Difference between stored and instantaneous renewable energy

What is the difference between stored and instantaneous renewable energy?

Good question, do you know and you're testing us?  I have an engineering background and I'm not sure.  Can you put the terms in context?

A little vague but... 25 percent give or take.
Let's take off grid solar: stored energy would usually mean batteries but batteries are not perfect and neither are the charge controllers that monitor the battery and control the flow into them.  Most people use lead acid which has an efficiency of about 80 percent and charge controllers that are about 95 percent so of the power that is pushed at them 75 percent of it is available to do work...
The flip side of that is if you are using the power while it is sunny and the current flow is coming from the panels directly to your loads your efficiency approaches 100 percent as there are very little losses involved. You would still need a battery bank in that scenario but its size could be shrunk to cover nighttime loads and a reserve for cloudy days. This is what is happening in off grid these days. Much larger arrays are being installed due to dropping prices and all sorts of creative dump loads are being used in the sunny times to act as alternative storage devices. I.E. electric water heaters in the middle of the day, dishwashers, electric hotplates, laundry timed to the sun, etc..  all things we have always done just now with much more resources to throw at it...
Cheers,   David

To me instantaneous renewable energy could be:
1) firewood/bio-diesel to heat or run a mechanical engine.
2) hydro to power a mechanical mill or a hydro-electric turbine to make electricity, a mechanical mill can also operate a heat pump directly to make heat too
3) wind to power a windmill (mechanical or mechanical-electrical, etc)
4) solar (Thermal and electrical)

To me stored (renewable) energy could be:
1) firewood/bio-diesel that has stored/converted solar energy to chemical energy
2) pumped-hydro that is converted electrical to potential energy at a higher elevation in a dam.
3) pumped/compressed air
4) chemical battery that has stored electrical energy as chemical battery
5) stored hot thermal energy as in molten salt
6) stored cold thermal energy

I think depending upon the situation, they could be one and the same.

I am thinking of a crane that lifts heavy objects like blocks of granite or concrete. It is in a stored situation, but in an instant, those blocks can be attached to, then dropped, the falling weight powering a generator to produce electricity.

Stored energy...but instant as well.

Water behind a dam is stored energy but instant.

The key thing about electricity is, a person needs both long-term power, like that of a boiler which kicks out ample power 24/7 pretty much, but also instant power so that if there are spikes in consumption, that stored energy can be converted into instant power. This is why hydro dams are critical to the power grid, open a valve and instantly power is pumped onto the grid during peak demands, but all day, every day boilers and their turbines kick out power for the grid.

In an ideal situation, the homestead would have a solar array for trickle charging the battery bank for constant electrical demands, but then a hydro set up for peak times. In this way neither system would have to be big, and the stream itself would not have to be big; heck a pond fed by a spring might work because a homestead might only open the penstock for a few hours for those peak times. All that could be automated...a timer opens the penstock which starts the turbine spinning, then a minute later the refrigerator comes on also via timer. In other words the hydro power is tied to the high demands of the refrigerator. This to me makes far more sense then putting in a dump load circuit...why produce power only to dump it into the atmosphere as wasted heat?

What you see instead is people dedicated to a single system, then scaling it up to meet their biggest electrical demand. That is one way to do it yes, but I am not sure that it is the best way. But as with most things in life; the best way to do them, is often the most difficult, and the more expensive way.

Travis Johnson wrote:I think depending upon the situation, they could be one and the same.

I am thinking of a crane that lifts heavy objects like blocks of granite or concrete. It is in a stored situation, but in an instant, those blocks can be attached to, then dropped, the falling weight powering a generator to produce electricity.

Stored energy...but instant as well.

Water behind a dam is stored energy but instant.

The key thing about electricity is, a person needs both long-term power, like that of a boiler which kicks out ample power 24/7 pretty much, but also instant power so that if there are spikes in consumption, that stored energy can be converted into instant power. This is why hydro dams are critical to the power grid, open a valve and instantly power is pumped onto the grid during peak demands, but all day, every day boilers and their turbines kick out power for the grid.

In an ideal situation, the homestead would have a solar array for trickle charging the battery bank for constant electrical demands, but then a hydro set up for peak times. In this way neither system would have to be big, and the stream itself would not have to be big; heck a pond fed by a spring might work because a homestead might only open the penstock for a few hours for those peak times. All that could be automated...a timer opens the penstock which starts the turbine spinning, then a minute later the refrigerator comes on also via timer. In other words the hydro power is tied to the high demands of the refrigerator. This to me makes far more sense then putting in a dump load circuit...why produce power only to dump it into the atmosphere as wasted heat?

What you see instead is people dedicated to a single system, then scaling it up to meet their biggest electrical demand. That is one way to do it yes, but I am not sure that it is the best way. But as with most things in life; the best way to do them, is often the most difficult, and the more expensive way.

Travis in a way the battery is the hydro dam. Instantaneous demand is met by the panels during the day and any large loads are covered by the battery. Hydro is not instantaneous. You can turn it on and off but there is a lag there and micro hydro is usually low wattage continuous power.  If its a large dam there is a longer lag and losses to transmission. My version of dump loads are not really dumps they are more alternative methods of storage.   Cheers,  David

No, I understand that. My pet peeves is when people bolt heaters onto trees so that excess power gets displaced through those sort of things. To me that is just a waste.

As for do it yourself micro-hydro situations, I always thought this turbine design was really simple. The longer the stem, the more torque you would get out of it, along with how wide the exit tubes were. It would be easy to couple bearings to this guy, as well as weld it up yourself. Weld on a pulley, and belt it up to a generator...

You could easily make the thing 10 feet high and get some pressure out of the water...or 20 feet or 30 feet...and there is no massive dam to make, you just have to channel water into the internal column. I realize it is not super efficient in prop design, but I would think the design is so easy to make that it would not really matter. That is, less efficient, but easy to make would be better than a super efficient turbine, and too complicated to make yourself.

Baker Mill

Travis Johnson wrote:No, I understand that. My pet peeves is when people bolt heaters onto trees so that excess power gets displaced through those sort of things. To me that is just a waste.

As for do it yourself micro-hydro situations, I always thought this turbine design was really simple. The longer the stem, the more torque you would get out of it, along with how wide the exit tubes were. It would be easy to couple bearings to this guy, as well as weld it up yourself. Weld on a pulley, and belt it up to a generator...

You could easily make the thing 10 feet high and get some pressure out of the water...or 20 feet or 30 feet...and there is no massive dam to make, you just have to channel water into the internal column. I realize it is not super efficient in prop design, but I would think the design is so easy to make that it would not really matter. That is, less efficient, but easy to make would be better than a super efficient turbine, and too complicated to make yourself.

Baker Mill

Nice and simple. I think a peltier wheel and a permanent magnet alternator is pretty simple and hard to beat. Its the required drop that is getting hard to find. I do not know about maine but if you try to dam so much as a creek you are in some big time hot water. So you are limited to sluiceways in free flowing streams so again getting hard to find. It is still the gold standard of off grid though.

I have got a spot on my land that has a stream, and a pretty big drop...I am guessing 40-50 feet of vertical head, but it is in the middle of nowhere. A remote camping spot, or perhaps a small cabin might be built there, but that would be about all that could go there. It has no real view, so no place to put a house, and then to try and bring a powerline back from that spot would be prohibitive. No good...

I have a few places I could put up a dam and it would be grandfathered because my family dammed the stream generations ago, but nowadays it all depends on who runs across it, and then they rat you out. Most times it is the people you never suspected too that call the authorities. Still, none of the places would ever be where I would put a house. :-(

Here is a picture of that stream area. It looks flat in the picture, but it is actually a pretty decent ravine. I am cutting wood out of there now and it is all I can do to pull wood up out of there with my skidder. (I am trying to get the White Ash out before the Emerald Ash Borer arrives...

Travis Johnson wrote:I have got a spot on my land that has a stream, and a pretty big drop...I am guessing 40-50 feet of vertical head, but it is in the middle of nowhere. A remote camping spot, or perhaps a small cabin might be built there, but that would be about all that could go there. It has no real view, so no place to put a house, and then to try and bring a powerline back from that spot would be prohibitive. No good...

I have a few places I could put up a dam and it would be grandfathered because my family dammed the stream generations ago, but nowadays it all depends on who runs across it, and then they rat you out. Most times it is the people you never suspected too that call the authorities. Still, none of the places would ever be where I would put a house. :-(

Here is a picture of that stream area. It looks flat in the picture, but it is actually a pretty decent ravine. I am cutting wood out of there now and it is all I can do to pull wood up out of there with my skidder. (I am trying to get the White Ash out before the Emerald Ash Borer arrives...

Yup those are some of the reasons the energy has gone out of small hydro; regulation and placement. In the three years I've worked for and now consult for a local alt energy company one small scale hydro has gone in. the compliance requirements were underway for 18 months before I got there and went on for the first year of my work there. All for a stream that already had a dam on it for 75 years... Its a beautiful setup though. Your creek looks ideal, high voltage 3 phase setups can cover a lot of ground but yeah if its too far away them's the breaks... It does burn me though that coal plants nukes, gas get a pass because they are far away but block a tiny reserve of water like thousands of fallen trees do or countless beavers and its a non starter.
Cheers,  David

I hear you...

That location is actually pretty good. In Maine I can build a pond 1/4 acre in size with no permits, so I could put in a small pond, then put in a dam and run a pipe down to a Barkers Turbine and produce power all legally, and pretty cost effectively, but as I said, it is so far away that it does not do me any good.

All my streams are like that. I have a few on me, but all of them are located so far away from the house. Literally all of them are located on the edge of my property so I am talking (2) being at one mile away, and the last being one mile away, all of which is no good to me. :-(

But as I said, heating my home is more of a concern for me, so I have pretty much looked at that. These included such things as compost heat, solar, sunflowers and corn, etc, but we have so much wood here, that while other options exist, the reality is, I have the equipment to log, so I can cut wood faster and easier than I can do the alternatives. For instance compost heat. Without question I can make compost heat warm my home, BUT by the time I gather the compost, then form the pile, in much less time I can cut firewood and heat my house all winter. So it is not that compost heat would not work, it just does not make sense for ME too...other people might be different.

Travis Johnson wrote:I hear you...

That location is actually pretty good. In Maine I can build a pond 1/4 acre in size with no permits, so I could put in a small pond, then put in a dam and run a pipe down to a Barkers Turbine and produce power all legally, and pretty cost effectively, but as I said, it is so far away that it does not do me any good.

All my streams are like that. I have a few on me, but all of them are located so far away from the house. Literally all of them are located on the edge of my property so I am talking (2) being at one mile away, and the last being one mile away, all of which is no good to me. :-(

But as I said, heating my home is more of a concern for me, so I have pretty much looked at that. These included such things as compost heat, solar, sunflowers and corn, etc, but we have so much wood here, that while other options exist, the reality is, I have the equipment to log, so I can cut wood faster and easier than I can do the alternatives. For instance compost heat. Without question I can make compost heat warm my home, BUT by the time I gather the compost, then form the pile, in much less time I can cut firewood and heat my house all winter. So it is not that compost heat would not work, it just does not make sense for ME too...other people might be different.

have you looked at charcoal gasification? For someone used to cutting and burning wood it's a viable solution. Of course there are a dozen solutions and never enough time🤣

Yes and no...

Last year I tried making charcoal the semi-old fashioned way, except I used a bulldozer to cover the burning wood. It was an utter failure. Either the wood completely burned up to ash, or it barely charred the wood.

I liked the idea of using charcoal because I use a pot bellied stove to heat my house. That means small wood, or buying coal. I thought maybe if I reduced the wood to charcoal it would be a good compromise: free coal so to speak.

Swedish scientist Kasper Moth-Poulsen leads a team, one of a number around the world, who are working on a number of promising MOST (Molecular Solar Thermal Energy Storage) technologies that enable storage of energy from the sun in a stable molecule. The technology has been proven in test devices and peer reviewed by other scientists. The molecule can be stored for up to 18 years and release its energy in the form of heat on demand, then be returned to a solar array and be recharged, thereby proving it is renewable.

One reason I am excited and keep posting about the MOST technology is that a lot of the infrastructure it uses encompasses mature technologies such as solar collectors, pumps, controllers, etc, and has the potential of retrofitting into houses that use hot water to heat structures using radiant floors, hot water or steam radiators etc. the liquid containing the energized molecules could theoretically be pumped from a central source or provided in containers that can pump out energized fuel and receive back expended fuel to be reused. Industries have for years used excess steam to create electricity from giant machines to small scale generators, so there are a ton of resources off the shelf on that front. I can see the newly emerging MOST technology, once it improves its performance such as gaining energy from a wider range of the light spectrum to be a game changer in generating steam hence generating electricity on demand.

Another related tech Moth-Poulsen discusses is embedding the molecules in glass so that it could release heat on demand. Which looks promising.

Travis Johnson wrote:Yes and no...

Last year I tried making charcoal the semi-old fashioned way, except I used a bulldozer to cover the burning wood. It was an utter failure. Either the wood completely burned up to ash, or it barely charred the wood.

I liked the idea of using charcoal because I use a pot bellied stove to heat my house. That means small wood, or buying coal. I thought maybe if I reduced the wood to charcoal it would be a good compromise: free coal so to speak.

I would not reduce it to charcoal in your case I would torrify it removing all the loose water and the bonded water but leaving the volatiles. A closed retort works well for that. incomplete conversion to charcoal is the bane of my charcoal making but that is for engines. In the case of a heating application that would be a benefit.

It is kind of interesting...

When I moved from the Tiny House we lived in, back into this bigger house, I brought with me my pellet stove. I am not sure why, but over here it does really good. I can run it at a much lower speed, and yet it will heat the house up really well despite the house being a lot bigger, like over twice as big as the Tiny House.

I looked into making wood waste into pellets, but the equipment was so expensive, and so time consuming to do, that it just is not worth it. So it set me on a different thought course; what if I burned product that was already sized to be run through a pellet stove? I experimented with corn kernels, and it does really well. (Corn burns much, much hotter than wood pellets).

So I calculated how much land it would take to burn corn pellets, and it was about 1 acre per year. Sunflower seeds was about 3 acres. To me that seems reasonable...what is the difference in dedicating 1-3 acre of land per year to keep your home warm? It really is no different then having a woodlot for firewood production. Time wise it would be about the same as well, rather than felling, twitching, cutting, splitting firewood, about the same amount of time would be in growing corn/sunflowers.

So it is an interesting turn of events...just what would it take to produce corn/sunflowers to heat my home per year? Having a beautiful field of sunflowers in the summer, knowing it was destined to heat my home in the winter, is kind of a cool idea.