# $5 / Kwh?



## Karter2 (Nov 17, 2011)

Did you have another source of info for them ?
That link, and the 21stcentech link http://www.21stcentech.com/baseload-renewables-goal-carbon-energy-equation-good/..... says very little about the state of the technology , other than its a sulphur based flow battery, and a lot of other much less informative word salad !
.?? One of those deals that sounds "too good to be true"....and we know what that usually means


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## brian_ (Feb 7, 2017)

PhantomPholly said:


> ... finished product cost in the vicinity of $5/Kwh. That would make it economical to store energy gathered in the southwest in the summer, trickle charge it up north, and release it in the Northeast in the winter.


So let's see if I understand this...


buy a kW-h of storage for $5
expect that it will last perhaps 10 to 20 years, but money isn't free (think interest, or expected return on investment) so that's at least $0.50 of capital cost per year
put $0.05 worth of electricity in it
resell that energy for maybe $0.10 half a year later
maintain the system for several cents/kWh
... and so make about four cents per year for a fifty cent per year investment... a loss of most of the investment.

I don't see how this makes sense. Energy storage needs to cycle a lot more than once per year to make economic sense at this cost level. If the same cost per unit energy can make a similar margin (between off-peak and on-peak prices) on a daily basis, that's 365 times more profitable... and thus possibly viable.

There is economically viable seasonal energy storage, but not for electrical energy: both natural gas and oil are produced year-round with net excess production in the summer stored, then drawn on during net excess consumption season in the winter. The underground caverns (and to some extent above-ground tanks for oil) used for this function cost much less than $5/kWh.


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## PhantomPholly (Aug 20, 2008)

Your math is out of context, and so gives the opposite impression from the reality. Their use of the term "seasonal storage" has to do with the implementation upon the entire grid, so you have to think really big for it to make sense.

Assume there were enough grid storage for the entire grid for a day. Setting aside the seasonal aspect, what that would enable would be the elimination of ALL peaker plants, reducing total CO2 emissions by about 1/2 and total energy consumed by something less than that (can't seem to re-locate the article I read on this the other day with those numbers, but even if they are somewhat approximate the benefit is still there). Each day the charge of the batteries would go up and down depending on demand, allowing all generators to run at a fixed level of output for maximum efficiency. That's worthwhile all by itself.

Now imagine if you had two or three total days' worth of grid storage for the entire grid, all solar powered, with more of that storage focused in the higher latitudes and the assumption that during the entire year there is a net energy transfer towards the poles. During the spring and fall you generate about what you need (assume solar). During the summer months you harvest slightly more energy than you need for current use, perhaps 0.5% per day from the longer daylight hours. Over the worst 3 winter months the "extra" drains down about 0.5% per day on average (there is still SOME sunlight, and probably some wind mixed in). Every day all the batteries charge and discharge to some degree due to peaking and sunlight hours, it's just that in the winter they run a bit net negative while in the summer they run a bit net positive. Especially bad winter? Turn on one or two of the old generators for a few weeks - almost nothing in the big scheme of things.

So, if grid storage "costs" about $5/Kwh * ~1 full charge cycle per day * 365 days * 20 years, the levelized cost of storage is 1,460Kwh / $1, or $0.000685 /Kwh stored and released. That's almost nothing.

Putting that into perspective, let's take the cost for a typical home to purchase 3 day's worth of storage. In the United States, the average home uses 900Kwh per month / 30 days = 30Kwh per day. 3 days' worth would be 90Kwh * $5/Kwh = $450 / 20 years = $22.50 per year per household for "energy storage expense." From the energy companies' perspective, it would make sense to install this as quickly as possible and REDUCE everyone's bill by 25% (giving back only a small portion of their savings but making them look like heroes even though their profits would soar through the roof).

These are all approximations, but they are close enough to make it clear that the price is in the right ballpark to make this work.


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## PhantomPholly (Aug 20, 2008)

Karter2 said:


> Did you have another source of info for them ?
> That link, and the 21stcentech link http://www.21stcentech.com/baseload-renewables-goal-carbon-energy-equation-good/..... says very little about the state of the technology , other than its a sulphur based flow battery, and a lot of other much less informative word salad !
> .?? One of those deals that sounds "too good to be true"....and we know what that usually means


Yep. This one may not pan out. One will. All this proves is that the chemical properties exist at a price which suggests someone will crack the problem.

For news on the chemistry (they all seem to point back to the same team), Google "sulfur flow battery news." For news on the company they formed, Google "Baseload Renewables" Yet-Ming Chiang. Yet-Ming has already formed 2 battery companies (A123 and 24M), so now is a bit more seasoned in the realities of commercializing a product then when he did A123. They are predicting 3-6 years to create a marketable product, which seems pretty standard. I think they will get it to market (low volume production) in less than the maximum - perhaps 4 years.


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## brian_ (Feb 7, 2017)

PhantomPholly said:


> Your math is out of context, and so gives the opposite impression from the reality. Their use of the term "seasonal storage" has to do with the implementation upon the entire grid, so you have to think really big for it to make sense.
> 
> Assume there were enough grid storage for the entire grid for a day. Setting aside the seasonal aspect, what that would enable would be the elimination of ALL peaker plants, reducing total CO2 emissions by about 1/2 and total energy consumed by something less than that (can't seem to re-locate the article I read on this the other day with those numbers, but even if they are somewhat approximate the benefit is still there). Each day the charge of the batteries would go up and down depending on demand, allowing all generators to run at a fixed level of output for maximum efficiency. That's worthwhile all by itself.


What you're saying is that the benefit is something beyond the difference in on-season and off-season (or sunny area and other areas) values, and what I'm saying is that the only reason there is any difference between on-season and off-season values is the elimination of expensive generation sources. It's already accounted for, and it doesn't seem like enough.



PhantomPholly said:


> Now imagine if you had two or three total days' worth of grid storage for the entire grid, all solar powered, with more of that storage focused in the higher latitudes and the assumption that during the entire year there is a net energy transfer towards the poles. During the spring and fall you generate about what you need (assume solar). During the summer months you harvest slightly more energy than you need for current use, perhaps 0.5% per day from the longer daylight hours. Over the worst 3 winter months the "extra" drains down about 0.5% per day on average (there is still SOME sunlight, and probably some wind mixed in). Every day all the batteries charge and discharge to some degree due to peaking and sunlight hours, it's just that in the winter they run a bit net negative while in the summer they run a bit net positive. Especially bad winter? Turn on one or two of the old generators for a few weeks - almost nothing in the big scheme of things.
> 
> So, if grid storage "costs" about $5/Kwh * ~1 full charge cycle per day * 365 days * 20 years, the levelized cost of storage is 1,460Kwh / $1, or $0.000685 /Kwh stored and released. That's almost nothing.


Now you've taken seasonal and daily storage and blended them. Yes, daily storage looks like it makes sense (even though you're ignoring all of the substantial maintenance costs); burying some seasonal storage in it doesn't change the lack of justification for the longer-term storage.

Although some energy utilities were run by criminals whose goal was to make themselves wealthy at the expense of consumers by shuffling numbers (think Enron), most are real businesses who would welcome a way to reduce their expenses; those capable producers are interested in energy storage and have put many billions of dollars into various technologies. Pumped hydro, flywheels, and various batteries are examples. I don't think anyone needs to tell them what is cost-effective, and it will be interesting to see what technology proves to be workable and in what situations it is justified.


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## Karter2 (Nov 17, 2011)

Without arguing all the numbers in detail, i suspect that the northern regeons need a little more than an extra 0.5% input over the winter months.
Even in Europe, Germany's 40+ GW of installed solar only gives less than 1GW (average ) during the winter months....less than 10% of its summer output.
Wind is better, but even more variable in winter.
...and were you suggesting transfereing power from the equatorial regeons to the poles ?....because i suspect that would be highly impractical and expensive.
Further , assuming a suitable system could be produced for 5 $/kWh, ..450 $/household for a "3day capacity" system,.. i suspect that a flow battery of that capacity could be quite a "bulky" item such that transport, installation, connection, etc, ..migh cost much more than the system value.


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## PhantomPholly (Aug 20, 2008)

brian_ said:


> What you're saying is that the benefit is something beyond the difference in on-season and off-season (or sunny area and other areas) values, and what I'm saying is that the only reason there is any difference between on-season and off-season values is the elimination of expensive generation sources. It's already accounted for, and it doesn't seem like enough.


If you were thinking in terms of exactly right now you would be correct. Solar panels have been dropping in price by half every 3 1/2 - 4 years for over 65 years, and show no signs of hitting theoretical maximums in the next 20 more years. In about 10 years, solar will be so cheap that in most parts of the world solar plus batteries will be cheaper than any other current generation system - and that ignores the possibility that some new invention beats them all.



> Now you've taken seasonal and daily storage and blended them.


Yes. That is the veiwpoint the power industry will take.



> Yes, daily storage looks like it makes sense (even though you're ignoring all of the substantial maintenance costs); burying some seasonal storage in it doesn't change the lack of justification for the longer-term storage.


Correct or incorrect, depending on the prices for the various sources of generation. From a business perspective, when storage is cheap enough and the choice is between building out ever more additional solar or building out more batteries, it will (as always) come down to price. Too, since storage = reliability (imagine storage units in your local substation, guaranteeing power for days if a main goes down) - which has a value all its own.



> Although some energy utilities were run by criminals whose goal was to make themselves wealthy at the expense of consumers by shuffling numbers (think Enron), most are real businesses who would welcome a way to reduce their expenses; those capable producers are interested in energy storage and have put many billions of dollars into various technologies. Pumped hydro, flywheels, and various batteries are examples. I don't think anyone needs to tell them what is cost-effective, and it will be interesting to see what technology proves to be workable and in what situations it is justified.


You are correct that no one needs to tell them - the price speaks for itself. At $0.000685 /Kwh storage prices, we are talking about two orders of magnitude cheaper - and even the stupidest nephew of a power company's CEO can do that math.


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## PhantomPholly (Aug 20, 2008)

Karter2 said:


> Without arguing all the numbers in detail, i suspect that the northern regeons need a little more than an extra 0.5% input over the winter months.


That depends on total storage capacity. I used 0.5% as an example because 100 days running negative on average would reduce local reserve to 1/2. Also assume some local generation (nuclear, wind, solar) even in the cold months. These are extremely rough numbers meant only as examples; the exact mix will depend on the cost of alternative generation in various regions.



> Even in Europe, Germany's 40+ GW of installed solar only gives less than 1GW (average ) during the winter months....less than 10% of its summer output.


True, although in fairness Germany is EXTREMELY cloudy in the winter. Still, Spain and France are not that far away and Spain in particular could host LOTS of solar across its deserts.



> Wind is better, but even more variable in winter.


Variability counts less with good storage.



> ...and were you suggesting transfereing power from the equatorial regeons to the poles ?....because i suspect that would be highly impractical and expensive.


That is a bit of a haul. However, power could be shipped north gradually over the entire year, and more storage would doubtless be most practical in the north (or south on the other side of the equator).



> Further , assuming a suitable system could be produced for 5 $/kWh, ..450 $/household for a "3day capacity" system,.. i suspect that a flow battery of that capacity could be quite a "bulky" item such that transport, installation, connection, etc, ..migh cost much more than the system value.


Perhaps. Then again, all you need for more storage is larger tanks. Tanks are cheap, the chemicals are cheap - so the whole system becomes cheaper per Kwh as it expands ("battery" part has to be big enough to supply peak Kw; tanks can be expanded ad infinitum).


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## Karter2 (Nov 17, 2011)

More info here..
https://spectrum.ieee.org/energywis...ould-provide-affordable-longterm-grid-storage


> ....The battery can store 20 to 40 Wh per liter of its electrolytes, making it 500 to 1,000 times denser than pumped hydro systems. Which means portable versions of this battery could be situated wherever they are needed near wind and solar farms. Plus, the cost of all the active materials in the battery is only $1/kWh, less than that for most any other rechargeable battery.
> 
> The battery is ideal for long-term storage because it is “scalable to a large size, made of earth-abundant materials, and has a stable chemistry in storage,” says Chiang. And as it gets bigger, storing energy gets cheaper. “System cost is a strong function of storage duration,” he says. “For long duration storage beyond a day, cost continues to drop and reaches $20 to $30 per kilowatt-hour.”


....So , suggesting more like $20 - $30 per kWh ..!...but still cheap storage if it can be done.
However these numbers do not add up, since even basic PP plastic water tanks (uncoated, not installed, cost roughly $0.5/ltr capacity , and at approx 30Ltr/kWh that 3 day, 90 kWh storage is going to need two 3000 Ltr tanks (special materials ?) ...at least $3000 just for basic tanks !....in addition to all the other process equipment , plumbing, electricals, and controls,
.....plus installation and set up etc etc.


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## PhantomPholly (Aug 20, 2008)

Karter2 said:


> More info here..
> https://spectrum.ieee.org/energywis...ould-provide-affordable-longterm-grid-storage
> 
> ....So , suggesting more like $20 - $30 per kWh ..!...but still cheap storage if it can be done.
> ...


I got so fixated on the materials cost I had not considered the cost of the tanks. Good reality check. Later in the article it says:



> “For long duration storage beyond a day, cost continues to drop and reaches $20 to $30 per kilowatt-hour.”


Not as good as I had hoped, but still 20% of the cost of today's best if they hit the $20 figure. Too, one supposes that if the tanks are made of appropriate materials they will last considerably longer than 20 years, giving a longer payback period.

Still in all, truly ginormous tanks are less per gallon to construct than small ones. I I did a quick search on 100,000 steel tanks (which can be coated with sealant) and they were less than the small plastic standalone tanks you mentioned. I strongly suspect that 10 million gallon tanks made of concrete would be cheaper yet, and would be more appropriate to a community (just like their water storage tanks).


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## Karter2 (Nov 17, 2011)

I was simply considering the 90kWh , 3day , domestic system that you had proposed.
For utility scale systems there would be many other options, possibly even in underground caverns as they do with oil and gas currently.


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## PhantomPholly (Aug 20, 2008)

Karter2 said:


> I was simply considering the 90kWh , 3day , domestic system that you had proposed.
> For utility scale systems there would be many other options, possibly even in underground caverns as they do with oil and gas currently.


Yes I get it. And this option is specifically aimed at Grid Storage, so we SHOULD assume they will employ best cost solutions. But still, there is a lower limit to the cost of physical storage, and it simply hadn't occurred to me how immense the storage tanks would need to be! 

Not all bad though. If they can drive it down to $30/Kwh, grid storage of at least a few days is a done deal and, as I have repeated ad nauseum, AGW is dead even quicker than I'd hoped. Curiously, if 24M succeeds in their original target of 80% cost reduction, it would beat this solution by every measure (smaller, cheaper) except for the availability of mass quantities of raw materials (Lithium). Will be interesting to see how the market plays out on these issues.


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