Energy companies testing "liquid air" as a means of storing backup electricity

May 22, 2013 by Bob Yirka weblog

(Phys.org) —Highview Power Storage, a British company that develops energy storage systems for utility companies has received $18 million in funding from several backers to investigate the use of "liquid air" as a means of storing electricity for backup purposes. Liquid air is air that has been chilled to the point of liquefying—when warmed it expands, allowing for the possibility of driving turbines to create electricity.

One of the main problems with most is that they can't produce electricity all the time—only when the wind is blowing, for example, or when the sun is shining. Because of that, developers have created energy backup systems. Such systems can store excess electricity for use when the primary source is unavailable. Most current systems rely on batteries, which work very well, but can become costly in the long term. Highview Power Storage is looking at using electricity from the grid to cool air till it liquefies, then storing it in huge tanks until it is needed.

The process is both simple and inexpensive. Air is pulled in from the environment, cleaned to remove C02 and (both freeze to a solid) and then chilled to -310F (-190C). The liquid is then stored in vacuum sealed tanks. When the need arises, the liquid is exposed to warm air, causing it to expand and in so doing, drives a that creates electricity. The whole process has been found to be approximately 50 to 60 percent efficient, which means heating the liquid air creates just over half as much electricity as was used to chill and store it. That's not very good compared to batteries, of course, which are typically 90 percent efficient, but liquid air has other benefits. Foremost among them is that liquid air can store power for decades, while batteries need to be replaced periodically. Storing air is obviously a lot cleaner as well.

Highview isn't the only company testing liquid air as a —Berkeley California based LightSail announced recently that it had raised $37 million to study the use of liquid air as a means of storing electricity. SustainX, based in New Hampshire also recently announced it had raised $20 million to do the same. In related news, engineering giant Ricardo is currently testing the possibility of using liquid air to power automobiles, though they remove the oxygen, leaving just liquid nitrogen.

Explore further: Intelligent façades generating electricity, heat and algae biomass

More information: www.highview-power.com/wordpress/?page_id=67

via TechnologyReview

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tadchem
2 / 5 (2) May 22, 2013
Cryogenic processes are typically very energy-intensive. The heat produced by the system is far less than the energy required to chill AND condense the air into a liquid, so the major energy input to the system is not ambient heat input from the atmosphere but the grid power used for liquifaction.
Add to that the complications of the special materials required to operate a process at cryogenic temperatures, and the engineering required to deal with the chemical and physical hazards of liquid Oxygen (liquid air fractionates upon evaporation).
antialias_physorg
3.8 / 5 (4) May 22, 2013
The whole process has been found to be approximately 50 to 60 percent efficient

Which isn't stellar but not bad for such a simple technology. Better than shedding the excess production from wind/solar at any rate (and considerably more scaleable than batteries)

And since energy prices fluctuate considerably between day and night, with a few percent more efficiency one could make a profitable business buying/storing energy during high availability times and selling it back when prices are high.
indio007
1 / 5 (6) May 22, 2013
Pump the air into the depths of the ocean and use it's crushing mass to aid compression.
antialias_physorg
4 / 5 (4) May 22, 2013
Pump the air into the depths of the ocean and use it's crushing mass to aid compression.

While there are proposed (and pretty cool) schemes where air is pumped into undersea storage
like this:
http://phys.org/n...bed.html
...it isn't for free: Pumping the stuff down requires energy (because you are pumping against the crushing force of the water down there). The forces down there don't aid anything in terms of efficiency. The thing they do help with is in making your needed storage tank smaller.

Also (significant) 'depths of the ocean' usually aren't anywhere close to where the producers and consumers are. So you'd have the added losses of getting the energy to and from your storage area.
Jeddy_Mctedder
1 / 5 (3) May 22, 2013
Energy storage economics isnt about energy efficiency its about economics. Liquified air is VERY ineffiecient but compressors and insulators are cheap.

Qhat are your alternatives? high pressure systems like compressed air? More effiecient sure. Cheaper per MEGAwatt hour stored....NO. Liquified molten salts? Low pressure steam? Many other heat repositories have been tried....as liquid electroactive batteries and other expensive methods are being experimented with. Let alone 'smart grid storage in electric car batteries. $$$$$$
antialias_physorg
3 / 5 (2) May 22, 2013
Exactly. You have to look at how it scales.
Batteries scale linearly (want 2x the energy storage? Need 2x the batteries which translates into 2x cost)

Compressed air (and especially liquid air) scales better. Want 2x the storage? The most important/costly part (the generator/liquifier) doesn't cost anything extra since no matter how small or large your storage you only need one (though having more at some point may be advisable - but it's not strictly necessary). And the cost of the reservoir for 2x storage just scales with the cube root of 2x.
ValeriaT
1.1 / 5 (9) May 22, 2013
Wouldn't be cheaper simply to invest into cold fusion research and to forget all these nonsensical salary and job generators masked for research?
hangman04
1 / 5 (2) May 22, 2013
the only problem i see is that for example you produce solar energy at lets say 15% efficiency. some of it goes directly into the grid while the excess is stored. but you loose another 40% while storing.
Doesn't this drop over all efficiency from the starting 15% to 10% lets say? :/ or i missed some facts....
NoTennisNow
1 / 5 (1) May 22, 2013
not to mention hydrolosis of water and then combustion or fuel cell. use cheap energy when available and use the H2 to generate electricity at peaking times. this is the payback.
antialias_physorg
3.7 / 5 (3) May 22, 2013
Wouldn't be cheaper simply to invest into cold fusion research

Since the output of that is nil - no (How many times has rossi announced great revelations in the past year alone? 3? 4 times? And still nothing. Once a fraud - always a fraud. )
ValeriaT
1 / 5 (6) May 22, 2013
And what do you expect? Piantelli published hydrogen fusion at nickel in dozen of articles - none of them has been replicated with mainstream physicists during last twenty years. Physicists do realize very well, they would lose jobs in existing research, if the cold fusion would be proven feasible.
antialias_physorg
3.7 / 5 (3) May 22, 2013
20 years of papers - and not one demonstrator?
You know: people can write down a lot of stuff - but merely writing it down without showing that it works experimentally doesn't make it any less BS (just look at your endlessly repeating posts)
ValeriaT
1 / 5 (6) May 22, 2013
people can write down a lot of stuff - but merely writing it down without showing that it works experimentally
I don't quite understand the meaning of your post - all articles of Piantelli and Foccardi were experimental only, they didn't provide any theory. How the scientists are supposed to show, their experiments work if not with writting of articles? Are CERN physicists supposed to organize the public demo of Higgs boson in TV News for being considered seriously?
djr
5 / 5 (1) May 22, 2013
Valeria: "How the scientists are supposed to show, their experiments work if not with writting of articles?"

How are the scientists supposed to know if their experiments work if they don't build a working prototype? Otherwise it is all theory - and no verification. If it does work - they can patent it - and then release the results for the world to check it out. We are still waiting on Rossi - don't hold your breath.
djr
not rated yet May 22, 2013
Hangman: "Doesn't this drop over all efficiency from the starting 15% to 10% lets say? :/ or i missed some facts"

Looking just at efficiency numbers can be misleading. The economics seems to be much more important in deciding the viability of systems. Think about a gallon of gas from tar sands - you have to dig it out - heat it to seperate it - transport it to a refinery - refine it - transport it to a gas station - and then the automobile engine is just 25% efficient. We do it - because the economics make sense.
sender
2.5 / 5 (2) May 23, 2013
Utilize Stirling Coolers on an Industrial Scale, welcome the cool revolution!
alfie_null
not rated yet May 26, 2013
So, if the physicists wouldn't behave like the ignorant imbeciles living in their ivory towers, we could have cold fusion developed for seventy years already and we would never solve the questions, like the utilization of cooled liquid air in automobiles (not to say about fossil fuel wars, which would never happen). The contemporary energetic and subsequent financial crisis is just their job.

Physicists are responsible for the world-wide recession?

What I take from this is that you are frustrated and angry. You go to great lengths to come up with reasons why things are that don't include the possibility you are wrong.

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