[HN Gopher] Lifting heavy bricks to store renewable energy
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       Lifting heavy bricks to store renewable energy
        
       Author : sieste
       Score  : 6 points
       Date   : 2022-03-20 20:26 UTC (2 hours ago)
        
 (HTM) web link (www.cnn.com)
 (TXT) w3m dump (www.cnn.com)
        
       | ncmncm wrote:
       | We have much better storage methods. The most mature is "pumped
       | hydro" to a water reservoir up a hill. (Not the same as a
       | hydroelectric dam, which needs, and damages, a watershed.) We are
       | building liquidified-air storage. (Liquifying air is very mature
       | tech.) We are preparing underground hydrogen repositories, in
       | places where we had been used to banking natural gas. We are
       | building ammonia synthesis factories.
       | 
       | Less mature tech is also ramping up. We are building out
       | factories to build out iron-air batteries. A 20,000 ton weight
       | suspended on cables in a deep mine shaft. Pumped hydro from a
       | deep earth cavity. Pumped hydro out of deep ocean tanks. Methane
       | and kerosene synthesis.
       | 
       | The most remarkable quality of energy storage tech is how its
       | cost is plummeting even faster than solar and wind generation.
       | 
       | The chemical synthesis and liquified-air tech is interesting in
       | that the production apparatus remains useful even after the tanks
       | are full, and building out tanks for more storage is very cheap.
       | They call attention to the separate qualities of storage that
       | will be optimized for each use: (1) How fast can it bank energy,
       | (2) how much power can it release when needed, (3) How quickly
       | can power output be adjusted, (4) how much of the energy you put
       | in do you get back, (5) Is the storage medium or equipment useful
       | for more than storage, (6) Is the stored energy transportable?
       | 
       | Places at high latitudes, and in general places where the mix of
       | renewables and transmission-line power are not stable enough, can
       | still ship in and stockpile chemical storage banked in places
       | with reliable power. Equatorial, coastal desert land will be an
       | excellent place to site solar collection for this purpose:
       | Coastal Peru, Boa Vista in the Cape Verde Islands, coastal Mali
       | or Senegal, numerous sites on and near the Arabian peninsula and
       | the Horn of Africa, northwestern Australia. Other coastal sites
       | with reliable wind, likewise. (Political stability is likely to
       | be more important than convenience, though.)
       | 
       | Perhaps the most surprising thing about storage is that, in
       | common cases, its round-trip efficiency doesn't matter very much.
       | Other things have come to matter more, as raw generating cost
       | continues on down. Hydrogen is a good example: it is so useful,
       | industrially and as a feedstock for other chemical synthesis,
       | that use for storage is just an easy bonus. Ammonia, similarly;
       | demand for fertilizer and ship fuel makes production a major
       | source of revenue when the storage tanks are full.
        
       | jacquesm wrote:
       | You could go inground rather than just up, repurpose old mines,
       | and maybe use a very heavy fluid.
        
       | downrightmike wrote:
       | Stupid. A complete waste of cement. Would be better to just
       | repurpose all the old railroad lines no one uses and use the
       | gravity lift that way. Iron > cement
        
       | zugi wrote:
       | This is such a clear and obvious way to store energy that I
       | assumed it had long ago been analyzed and assessed to fall short
       | of other options in terms of energy efficiency, capacity, and
       | cost. Those and other numbers are what matters, and the article
       | doesn't provide any of them.
       | 
       | Without data on how its efficiency, capacity, and cost compare to
       | pumped hydro, batteries, flywheels, and other alternatives, it
       | looks like a student science project done at larger scale.
        
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       (page generated 2022-03-20 23:02 UTC)