this post was submitted on 07 Feb 2024
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An abandoned mine in Finland is set to be transformed into a giant battery to store renewable energy during periods of excess production.

The Pyhäsalmi Mine, roughly 450 kilometres north of Helsinki, is Europe’s deepest zinc and copper mine and holds the potential to store up to 2 MW of energy within its 1,400-metre-deep shafts.

The disused mine will be fitted with a gravity battery, which uses excess energy from renewable sources like solar and wind in order to lift a heavy weight. During periods of low production, the weight is released and used to power a turbine as it drops.

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[–] [email protected] 137 points 7 months ago (8 children)

holds the potential to store up to 2 MW of energy

2nd paragraph and he's already lost me. It would be nice if tech columnists had the equivalent of even a single semester of high school physics.

[–] [email protected] 75 points 7 months ago (4 children)

I googled Pyhäsalmi Mine gravitricity "2 MW" and EVERY article covering this has also cited 2 MW.

Now, under Occam's Razor, what's more likely:

  1. Absolutely none of the article writers have any clue what the difference between a MW and a MWh is because none of them remember any physics
  2. Some of them could suspect that it's wrong, but an authoritative source of the claim wrote/said 2 MW capacity when they meant "2 MW peak generation" or "2 MWh storage" (I'd presume Gravitricity, but I'm struggling to find such a source, myself)
  3. One writer miswrote/misquoted as per 2, and everyone is mindlessly recycling that original article's contents with no attribution or care.

I don't know which one it is. But I'd generally lean against 1.

[–] [email protected] 24 points 7 months ago (3 children)

#2 is certainly food for thought. So the idea is that from a journalistic fact-checking point of view, it is more important to convey the information exactly as it was presented than to verify its accuracy?

This would explain why science/engineering-based articles are so commonly inaccurate or missing in critical details. The journalist can fall back on saying "I have a recording of an interview with the expert after we downed a few pints at the pub, and I'm just parroting back what he said. Don't shoot the messenger!"

[–] [email protected] 13 points 7 months ago* (last edited 7 months ago) (2 children)

Just FYI, you need an escape backslant (\) preceeding the octothorpe (#) to not have your entire first paragraph bolded.

[–] [email protected] 17 points 7 months ago (1 children)

TIL that # is called an "octothorpe". Thank you kind stranger.

[–] [email protected] 1 points 7 months ago

It's also correctly called:

  • hash
  • pound sign
  • number sign

But cool people use the bespoke octothorpe.

The first appearance of "octothorp" in a US patent is in a 1973 filing. This patent also refers to the six-pointed asterisk (✻) used on telephone buttons as a "sextile".

[–] [email protected] 3 points 7 months ago

Noted. Thanks!

[–] [email protected] 5 points 7 months ago (1 children)

I'd honestly prefer raw parroting in most cases, even if it's "obviously" wrong. I don't want people selectively interpreting the facts as have been conveyed to them, unless they're prepared to do a proper peer review.

[–] [email protected] 2 points 7 months ago* (last edited 7 months ago) (1 children)

That’s what [sic] is for though. You fact check, and then leave the quote as the press release had it.

The problem is that most of these articles are basically reprinting of the press release without any editorial additions at all.

[–] [email protected] 2 points 7 months ago

I'd wager they let bots crawl articles and have said ai bots rewrite them slightly. Internet journalism is completely lost.

[–] [email protected] 1 points 7 months ago

Then there's the issue between scientific jargon that is different from general public use. A scientific theory has a specific definition, but it's easy for general population to dismiss them as "just a theory".

[–] [email protected] 7 points 7 months ago

Or is all just LLMs summarising the same badly translated source.

[–] [email protected] 5 points 7 months ago

Though btw, I also think it's fascinating the difference if you look up Pyhäsalmi Mine gravitricity "2 MW" vs Pyhäsalmi Mine gravitricity "2MW"

You'll get different articles entirely

[–] [email protected] 1 points 7 months ago

#3 is a corollary of #1.

[–] [email protected] 23 points 7 months ago

How many horsepower is your car's gas tank?

[–] [email protected] 22 points 7 months ago (1 children)

Mistakes like this could be avoided if we just used joules for energy and watts for power.

[–] [email protected] 9 points 7 months ago (2 children)

Or just joules per second for power. Eliminate watts entirely. Dumbass unit

[–] [email protected] 13 points 7 months ago (3 children)

Well, Watts are just a different way to write Joules per second. The unit we should eliminate is {k,M}W.h which introduce a 3.6 factor in conversions to/from the regular unit system

[–] [email protected] 7 points 7 months ago (1 children)

My fave has gotta be kwh/yr/ft². I came across that while researching the lighting requirements for hydroponics.

[–] [email protected] 1 points 7 months ago

Well, it kind of makes sense to give a figure in such an unit. It allows you to quickly calculate how much you're gonna spend on your electric bill (but only if you're based in the US), since all weird conversions are already done

[–] [email protected] 3 points 7 months ago (1 children)

These cursed time units remind me of the super messy imperial units. Unfortunately, the French revolution wasn’t able to fix that, but it did fix a whole lot of other nonsense.

[–] [email protected] 2 points 7 months ago* (last edited 7 months ago) (1 children)

What's even worse is that some units differ between the US and UK, such as a cup. So you can't even assume the wacky units are even consistent within themselves, you need to know which country you're talking about.

[–] [email protected] 2 points 7 months ago

You know, there’s a reason why NASA and the US military use metric units. You just can’t afford to screw these things up because the units are a bit wonky.

[–] [email protected] 2 points 7 months ago (1 children)

Yeah but if we all wrote "joules per second" instead of watts we'd encourage everyone to measure energy in joules instead of watt-hours. It's like speed, we don't need an entirely separate unit that just means m/s

[–] [email protected] 2 points 7 months ago

It's especially confusing when trying to size a surge protector. The surge protector uses joules, whereas most devices use watts, and you generally need more protection the more power your devices pull.

[–] [email protected] 0 points 7 months ago

Like Mach 1 and Mach 2?

[–] [email protected] 10 points 7 months ago

It's the independent 🤷‍♂️

[–] [email protected] 9 points 7 months ago* (last edited 7 months ago) (2 children)

That's a miniscule amount compared to PSH facilities, whether it's 2 MW capacity or 2 MWh storage.

It's a cool concept but practically seems limited to niche applications due to the small capacity. Granted it is a prototype, but it also seems intuitive that pumping large amounts of water would be more efficient than moving solid blocks of heavy material for a gravity battery design.

[–] [email protected] 17 points 7 months ago (1 children)

My guess is that that number is simply completely wrong. Bo one would brag about a 2 MW generator or a 2 MWh grid storage.

The thing is, moving a rock up does not need a huge reservoir. You would only (more or less) need the vertical space

[–] [email protected] 10 points 7 months ago

I was thinking that you would need increasingly beefy motors and cables/cranes as the size of the rocks scales. But for a reservoir, you could use the same pump over a longer period of time to store much more energy. It's also easy to utilize a body of water with a volume much greater than the volume of a vertical cylinder.

[–] [email protected] 3 points 7 months ago

They were actually planning pumped storage there earlier, with a claimed capacity of 530MWh https://yle.fi/a/3-12593341

[–] [email protected] 7 points 7 months ago (1 children)
[–] [email protected] 2 points 7 months ago

Jay-z's preferred unit of energy

[–] [email protected] -1 points 7 months ago (2 children)

Alright, I've been to high school but never understood "Wh". For speed we say "They are moving at 25 km/h aka 25km per hour" --> in one hour the object will have traveled 25km. per indicates division. Same for flow rate (cubic meters per second --> l/s) --> "The swimming pool of 5m³ was filled at 0.5m³/h and took 10h to fill".

If something generates or consumes 10W per hour, shouldn't that be 10W/h not 10Wh? If I hold an object that weighs 100g for an hour, doesn't that mean I have been exerting myself at the gravitational force of the 100g object for 1 hour --> (100g * 9.832m²/s) / h --> (100g*9.832m²/s) / 3600s and thus the units being g * m² * s⁻² which are joules? How does that equate to "watt hours" Can somebody explain this to me conceptually? It makes no sense to me.

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[–] [email protected] 3 points 7 months ago (1 children)

What you're forgetting is that Watt isn't a unit of energy, it's a unit of power, that is energy per time. So you wouldn't say something generates 1W per hour, you'd just say something generates 1W. And if you multiply that by a unit of time, you get total energy. So an engine producing 2MW running for 5h would produce 10MWh, or 36GJ.

[–] [email protected] 1 points 7 months ago* (last edited 7 months ago)

100g * 9.832m²/s

That should be 100g * 9.832m/s², or better yet 0.1kg * 9.832m/s² to get a number in newtons (N).

From a high school physics perspective, holding a 100g object steady for any length of time does no work, since work is force applied over a distance, measured in joules (J). What you do have is gravitational potential energy. Potential energy is the ability to do work, also measured in joules. Once you release the object, then you actually start getting numbers for work and power.

Power, measured in watts (W), is work done per unit time. So 10W/hr would be (10J/s)/hr. I guess that would be the rate of change of power consumption, if that were useful to you?

In theory, energy and work should be measured in joules. Simple as that. But this unit of kwh (kilowatt∙hour) has come into vogue, presumably because that's what power utilities show on the meter outside your house? 1 kW∙hr = 1 kJ/s∙hr ∙ (1000J / kJ) * (3600s / hr) = 3.6MJ. So now we're back from power to energy consumption.