Europe’s deepest mine to become giant gravity battery
Europe’s deepest mine to become giant gravity battery
Estimates suggest abandoned mine shafts could store enough electricity to power the planet
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.
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!"
Or is all just LLMs summarising the same badly translated source.
Though btw, I also think it's fascinating the difference if you look up
Pyhäsalmi Mine gravitricity "2 MW"vsPyhäsalmi Mine gravitricity "2MW"You'll get different articles entirely
#3 is a corollary of #1.
How many horsepower is your car's gas tank?
It's the independent 🤷♂️
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.
They were actually planning pumped storage there earlier, with a claimed capacity of 530MWh https://yle.fi/a/3-12593341
Jiggawatts
Jay-z's preferred unit of energy
Alright, I've been to high school but never understood "Wh". For speed we say "They are moving at
25 km/haka 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 at0.5m³/hand 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) / 3600sand thus the units beingg * m² * s⁻²which 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.
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.
2MW is a measure of power, not energy.
Time for something to free fall 1.4km is about 17s, so the minimum capacity is 34MJ or 9.4kWh in order to make their statements true. $1.50 in electricity.
The weight doesn't have to "free fall" for this to work. It could be a huge boulder that's lifted a few centimeters per hour. And then it can be dropped a few centimeters per hour when needed.
Run the numbers.
How heavy a boulder? 10,000kg?
Potential energy is mass x height, so 10,000kg x 1,400m which is 14MJ of energy. Sounds like a lot, right?
One Joule is a watt flowing for a second and 1,000 watts flowing for 3,600 seconds is 1kWh. 3,600,000 Joules or 3.6MJ. So our 10 ton rock up a 1.4km shaft only stores 4kWhs? 60¢ of electricity?
Everything is linear here, so even having a 100 ton rock will only get us to half a EV battery.
Edit: if you're wondering where the other 90 cents went, this example won't produce two megawatts. It would only produce about 700 kilowatts.
It will be similar to a big pulley.
The weight will pull the turbine, the turbine will require a torque to generate current. This torque will act as an upwards force against gravity. This force will slow the fall of the weight significantly. The turbine 'consuming' the torque allows the weight to fall.
The higher the power output the faster it will fall. This will be adjustable. No power out = stationery. A small amount of power out, the descent speed will be tiny. A faster fall a higher power output.
This won't be designed to fall at full speed. It'll be designed for a long slow descent. The theoretical power will likely be much higher. It will be limited by the turbine and wiring capacity that's rated at 2MW.
If your calculations are correct it will be able to generate $1.50 a second. It will also consume power that is below market price/free/paid to consume when it 'charges'. It also provides the utility of stabilising the electrical grid against renewables. Increasing the capability of the grid to support more cheap renewable energy, without the lead time of nuclear or the pollution of biofuel.
I sincerely doubt this is accurate or why would they even bother.
All solid weight gravity batteries are a scam. The sound good enough to get grant money, but if you run the numbers, they are pitiful batteries.
To make it worth while you need literal lakes of water.
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:
The illustration also showed a bucket wheel excavator. Don’t remember seeing that the last time I visited Pyhäsalmi.
Interesting. Earlier they were planning pumped storage there, with a claimed capacity of 530MWh https://yle.fi/a/3-12593341 Seems like that fell through https://www.epv.fi/en/project/a-pump-storage-station-for-pyhasalmi-mine/
Every source I can find says "2MW" of capacity. I assume they meant 2MWh, though that doesn't sound like that much.
They’re planning to use the 530 m long secondary shaft at first. The entire mine is a lot deeper, so obviously, there are other shafts too. You gotta start somewhere.
Is it just 2 Mw or is the article wrong?
Either way its wrong.
I been promoting this shit for a while now. Energy storage can be surprisingly low tech, it just needs to be built
Isn't this a little goofy? It presumes there will be extra electricity. Do you see any sign that we'll be producing significantly more than we need? All i see is stupid decision after stupid decision. Can't even build a nuclear reactor these days so barring a fusion breakthrough there are no big leaps to be made. That said, fusion does appear to be coming, but that'd also make this moot and hence silly.
On-demand (or surge) power generation like this is much different then base power generation like you get from solar, wind or nuclear (or theoretically fusion).
Long story short, any functional power grid needs both because generation has to match demand, and demand is uneven and wonky.
The most common surge power source is small natural gas plants. This is a replacement for those.
It presumes there will be extra electricity.
There's always extra electricity. Eg. Solar generates power during the day, charges this "battery" and then powers lighting at night when demand is higher and people need to be able to see.
There’s always extra electricity. Eg. Solar generates power during the day, charges this “battery” and then powers lighting at night when demand is higher and people need to be able to see.
And this is only set to become more of an issue. Solar and wind are going to be a larger share of the energy mix, but they will still be unreliable. Energy storage, whether physical or chemical, will need to be part of the solution.