PowerSwitch

Report here
http://www.bbc.co.uk/news/science-environment-19785689

Not a source of energy of course but a potential means of storage.
No rare or costly materials are used, but a lot of high technology is involved in cooling air to liquify it.
The cooling process makes a lot of low grade heat which is unavoidable waste unless some demand exists for low grade heat (water distilation ? greenhouse heating ?)
Heating the air to turn it back into high pressure gas produces a lot of "cold" which is again a waste unless some demand exists for this cooling. (bulk frozen food stores? cooling a large data center? central air conditioning for a business district?)

In another thread, the coming shortage of helium is noted, this element being a by product of natural gas production.
Helium exists in the air, but only in minute volumes. In principle it could be extracted from the air, but in practice the process is totally uneconomic on account of the vast volumes of air that must be liquified in order to extract minute amounts of helium.
If however large volumes of air are being liquified in any case, then the extraction of helium and other rare gasses might become more economic.

On another forum some chaps are advocating using unpopular wind turbines unreliable irregular output to be used to split water into hydrogen and oxygen which can then be stored in vessels and burnt when needed to generate power at peak times ???

northernraider wrote:On another forum some chaps are advocating using unpopular wind turbines

Only the unpopular ones? How do you decide which ones to use then, as many are popular with some people, and unpopular with others .

The Institution of Mechanical Engineers says...

Ah! Toys for the boys then!

mobbsey wrote:

The Institution of Mechanical Engineers says...

Ah! Toys for the boys then!

Yes, there is no reason that it should not work, but it is debatable if such cost and complexity would pay its way, or even if if we need such storage at all.

Variable output hydroelectric plant, import/export, demand side control, and the meeting of peak demand by natural gas burning are all possibilities that are probably cheaper and/or simpler.