Sand battery: Finland's answer to a renewable energy headache | Hacker News Reader

Sand battery: Finland's answer to a renewable energy headache

cnbc.com

In Finland in summer you can have around 20 hours of sunlight per day, so there's a lot of energy free for the taking. But could this tech work affordably at the level of individual properties (homes, apartment blocks) ? Could it be scaled down ?

And well, if you can have a heat battery then why not a cold battery too ? Winter cold spells in southern Finland can hang at around -20C (subzero F), so you could store that for summer use.

Years ago there was a meme that when Helsinki's snow removal created giant piles of the stuff ("lumikasat"), sometimes a pile lasted thru the summer - greatly diminished, but extant. It was a fun meme but then it disappeared from the mediascape: maybe the city thought it was bad PR for tourism.

Once I asked the cold-battery question as well and I got a very smart answer: there is no "colder", there is just less warmer.

Related: using the excess heat from data centres in district heating:

https://northwiseproject.com/nbis-stock-mantsala-data-center...

I heard a long time ago about using molten salt heated by solar mirrors for something like this, but the corrosiveness of the salt proved to be challenging. I wonder if these two technologies could be combined...

no, these technologies can not be combined

molten salt works where there is very reliable sunshine in a hot climate, and is heated from huge assemblies of mirrors focusing on a single tower mounted heat exchanger, and is very high tech,runns very hot indeed,with many pumps and exotic materials, to run a conventional steam turbine.

heating sand for heat storage is much simpler, useing off the shelf electrical equipment, and materials to convert excess electricity to store heat at temperatures similar to what can be produced by domestic apliences, that is then used very localy for space and possibly water heating.

one is farm tech, the other is nasa grade.

This does seem like a prett niche solution because the electricity is converted into heat and then just used directly as heating - which removes a lot of the utility of electricity.

It is a great solution for places where heating is the primary use of electricity and I hope it finds broader applications.

Roughly a quarter of global energy is directed towards industrial heating. There are many "hot rocks" companies who have been commercializing ways to time shift cheap/free daily solar to night or even longer stretches.

I personally like Rondo's pitch[0] which is stacking concrete bricks into "heat batteries".

[0] https://www.rondo.com/

This seems of particular use in countries with extreme winter conditions such as Russia, Canada, etc. I would like to see this catching on for those with communal heating systems which are common all over Russia and Eastern Europe/Central Asia.

Trust the Finns to invent communal night storage heaters :D great stuff.

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