Guest essay by Eric Worrall
Hydrostor has created an interesting innovation in energy storage. The energy is stored as compressed air, in giant underwater balloons.
Hydrostor’s system works in several steps. Electricity is run through a compressor and converted into compressed air. This compressed air is then sent underwater.
“There, we have a whole series of what are effectively balloons, that fill… like lungs under a lake,” he added.
“They fill with air, and when they’re full you stop charging the system and it can sit there indefinitely. When you want power back, again, a valve opens … air comes rushing out, we run through a low pressure turbine called a turbo expander, and that reproduces power back to the grid.”
Energy storage is becoming increasingly important. In the United States, the Office of Electricity Delivery & Energy Reliability states that the development of technology to store electricity so it’s available on whenever it’s needed would be a “major breakthrough in electricity distribution.”
Read more: http://www.cnbc.com/2015/12/09/underwater-balloons-clean-energy-savior.html
This isn’t the first time I’ve heard of storing energy with compressed air. Hydrostor’s innovation is to reduce the cost, by using water pressure to maintain the storage compression, without the need to create high strength pressure containers.
Using water to supply the pressure to collapse the balloons might also improve the efficiency of energy retrieval. By storing the air underwater, and using the water pressure to collapse the balloon, the air would be retrieved at a near constant pressure, until the balloon was empty. Hydrostor claim an efficiency of 60 – 80%.
Hydrostor seem to be aiming at grid stabilisation rather than storing multiple days worth of grid supply, so it seems unlikely this proposal, as it stands, will fully solve the renewable intermittency issue.
Could compressed air storage be scaled up enough to solve intermittency? Even if you had enough renewable capacity to cover 100% of grid requirements, on average, if you wanted to go further than Hydrostor’s current plans, to completely eliminate the need for backup gas turbines for renewables, you would need to store enough energy to maintain full grid supply for at least a day, more likely several days.
My concern is energy stored as compressed air could, in principle at least, be released all at once, in the event of a storage system failure.
Imagine you wanted to store one day worth of energy to supply a major city, in case the wind didn’t blow that day – enough energy to maintain a 1 gigawatt supply to the grid.
To maintain a 1Gw supply of energy for one day, your storage solution would need to store;
1Gw x 1 day
= 1000,000,000 W x 86400 seconds
= 86,400,000,000,000 Joules of energy
= 86.4 TJ.
This amount of energy is the same magnitude as the energy released by Little Boy, the nuclear bomb which destroyed Hiroshima (63 TJ). An abrupt release of 84TJ of energy next to a populated area would cause serious damage.
How would such a release of energy manifest? During the Lake Nyos disaster, when 100,000 tons of volcanic CO2 at the bottom of Lake Nyos was abruptly released, the rising gas created a 25m Tsunami which did extensive damage to the thankfully mostly uninhabited shoreline.
In the case of Lake Nyos, the Tsunami damage was secondary compared to the lethal effect of normal air being displaced over a large geographic area, by an asphyxiating cloud of concentrated CO2. But a large Tsunami smashing into a densely populated coastal city, adjacent to the storage facility, could still cause serious loss of life, even if the gas bubble which created the Tsunami was breathable air.
Risk concerns aside, in my opinion Hydrostor’s solution is still a very interesting innovation. Storing energy underwater, utilising the natural pressure of the water, should substantially reduce the cost of creating storage “balloons”, compared to other schemes for using air pressure for energy storage, by dramatically reducing the required strength and potentially the cost of the materials used to construct the pressure containers.
Don’t forget the barnacles and other crustaceans!
I wonder what a large lobster might make of this, or even
a large shark? Snip-snap, Gnash-slash, Oops-bang ?
Great White sharks especially have been know to tear “rubber”
boats to sheds. Marine boring worms? Limpets will eventually
grind deep grooves into the surface and weaken it, perhaps.
But in the sea these people imagine, it is just an imaginary sea
in some computer model maybe, and they can just turn off the
Crustaceans etc., and even turn off the corrosive chemicals.
This won’t be so easy with the actual real sea though.
Wouldn’t all those inflated balloons cause the water level to rise? Another example of ‘it’s not a crime when we do it’.
Isn’t this just a more complicated way of implementing a hydro solution?
Instead of raising all the water up a hill you raise some of it at the bottom of a lake.
No this is a pneumatic system, which is being proposed.
Still there is no “free lunch” and the energy losses, plus
the cost of infrastructure, and inaccessibility of working
parts, as well as the highly corrosive environment in the
sea, makes this impractical at best, and horrendously
costly into the bargain. Frankly there are easier ways
to “store” large scale electrical energy than this, but
all of them do incur large scale energy losses as well.
The “Giant Crystal” seemed promising some years ago,
and what became of that “breakthrough” in energy storage ?
Then there were the “Photonic Crystals” that could store
“Light” from a heat source, what happened to that ?
You see maybe those folks should have said it
was all about saving the planet from the daemonic
CO2 Gas …aaaaarrrrgggh ! Then they would have
had as much funding as Solyndra …. oooeeerr !
Electricity is only part of the energy picture. Transportation requires the ICE for power density, flexibility, tonnage, and range.
Not as silly as the Kilometer high granite piston raised by water pressure, but less efficient then the molten salt converted coal power plants. This CAGW scam sure brings out the crazy ideas.
I like the “Water Hyacinth” idea. Supposedly the World’s fastest growing plant, You just set off in a boat, and rake them up, dry and burn them. Next day there is just as many as before, they grow so quickly. Trouble with that idea is you might need hundreds of lakes, the size of Lake Superior, and the plant only grows in the tropics. Ah well it seemed a good idea, at least for those living around Lake Victoria. The plant is a menace to the environment now, and out competes other plant species, The UN & World bank has spent Millions trying to eradicate the plant. But just rake it up and flaming well BURN IT IN FURNACES, to MAKE ELECTRICITY, also FERMENT IT IN VESSELS to MAKE BIO-GAS for cooking and transport.
Still the UN and other halfwits, are trying to kill this plant off by using poisonous herbicides and infesting teh lakes with foreign predator insects, and so on. Hundreds of Millions wasted by imbeciles on half baked nonsense, when the answer to several local problems is STARING THEM IN THE FACE.
Who are these fools that decide crazy policy ?
The local people should not wait for UN approval,
just get in the boat, collect a load of Water Hyacinths,
and get started on your own local bio-gas business.
Are there any readers from the Lake Victoria area in Africa ?
Perhaps they might tell us what is happening with Water Hyacinth Power..
I worked near Lake Victoria years ago. Solutions to world problems are not being hatched in that country. They can’t even solve their own problems.
“Trouble with that idea is you might need hundreds of lakes, the size of Lake Superior, and the plant only grows in the tropics.”
Use Sargassum seaweed instead. It floats on seawater in the tropics. Just put some in a net bag and attach it to a bouy. Come back later and collect the excess We have plenty of tropical ocean available to do this. It aso grows very quickly.
Sargassum doesn’t cover the ocean because currently move into colder water where it dies or the accumulation of barnacles and corals causes the Sargassum to sink to the bottom . Putting it in a net bag attached to a bouy will prevent it from drifting into cold water and regular harvesting would prevent it from sinking.
Also you would not need hundreds of lake superiors 3 or 4 might be enough to meet much the US natural gas demand. At one time the American natural gas association calculated that 23 quadrillion BTUs of energy could be created by harvesting kelp off the california coast.
OK Water Hyacinth don’t just grow in the tropics. Some missionary’s wife thought the flowers were pretty so she brought some back to the US and let it escape into the wild. It is now the bane of the southern states boaters, ecologists and fisherman since it covers vast numbers of lakes and ponds.
The Florida Dept of Agriculture has spent millions trying to come up with a way to 1) get rid of the stuff or failing that 2) find some economic use for the stuff. They even invented floating hyacinth harvesters to collect the plants. And so far as I know they only method they found to dispose of the stuff is to try to make cows eat it. Cows apparently don’t much care for the taste.
You can’t economically burn the stuff since it is 90% water and the energy required to dry it to a burnable condition vastly exceeds the energy recovered by burning. You can’t practically spread it on the ground to dry since that would take square miles of drying racks.
I’m sure that this applies to any aquatic plant.
This is a net consumer of energy just the same as pumped storage is. Do we have that much “clean energy” to throw away on this stuff?
This company has no idea about the real world energy losses involved. Real world compression pumps run between 65% and 90%, with most topping out at about 80% to 85% efficiency, with 75% being a decent real world average of the varying types of pumps. This includes gas friction within the compressor, the mechanical losses (bearings, friction, seals, etc.), and gear-box losses.
So, right away, one loses 25% of the energy, simply and ONLY at the compressor. Then we have to add in the pipe head losses – both incoming and outgoing, the heat losses, and overcoming the pressure of the water outside the balloons.
This last is no little thing. The balloons will not inflate against greater water pressure from outside. (And if they don’t inflate, then why even use balloons instead of simple storage tanks on land?
At every stage of this pie-in-the-sky idea, there are energy losses, and it seems to portray all of this as 100% efficient. It is anything BUT 100% efficient.
The energy taken out will be much less than put into it. All in all, perhaps less than 50% available. This is a non-starter to anyone who has to deal with system efficiencies.
The amount of work done just to inflate the balloons is incredible. And that stage alone will run at best at perhaps 65% efficiency, what with the heating up of the gases – which itself is LOST ENERGY. They are never going to get that energy back out of the system. So for every 1,000 kilowatts put into it they are losing 250 kilowatts. HOW is that supposed to be a good system? ONLY if there is so much energy being produced essentially for FREE does it make any sense. Because if they have to PAY to produce the electricity to drive the compressors, it’s a losing cause.
Energy and cost-wise, the faster it goes the behinder it will get.
Better to simply shut off the valves on the inlet end and not run any gases through this system at all. And then scrap all the equipment or sell it all on eBay.
“The energy taken out will be much less than put into it. All in all, perhaps less than 50% available. This is a non-starter to anyone who has to deal with system inefficiencies.”
And yet people found cars (30% efficient at best) very useful . Incandescent light are also very inefficient (about 10%) and yet we have used them for almost 100 years. Just because something is inefficient doesn’t mean it is useless. Blissfulness primarily determined by a systems coast benefit analysis. If you have excess energy and CAES can store it at a ,lower cost than the compititionm it will be used.
Yes that’s true but cars can use a cheap high density fuel to get around their inefficiency, aka gasoline or diesel. Lamps are supplied mainly by cheap high density fossil fuels or nuke plants for the most part. Power plants make mighty efforts to recover a tenth of a percent of efficiency. And so do auto manufacturers (increased mileage).
So you are trying to replace cheap high density fuel with expensive low density and unreliable solar or wind power. When you go that route every tenth of a percent of efficiency counts much more.
Incandescents are 10% efficient only when you’re not heating your home. When you are (as I am 7 months of the year), they are 100% efficient.
As a heating system, you need to take into account:
– the normal heating system (thermal heating is less “efficient” in term of energy than electromotive heating, but more efficient in term of entropy)
– where the lamp is (floor is better for convective heating)
– radiant vs. convective heating
Conceivably, the “balloons” could be made of graphene, which is incredibly strong a durable and also is impervious to gas molecules. If we can only learn to make graphene in large sheets economically and deal with its thinness.
It would seem that moving the contaners up would be the equivalent of any pump needed to release the stored and pressurized gas as it expands.
“Conceivably, the “balloons” could be made of graphene, which is incredibly strong a durable and also is impervious to gas molecules. ”
The balloons don’t need to be strong. The pressure on the inside and outside of the balloon is the same so very little stress will be on the balloon. A thin steel or concrete can with a open bottom would work. Most of the stress is on the the Anchor which would have to hold it down. We have built very large Anchors to hold floating oil platforms in place so the anchor is not a show stopper.
huh wonder what an errant anchor drop (they do break off chains) or incorrect anchor drop would do….
Ruin somebody’s day no doubt.
Of course this uses up energy
Energy is lost when air is compressed, through leakages and when converted back again.
But all energy is wasted if it is generated when there is no demand for it.
So if you have a system with lots of investment in unreliable energy sources (like wind and solar) then this may have a place.
Better to not have such a system, of course, but many countries have been ill-advised.
Leakages are a minor part of the losses. When you compress air you generate a lot of heat and that energy is lost to the environment. When you expand it you have to put heat back as the temperature drops. You had also better dry the air or you will get the outlet lines plugged with ice. Compressed air is a TERRIBLE storage medium.
A much more promising concept (which is not to say that it would be competitive with fossil fuels) is underwater concrete spheres that the water is pumped out of when there is power available, and allowed to run back in through when power is needed. Basically it is pumped hydro storage using the depth of the ocean rather than the height of mountains.
http://dspace.mit.edu/handle/1721.1/78934
http://earthtechling.com/2013/04/floating-wind-turbines-with-undersea-energy-storage/
This is a similar concept yet with much larger storage capacity.
https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
This is the largest pump storage facility in the world.
https://www.google.com/search?q=bath+county+pump+storage&rlz=1C1PQHA_enUS615US615&espv=2&biw=1093&bih=514&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiqpvWE8dbJAhUBR2MKHTAqD7UQ_AUICCgD
Here are many pics of the Michigan facility.
https://www.google.com/search?q=Ludington+Pumped+Storage+Power+Plant&espv=2&rlz=1C1PQHA_enUS615US615&biw=1093&bih=514&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjHy9n57NbJAhVS6WMKHcE1DU0Q_AUICCgD
These days the creator of an idea doesn’t need to genuinely interest themselves in whether the idea will potentially lead to a commercially viable system which generates or stores energy at a competitive cost per generated watt or stored joule.
An idea is “successful” for its creator as soon as govt. agencies or gullible investors can be convinced to pour cash into the pockets of the creator.
And the govt. is now the first port of call. Since the ideal investor is one who is infinitely gullible, with access to infinite funds. The govt. comes damn close to meeting those requirements.
Intriguingly though, once a person has obtained a multi-million DOE grant or similar, then investors of private money seem to be reassured that the project is legit. They seem to treat this a proof of “due diligence”. It is anything but.
They do not seem to have learned that the DOE is even more gullible and even more fast-and-loose with “other people’s money”, than even they are with their own.
The Solyndras are going to keep coming until someone patches the faucet.
Good point inde. I have been amazed that the communist societies have been able to feed themselves at all with the kinds of things you wrote about going on in a much larger scale. Most beaurcrats haven’t a clue how anything except the human mind works.
But then, ironically, they were equally mystified as to how capitalist societies worked.
As illustrated by the oft quoted question from a Soviet official, “Who is in charge of the bread supply to London?”
This quote seems to now be at the start of every article on “free market” solutions. For example:
http://www.ft.com/cms/s/0/61a032ac-8939-11dd-8371-0000779fd18c.html#axzz3uOXv1rJ4
Seems like it can only store as much energy as the volume of the balloon multiplied by the geopotential energy due to the height of the water column above it. In other words the same as classical pumped storage which requires a large enough reservoir at the top of a local mountain of sufficient height.
Except now you have to economicallybuild a whole bunch of interconnected underwater balloons a long way underwater with the cumulative volume equal to a valley-sized reservoir. Good luck with that.
Assume an offshore 1 GW day facility at 1000 ft. How big would the balloon have to be. Just need some feel for the scale.
There are tunnels around that are built in sections in a dry dock, towed to where they will rest on the ocean floor, flooded, and sank. The sections are bolted together and then pumped out. The builders of these tunnels must have solved the bouancy problem.
This idea further raises the already unsustainable cost of wind electricity.
There was a plan back in the late 60s to fill vast reservoirs near the Great Lakes at night by pumping the water while electrical use was low and then run the water through pen-stocks when there was peak demand during the day. So this is not a new idea just more recycling of an old one. Toronto Hydro is running a test of the system…it will be interesting to see if it is cost effective, which was the major hit against the water idea.
Pump storage was considered by the local utility – until the boaters & fishermen got their panties in a knot over the fluctuations in the reservoir level.
Rube Goldberg would be proud, just a few additional complications to round out the idiocy of the whole project and it would be perfect.
What appears to be overlooked is the buoyancy of these balloons. They would need to be massive. How do you anchor them to the seabed or lake bed. To store worthwhile energy they would need to be in deep water . Seawater increases in pressure at approx. 0.5 lbs per foot of depth. At a depth of 500 feet (a common offshore oilfield working depth) this would give a 250 psi pressure at the surface. To get worthwhile energy the pipeline infrastructure would need to be enormous. I don’t think this is a winner
Have a pipe 20 meter in diameter and 1000 meters long made with 1/2″ walls.
Have one end capped.
Made from marine steel it weighs about 6300 tonnes.
It basically it difference kind of ship and you make it as you make ships in shipyards.
Once made in shipyard, you put temporary plug in open end- inflate a balloon to seal
the end. So you launch it into the ocean, and tow it to so location [in deep water].
Once towed to some spot, remove the temporary plug- deflate balloon end.
Then the ocean water will enter the pipe,
What will happen is water will enter the open end and air will trapped by closed end, and it will
flip vertical.
So you have 900 meter of pipe submerged and 100 meters of pipe above the waterline.
Now rather than store energy, I would use this pipelauncher to launch rockets into space.
Or one charge about $100,000 or more to accelerate rockets by about +100 mph.
One accelerate a rocket by making the pipe go up vertically.
By added or removing air from inside the pipe and pipe will go up and down.
And the air pressure inside the pipe remain constant.
And it floats by having enough air pressure to push the water inside the pipe
below the waterline. And one need 1 atm pressure to push the water inside
the pipe, 10 meters below the waterline.
Or having water depressed below the waterline this causes displacement.
So ships can displace +100,000 tons, but this type ship displaces less- tens
of thousands of tonnes.
The 20 meter diameter is has area of 10 meters squared times pi:
314.16 tons per 1 meter of depth, or 3141.6 tonnes per 10 meters which requires
14.7 psig.
Since it weighs 6300 tonnes, this means it has have enough air pressure to lift
this weight: 6300 / 314.16 is 20.05 meters . So needs about 30 psig to float,.
If instead one adds 60 psi. it will have 6300 tonnes of upward force.
The gross mass of Saturn V [largest rocket to ever fly]: 2,290 tonnes.
So this require 60 psi to go up at 1 gee acceleration and to lift addition mass of
rocket at 1 gee acceleration requires more than 60 psi.
To add the needed air [one needs a lot]. One pour liquid air into the water inside
the pipe- the warm sea water will vaporize the liquid into gas. And to use less
liquid air, you also heat the air with burner- so a max average air temperature over a period
of couple seconds could be 100 C.
Without considering mass of rocket, if one adds enough air so there is constant pressure
of 60 psi, the pipelauncher will accelerate upwards at 1 gee. And waterline level inside the pipe
with constant pressure of 60 psi will cause water to be 40 meters below waterline.
So keeping waterline constantly at 40 meters below waterline cause pipe to go up vertical, at speed like jumping off an office building.
But anyhow, as far as underwater balloon. if had 30 psi with the pipelauncher and the top was floating say 5 meter above the water, and removed air so it top was barely floating above the water. And then put say 100 tons of concrete on top of it. Then it sinks.
And as it sinks, the air inside become more compressed and it sinks faster [and faster].
And were that to continue falling say 4000 meters below the surface, the air would compress until
it was a liquid. and might impact the ocean floor at around 100 mph.
Were you to add some helium inside the pipe, it could un stick itself from ocean bottom, and rise
upward, gaining speed until it flew out of the water.
Rube Goldberg is right How many levels of primitive and unrealistic logic is involved in all this? First the
technologically primitive wind and solar (unreliable )power generators, then we try to avoid their disadvantages by creating more primitive technology “solutions”, which, by the way,, are not solutions at all. The wind might not blow for weeks or even months, and the skies can be cloudy for weeks as well. Storage systems STORE energy , they do not generate energy and they can’t store very much of it, and if something happens and all that stored enegy is used up, how are you going to both supply the grid and restore the storage when the winds blow again or the skies clear? This is elementary school logic. Compressed air storage has been atempted using abandoned mines, andthe problem was that when compressed air is released , it becomes cold and loses energy. Natural gas warmers were used to heat up the air that was released to drive turbines.What a joke – using fossil fuels to make a non-fossil fuel system work efficiently (more or less). So far , compressed air as a storage medium (for cars, energy, etc) has been a big bust.
Thank you, Prof. Irwin Corey.
Promises are sooo cheap aren’t they? http://finance.yahoo.com/echarts?s=TATAMOTORS.BO+Interactive#{%22range%22:%221d%22,%22allowChartStacking%22:true}
When you consider the efficiency of compressors not to mention the turbines sounds really energy wasteful.
Couldn’t they at least tie the balloons into interesting shapes like giraffes, flowers, bunnies, etc?
Now, that’s the only sensible suggestion on this thread.
All of a sudden, this looks to be doable.
You really should present that on Indiegogo-a-gogo.
With a flashy video.
It’s going to be the next “solar pavements” smash money-spinner.
i’m jealous of you already. I hope that you have the patent rights sorted.
Mark and two Cats – Make the balloon shapes look like polar bears and you’ll get your funding!
I’m really bad at animal shapes… 🙂