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Comment by atlantas | Hacker News Reader

Let's say we decided to go all-in on transforming the US to 100% renewable. Solar, wind and enough batteries to ensure continued power for times lacking sun/wind. For all homes, businesses, industry, transportation.

Do we have enough lithium and other materials for that? And what is the environmental/carbon cost of extracting and refining it? I assume it would be net positive, but I don't know for sure, nor to what degree.

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> University of California: Can the Salton Sea geothermal field prevent the coming lithium shortage?. https://www.universityofcalifornia.edu/news/can-salton-sea-g...

We don't need to store every last kWh of power generated. A significant portion can be absorbed at time of generation by dispatching it to smart loads.

Lithium is also not the only storage technology we have. Pumped hydro, chemical storage, and heat storage.

They are a little more theoretical at this point but there is also compressed air and mechanical (concrete blocks lifted by a crane) storage as well.

concrete blocks are a really stupid battery. It's just a worse version of pumped hydro.

It also has some significant advantages over hydro: can be built anywhere, requires a small fraction of the space, doesn't destroy vast landscapes by putting them under water.

concrete only is 2x more dense. To get the same amount of storage as pumped hydro, that means you need to use at least half as much space. If you see a cute design for lifting concrete that isn't about the same size as a lake, it's a scam.

Maybe concrete lifting facilities would be about the same size as a lake if you built thousands of them (one per small town?) and added all that mass up?

You would pretty quickly lose any economies of scale if you had to replicate the motor/generator, hoisting mechanism, etc across thousands of lower capacity facilities. The whole idea behind concrete blocks is that the storage medium is common, cheap, and easy to scale up, but that ignores significant other challenges.

Even ignoring the space concerns, and just looking at the cost, it's completely nonviable. For example, the Grand Coulee Dam has been functioning for 80 years, has a 170 meter height, and holds 9 billion kg of water for a (construction) cost of 2 billion dollars (adjusted for inflation). If you compare that to a crane based system a single tower crane can (in optimal circumstances) reach a wide enough area to lift 500,000kg a similar height (I'm being extremely generous with this estimate). That crane will cost you well over 1 million dollars, will only last around 20 years, and you would need about 4000 of these cranes to have the same capacity. Putting this all together means that the cranes will cost 20x more than the hydro solution even if you ignore the much higher maintenance and operational costs. This is also assuming that the cost of 9 billion kg of concrete is negligible (which it isn't), and that you aren't going to need to replace blocks as they get smashed into each other (which you will). Also, the crane solution will have lower efficiency, won't work in high wind, and is utterly stupid for about 50 other more boring reasons.

Does that include this kind of design: https://www.siemensgamesa.com/en-int/newsroom/2019/06/190612...

> "The heat storage facility, which was ceremonially opened today in Hamburg-Altenwerder, contains around 1,000 tonnes of volcanic rock as an energy storage medium. It is fed with electrical energy converted into hot air by means of a resistance heater and a blower that heats the rock to 750°C. When demand peaks, ETES uses a steam turbine for the re-electrification of the stored energy. The ETES pilot plant can thus store up to 130 MWh of thermal energy for a week. In addition, the storage capacity of the system remains constant throughout the charging cycles."

Thermal storage of various sorts looks pretty reasonable. I think it's constructing towers or digging holes to store gravitational potential energy that's being dismissed.

We don't really need lithium for large-scale storage at all. The advantages of lithium batteries in terms of density are important for transport but irrelevant in fixed operation. Also, the round-trip efficiency of the storage isn't terribly important if you can arrange for an abundance of carbon-neutral input, which we can. So grid-scale decarbonization isn't really dependent on lithium, because it could use other kinds of batteries like iron-air or whatever.

In fact, the biggest barrier to other technologies catching on in the grid space is that lithium is too cheap!

Too cheap for short term storage, but lithium isn't cost competitive for long term storage. That's where pumped hydro and perhaps chemical storage can be more effective.

There are several chemistries that are good for stationary batteries.

Lithium is interesting because it allows to produce lightweight batteries, usable in mobile phones, flying drones, and cars. For immobile land batteries, and even for larger sea ships, using batteries that weigh 2x is not a problem. Especially if they cost less per kWh stored.

Yes! just that need to start mining massive amount of it.

But there are batteries that don't rely on lithium and many other alternative technologies.

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