As someone who follows the energy space closely, Lithium ion batteries now have so much momentum and $$$ pumped into them via R&D work, it's going to be hard for competing energy storage technologies to catch up. Flywheel and hydrogen fuel-cell also often come up but I think we're at a point now where batteries are going to take off simply because of their wide area of applicability. With that economy of scale costs will drive down and even more research and $$$ will flow.
I've been surprised by the development honestly. 15 years ago I assumed heavy industry and automotive would make the big decisions about what energy storage tech we go with and the rest of the economy would follow suit and start working with either hydrogen fuels cells, supercapacitors, kinetic storage, or chemical batteries based on the R&D they did.
Instead it's been consumer electronics that led the way and heavy industry is stuck with chemical batteries because that's what worked best on an MP3 player.
1 it would require building out entirely new infrastructure, running up against severe NIMBYism at this point. It's incredibly hard to even build new power lines right now. Try a highly combustible, very leaky gas.
2 it's far cheaper to just strip H2 from natural gas, which releases carbon (unless you capture it, increasing cost), so not carbon free unless you force using electrolysis from renewable power sources
3 Electrolysis efficiency is ~70%, fuel cell efficiency is ~60%, so round trip efficiency is <50%. Much more waste than a battery (~80%). You're both using essentially the same electricity to create the power, but hydrogen is wasting more of it, so will necessarily be more expensive
4 in vehicles, fuel cells end up charging the battery toi power the motor anyway, so the energy loss from the battery is a wash
The one thing they have is range and speed to refuel, but as batteries get cheaper and better that will be minimized before H2 gets big enough to take over.
There's lots of big companies with smart people who are still pushing for this so hopefully they know what they are doing (mostly in Japan it seems)
The nuclear waste problem seems to be not so severe in the age where everything is tracked every second; and it doesn't need to be solved completely - just raise the cost of (illegal) waste extraction to be considerably higher than getting it from alternative sources, and you're set.
Looking on the bright side, anything that drives Li efficiency/density research is probably a very good thing.
So is a lithium battery explosion. So is a gasoline explosion. So is a flour mill explosion. So is a wind turbine explosion.
Energy is energy, and losing control of energy is never great, no matter where it comes from. So while I catch your meaning, it might be better to phrase it with respect to how controllable that energy is.
From what I know of flywheel storage, the problem mostly comes down to keeping the wheel from coming apart, and containing it when it does. The nice thing about using flywheels for grid storage is that you can bury them and make them large. The earth contains your explosion risk and the lack of jostling means that your bearings don't need to take as much stress and limits that failure risk.
I thought the trend in flywheels was magnetic suspension and removing mechanical linkages? Admittedly I haven't kept up.
What gives you that impression? Seems to me that it explodes if you contain it, and if you don't contain it, it can spout jets of thermal energy at virtually any angle. With flywheels you need to arrest it in bulk heavy objects that don't tend to sustain fire. That seems a lot simpler to me.
The bigger problems with flywheels are cost of manufacture and (depending on the technology used) efficiency for overnight storage.
> I thought the trend in flywheels was magnetic suspension and removing mechanical linkages? Admittedly I haven't kept up.
IIRC flywheels with limited motion gimbals (to reduce the tolerances on the wheel) are becoming more popular, still magnetic bearings.
Insulation is cheap, effective, and very compact. And it's easy to transfer heat quickly, also (either via injecting lots of cold extinguisher or flush lots of hot oxidizing gas)?
Cool, thanks for the update on flywheels. I ... am not trying to create a false dilemna, here. Fuel cells for stranded methane deposits are great. Flywheels have outstanding responsiveness and energy density. Li / compressed air / pumped water et al scale well. They all fit into a more resilient grid storage strategy that permits a transition to periodic sources of input from non-renewable base load.
And anyway, you tried to be too clever. I said "non-renewable" and not "carbon free" just to avoid this conversation. Unless you can start synthesizing utility grade quantities of well-behaved fissile material at a net energy surplus then it's not renewable even if we have decades/centuries of supply.
Someday, even the Sun will run out of fuel. In the long run, we are all dead - unless someone figures out how to reverse entropy.
edit: Love reading that short story, it somehow never gets old.
Humans are plenty smart and the people of tomorrow will be better equipped to solve tomorrow's problems.
It's not even a matter of "ripping off a band aid" and paneling up the planet - solar panels aren't going to last hundreds of years either, we will be lucky to get 30 years out of them. Can we make more, sure, but we could also do nuclear and then make solar panels in 500 years when we're running out of fuel.
The biggest problems are that we need to come up with the political will to reprocess waste (extracting additional usable fuel and compacting the amount of true waste that needs to be disposed of) and then dispose of it in a proper repository rather than just letting it sit around on-site indefinitely Fukushima-style.
Which is itself a good thermal-runaway damper, to speak to the second sentence of your second paragraph.
Having witnesses a corn silo explosion, I was unprepared for the ferocity of that ignition.
>So is a wind turbine explosion
Off to YouTube...
Assuming the flywheel keeps its integrity it's much harder to predict the "blast radius" of where that thing is going to go.
Not AFAIK for the last, though precessional torque bearing load is a nontrivial consideration.
Wikipedia claims flywheel loss rate circa 2013 of 5% per day.
That compares to recent estimates of Tesla li-ion loss rates at under 5% per month -- 0.16% per day.
Amber Kinetics is one company building fixed flywheel storage products. http://amberkinetics.com/
They have one 32 kWh, 5-ton, 98% steel flywheel installation on Oahu; pictures here:
Angular momentum in 100 kWh - multi MWh rotational systems is large.
No, they're not all the same.
Compressed air, flywheel, flour mill - very dramatic events.
Lithium battery - much more mild, typically.
Gasoline - it depends.
Any tech that falls outside of the growth curve seems to run into issues with production or cost that delay it until it fits under the curve. Something cheaper and easier gets picked first.
The first modern EVs had lead acid batteries. More sophisticated than your starter battery, sure, but lead acid all the same. Which is why Tesla was a big deal. We talked about LiPo for something like fifteen years before it showed up in consumer electronics, and then they started catching on fire.
All of this stuff is painfully slow. The big story in EVs is how crazy efficient the motors can get. A company I used to follow (whose name is escaping me now) had a motor that was 95% efficient in its sweet spot. They had scaled up the design to 100 HP.
The batteries would be called Nickel-Carbon or something like that rather than Lithium-anything, if they were named by the amounts or costs of materials in them.
The big advantage there is independent scaling: peak discharge is tied to the total membrane area / pumping capability while capacity is tied to the amount of reactants that can be stored.
Not the best on technical merits alone, but good enough along with a massive force of investment and wide adoption.
I've noticed this with steel products and plastics.
Brings up one advantage batteries have, they are small. That you need to make a trillion of them works directly towards the cost being a small percentage over material and energy inputs.
So is keeping batteries up to date. Many a failure has been attributed to stuff like:
- batteries gone bad without anyone noticing over the years (lack of acid, crystallization, loose contacts, dust in cooling components, ...)
- switch-over between grid and battery inverters fails somewhere
- some part of the inverters fail when they're idling for years and then have to go into full load suddenly
A huge flywheel only needs bearing lubrication, that's it.
Batteries can and indeed do go bad without warning, but current sophisticated UPS monitoring systems are able to detect failures, track battery ages and raise alerts (whether anyone actually acts on those alerts or not is another matter...). I've also found that lead-acid batteries last longest as long as there is some amount of power continuously trickling through them - I have an APC UPS at home with its original batteries from 2010, and they still provide ~1h of runtime at 20% load. And with most DC-grade UPSen, batteries can be replaced in situ without powering the device or any connected equipment off.
Or would it just make all of the other technologies much more efficient?
On the other hand, used Li-ion from electric vehicles could be so widely available that they also win for stationary storage.
It reminds me a lot of when people pushed plastic for everything in order to save the trees and reduce paper consumption. Some 40 years later, we're now trying to get off plastic and dealing with massive environmental issues surrounding nearly every kind of plastic.
We have. We've painstakingly analysed the energy and material inputs and the pollution outputs of the entire lifecycle of a lithium battery pack. After considering all these factors, lithium batteries remain an attractive energy storage option.
>the incredible task of recycling these once they've outlived their usefulness
Recycling lithium battery packs is complex and hazardous, but no more so than a multitude of other industrial processes. There is already substantial recycling capacity, thanks in part to the EU's WEEE directive. Using existing technologies, only 1% of the pack mass goes to landfill. We can't yet recover all of the lithium in a useful form, but we can recover most of the cobalt.
Then cars came along and they were all like "Yay! The pollution problem is solved!"
I too wonder what the impact of so many lithium batteries is going to be. I mean, I know they are saying that they are extremely recyclable, and I hope that's true. But I wonder what the unintended consequences of this switch is going to be.
Maybe it's just me, but not a fan of bare links unless the URL is descriptive.
Recycled lithium is as much as five times the cost of lithium produced from the least costly brine based process. It is not competitive for recycling companies to extract lithium from slag, or competitive for the OEMs to buy at higher price points from recycling companies. Though lithium is 100% recyclable, currently, recycled lithium reports to the slag and is currently used for non-automotive purposes, such as construction, or sold in the open-markets. However, with the increasing number of EVs entering the market in the future and with a significant supply crunch, recycling is expected to be an important factor for consideration in effective material supply for battery production.
Closed loop recycling, where the recycled materials are sold back to OEMs, is likely to help against potential price fluctuation of metals or compounds. EV battery recycling is expected to play a significant part of the value chain by 2016 when large quantities of EV batteries will come through the waste stream for recycling.
This would light a home for an hour, with LED bulbs and careful usage. And all it requires is a room-sized storage tank.
So if I wanted something that ran my house all night, I'd need a storage tank larger than said house.
If you charge or discharge Lithium polymer or lithuium ion batteries "wrong" they explode too.
I wouldn't want to be near a flywheel that stores 360 Wh of energy when it breaks.
I imagine something similar could be done. It's not like there are zero safety mechanisms with compressed air.
TNT has about 1/10 the energy density of petrol or diesel. Capacitors have lower capacities than batteries.
I'm not sure they ever explode in a bomb like way?
No different than people who have LP tanks outside their homes. Or fuel oil tanks buried in their yards. Or coal bins in their basements. Or natural gas lines coming their house. Or pretty much any other storage method except a dam for your water wheel, but even that can burst and flood your home.
Worst case with compressed air is a total disintegration of the tank, the room it's in, and the rest of the house along with the occupants.
There are things you can do to make it safer, like installing the tank at the bottom of a pool or buried under a few feet of dirt, but they add complications and expense.
Spoiler alert: State of the art is 30x better
Unfortunately, these real-life steampunks (not cosplay kids) usually also would rather spend time working on their projects and not documenting them, so there's not very much on the internet compared with the number of people active in the hobby.
Keep an eye out at county fairs and small town carnivals and rodeos. They usually show up.
Do you have the equivalent of 50 LED bulbs (60W equivalent ) burning at a time? Do you consider that careful usage?
Beyond that, this is being pushed in the article as a rural/off-grid approach. For urban residential, it makes a lot more sense to centralize storage and run houses off a regular grid, than to try to make each house an independent entity.
In the medium run, we need to shift the grid itself from the current baseline+peak model to a solar+storage model (rolling wind into this), with distributed metering on the storage grid. Capture solar/wind power when the sun shines and the wind blows, and sell it when consumption outstrips supply, with pricing set dynamically on a distributed network.
Once you have that, for on-grid purposes, we'll probably see a diverse world of storage - car batteries, compressed air, industrial battery sites, water storage, thermal storage, etc.
Another non conventional way to store energy is using gravity power modules (example: http://www.gravitypower.net/)
Storing hydrogen from electrolysis via solar panels also sounds interesting. Basically once your batteries are charged you start making hydrogen.
The direct use of compressed air is interesting. Taking it to the extreme, you could have compressed air as your primary utility piped through your home, and have appliances that run off compressed air. Refrigeration cycle is compression based anyway for example. You would still need some electricity for control circuits for example, but you might be able to keep the heavy lifting air-based.
Your refrigeration example is interesting - now I'm curious if there's any refrigerators on the market that can power the compressor via compressed air intake (so it would still use closed-loop refrigerant, but the compressor would use air instead of electricity)
Picturing the different logic gates running on compressed air is a hoot.
From my armchair perspective, storying it in chemical bonds (like nature does) makes a lot more sense.
But we don't store atomic hydrogen; we store molecular hydrogen (H2).
That is, unless electricity is used to light corn crops. Still not very efficient.
In practice I think that adding the fittings and the long hose from the tank to your work area probably makes this somewhat impractical, but it's a cute idea.
The interesting part is that they are trying to make the storage adiabatic, i.e., they store the heat that is generated while compressing the air in a phase change material (i.e., a material that will become liquid when hot, since a lot of energy can be stored in phase transitions) and get the heat back to warm up the cold expanding gas on decompression.
The issue is that even with the phase change storage, heat will dissipate into the rock within a couple of days, making the whole process inefficient for long-term storage.
The low efficiency is mainly since air heats up during compression. This waste heat, which holds a large share of the energy input, is dumped into the atmosphere. A related problem is that air cools down when it is decompressed, lowering electricity production and possibly freezing the water vapour in the air. To avoid this, large-scale CAES plants heat the air prior to expansion using natural gas fuel, which further deteriorates the system efficiency and makes renewable energy storage dependent on fossil fuels.
Small-scale compressed air energy storage systems with high air pressures turn the inefficiency of compression and expansion into an advantage. While large-scale AA-CAES aims to recover the heat of compression with the aim of maximizing electricity production, these small-scale systems take advantage of the temperature differences to allow trigeneration of electrical, heating and cooling power.
I don't know if it ever became anything, though.
As much as people consider the oil industry a bunch of evildoers, it is always at the forefront of the absolute latest in tech. Hard problems + money does that.
Air brakes on trucks run in reverse. Compressed air releases spring pressure therefore releasing the brake.
I think pneumatic brakes almost universally work this way, because it's fail-safe w.r.t. line leaks. E.g. in trains the main air line is for powering pneumatics as well as releasing brakes; at nominal pressure (8-10 bar iirc) the brakes are released, at lowered pressure (3-5 bar) the brakes are fully applied. If the line ruptures or the train splits all brakes across the train are fully applied.
> Almost any electrical appliance can be adapted to work off of alternate power, such as compressed air. Some Amish women have been using compressed air to power blenders in the kitchen for years. In one house, compressed air powers a water pump, sewing and washing machines, and drills and saws in the shop. Some Amish businesses have as their specialty adapting such appliances so they can be powered by compressed air.
They also have quite a few interesting compressed air kitchen appliances...such as mixers, grain mills.
A compressed air tank is arguably less of a bomb than the battery under your feet in a Tesla and the cleanup is much better.
Compressed air tank failures do not result in instant fire. Most failures take the form of leaks. Catastrophic failures of properly designed pressure vessels operating at their intended pressure are basically nonexistent because a damaged pressure vessel will usually fail by leaking at the point of damage.
Compressed air, however, does explode out of any weakness in its fittings, often with no warning. Catastrophic failure of a weak joint, coupled with a pressure difference of several atmospheres, can turn any ejected fittings into artillery shells. There's plenty of videos of air compressor explosions on YouTube. Yes, this is considerably rarer than a lithium battery fire, but don't forget that lithium batteries are relatively new to the scene. Compressed air has been in use for hundreds of years and the dangers, despite being understood, are still present. A lot of them stem from human overconfidence, and the attitude of 'eh, one more bar can't hurt, can it?' Even a small workshop compressor operating at less than 10 bars can cause life-changing injuries to anyone present should it fail. I'd argue cleanup from these types of failures are much, much messier than lithium fires.
The comparison to lithium batteries is pretty accurate because unlike gasoline, a spark is not necessary to start the fire. However, a lithium battery fire can generally be spotted by temperature rises before it becomes dangerous. Failure of a pressure vessel is much harder to predict. Just a tiny manufacturing defect in a square-centimetre of a pressure vessel can create a weak spot that'll be the first place to fail as it comes under operating pressure, or cycled repeatedly.
Don't get me wrong, I'm interested in off-the-grid living and had not considered compressed air as a power source until reading this, but I do feel the article skips over the safety aspect of compressed air. There's a reason many of the fittings are only sold to industries - used improperly by amateurs, the pressures they're discussing could be fatal if something goes wrong. My advice to anyone reading this article is to fully understand the dangers of compressed air before building something like this.
Gasoline, on the other hands, just burns in a hot concentrated fire. It takes entire minutes to kill that which is nearby.
There is very little outside compressed gas that can explode disastrously without oxygen. A tank of compressed gas is probably high up on the 'bomb in the house' category. Just under the water heater I suppose.
Its also interesting that we're only talking about 116 PSI - I'm guessing CFM is more important.
> A simulation for a stand-alone CAES aimed at unpowered rural areas, and which is connected to a solar PV system and used for lighting only, operates at a relatively low air pressure of 8 bar and obtains a round-trip efficiency of 60% -- comparable to the efficiency of lead-acid batteries. 
However, to store 360 Wh of potential electrical energy, the system requires a storage reservoir of 18 m3, the size of a small room measuring 3x3x2 metres. The authors note that “although the tank size appears very large, it still makes sense for applications in rural areas”.
This benefit alone would make me hope for compressed air energy batteries to receive tons of funding, and become cost-competitive with other forms of batteries.
Also, consider that there are three important elements in a battery "economics":
1) Weight / energy density - how much energy can you store, per weight of the battery? Important for cars.
2) Volume / energy density - how much energy can you store, per volume of the battery? Important for cars as well.
3) Cost / energy stored - how much does it cost to store a unit of energy? This can also be divided into two elements: setup (e.g. the cost of producing the battery and deploying it) vs maintenance (how much does it cost to keep the battery alive, over the years?)
There are also other minor factors, such as reaction to environmental changes (e.g. temperatures, etc).
It might work for some applications, but in 120 years we haven't been able to make it work for cars, at least.
There's also a few articles on the website about compressed air cars and city-wide infrastructure
Ok, but has anyone worked on the problem in the past 120 years?
Using wind power to compress into high pressure tanks, then when you need extra energy you pull it out and pipe the air expansion pipes through heat exchanges in the data center. That way heat from the data center goes to warming up the air (better efficiency when you feed it to the turbines) and it cools the data center which is part of what one might use the energy for in the first place.
If you put the air expansion pipes in a conveniently located source of water you could chill that water to freezing.
Compressing air into the data center however would not be a win. During compression the air gets hot. In the system that I was pushing the compressed air tanks were outside in the wind so that they were benefiting from the cooling effects of the same wind that was pumping air into them.
For alternatives, my money in the long run is on molten salt batteries  for large scale. Technology also has benefit of increased industry knowledge of how to utilize molten salts safely which will benefit LFTR research.
It also makes sense for oceanic wind turbines, which can use periods of high wind vs low demand to pump air into large under-sea air storage bags, using the sea as free cooling/heating towards isothermal operation.
The title of the article strikes me as one of those marketing titles possibly planted by a press release. Position the competing product as if it’s somehow bad. “Protein-free!”
I’m not buying it.
There's a retrofit for garbage trucks that pays for itself in 2 years, or you can buy them new.
EDIT: Not really used as a battery, but probably could be.
Wait, did you read the article? :)
Wait... wait... I'm... not sure I believe the extend of this statement. If this isn't wrong it's certainly awkwardly worded.
- A 2005 study demonstrated that cars running on lithium-ion batteries out-perform both compressed air and fuel cell vehicles more than threefold at the same speeds.
- A 2009 University of Berkeley Research Letter found that "Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix."