Topic: Energy storage solutions? (Read 316 times)

No clue on your legality, but could you buy a hosted solution not in your country?

Ja. one MUST always refer to the battery manufacturer website and factory data sheets for the full picture. Actually that applies to buying any power electronic device. Even reputable manufacturer authorized distributors rarely give all the details (but will provide the links you want). Random resellers of things, well.....

There is a 3rd/4th solution as well: Storing the power in large banks of supercapacitors which have a massively long lifetime but do self-discharge or the latest variant of them, hybrid supercapacitors that combine supercaps & Li-ion batteries into 1 device. In essence the caps handle whatever amount of load be it short high-current or long term output with no change in apparent capacity. btw: That article delves quite nicely into what a capacitor is and how they work

Of course both are very expensive but to a point it is balanced by them essentially being zero maint for 10-20+ years.

One available provider of them is https://powerquality.eaton.com/emea/supercapacitor/default.asp Per that page, No doubt using a lower% of full power rating gives more time. In other words long enough for the overall much cheaper (for hours/days/more of running) diesel genset(s) to kick in. Direct link to their supercap only UPS solution http://pqlit.eaton.com/ll_download_bylitcode.asp?doc_id=30241

Ya i do understand, I have actually done my deep research on this subject when we had power outages in the past, there is always an exact depth of discharge that gives you the most cycles, also most specs sheets i saw state that 21c is the best temp for the battries, above or below and you start losing.

Also the speed of charging, some mppt will charge up to 90% fast and then slow down for the remaining 10%, beside a few more factors that make a huge difference.

Keep in mind almost ALL of these companies hide crucial info when they sell you a battery, i had an offer for german made battries that were sold as 100ah, when diving deep into the specs it turns out that it can only give you that much if you discharge it for 100 hours, so if you plan on using it at full load for 2 hours, it is no more a 100ah, more like 70ah.

And even when they you give some sort of warranty on the number of cycles, the terms and conditions will usually require nuclear reactor standards.

Battries are rather complicated and very expensive, i ended up buying a diesel generator, assumed it would die on me in 5 years, accounted for service and repairs and despite all that it was a lot cheaper.

Depends how you use them.Lithium batteries have a certain amount of charging cycles before they really start to loose capacity. But that is for full discharges. Partial discharges are proportionally less of a burden on the pack, and no one does full discharges ever if they avoid it. So If you over design what you need, you will obviously pay more. But this is where you need a lot of math. Paying 2x up front to get 3x the lifespan may be a good deal for you. Paying 4x up front for 10x the lifespan for someone else might be better for them.

The recycling depends on composition of the battery. Figure anywhere from $0.12 to $0.40 per kilowatt hour for large recycling (read tons and tons) for smaller amounts it's by the pound.

-Dave

Over 1.5k cycles by how much? Double? Then the price will likely be double as well, i qouted prices from the local markets, could not find any large lithium battries here, but if anyone knows how much the 100a battries go for and check their specs for number of cycles, we can run a different math which i am pretty sure won't result in a very different value.

You are right about dead battries, we sell them here too, for like 10% of thier prices as new, they buy them based on weight not capacity or anything else.

Most lithium-whatever other chemical stuff car batteries have a lifespan of over 1500 cycles. That is usually the base number.
Obviously the way they are used is going to matter along with temperatures, charging speed, and a lot of other things.
And there is a market (at least here) for the used almost dead ones. So I think the $0.20 is high.

The efficiency of the charging and discharging circuits depends on how much you spend. Like many things you can spend a lot more money and get some charging equipment that is well over 90% efficient. Or you can get get generic crap that is a lot less. Same on the output side.

Pay now or pay later.

-Dave

I am familial with the guy's channel, he does most of the stuff for experimental purposes, in fact, he is so smart not to know how much power he was going to get from the water tank.

But one thing to take away from it is how much power he needed to fill the tank, the best case scenario would be 50w coming from the solar for 5 hours, so 250 watt-hour just to store less than 4 watt-hour, the efficiency is just awful, does not matter how he improved it will still not offset charging a battery instead of running a water pump.  


For TheBeardedBaby's situation i assume that not even batteries are worth it.

The first thing we need to account for would be the loss of charge vs discharge, it is anywhere from 20% to 30% depending on the quality of the system.

So in order to fully charge a 12v 100a battery at its max 1200wh you are going to invest not less than 1450wh.

So if the night rate is less expensive than day rate*1.25 the idea fails before doing any more math.

The second thing we need to look into is the number of cycles the battery has on it, the average one has 1500 cycles at 50% dod and costs about 200$.

So every KWh of battery storage costs about 300$, and every cycles wipes out 20 cents of that value ( best case scenario)


Now lets assume day rate is 10 cents vs 20 cents for night rate.

So to suck 1kwh of the grid into the battery you are going to need 12 cents( remember the efficiency issue).

To use that you will waste 20 cents of battery value, that means your night rate is now 32 cents, a lot worse than the grid.

All of this, not taking into account the cost of the other components in the system.

Batteries are only good for emergency back up, when the power cuts at night and you need the lights for a couple hours,  
You do not care if its 20 cents or 50 cents, other than that it is way more expensive than the grid.

I know it wasn't as you mentioned the capacity of the system yourself, I was just amazed, really amazed that somebody actually went through all that trouble for, and I'm pretty sure he did it for the ad revenue, not for the 14kJ of energy.

Back to your (and this whole planet) problem, the thing is pretty simple, there is no secret solution that only a few know about and that solves everything. You can store energy in just a few ways:
- electrical, for home users there is only one, batteries, you won't be able to build a SMES in your home
- mechanical with either the mentioned air system or pump storage (barrel on top of the house or concrete block on a crane)
- thermal, again for a house use maybe only a miniature steam accumulator that will only charge your phone with a full load, but its better to just use a boiler and heat your water for the next day with cheaper power, and of course liquid nitrogen tanks, a thing that actually is in use and works but that's one risky toy for a hobbyist.
- chemical, don't know a single one that could be used for a home, in theory you could try electrolysis and then store hydrogen, then use it to generate energy, and so on, but again, not something we see on small scale.

So, batteries!  

My idea here was not really to implement the system from the video, but to find alternative ways of storing power/energy than the standard batteries.

You've got to be s***! 
Somebody actually put a 200l barrel of water on the roof and let it flow to generate enough power for like what, 3 hours of using your smartphone? Unless you're owning a skyscraper and you somehow manage to put a hundred-ton reservoir on top of it I won't see how you would manage to store energy to last you a few days.

No, just no! You're better of going into the field and getting grass to feed a couple of dozen hamsters to power your grid than this.
I wonder how much this whole setup was worth in used lithium batteries, I have a feeling he overpaid 10x times.


I see another kind of bear on the horizon:

 

My friend, Norway has build the communism at it's greatest. It's one of the most social countries, no poor people (very low percentage), everyone are equal, basically no lower class and of course taxes are sky-high.

We do not suffer of the gas/oil shortage at all, thinking that we have enough oil for generations to come, but the prices are quite speculative. The government takes quite a big cut off the fuel market prices and they are the one to speculate with them.

With the electricity the situation is different. Norway is divided in different areas and electricity prices are different in each one. Most of the electricity is produced by the hydroelectric plants and the prices depend a lot of the weather. Most of the time, when the summer is shitty and rainy, the electricity bills are low. I've experienced a 0 bill for July this year so I cannot complain. But things are to change soon and the prices will rise no matter the weather. I wish the salaries could also follow but that will take a while for sure.

When I started this thread I was wondering if there's an efficient way to store energy something like this solution here. In the video the big water tank stores the power of a one 1.5v AA battery, so there's a very low efficiency, but it shows the possibility to store power in alternative ways than the use of lithium (or other type of)  batteries.

Back in the day I had a lot more free time to experiment and play with hydrogen cells, solar panels, wind turbines and off-grid projects, but after the kids came,I left this field (and many others as well) to focus on the family so I'm quite off the rail tracks of the latest inventions/approaches.

In this particular example, it might be a joke, compressed air storage only makes sense if you have access to power that you don't/cant use at a given period of time, so instead of wasting 100% of it, why not save some of it for later use?, I believe they could be as effienct as 70% or so "of course under some special conditions".

In fact, the same goes for batteries, it only makes sense to store the otherwise wasted energy, but paying the day rate to get that power at night will most likely never work, I don't have the exact numbers but I know if it made sense, everyone would be doing it which will then force the day/night rate into an equilibrium whereby the rates will be same since the demand on the day time will be (normal day demand + night demand).

Batteries are still very expensive and very inefficient, they all have limited cycles which if you take into account you will most likely realize that you can't just charge them with PAID power, that power needs to be excessive/wasted to justify the cost of the battery and the loses that will happen in getting the power in and out.

Furthermore and more importantly is the fact that EVEN if it did make sense to pay x during the day to store the power at night, you could still make more profit selling it than using it to mine, assuming you pay 15 cents to buy it, and it costs 30 cents at night, it means you are mining at 30 cents which is a direct loss, selling it for 25 cents and netting a 10 cent per kWh you sell back to the grid would be far more profitable and requires no initial investments in mining gears and has far less operational costs.


TheBeardedBaby, we were told on the news that Norway is the third largest exporter of gas, are you guys also suffering from this gas/oil shortage?  I would love to know the average power rate in Norway, I always thought it was supposed to be cheap, but I also understand that this is not how capitalism works, which is why I am so thankful we don't have it here.

The cost of electricity is very high at the moment, and it does not look like it is going to get better soonest. Any additional source of power to sustain mining activities is highly encouraged so it doesn't become completely discouraging to run a mining operation as it is already looking very discouraging considering the soaring cost of power.

Also on the amount of money one has to spend on power, more money to spend will definitely do a lot better, getting you better alternatives than when you have a limited budget.

A lot depends on the available dead space you have and how far down the rabbit hole you want to go.
I know someone with a small 750 SQF house that has a 750 SQF basement filled with surplus 12V batteries from a data center offline backup. Can easily run his house for days. But it's a small efficient home.
Tesla powerwalls are great, but you can repurpose other batteries for that instead of just theirs:

https://offgridsolarbook.com/blog/2019/5/29/second-life-battery-pack-with-nissan-leaf-modules

https://www.repurpose.energy/

https://www.springwise.com/innovation/mobility-transport/re-purposing-used-EV-batteries

-Dave

No, it is NOT a 'joke'.
Just a different version of the more common pumped-storage solutions that use water which is pumped into reservoirs and released through generators when peak loads need it. Yes it takes a fair bit of energy input to do the pumping but typical power-in to power out is still a bit over 50%. The point of it is to suck up excess power when available by using massive electrically driven pumps or compressors to fill the potential-energy 'bank' (the compressed air or elevated water reservoirs) and then on very short notice release that stored energy to be able to put back into the grid a large % of the power put into the system to handle short-term peak loads.

A perfect example of a massive one built in the 1960's is here It um also had massive failure in 2005 when one of the side walls gave away due to water level sensor failures and design faults. 1 billion US gallons (3,800,000 m3) of water was released in 12 minutes....

Ja it makes zero sense to use either method for small-scale operations but on the Utility scale both are very practical.

You need to run the numbers to see if it's economically feasible. Without subsidy the solar/storage thing is very expensive, especially in a constant high load situation.

Compressed air storage is MASSIVELY inefficient, it's a joke.

I think your best bets are to run it only during cheap hours or have it hosted at a facility with better power pricing.

Poor energy density, poor efficiency if you're not recovering the heat, you need to turn all that into electricity, a ton of maintenance compared to a simple battery, simply not feasible at a small scale.


A tesla powerwall goes for $11500, we don't know how much electricity you use and how big is the difference between the day and night tariffs.
Let's assume it's 60 cents ? as I see 6.08 kroner per kWh, let's say cheap at night is 10 cents and you get 7$ a day, so 4.5 years you're going to recover the investment. Oh, add another half a year because it too has an efficiency, on paper 92% but, that's paper.

The US and other countries have had scaled up variants for well over 10 or more years. They use sealed underground caverns, smallish mines, and tapped out salt domes. Pressures usually top out at less than 100bar but when you have millions of cu/ft of storage that represents a shitload of stored energy. Just google "compressed air energy storage" or ref https://energystorage.org/why-energy-storage/technologies/compressed-air-energy-storage-caes/

nice if you could scale it.

at op telsa system is costly and glass mat batteries are very heavy

Some where in these threads is some info on a guy that purchased used golf cart batteries and refurbished them on the cheap.

heavy and take up room but he did it pretty cheaply.

maybe loyce could find the thread it is old pre 2018

It's a good topic, actually the best solution I've seen is "compressed air energy storage system":

https://news.cgtn.com/news/2021-10-22/China-s-first-compressed-air-energy-storage-system-connected-to-grid--14zydqC3KRG/index.html



Not sure if anything is available on the consumer market, but it's something worth making yourself, maybe.
I expect it to take a lot of space and be pretty loud....