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Comment by Panzerschrek | Hacker News Reader

Gathering solar power isn't a problem, but storing it is. Lithium-ion batteries can be cheap now, but I am afraid that we just have not enough lithium sources to build as many batteries as we need.

Also it's unclear for me how to deal with winter. Storing energy gathered in summer for consuming it during winter isn't viable, sine it requires too much storage capacity. The only way left is to have enough solar cells to produce enough energy in winter, but it may be too costly, since typical winter power output is several times less than during summer.

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Please don't project lithium shortages as a compelling story. Firstly, unmined resources are large. Secondly battery technology is changing. Thirdly, you need to cite sources if you want to assert we can't make enough.

You ignore pumped hydro as well. Battery stacks are not the only storage.

I'm not a power engineer or any kind of engineer but I think you are repeating fright memes not actual information. I read widely and nothing I read suggests we face any lack of capacity to install battery storage, or pumped hydro.

I'm fascinated with seasonal heat storage using large underground water tanks. Apparently one drains the heat in winter, and dumps heat during the summer?

As @blahlabs notes in peer comment sand batteries / heating buried dirt works better than heating water for seasonal power storage and smoothing.

In simple terms there's better efficiency and ease of use from having a higher delta (temperature difference) and dirt / sand / salts heated to 600C are significantly hotter than water at 100C.

Once water turns to steam drama and expenses climb.

Makes perfect sense. Now I wonder why these big water batteries were built in the first place.

Sand batteries are a similar concept, with the advantage of being able to store at over 100°C. I believe they can store heat for months.

https://polarnightenergy.com/news/worlds-largest-sand-batter...

> or pumped hydro

You might like: https://news.ycombinator.com/item?id=45332157

$8 million AU for a small town pumped hydro 'battery' for smoothing out edge of electrical grid brownouts.

It's operational now, the Western Power web pages haven't fully caught up with the present.

Interesting! I wasn’t aware of pumped hydro. I checked one of the links in the thread, and it does look like a promising technology.

Has it been proven at the scale and reliability needed to balance a fully solar-dominated grid year-round?

The problem with pumped hydro seems to be that the places with the topography needed to create artificial lakes that lend themselves to hydro storage are rather limited. Other than that, it seems to be doing well!

Walpole has gentle hills, not mountains, and a farm dam full of water was sufficient for 30 MW hours of storage.

https://www.abc.net.au/news/2024-12-01/australian-first-mini...

Very few places are flat without hills ( Much of Mali is really flat, for example ).

> Firstly, unmined resources are large

Mining at scale is a very dirty business, we're just displacing the problem, the root cause is our unlimited quest for "more", electric or fossil it doesn't end well

You're changing the subject, nobody disputes mines are messy. The point made was we lack capacity and materials.

> Firstly, unmined resources are large.

But where are those resources?

Because we have relatively cheap lithium batteries mostly because we exploit third-world countries (often including child-labor) and conveniently ignore that part.

Had lithium to be extracted paying regular wages i doubt it would be as cheap as it is today.

> But where are those resources?

There's a service for that, sold to S&P a decade or so back now:

https://www.spglobal.com/market-intelligence/en/industries/m...

> we have relatively cheap lithium batteries mostly because we exploit third-world countries (often including child-labor)

Citation needed, there's no child labour at Greenbushes and other large global production sites: https://en.wikipedia.org/wiki/Lithium_mining_in_Australia

Children are less effective at mining than massive excavators and 100 tonne HaulPaks.

> Had lithium to be extracted paying regular wages i doubt it would be as cheap as it is today.

Pay and conditions at largest hard rock lithium mine globally: https://calculate.fairwork.gov.au/payguides/fairwork/ma00001... https://www.fairwork.gov.au/employment-conditions/awards/awa...

Basic weekly pay rates ~ $1,000 (AU) .. plus public holiday and Sunday loading, increases for specialized skills, Night shift rates, trade skills, more paid vacation time than in the US, long service leave, etc.

Currently a good many lithium mines are shuttered, closed down until the market demand rises, after many of them were opened in anticipation of much greater demand.

Moreover, lithium batteries are not essential to the problem of large scale grid storage; they are energy per kilogram of weight efficient and ideal for cars and battery power on the go; for grid storage there are much heavier batteries that deliver less energy per kilogram .. and that doesn't matter as the battery farms don't move.

> Gathering solar power isn't a problem, but storing it is

I would agree that storage should not be ignored when we talk about the cost but even without storage solar is not useless. Solar + peaking gas power plant is better then gas alone 24x7.

Many sunny countries still burn coal and gas in the middle of the day when solar can provide 100% of energy demand (e. g. in Algeria and many other African countries share of solar is <1%). Dropping cost of PV may help to change this.

Plants use sunlight in the summer to make sugar that they store for the winter. Perhaps we could make sugar too? Or methane, ammonia, etc.

Producing some sort of fuel using excess electricity to burn it later is a possible approach. But conversion has losses and storing fuel and maintaining facilities for burning it (basically gas power plants) adds more costs to initially cheap solar energy.

It's already cheaper to install residential batteries and use cheap off peak rates than install solar.

Sodium Ion looks far more promising for home or industrial scale battery storage.

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