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.
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.
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.
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
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.
They were actually planning pumped storage there earlier, with a claimed capacity of 530MWh https://yle.fi/a/3-12593341
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:
- 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
- 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)
- 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.
#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!”
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.
Just FYI, you need an escape backslant (\) preceeding the octothorpe (#) to not have your entire first paragraph bolded.
Mistakes like this could be avoided if we just used joules for energy and watts for power.
Or just joules per second for power. Eliminate watts entirely. Dumbass unit
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
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.
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.
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.