Falling lithium-ion battery prices to drive rapid storage uptake
pv-magazine-usa.com
pv-magazine-usa.com
If you look at Tesla's plan to be making 10,000 model 3's a week, with a nominal 90 kWh battery in each that is 900 MWh a week of capacity or 46 GWh capacity a year. But it is all tied up in cars of course[1].
The power companies have been screwing around with rate plans to keep grid-tied solar from being as economic as it could be and so I do see a lot of people such as myself moving to a whole house storage system at some point.
[1] I fully expect a TV show to have a scene where they need more power and the 'genius' hero looks out the window and sees a row of electric cars charging and "hacks the system to feed the car's energy into the power grid for the extra energy needed to save the day" along with the gratuitous cars exploding as they are being drained too quickly but reaching the minimum level of power at just the right time to save the world.
The "Gigafactory," is a drop in the ocean if you count noname Chinese factories, but it will be one of the biggest market players outside of China
My father-in-law, who is a big booster of South America, feels that if Argentina, Brazil, and Chile got together they could move up the 'value chain' and produce batteries for export. I do know that much of the raw lithium comes from Argentina and Chile so I expect there is some truth to that idea.
It is just another way of checking various numbers. You can start from world production of Lithium salts. And remember that they are used in all lithium batteries not just the rechargeable type like we're talking about here.
Source: traveling in big cities and tourist areas.
I swear, it's Musk's biggest weakness, not realizing the costs of mistakes people make when they're tired. I couldn't get through his recent biography because I kept seeing mistake after mistake being chronicled that wouldn't have happened if people were working reasonable hours. I figured the setbacks to SpaceX due to sleep stupid were at least 6 months before I had to stop reading somewhere around their early launches...
I just know that people get really dumb when they're tired, and it's the same kind of dumb as oxygen deprevation where people actually think they're not effected.
I'd be curious if these 12 hour shifts are preferences for personal reasons, or if there are measurable benefits in the factory as well.
William Bratton, who headed the NYPD (twice) and the LAPD, was big on this. When he first started running the NYC transit police, he'd get on the subway late at night and ride around, talking to the cops on duty. Once the rank and file got used to seeing the commissioner on the subway, things started to improve.
A useful test for your local police department in a city of any size - find out who's the highest ranking cop on duty at 1 AM on a Saturday morning, peak time for most city PDs. If it's a lot lower rank than who's on during the day, the department is not well managed. Such police departments are derisively called "9 to 5 departments" in the business.
86,400 sec/day
So, yes.
Model 3 has a base 60kWh battery, with upgrade available to 75.
Tesla hasn't confirmed how large the pack is at all, but they have specifically confirmed it's less than 60.
I think it's either 40 or 50.
https://electrek.co/2016/04/26/tesla-model-3-battery-pack-co...
I would imagine they would quickly switch the powerwall to use the new battery size that the gigafactory is producing..
It's trivially easy to change the size of cylindrical batteries. Li-ion batteries are essentially a tape, and the second to last step of production is to roll the tape up and insert it into the battery. Different cells just require different cans and widths of tape.
Realistically, there are probably no changes coming in the next 30 years that will require rebuilding anything significant.
https://www.bloomberg.com/news/articles/2017-08-03/germany-g...
As soon as someone departs for a long trip and the battery isn't charged, there will be a huge class action lawsuit.
The lemon law attorneys will also have a field day!
This is a really dumb idea.
As you plug in your car, you set the time you need it charged, then you charge for a discount for your cooperation.
If you change your mind and use the car earlier than expected, you know what you signed up to. No need for a lawsuit.
Your car or charger module has electricity spot prices available to it and you can select a strategy for it to automatically follow.
E.g.
* Rapid charge (charge battery, ignore price)
* Economise (charge battery at low price)
* Make money (charge/discharge according to price to profit from the difference)
In a way, electric car batteries have demonstrated to outlive their cars by 2x-3x (there are already several Teslas who were driven beyond median lifetime of a car and they lost just a few percent of capacity). So when i car is trashed, a battery is essentially still new. They can be bought out for say half the price and used for electricity storage. If there is a billion electric cars in the world instead of the current billion gas powered ones, and they are on average 55kWh of which 10% is lost while they are in a car, and another 20% is lost while they are used for grid storage, on average they will have 45kWh of capacity. Grid storage takes 6 hour capacity (pumped hydro plants usually have 6 hour storage, enough to compensate any daily cycles), so 7.5kW power per battery or 7.5TW overall... the world has 6.3TW of installed generation capacity.
Probably grid storage will be a side business of car makers because all storage plant will need to use same type of battery. Maybe they'll even offer like 10% discount on a new car on a condition that the battery is theirs and to be returned when a car is scrapped.
Also, the life-time of a car that needs a $20.000+ battery replacement will obviously prematurely make the car utterly worthless.
Usage and weather most certainly have a huge impact as well.
Don't get me wrong, I'm interested in a used model 3 when that time comes. But that hinges on that you can replace the battery for a reasonable cost, reasonable even for an older car.
No, Teslas will never need battery replacement. Contrary, batteries outlive cars severalfold (yes they can be bricked by grossly violating their usage rules in a way BMS can't prevent, but this is not wear and tear - it is equally easy to do with a brand new or 10 year old car - that's approximately an equivalent of what happens if you fill a gasoline car with diesel). With a normal averagely intense usage and a good driver, a battery will last 40-50 years which is much, much more than it makes sense to keep using a car itself.
"Tesla Tech Talk (06/13) - Speaker's main points: 1) battery degrades everyday 2) battery degradation is non-linear over time; meaning it starts very very slow, but after 4-5 years, it gets faster 3) after the first 5 years, degradation may be as low as 5%. But by the 8th year, they expect about 30% degradation."
Batteries will without any doubt seriously affect second hand markets for EVs. Especially when considering cold climates and the fact that the range can be quite limiting even when the battery is brand new.
in 2013, there was no data to tell what happens after 8 years of typical use, first Model S was just a year old by then and even more intensely used ones didn't have that much use - 8 years of normal use equivalent. Now there are many of those that were driven beyond median lifetime of a vehicle.
Is that an ad?
It is expected for the capacity to drop off significantly with age. The main weapon tesla has used against this is good cooling and sensible charging patterns, but that is just stalling the inevitable.
Now, it seems the development effort devoted to lithium-ion has paid off so well that they are the best OVERALL battery solution. The single-minded effort we put into cell phones and cars is so strong that it now reaches all the way to homes and the grid.
To me, this suggests that all sorts of cool technologies might be possible if we as a society could concentrate on making them work.
That's also why I don't care about all these fears about us not having enough lithium: nobody is going to power the world on lithium, it's just the cheapest method right now because of the massive amounts of research money already dumped into it, and great economies of scale. Other technologies will catch up as their use-cases become more valuable.
That is something I've found really curious because if you tear into just about any lead acid battery it still looks like technology from the 1950's. Just about everything else has shrunk, become lighter, used less material, etc. But lead acid's last major "breakthrough" was in the 1970's with gel cells. I would have expected lead acid to look more like a capacitor at this point (thin layers of material rolled/folded up) but its still these fairly thick plates sitting in electrolyte with non-existent charge control. Surely some creative person sitting in a lab could come up with way to minimize sulfation or to decompose the lead sulfate within the battery without basically melting them down and building new ones.
Who is afraid of that? Take a look at this: https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...
Lithium is #33, estimated at 20 ppm of the crust. We presently mine 64000 tons per year. It is more common than lead, which is #37 and only 14 ppm. Yet we mine 4.8 million tons of lead per year. Now examine boron. #41, 10 ppm and 9.4 million tons per year. Are these unsustainable? Are we on the verge of peak boron and peak lead? Probably not. We have twice as much lithium so we probably aren't going to run out of lithium even if demand increases by a hundred-fold.
I am not a geologist, so maybe much of this lithium is more inaccessible than I'm assuming. But everyone who says we are going to run out of lithium have been only looking at the known deposits and are ignoring the possibility that more mines will open to meet demand.
I suggest that something is wrong with your assessment.
But statements like this should really be talking about the "economically extractable ore", and it needs to include economic thresholds. There's a price curve there, and I suspect that for lithium it is a steep one because of how complicated its manufacturing is relative to lead.
I don't know if we're near the limit though. I don't really buy it personally, I'm much more worried about rare earths.
Hard rock lithium is most commonly extracted in the form of spodumene which is about 6-7%[1] (8% when totally pure) lithium oxide. Rich lead ore may have 3-8% lead content. Obviously comparing the two is difficult since lead is about 20x denser, but they're on the same order of magnitude. As a ratio of rock in to metal out by volume there is probably a bit more lithium, but by mass lead ore is probably 2-3x more concentrated.
For both lead and spodumene, the ore is crushed, separated by density, ground, counditioned (treated with acid to remove organics/slime), froth float separated, cleaned, filtered and dried[2]. That gives you metal that is ready to be reduced in a furnace (or electrolytically or chemically, for lithium). Both processes use the exact same machinery and chemicals (sulfuric and hydroflouric acid, and NaOH). Both processes are almost identical except that the lithium is collected at the low-density end and lead is collected at the high-density end.
Brine production is much easier and involves a well, a pump, a bulldozer and a bunch of sodium carbonate (water softener)[3]. It is significantly cheaper than any other metal production method, as well as low-energy, low-waste and low-impact. The only downside is there is a lot of water loss to evaporation. It's a relatively small amount of water, especially compared to a farm of the same size, but brine mines exist exclusively in places without much water to start with (otherwise the brine would have washed into the ocean already). It's a tradeoff.
Regardless, the difficulty in producing lithium is most certainly not most of the price difference. First, annual global lithium production is ~36,000 tonnes vs 5 million tonnes for lead, a 140x difference. Lithium's lower density could account for a 2-3x price per tonne difference, but it is vastly more likely that economies of scale are the culprit.
Not only that, but the current lithium price surge is entirely due to market contraction. It takes 2-3 years to build a mine, and longer to decide to build one. Tesla wrecked the battery market in less than two years, becoming the largest battery consumer. There simply hasn't been time to open new mines yet. The prices will drop as soon as they catch up.
Finally, the majority of lead is produced by recycling. That 5 million tonnes mined each year is less than 50% of all lead. The recycling industry obviously drops the price of lead immensely, and lithium will take advantage of recycling too, when and if it ever needs to.
>But statements like this should really be talking about the "economically extractable ore"
There is no such thing, really. Not even for oil. The content of the ground is not mapped that well. As soon as people go looking for lithium, the reserves will skyrocket just like they did with oil. Trust the crustal content more than the global reserves. Lithium is so cheap and ubiquitous that nobody has gone looking for it since the 50s- Seriously, that's the last time the USGS did a survey of US lithium supplies.
>I'm much more worried about rare earths.
Don't be. They're only used in hybrid cars (neodymium) and even then they aren't needed. You don't need magnets to make a motor, just steel and copper. The other green use for rare earths (tellurium) is in thin-film solar panels, which make up 5% of all solar panel production. Rare earth elements aren't even the first choice for these technologies, and a contraction in supply will push them out of favor entirely. Seriously, the only reason we use thin-film solar is because it's cheap, even though it's less efficient. If it's not cheap, then we won't use it at all. Good riddance.
[1]: http://encyclopedia2.thefreedictionary.com/Lithium+Ores
[2]: https://www.911metallurgist.com/blog/froth-flotation-spodume... [3]: https://www.thebalance.com/lithium-production-2340123
My rare earth worries are based on this DOE report:
https://energy.gov/sites/prod/files/edg/news/documents/criti...
It actually calls out dysprosium as the biggest problem, with neodymium, terbium, europium, yttrium, and indium as the next biggest worries.
This is fairly old though, I read it back in 2010. I've read about a number of breakthroughs on higher strength-to-weight magnetic materials and I'm sure solar has responded to this report accordingly as well. It's comforting to know that things seem to have worked out seven years later!
I think a lot of the stress in 2010 was because China was limiting exports and it became clear that the USA was at a strategic disadvantage because of vulnerability to Chinese actions. Glad that Obama took it so seriously by supporting funding to develop those new technologies.
Is it really worth investing in gargantuan quantities of energy storage if they need to be replaced every few years? I'd be eyeing EDLC technologies or something like molten salts over giant stationary phone/laptop/car/etc batteries.
It's not the most long-lasting technology, but we replace most infrastructure every 20-years already. A 10 year lifetime wouldn't be that bad.
wait. does that mean that, effectively, for a careful Tesla owner seeking to maximize battery life, most of the time her practical range will be roughly 70% of the stated value?
An li-ion battery will do about 500 discharge cycles from 0-100. They'll do several thousand from 20-80, and tens of thousands cycles from 30-70%. If you have a few days of storage, the battery as a whole will last an incredibly long time even when cycled every day.
As for why: When the battery is kept at a high or low voltage, it puts an overpotential on one side or the other of the battery. There's more or less lithium on one side of the battery and it tries to diffuse across the battery very slowly. It never makes it to the other side and reacts with the electrolyte and is lost, reducing capacity.
The closer it is to 50%, the less lithium is pulled/pushed out into the electrolyte.
Not entirely. The real killer feature of LiPo which has allowed things like Roadster and Model S to exist is their high discharge, or "C" rating. The power density of LiPo is far beyond any previous chemistry available for batteries at scale. Energy density and power density are two completely different things [0].
https://www.quora.com/What-is-the-difference-between-power-d... [0]
If lithium ends up with the same advantage, other technologies that ought to be better may end up lagging even in the long term.
It's an interesting phenomenon. In the case of batteries, I wonder if we fully account for all the costs though. Lead-acid, for example, is a very sustainable (long-lasting, highly recyclable) battery technology that is inherently suitable, but if the full mining/recycling/disposal costs of lithium-ion are not priced in, the market won't account for this.
- His mobile chicken coops need to be lightweight. Before thin-bladed sawmills, milling lumber to be smaller than ~2" was cost prohibitive as each cut had a 0.25" kerf. Making 1"x1" planks would mean nearly half of the wood goes into the waste pile!
- Cheap electric fences allow pastured hog farming to be mobile. Pigs will wreck strong fences, but a lightweight deterrent allows quick placement and removal.
The current issue is commercialization (i.e, doesn't exist) and low conductivity of the sulfur cathode (meaning a low discharge rate to avoid self heating) -- it could be a decade + away.
Assuming that households consume between 30 kWh and 15 kWh electricity daily on average and you want to have storage capacity for 1/3 of daily electricity consumption to get wind or solar energy work, you need 10-5 kWh per household. That's $2000 - $1000 per household. If that battery lasts 10 years, its $200 - $100 per year.
It's workable and scales if we are able to reuse lithium. When does that happen? (recycling is not reuse)
Here's one company that makes them.
If that's really accurate, then I'm staggered at how much energy folks must be using to keep cool, and makes my efforts at saving energy seem paltry in comparison.
I have been keeping daily logs this summer and find that my daily power consumption swings between about 25 kWh on cool days to 65 kWh on really warm days. Definitely a lot lower than 100 kWh mentioned previously.
I went to Egypt as a teenager and remember the temperature in Sharm el Sheikh cracking 50C. We would literally sprint from the A/C in the hotel across the beach to the water because the sand was too hot to walk.
Equivalent latitude doesn't mean equivalent climate. As an example, which of these cities is further north, Buffalo, NY, USA or Cannes, France? Hint: it's the one known for topless sunbathing, not the one known for sub-zero outdoor football games.
Based on this very scientific single-neighborhood sample, I'd guess 40-60kWh/day would not be unusual during the peak summer months.
https://en.wikipedia.org/wiki/Wind_power_in_Texas
The source in wikipedia is out of date, but it's still true as of Q3 2016:
US insulation requirements in Dallas is R-20 in the walls [1]. The PassivHaus standard is R-40 to R-60. I believe Germany requires R-5 at a minimum. Mainstream US construction design and practice still doesn't account for thermal bridging, so that defeats much of the insulation we're throwing into our buildings.
[1] https://eepartnership.org/wp-content/uploads/2016/02/Texas-2...
A/C efficiency ("power factor") is measured using the ratio of heat (energy) moved outside to the amount of energy put into the air conditioner , which is usually >> 1 unless there is a huge temperature difference between inside and outside.
An ideal furnace has a 1:1 ratio of heat energy injected into the house to energy used to run the furnace. Heat pumps can get over 1:1 ratios, but come with caveats and are more expensive than A/C units.
Also, you can make it feel cooler with a dehumidifier, which often is more efficient than cooling. For furnaces, you need a sweater, but your article assumed a 70F indoor target.
Heating can also be made more efficient easily with insulation, and heat generation through CHP or geo heatpump.
Last month my average home used between 100 and 120 kwh per day [2].
Luckily we rarely have to heat in the winter - although it's not uncommon to have the A/C running for Christmas.
[1]: http://www.statesman.com/news/local/wipe-that-brow-austin-re...
That's half of my entire energy usage for a month...
Have you considered a swamp cooler?
They do not work well if it's hot and humid, for two reasons. One is that the water doesn't evaporate as well, so they don't cool well. The other is that the whole point is comfort, and in a humid climate you don't achieve that unless you remove both heat AND humidity, but swamp coolers add humidity.
Texas has some desert areas (western part of the state), but most of the population lives in the part of the state that isn't a desert.
The good news is with modern construction techniques and equipment, you can cut energy usage WAY down. You can cut energy usage a lot with stuff like a radiant barrier in the attic, attic vents, lots of insulation, double pane windows, a "tight" house with little air leakage, proper angles to keep direct sun from heating up the house at the wrong times, and a high-efficiency AC unit that you service and maintain properly. In fact, a lot of those things are actually more beneficial than getting solar panels.
This is the figure in an environment where electricity costs nothing and there is zero pressure from home design to the actual AC unit to reduce consumption. Let's face it, this attitude isn't going to fly in the future. You could probably cut that figure by a good 10% by installing your choice of solar panels or a bunch of trees, just from less sun hitting the structure.
(Cut it in half if you consider the average American in the South lives in a freakishly large house fit for a queen with entourage and is cooling all of it..)
(Interestingly Canada's per capita consumption is comparable to the US despite being much further north)
Investing in insulation or other things might or might not make sense. High electricity price for a long future period would also encourage investment.
Alternatively, constructing your house in a benign climate, if you do a lifecycle analysis and look at the upkeep cost.
That applies to lead acid batteries. Lithium ones are much more forgiving on that (as long as you stay within design limits.)
http://energyblog.nationalgeographic.com/2013/09/17/10-myths...
5gkal per hour is more than enough to keep a 50m2 room with huge windows at 21-22C in scorching heat.
If your house is huge, like 200m2 McMansion, and your ventilation does no recuperation whatsoever, and you have near nil heat insulation (like most of housing in US,) you will barely use 50kw/h per day even if you live in the middle of Sahara
It should be noted that peak energy expenditure for air conditioning happens more or less at exactly the moment when the influx of energy from the Sun is also at its peak. That's, like, a gigantic hint that mother nature is dropping on you, hoping you'll notice it. The disease, and its cure, are gushing forth from the same place at the same time.
Probably most of the energy for air conditioning in the future will not come out of storage, but it would be produced at the moment when it's consumed, by solar panels or some other solar technology.
> "The hottest part of the day usually starts at about the end of the prime solar hours."
https://en.wikipedia.org/wiki/Diurnal_temperature_variation#...
Soon.
https://electrek.co/2015/08/16/the-power-of-controllable-cha...
Also, covering 1/3 of daily use seems low to me. It wouldn't get one through a few windless winter days with dense cloud cover, for example.
On the other hand, there is lots of lithium. If the environmental impact of lithium mining going off the roof is not a problem, there is no reason to reuse.
Even as an upper bound that's still a silly thing to say. It means comparing a lab-scale extraction with massive multinational, highly-automated mining operations. At scale lithium recycling would certainly be much cheaper than five times more expensive.
Going off the electric grid should become fairly easy. Cheap solar and storage should make this feasible for an eco-conscious household...
Reusing the lithium from the batteries means recycling the batteries.
I assume you mean reuse is not recycling ie using old batteries as lower-capacity storage is not workable indefinitely.
First off the most pressing issue is that there is no practical replacement for cobalt in many li-ion applications. Chemistries without cobalt, like lithium titanate or iron phosphate, have a price and weight premium and reduced capacity. Cobalt is rarer than lithium, makes up more of the battery, and is harder to mine. The price might go up very quickly past a certain point, if supply from the DRC becomes tighter.
Lithium is very widespread and relatively abundant but most importantly its final impact on the price of a battery is only a few percent. If it becomes more expensive to reclaim or mine, it will still have a pretty small impact on the cost of batteries.
There is one company in Colorado making Li-S batteries at small scale: http://www.solidpowerbattery.com/
Unfortunately the damn thing tries to swell to 200% size when you charge it and lasts for six cycles. Someone may figure out how to make it work but most likely itll use nanotech (like a123 did with FePO4, or a graphene coating). The fact is its such a hard problem there are very few ways it could be done cheaply. Right now LiS is only applicable to very, very niche applications. SolarImpulse used them. They come at a very high price and limited longevity.
GW is not a unity of energy storage capacity. It's a unit of power.
In the current stage of the grid and storage, storage capacity is used not for long duration transmission of energy, but shorter term filling in of power gaps. In the past few years that's been frequency regulation, and now the replacement of peaker plants, or instantaneous response when waiting the 10-15 minutes for a peaker plant to come online.
Maybe sustained charge speed is a (little bit) more meaningful thing you can express in GB.
I am with the parent -- this is either a typo or a journalist quoting something he knows nothing about (what's that "h" in GWh? Strange capitalization; probably a typo; let me strike that).
Currently, grid discussions happen mostly in the MW or GW space. Maximum instantaneous discharge speed is pretty much the most important characteristic for storage, up until very very recently, since it was mostly used for frequency regulation. Lately more and more articles are discussing total energy capacity instead, as this is discussed in wider circles than just those interested in the grid. Also note that the duration of discharge for a storage system is often implicit because it is deployed in an energy market where the bids are on fixed time periods (e.g. 4h).
Ideally we'd know both the GWh and the GW, but the collated stats have been mostly GW so far.
Guessing that they don't understand GWh vs. GW is pretty far off base. Though this may be a confusion of units that happens often in discussion with lay folk, it's not much of a concern when talking to people that are discussing the grid.
And really, as you say, everybody talking about storage systems should be quoting both energy and power.
In this article, which is what we're discussing here, it is very clearly either a typo, or it's some journalist spouting off above their pay grade.
And if you're used to thinking about utilities, it makes a lot of sense, you think about power capacity, and then the duration afterwards. GW is a more direct way to approach that. If you want to get duration from GWh and GW, you have to do a mental division, which is slower than multiplication.
This is the best reason why they should quote both numbers: so we can be sure they haven't gotten confused and quoted energy as watts.
I don't work in power systems, I work with low-voltage DC stuff, so when I think "the capacity of the battery system" I think it would mean the maximum stored energy.
But "The maximum amount that can be produced" is also a valid definition of capacity, and I'm guessing this definition might be used in power generation more often ("the generator is operating at half capacity").
If you're interested, the context is that capacity was historically used in the utilities industry to refer to generation capacity, which is in MW or GW. E.g., the capacity of a power plant could be 500 MW, which for the decades of power production preceding renewables, could be sustained indefinitely as long as you're feeding it fuel.
By extension, when you talk about battery capacity in the context of the electrical grid, you're talking about the MW or GW of generation that you can replace during peak loads. The ability to distribute batteries across a grid to meet peak demand (and defer infrastructure/peaker plant construction) is the best way (today) to justify investments in batteries.
Wrong.
The watt is a measure of power, not of stored energy. These are different physical notions. So, yes, you could say that some storage facility can output up to so many GW, but that's actually a measure of how much energy per second can exit the system when it's being used.
The proper unit for measuring an amount of energy that's stored in the system is the Wh (or its multiple the GWh), which has the same dimension as the joule, which is the standard unit of energy.
GW is like how many liters of water per second can exit the storage tank when it's being emptied. GWh is like how many liters of water total are stored in the full tank. And yes, both are important when designing a battery system. But saying "GW is [...] a valid and important measurement as the amount of energy it stores" would fail you high school physics.
GWh is static energy (or simply - energy). GW is energy moving from point A to point B, which is power.
Here's a brief introduction to the basic meaning of these terms:
https://cleantechnica.com/2015/02/02/power-vs-energy-explana...
At no point do you actually say what was wrong about what you quoted. What do you feel is in error?
>GWh is static energy (or simply - energy). GW is energy moving from point A to point B, which is power.
Yes, obviously. This is HN. Generally it pays to assume that people know what they are talking about around here.
It may be that you don't care about the power rating of the storage instance, but a utility does! They care about the power rating just as much as the total storage amount, as they are both essential design parameters. Particularly in the case of lithium ion, since many applications use discharges or charges less than an hour long (lithium ion batteries are typically designed with a W:Wh ratio of 1:1 - 1:4).
The original article is citing a market report from IHS Markit. Now, I can't find the particular news release for this one, but IHS Markit uses both terms GWh and GW when talking about storage, and as market researchers if they were messing that up it would be a worthless report. So lets look at one of the recent reports:
https://technology.ihs.com/590967/global-battery-energy-stor...
and one easier to check number:
> This was largely a result of over 100 MW of projects being completed and commissioned in California in early 2017 as part of Southern California Edison and San Diego Gas and Electric’s response to the Aliso Canyon gas leak.
Let's look at this other report on that 100 MW:
https://www.greentechmedia.com/articles/read/aliso-canyon-em...
>(CPUC) expedited the approval of around 100 megawatts of energy storage in Southern California Edison and San Diego Gas & Electric territories, in response to the Aliso Canyon blowout.
>Tesla, Greensmith Energy and AES Energy Storage celebrated the completion on Monday of three large-scale lithium-ion battery projects totaling 70 megawatts -- consisting of 20 megawatts, 20 megawatts and 30 megawatts, respectively.
Now, here all megawatts! And the mean it, because these the AES batteries were 37.5MW and 150MWh, and the Tesla battery is 30MW and 80MWh:
http://www.utilitydive.com/news/inside-construction-of-the-w...
So yes, they mean GW and not GWh, and yes, that is a very meaningful statistic when talking about the grid. It's not the only one, and for bystanders, maybe they care about the Wh more than the W, but it's not like you can design a system without known both.
The whole comment past that point is an explanation why that statement is wrong. Read it.
You're clearly confused about the difference between power and energy. There's no meaningful discussion on this topic until you figure that out.
> lithium ion batteries are typically designed with a W:Wh ratio of 1:1 - 1:4
The comment you replied to said "just a valid and important measurement as the amount of energy it stores". The comment didn't say power was the same thing as energy, it says that the power is as important as the energy. I don't think this would fail high school physics.
> GW is [...] a valid and important measurement as the amount of energy it stores
There's no way to sugarcoat it. This is like saying km/h is a measurement of distance.
> GW is [...] a [..] measurement as the amount of energy it stores.
Which doesn't parse. If the text read "of" instead of "as", I might agree with you. As it stands, it doesn't correctly parse either way. Given the full context of the statement, the more likely original intention was that:
> GW is [...] just a[s] valid and important [a] measurement as the amount of energy it stores.
Which is entirely true... Both the overall capacity, and the rate at which it can deliver power are critical metrics for an energy storage system.
Which doesn't make sense, after giving it a second's thought—batteries wear out after just a few years, while capacitors (very nearly) don't, so it'd put a hard lifetime on drives. (Though, for server use-cases with constant workloads, they have hard lifetimes anyway...)
But it's an interesting question! If—rather than UPSes as specialized enterprise-level hardware—we instead had Li-ion cells on computer motherboards (picture a big brother to the CR-2032 CMOS battery) that kept the disks alive for up to, say, 30 minutes after power loss—could we architect our storage subsystems differently?
(Sorry if that's a complete tangent from the topic at hand, but I'm not sure where I'd post this otherwise!)
More interesting (in my eyes) would be to power down spinning disks and processors, but keep caches and ram alive. Then once power is restored, you could basically supply power and continue where you left off, without any reboots etc.
Then again, power loss should be fairly infrequent, and you have to architect against connection cuts or physical disruptions anyway.
Anyway, its great, I used it today to ride out a nearly hour long power outage with a couple of fairly trivial UPSs connected to my NAS, desktop, etc. The desktop was already in standby because that is its default state after being idle for 30 mins. But the NAS went into that mode when the UPS indicated 70% battery life.
The problem of course is that UPSs/etc have miserable power conversion efficiencies when supplying just a couple watts of power, like 10-30% efficiency, so they tend to have max run-times less than 2 hours even when completely unloaded.
More on point, for servers, if your server is lightly loaded, or loaded for only parts of the day, using WOL to wake it and going into standby after a few minutes can save a fair amount of power. With SSDs, the resume times are generally less than a second unless you have bad cards/drivers that take forever to reinit.
I had a vague idea that I had heard something similar before:
http://www.zdnet.com/article/google-reveals-secret-server-ha...
It's definitely a clever idea! Makes maintenance much less risky as it's distributed, and also reduces the chance of having a single large UPS fail when it takes over the load!
You could, therefore, have a really, really big disk cache, and a relatively slow-to-flush disk. With such an architecture, you could build systems that use disk+cache the way Optane NVMe is being used, without having even needed to invent Flash memory to get fast, highly-parallel writes first.
Now, they use super-capacitors and a flash memory device to flush the volatile RAM buffers to flash memory, then on next power up the firmware can flush the flash buffers to disk. This all happens within the RAID controller so the host OS just thinks it already got write confirmation back when the PCIe transactions finished and the data blocks landed in the controller's RAM.
Not relevant to disks, but you could have battery-backed DRAM? Commonly used in RAID clusters as a cache.
The main problem with storage architecture is too much hardware that lies about whether it's actually committed a write.
In that article they claim the digit of $200, while you can buy an assembled 1kw/h battery pack in China in retail quantities for around $120 today.
Typically grid storage batteries are rated to 10+ years or ~5000 cycles or something on that order of magnitude.
One way to get your cells to last that long is to lessen the discharge depth; that may account for some of the price difference.