hot flame for.

Edit: Might also be interesting to run in a greenhouse to increase relative co2 levels for plants.

I couldn't find a used concentrator for anything close to what he paid, but I did find DIY plans online. (Seems surprisingly doable!)
Here's how it works when finished:

Not manufacturing as such but an idea is to run a compressor to fill cylinders with compressed air. These cylinders can be used to run air tools, inflate tyres, for scuba diving or .....

You could mine bitcoin in the summer

I make sea glass with an old cement mixer in the summer. The thrift sores in the area accumulate an excess of glass items some broken some not that they end up throwing away at the dump. I step in and haul it away before then. Could be a good side hustle for some with excess electricty. I get way more clear glass than colored glass but seperate the colors. Upsized tools I use for making frit for enameling and can get a pretty consisten 3/8 glass pebble. Scavenge some cool pieces or colors for making sea glass jewelry. You could probably even use wind to turn the drum.

Steve Farmer wrote:Not manufacturing as such but an idea is to run a compressor to fill cylinders with compressed air. These cylinders can be used to run air tools, inflate tyres, for scuba diving or .....

As a means to an end... air powered tools do consume vast quantities of air, so a LOT of storage would be in order, or working while the compressor is running. There are some tools perfectly suited to be air tools and others that are useful mostly for the convenience of having an air hose handy.
Compressed air has a poor conversion ratio of energy input --> energy out, compared to just using an electric tool.  There's also the risk of loss due to leaks.

Tire filling and SCUBA tank filling is a great idea, as it could replace grid use for this entirely.

Combined with the oxygen concentrator, and possibly a high-pressure industrial compressor, the oxygen could be bottled up for torch use, rather than used directly from the concentrator. (which is pretty neat on it's own!!)

Are you going to be onsite when the excess is being produced? I'd be careful with things that might go boom, compressed air, o2 production, cracking h2o into h. Maybe pumping warm water to a mass battery/heat sink since the sun would also be able to heat the fluid when the sun is out.

Here is an interesting cross pollination. I would never have thought of a Bitcoin miner as being a good manufacturing use for extra solar energy...
https://permies.com/t/233897/Bitcoin-heaters
Cheers,
David Baillie

David Baillie wrote:Here is an interesting cross pollination. I would never have thought of a Bitcoin miner as being a good manufacturing use for extra solar energy...
https://permies.com/t/233897/Bitcoin-heaters
Cheers,
David Baillie

Rather than solely running a space heater, or solely "manufacturing" with a result of "waste heat" (server farm, cooking/canning, baking, etc...) having a setup that can utilize both is ideal. Being able to zero out your heating cost with the heat from a Bitcoin miner sounds good for half the year (I suppose you just need a way to reject the heat in the warmer months, to not induce higher cooling costs).

Of course it reminds me of the joke about... An Irishman's Dying Wish:
An old Irishman, Paddy, is about to go to his eternal reward. He looks at his grieving friend, Mike, and says, "I have one last request, Mike.""Anything, Paddy," Mike says. "What is it?""In me kitchen pantry you'll find a 100- year-old bottle of whiskey. When they put me in the ground will you pour it over me grave?"
"I will, Paddy," Mike says. "But would you mind if I passed it through me kidneys first?"

I hope this is the right place to put this idea..
I’ve been thinking about storing excess solar energy as potential kinetic energy. Like a weight on the end of a rope (hanging in a well perhaps?) and that rope is pulled up and wound around a generator shaft. Then when the solar panels aren’t producing energy the weight will descend causing the generator to become active. There would have to be some gearing involved to slow the descent of the weight but I think there’s real potential with this idea.