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.
That’s so cool!
This is one of those ideas that in hindsight seem so simple and obvious that it makes one wonder how nobody thought of it prior. Absolutely brilliant.
They have done this before, only instead of using a big weight, they use water. Lookup “Dinorwig Power Station” for a good example.
I read of another it was the same physics but different scenario. I think it was like excess energy moves heavy carts up a hill. When energy is needed, these carts get released and their potential energy from hill and the basic idea of regenerative breaking to repurpose it’s kinetic energy.
That’s similar but different in a lot of meaningful ways. Hydro pumping like that requires a relatively large body of water next to a large geographical height right nearby. This new system doesn’t require any water, and it uses a man made hole in the ground that’s already been created and which otherwise would be simply unused
Not if the energy would go to waste. This is a mechanical battery to store surplus power generation from things like wind and solar.
Is it more or less efficient than a derelict mine and an unstored energy surplus?
Very interesting, and good to hear.
Though, I’m not sure why they would drive a turbine to drive a generator, instead of just driving the generator directly. Their illustration doesn’t show any turbines either.
Just guessing here but I think they are playing with gear ratios. A large turbine with high resistance being slowly turned by a heavy weight could generate power for an extended period of time.
EDIT: Maybe the shaft is the turbine. Like a big rotating corkscrew.
And that’s my confusion, why use a turbine (connected to a lift) to turn the heavy weight into a flow of steam or liquid, presumably to convert this flow to electricity using another turbine with a generator connected to it, instead of simply converting the heavy weight to electricity using a lift (or corkscrew) to turn the generator?
This is, of course, assuming that a turbine only is a turbine when it is driven by steam or liquid.
I guess the publishers of the article either got the definition wrong, or there’s a less used definition of turbine which I am not aware of.
The turbine is the part that turns potential energy into rotational energy. The generator turns that rotation into electricity.
But isn’t the definition of a turbine “a type of machine through which liquid or gas flows and turns a special wheel with blades in order to produce power” with the “power” (aka. rotational energy) going to a generator?
Where does the liquid or gas come from? Isn’t this battery supposed to lift heavy, solid objects?
It doesn’t outright state that it uses solid weights, but their illustration looks more like they’d use a lift with sand or weights, and not a turbine with liquid or steam:
I wasn’t suggesting that a turbine could be used (directly) for sand, I hope you didn’t get that impression, I was just trying to address that commenter’s point of confusion about generators and turbines.
To your question, a flow is cause by a difference in energy potentials between two connected points in a system; Potential energy causes the gas or liquid to flow through a turbine. The more potential energy, the higher the speed, or pressure (depending). Also, not all turbines drive generators. The output could drive anything where you need rotational input, including a vehicle’s transmission. For a lot of reasons, that isn’t usually done.
If I understand correctly, the idea is to store something heavy up top, send it down below using the weight of the sand to somehow (unspecified?) generate electricity, then send it back up when there is an excess supply of energy generation, leaving it available to use again when energy production is reduced. Battery really describes this system better than generator, because it’s only a hole in which to dump excess energy and then pull it out (which, in a roundabout turn of events, the “hole” in this instance is above ground, and then you “pull it out” of the hole by sending it back down.).
All that said, this seems like a boondoggle. I think there’s a lot in this press release that is unsatisfactory, and I’m extremely skeptical that this makes good sense until I see definitive independent proof otherwise.
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.
I been promoting this shit for a while now. Energy storage can be surprisingly low tech, it just needs to be built
2MW of energy 🤦♂️
