The latest developments in energy storage technology

[mheslep]

Some, yes, but most do not have equipment for that and cannot use their solar panels in a blackout.

Not sure what you mean here. As you know, any generator wired into the house utility panel must have a transfer switch, i.e. one or the other powers the residence so the generator can't throw power onto the grid.

I don't know, but I would think a home solar array connected to the grid, and almost all of them are, must have some kind of equivalent mechanism in the event of a blackout to block a backfeed to grid, creating havoc. Most likely this occurs via the inverter sync to the line. No line detected and the inverter opens the solar circuit. Its also feasible to have a double throw switch, so that when the line frequency drops the inverter runs free connected to the house load. I don't know if that's practical.

 

[russ_watters]

I think that you will find the opposite. Residential solar (or generator, battery, wind, or hydro) grid connection equipment are not forbidden to disconnect from the grid in a blackout, they are mandated to do so. You say that most solar owners are grid connected but do not have that grid interface equipment. I say that they are mandated to have it for grid safety reasons.

Somehow it seems we are talking past each other. I know that most solar systems are grid connected and have equipment to manage the direction of flow of electricity.

What I am talking about is just what happens when the grid experiences a blackout. What happens most of the time is that the solar array's inverter shuts off and the array is no longer providing power to the house or grid; and specifically the house is without power. I don't know the nuts and bolts of how it shuts off; what/where it disconnects, all I am saying is that you cannot use most solar systems for backup power (in the event of a grid blackout).

So, conversely, is it your position that during a blackout most residential solar arrays continue powering the house?

 

[russ_watters]

Not sure what you mean here. As you know, any generator wired into the house utility panel must have a transfer switch, i.e. one or the other powers the residence so the generator can't throw power onto the grid.

I don't know, but I would think a home solar array connected to the grid, and almost all of them are, must have some kind of equivalent mechanism in the event of a blackout to block a backfeed to grid, creating havoc. Most likely this occurs via the inverter sync to the line. No line detected and the inverter opens the solar circuit. Its also feasible to have a double throw switch, so that when the line frequency drops the inverter runs free connected to the house load. I don't know if that's practical.

I'm not sure about the actual nuts and bolts, but the problem I see is that because the solar array provides intermittent power you can't use it in a blackout at all without a battery backup/UPS - which most residential arrays don't have. And the system would need to balance the load between 3 sources of power instead of 2 and the control circuit has to be on the UPS; a different/more difficult control problem.

 

[Nidum]

@ Trainee Engineer - Is there any way that you can use the flood water or fallen tree wood to generate power ?

 

[russ_watters]

Those are pretty extraordinary claims Russ. The backup power industry and the residential solar power industry would be very surprised to hear that.

I'm going to have to call for your source. Name one verifiable municipal ordinance or code anywhere that says what you claim.

Not meaning to punt on this, but I'm still not certain you are asking me the right question. However, here is a solar integrator that says none of their arrays work during a blackout, for the reasons I have stated:

https://www.solarenergyworld.com/faqs/power-goes-will-solar-system-keep-making-energy/

Many people considering going solar ask if a solar system works during a power outage. If you have a solar battery system as well as a solar PV system, your power will continue to work. However, since your system is grid-tied, for safety reasons, if there is a power outage your solar system will automatically shut off when the power goes out. Solar batteries can add as much as 30% to the cost of a solar system presently, so most homeowners do not go with this option.

Should you wait to go solar until battery back-up is less expensive? Why wait? You can start saving money right now, without battery backup. None of Solar Energy World’s 2000+ Maryland customers have solar battery back-up...

 

[Dan8420]

Hey guys, first post here. On the topic of energy storage though, what're your thoughts on the Vanadium Redox Flow Batteries? From what I am reading they have a long life span compared to other batteries. I realize energy density is low so large installations are necessary for any sort of 'whole home backup' or micro grid backups. However, the life span could help offset that I believe. Thoughts?

Here is a couple articles I have been browsing, can provide more if requested.

https://energy.gov/sites/prod/files/VRB.pdf

https://en.wikipedia.org/wiki/Vanadium_redox_battery

 

[anorlunda]

Not meaning to punt on this, but I'm still not certain you are asking me the right question. However, here is a solar integrator that says none of their arrays work during a blackout, for the reasons I have stated:

I did some research myself Russ. You are correct. My apologies.

A transfer switch allows backup power during blackouts, but most solar DC/AC inverters-grid interfaces do not include the transfer switch. Add-on transfer switches are also difficult to make work. You need a grid-interface with an integrated transfer switch, which is not the cheapest.

 

[Trainee Engineering]

@ Trainee Engineer - Is there any way that you can use the flood water or fallen tree wood to generate power ?

not sure how to do that, can you explain more?

 

[sophiecentaur]

not sure how to do that, can you explain more?

The water / logs idea is really a separate matter. The railway could perhaps carry logs downhill but they would need to be brought to the rail head and loaded. The chemical energy available in a log is far greater than its gravitational potential energy and then there's the cost of (low efficiency) collecting and loading.
If there's enough rainwater, why not use a straightforward hydro system in parallel? The use of water and logs as a downhill load is not attractive because they have relatively low density.

 

[Nidum]

I meant hydro system for electrical power generation and fallen tree wood as fuel for direct heating and for engine based electrical power generation .

 

[Nidum]

Feasibility of hydro power depends on nature of flooding . Running water is needed for simple generation schemes .

A wood charged gassifier is quite easy to make . Yields charcoal and fuel gas .

A steam engine based system is a bit more difficult but certainly quite feasible .

 

[sophiecentaur]

A wood charged gassifier is quite easy to make . Yields charcoal and fuel gas .

Wood is only good for 'fun' in towns or in country places where it is readily accessible. The American railway system demonstrates the problems with wood. They cut vast swathes through forests until it became uneconomical to gather wood at great distances from the rails. Then they had to move to coal.
Transporting wood to a static "steam based system" is, likewise, not economic under most conditions, these days.

 

[Nidum]

The core question of this thread was about a single user system for providing backup power for domestic use when the local electricity grid system was turned off during flooding .

 

[sophiecentaur]

The core question of this thread was about a single user system for providing backup power for domestic use when the local electricity grid system was turned off during flooding .

More than that, I think. This OP is about storage and the thread has definitely gone that way (rambling, as usual). Scale is a major factor in selecting what's best. The most efficient energy management strategy involves providing all your energy by cheap methods and storing any spare energy. Backup is another question and we are sometimes stuck with having to use inefficient / expensive sources during periods of high demand or failure. Hydro for peak loads could be workable as long as the capital cost (dams are damned expensive) and capacity work. Using wood as an energy source has limitations as discussed earlier- it costs a lot to move it to where you want. Capital cost of a gassing plant would be hard to justify for a private individual - wouldn't it? So would an anaerobic digester. Good for a small community, perhaps.

 

[nsaspook]

I did some research myself Russ. You are correct. My apologies.

A transfer switch allows backup power during blackouts, but most solar DC/AC inverters-grid interfaces do not include the transfer switch. Add-on transfer switches are also difficult to make work. You need a grid-interface with an integrated transfer switch, which is not the cheapest.

There are a few inverters now that allow for limited isolated AC power from a grid-tie system (without battery backup) during a blackout. Without storage it's completely dependent on sun-light but that's better that nothing in an emergency.
http://www.sma-america.com/products...-5000tl-us-6000tl-us-7000tl-us-7700tl-us.html

 

[Trainee Engineering]

so far, I notice that there are 2 methods to address long-duration blackout here:
1. generate the needed power on and use it day by day
2. generate and store the needed power for the entire 3-week period (in my case, it's 21 days @10kWh, totalling 210 kWh) in one go and store this for the whole year

if possible, I prefer method #2. is there any battery out there with such capacity that's cheap and durable (minimum leakage through long period of time).

 

[sophiecentaur]

in one go

You would need to define what that means. As it stands, it implies a massive Power capability which would be unused for most of the year. Not good value. The cost of a very high spec battery would make it less attractive than using a cheaper (lead acid, for instance) system that's charged up with the cheapest source (overall cost = capital plus energy input) you can get hold of and possibly trickle charged from another source until the time it's actually needed.
But a battery bank that's only used once a year is probably not good value. You could not expect many years of use. Otoh, a second hand diesel generator set would not cost a lot and the fuel could be bought over the year (getting it at the cheapest prices) and stored in a tank. It's not a green solution but does that matter for three weeks of the year. A system like that could last you for decades.

 

[anorlunda]

cheap and durable

It would be far more effective to reduce the energy demands during the blackout period from 10kWh to 1kWh per day. At that level, solar+lead-acid batteries, become much more affordable and practical.

If you can eliminate the AC inverter, it becomes more cheap and durable. LED lighting and device recharging are best done with DC. 12VDC refrigeration systems are very energy effective, cheap, and durable. Propane fueled refrigeration systems are another alternative. There are many ways to pump water without use of electricity.

It becomes more of a social problem than a technical problem. You must convince the people to make do with less. If your goal is to provide during blackouts the same convenience, comfort and cost levels as the power grid provides, you'll fail.

Can you list for us how the 10 kWh/day is being used?

 

[mfb]

A storage system for the full three weeks will cost at least a factor 10 more. You said price is not an issue in post 1, but where is the big disadvantage of on-demand production if it saves more than $50,000?

Reducing electricity consumption will help in both cases, of course.

 

[Trainee Engineering]

You would need to define what that means. As it stands, it implies a massive Power capability which would be unused for most of the year. Not good value. The cost of a very high spec battery would make it less attractive than using a cheaper (lead acid, for instance) system that's charged up with the cheapest source (overall cost = capital plus energy input) you can get hold of and possibly trickle charged from another source until the time it's actually needed.
But a battery bank that's only used once a year is probably not good value. You could not expect many years of use. Otoh, a second hand diesel generator set would not cost a lot and the fuel could be bought over the year (getting it at the cheapest prices) and stored in a tank. It's not a green solution but does that matter for three weeks of the year. A system like that could last you for decades.

in one go means I store all the energy (210 kWh) now to be used next year. but in one go may mean I collect the energy in a week, or in a month, no problem. it just means that I don't need to store up energy for a day, and then consume all the next day, and keep repeating that cycle everyday.
btw, when it's flooding, the water doesn't really move. we just wait till it recedes, and the river is quite far away from my residence complex. like this one

It would be far more effective to reduce the energy demands during the blackout period from 10kWh to 1kWh per day. At that level, solar+lead-acid batteries, become much more affordable and practical.

If you can eliminate the AC inverter, it becomes more cheap and durable. LED lighting and device recharging are best done with DC. 12VDC refrigeration systems are very energy effective, cheap, and durable. Propane fueled refrigeration systems are another alternative. There are many ways to pump water without use of electricity.

It becomes more of a social problem than a technical problem. You must convince the people to make do with less. If your goal is to provide during blackouts the same convenience, comfort and cost levels as the power grid provides, you'll fail.

Can you list for us how the 10 kWh/day is being used?

1.5 kWh --> fridge
2 kWh --> AC
2 kWh --> rice cooker, 2 TVs, LED bulbs
1.5 kWh --> PC whole day
3 kWh --> spare, just in case. so basically, 8 kWh should be enough.
ideally, I'd prefer not change any lifestyle, even during blackout, but if it's not possible, then will resort to "graceful degradation", meaning, sacrifice the least needed ones. the listing above is already sorted based on importance, top being most important, bottom least important.

A storage system for the full three weeks will cost at least a factor 10 more. You said price is not an issue in post 1, but where is the big disadvantage of on-demand production if it saves more than $50,000?

Reducing electricity consumption will help in both cases, of course.

I'm not against on-demand production, but as someone said (forgot where exactly in these posts), solar power only brings misery, and my alternative is methane or gasoline generator, which also needs to be refilled everyday, and when it's flooding, not sure if that's going to work

 

[rbelli1]

when it's flooding, not sure if that's going to work

If you don't have a flood safe place to store a generator and three weeks of fuel you will certainly not have a place to store three weeks worth of batteries.

For 8kWh per day for three weeks you need about 250 liters of batteries.
https://en.wikipedia.org/wiki/Lithium-ion_battery

You need only about 60 liters of diesel.
https://en.wikipedia.org/wiki/Diesel_generator

The converter for both systems will be of a similar size magnitude.

Another benefit of a generator is that you will be able to find someone to repair it with little or no trouble. You can learn basic maintenance yourself in a few hours.

Is seems to me if you are willing to spend a large sum of money on a backup system you could go the generator route and outfit your entire apartment complex and provide operating costs for many years with the same amount of money.

BoB

 

[Rive]

so far, I notice that there are 2 methods to address long-duration blackout here:
1. generate the needed power on and use it day by day
2. generate and store the needed power for the entire 3-week period (in my case, it's 21 days @10kWh, totalling 210 kWh) in one go and store this for the whole year

if possible, I prefer method #2. is there any battery out there with such capacity that's cheap and durable (minimum leakage through long period of time).

With stored 200+kWh you will sit on the very top of a veeeeeryyyyy water sensitive bomb. Do you really want that? During a flood?
The grid is down exactly to prevent such situations. But with such scale battery backup, it's worse than it would be with the grid on...

I suggest to build a limited capacity battery backup, which can provide adequate power for limited usage for 1-2 days: and back it up with some generator.
The limited battery backup can be built safely.
The fuel is not that flood sensitive.
The battery alone can handle 90% of the daily load.
The generator can recharge the battery fast.
The battery and the generator together can handle the rest of the load.

This way it is a classic, widely used system: esy to build, handle and repair.

 

[jim hardy]

i grew up in hurricane territory, South Florida. Onsite generators became affordable to average folks only around the 1980's . One learns to get by without central airconditioning , and in S Fla you can get by without hot water because it comes out of the ground seventy something F.
So a couple KW gas generator will do just fine for a fridge and lights.
A Coleman gasoline campstove got us by for two weeks after Andrew (1992) , i had no generator.
After Hurricane Irene friends loaned me a 4 kw generator and i considered it a luxury for it'd start a one room "windowshaker" airconditioner that even drowned out the generator noise so we could sleep comfortably on 90 degF nights. I was without electricity for 3 weeks.
What you miss most is refrigeration. I'd get a propane fridge from a RV place for the garage, and a small generator to keep the freezer cold. Harbor Freight sells a 800 watt two stroke for 88 bucks when on sale.

Back to topic of energy storage

Did anybody watch NOVA this week ? Some guy has solved the pyrotechnics problem with lithium batteries. He uses a permeable plastic between the plates, in the Nova show he drives nails through it with no ill effect.
http://www.pbs.org/wgbh/nova/tech/super-battery.html
old jim

 

[sophiecentaur]

I'd get a propane fridge from a RV place

The Waeco (and others) 12V compressor fridges are 'real' fridges and are very economical on current - averaging only around an Amp. I have a small one (really tiny) that will deep freeze its contents to -18C. It would be worth doing the sums to try to include this in any electrical power budget. Propane has its place, of course, when the electrical supply won't support even that low level of power.

 

[jim hardy]

The Waeco (and others) 12V compressor fridges are 'real' fridges and are very economical on current - averaging only around an Amp. I have a small one (really tiny) that will deep freeze its contents to -18C. It would be worth doing the sums to try to include this in any electrical power budget. Propane has its place, of course, when the electrical supply won't support even that low level of power.

Certainly that's good sensible advice. 12 volt appliances are becoming more available, too.

I think nowadays DIY'ers could add a 12 volt system to their house, a few LED lights in every room and an inverter big enough to carry the fridge via extension cord.
An automobile alternator , lawnmower engine , and "utility battery" like used in riding lawnmowers is the 'poor man's' answer. I plan to do that in my guest house.

I have a gas kitchen stove because electricity can go out. It was sure nice after Hurricane Irene to have hot coffee, i invited neighbors over next morning. Wind was still over 40 mph but we thanked our lucky stars it went west of us.. old jim

 

[OCR]

Did anybody watch NOVA this week ? Some guy has solved the pyrotechnics problem with lithium batteries.

Yeah, I saw that...[COLOR=#black].[/COLOR]

 

[Trainee Engineering]

ok, another question. I take it Tesla's Powerwall is currently the most advanced phase in energy storage tech? we can only manage to store 14 kWh worth of energy in such a huge space? and it's still very expensive too.
so, if we use the analogy of data storage, we're still in floppy disk era where we can only store 1.44MB worth of data, not yet in CD/DVD era where we could store hundreds of MB, let alone flashdisk era where we can already store gigabytes worth of data in a very small package. is this analogy describe current phase in energy storage technology?

 

[sophiecentaur]

Certainly that's good sensible advice.
old jim

I have the seal of approval so I'll continue. The bare refrigeration units are available for self fitting into boats etc. and you can make the enclosure as thermally efficient as you like, unlike a ready made fridge. You can keep the mean consumption very low if you use thick enough insulation and use a 'chest' design with a thick lid. The biggest demand is when you put a new item in that's not already cold (or if you actually try to freeze down stuff). They're blissfully quiet runners, too and you can put the external condenser a good distance away from the unit. A bit on the pricey side but it does what it says on the tin.

 

[sophiecentaur]

flashdisk era where we can already store gigabytes worth of data

1TB on a USB stick is available in my local shop. Where will it all end?

 

[Trainee Engineering]

1TB on a USB stick is available in my local shop. Where will it all end?

yeah, I mean, we're still at 14kWh in 44 in × 29 in × 5.5 in package, so if I want to store 210 kWh, it will take 15 units which will take a lot of space.

 

[mfb]

Packing data better is much easier than increasing energy density. As analogy, replace a single rock by many small pebbles: you increased the number of objects (data), but you didn't increase the total mass (stored energy).

Batteries have a low energy density compared to chemical storage systems (like fuel for the generator). They are also more dangerous in connection with water.

 

[mheslep]

... if we use the analogy of data storage, ...

Not a good idea. The advances in information technology involved storing a fundamental unit of information (on/off) in ever smaller physical structures. Much of IT hardware engineering became exercises in managing complexity, i.e. how does one quickly carve 10 million transistors into a square mm, control all their interactions, and have them finally act as a useful macro level device. Energy storage has few if any parallels.

 

[jim hardy]

I take it Tesla's Powerwall is currently the most advanced phase in energy storage tech? ...
so, if we use the analogy of data storage, we're still in floppy disk era where we can only store 1.44MB worth of data, ...
is this analogy describe current phase in energy storage technology?

Energy and data are not alike.
Energy in quantity will hurt you.

I am skittish whenever:
in high places (gravitational potential energy)
going fast (kinetic)
in airplanes (both of above)
around high speed machinery(mechanical)
around high pressure steam(thermal)
around dynamite(concentrated chemical energy, ) in 1960's we kids could buy it in rural hardware stores, and did , but i learned to respect its capability
around electrical sources capable of high current (because copper vapor follows same gas laws as dynamite vapor)so i think your analogy

yeah, I mean, we're still at 14kWh in 44 in × 29 in × 5.5 in package, so if I want to store 210 kWh, it will take 15 units which will take a lot of space.

is more in tune with steam power ca 1830
when to make ten horsepower took a reciprocating engine weighing many stones and a riveted firetube boiler prone to explode destroying the building and cooking its occupants.
http://www.hevac-heritage.org/electronic_books/boiler_explosions/1-BOILER_EXPLOSIONS_IN_PICTURES.pdf

I'm just not ready yet to admit big lithium batteries into my life.

Boeing was too stubborn to face that with 777 ..

mfb and mhselep have it right.

old jim

 

[NTL2009]

I recall seeing an estimate somewhere, of just how far a lithium battery could advance. It was beyond my feeble knowledge of chemistry, but they were able to estimate just how dense you could go with lithium, if you assumed you could magically avoid all the real world limitations. IIRC it was between one and two orders of magnitude. And then the real world intervenes.

Anyone here know of a source, or able to take a stab at it?

 

[discountbrain]

Hi all,

I'm interested in the latest development in battery technology. as of now, from what I understand, the most advanced tech in energy storage (battery) is created by Tesla, the PowerWall. but, even that, can only store 14kWh per unit. my house consumption is about 10kWh per day. my question is, what are the type of batteries out there available to the public? I'm only concerned of these things:
1. capacity --> I need to store 2-3 weeks worth of energy (in case of blackouts), so, it's somewhere around 140kWh - 210 kWh. if possible, I need it to be less than 10 units (so each unit is around 21kWh)
2. durability --> must be able to store huge amount of energy for a long period of time without dissipating. Now, it won't be charged and discharging frequently. charged only after a blackout, and won't be discharging until the next blackout, so storing for long time
3. warranty --> if possible, above 10 years warranty that energy leakage is less than 5%

price is not an issue. what are my options?
what's the latest type of battery suited for this type of usage?

thanks

I just learned Eos Energy is planning to sell their rechargeable zinc/air batteries to the consumer in 2017. I'm calling them tomorrow to see when I can get some. They have been selling them to utilities for a while now. Zinc is quite inexpensive, these batteries can be cycled over 5k (maybe 10k) times, they store 3 TIMES the energy of Li-ion batteries. Look at their website; they are many times superior. I think I'll buy Solar World solar panels. They are made in the USA and some of the most efficient ones there are. This year will be the year I go off grid. I will install this myself-I think installers might think they can rip u off. I will buy a transfer switch and get a certified electrician to install it. This will be so I will still be attached to the grid while makings sure everything is working OK. Transfer switches are not uncommon. They are for when someone has their own generator hooked up to their system.