Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

Hydro energy generation is fairly built out, but the Nordics have lots of places suitable to build out hydro energy storage. Hydro generation requires a flow to dam, but storage doesn't.




We don't really. Hydro storage requires reservoirs where you can freely adjust the water level. Most of our lakes have shorelines that have been built out, and the property owners get really angry if you suggest frequently adjusting the water level significantly.

The largest planned hydro storage projects are using decommissioned mines, and those are going to run out quickly.


You could just build a back-channel for the existing hydro-dams? Those reservoirs are only full for a short period and that is when you dont need pump energy.

But where? In Finland, at least, the land is relatively flat when compared with Norway and Sweden, and with a large rural population there aren't really any good locations.

In my local area, we had major flooding this spring because the hydro plant operators were sleeping on the job (or whatever they did instead of regulating water levels). And that was a simple 2m increase in water levels.

NO/SE have some more geographically suitable locations, but last time I checked, flooding them was considered too environmentally destructive too the local environment.


Yeah, you're right regarding the environmental concerns.

Most of Norway's hydro dams were built a long time ago when there was little focus on the environmental effects.

The last major plant went live in 1993. Most of the focus now is on far smaller schemes, that doesn't really add up to a lot compared to Norway's established generating capacity (which outstrip the total electricity use anyway), but which also meet far less opposition.

Part of the reason for that was growing local opposition to larger plants, and sometimes national opposition, culminating with the Alta controversy[1] in the late 70's that were some of the largest civil protests in Norway since the end of WW2. The protests eventually failed, but it had a lasting effect on Norwegian politics.

[1] https://en.wikipedia.org/wiki/Alta_controversy


If you pump the water back into the existing reserviors you will have less flooding?

I suggested a pump-water extension to existing hydro power reservoirs.

Like your EV recharges when you release the pedal.

Right shouldn't talk about EVs with a Finn, that analogy will not fly. Ok, like if you plan carefully where you throw up your koskenkorva you can re-use it.


The reservoirs in Finland aren't quite at the scale your Explorer Vodka-fuelled Swedish mind believe them to be. Most are small generators hooked up to the local rivers, and are required to prioritize keeping the water from flooding residential areas.

There's a reason we're looking at using old mines for pumped hydro rather than trying to pump water upriver during a spring flood because other power sources have surplus generation.


You could use the ocean for the bottom level and an artificial reservoir for the top level. You're not going to noticeably affect ocean levels.

Or just use a large lake. You're not going to noticeably affect the water levels of a large lake. You might pump 10 billion litres of water, which is .02% of the volume of Mjøsa.


> You could use the ocean for the bottom level and an artificial reservoir for the top level. You're not going to noticeably affect ocean levels.

Then you have to deal with the problem of sea water corroding everything it touches.

> You might pump 10 billion litres of water, which is .02% of the volume of Mjøsa.

It's not the amount of water that you pump, it's the amount * the elevation delta. Where are you planning on getting the elevation delta from?

Neither of these challenges is technically insurmountable, but this is a field where capex + opex/KWH is everything.


> Where are you planning on getting the elevation delta from?

Elevation delta is not hard to find in Norway! A typical pumped storage facility uses 100m of delta; I imagine Norwegian ones would use more.

> but this is a field where capex + opex/KWH is everything.

And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.

The original post is efficient for heat storage, but converting low grade heat to electricity is not efficient.


> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.

This is incorrect. There is currently not a single pumped hydro station that is suitable for seasonal storage. They're all designed to drain their upper reservoir in 4-16 hours.

It's the only thing that's half economical. Do the math: Even a modest power plant - 1 GW output - that can run for 1000 hours means you need a 1 TWh (even typing it feels ridiculous) storage reservoir. If you only have 100m of head, that's 3 cubic kilometers of water. That would mean building an artificial lake that immediately would be Norway's 6th largest body of fresh water, and draining it completely every winter.

And effectively, you'd have to build it twice - you also need a lower reservoir. Because there's nowhere to get 3 cubic kilometers of fresh water to fill it otherwise, and you really don't want to do pumped hydro with seawater.


And yet it's still far cheaper than any other form of seasonal storage.

Seasonal storage is crazy expensive. You need a lot of power, and a lot of energy, but you can only amortize the cost over one or two usages per year.


Norway already have seasonal storage with a storage capacity equivalent to 6-8 months of total electricity use in the form of its existing hydroelectric plants, with no need to pump things back up again.

> And yet it's still far cheaper than any other form of seasonal storage.

Only for countries with very suitable landscape, and the willingness to use it - damming high altitude valley is extremely unpopular and bad for the environment.

Also, pumped hydro is expensive. Initial capex is higher than today's lithium batteries, if you design comparable systems. The only reason anybody is still building new pumped storage is that you can use it for 100 years (instead of 20 for the batteries, although nobody really knows how much they'll actually degrade).

I think we'll find hundreds of TWh of seasonal storage elsewhere. Thermal storage is extremely attractive if (or once) you have district heating installed. Takes care of a massive junk of domestic heating, and could take over light (food processing, paper,... ) and medium (chemical, ...) industry. Just don't try to turn it back into electricity...

Once steel and concrete get electrified, we might get seasonal hydrogen storage in underground salt caverns. Concrete and steel need absurd amounts of high heat which probably means making lots of hydrogen, putting those in the right locations might make additional hydrogen for fuel cells/gas turbines available, relatively cheaply (still extremely expensive, seasonal storage always is). But who knows...


For some applications, you don't actually convert the heat to electricity.

This sounds pretty cheap if it works out:

https://austinvernon.site/blog/standardthermal.html


> A typical pumped storage facility uses 100m of delta

Most projects seek 200-600m. This map doesn't even consider pumped hydro <200m: https://maps.nrel.gov/psh

> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.

Based on what? Cost is particularly variable for pumped hydro. It can be one of the cheaper options when stars align. But you need 1) a suitable geography that minimizes the cost of damming or digging a resivoir with sufficient head 2) available for development without too much backlash 3) Near enough grid resources to minimize infrastructure and line losses. I'm surely leaving pieces out.

It can be cheap, but it has far more hoops to jump than alternatives like batteries, hot sand and other "storage-in-a-building" designs which can be built where needed and using fairly standard industrial construction.


The problem is where to store it.

10 billion liters of water is 1,000 m^2 * 10m deep. There is no suitable location for that that is both elevated enough and near enough to Mjøsa to be financially viable.

Norway also existing hydro reservoirs with a capacity equivalent to around 6-8 months electricity supply, so it's not really a major need for Norway, anyway, but this is a fairly general problem: Finding suitable locations that are close enough to a water source, and provides a large enough potential reservoir is hard.


> Finding suitable locations ... is hard.

No it's not. Here's almost a million of them: https://re100.eng.anu.edu.au/global/

If big ones are hard, you can make a bunch of smaller ones.


Looking at a few of them, a few obvious problems are apparent.

Firstly, it takes a rather liberal idea of how close the basins need to be to each other to be viable.

Secondly, most of the ones I looked at would require extensive relocation of existing populations and/or large-scale infrastructure changes, such as re-routing important roads.

The first few I looked at also do not have a sufficient water supply nearby - you'd face either covering them or you'd quickly run into problems of evaporation that you have little ability to replenish/replace.

A lot of the ones I quickly looked at would also face "fun" issues such as no nearby infrastructure such as roads to bring in construction materials.

I have no idea how many suitable locations there are on that map, but it seems pretty apparent it is a small fraction of the ones marked before you even consider how many would be politically unviable because of public resistance to the environmental destruction.

To be clear, I'm not at all opposed to investigating pumped storage, but it's also not nearly that simple.


True, but that disrupts ecosystems. Or so the argument against go building storage dams go.

That said, there's been a fair bit of talk here in Norway recently about tax incentives blocking hydro owners from upgrading old generators, improving efficency. Apparently a lot of currently unused power available if they "just" did that.


I think hydro storage is a lot less disruptive because you don't need as much space. Traditional hydro reservoirs have to last all season.

I wonder if it's possible to also increase the amount of generation on existing dams? I could imagine there being situations where there's excess peak flow capacity but it isn't utilized because the flow rate would be unsustainable. But if we're looking for storage it could make sense.

Hydro doesn't work so well when things freeze over. Geothermal on the other hand...

It doesn't get cold enough for long enough for lakes to freeze solid.

I imagine the thaw/freeze cycle would be hell on the equipment to run pumped hydro storage.

Are there extant succesful examples of pumped hydro in cold regions?


You have Juktan in northern Sweden which was pumped hydro from 1978-1996, and now they want to re-build it back into pumped hydro again https://sv.wikipedia.org/wiki/Juktans_kraftstation

A reversable pump-turbine is not significantly different from a standard hydro generation turbine, and there are tons of examples of those operating in cold regions.

> Are there extant succesful examples of pumped hydro in cold regions?

There's some pumped hydro at Niagara falls in Canada, which is far enough North that it should see a bit of a that/freeze cycle but is still a relatively mild climate.

Don't know anything about what issues this does/doesn't present to them, just happen to know it exists.


For reference, Niagara Falls is at roughly the same latitude as Barcelona and Milan. Vääksy, Finland, is approximately 1,250 miles (2k km) north of there, slightly north of Anchorage, Alaska.

Latitude is a poor point of comparison here, North America tends to be substantially colder than Europe at the same latitude.

Or concretely Niagara Falls goes from an average low of -6.44 C in February to 21.0 C in July. Barcelona an average low of 4 C in January to 20.2 C in August (according to the internet).

But yes, it's warmer than Finland, just cold enough to see something of a freeze that cycle.


A couple days of -6 is probably a lot easier. Its probably still economical enough to heat the equipment on the days below 0. I imagine having a couple months of -20 is a bit different.

Surely the turbines could be fed from subsurface water that is not frozen.

Some of the hydro power is run-of-river hydro power stations, which has lower flow when it is cold.

There's not much geothermal available when you are standing atop the baltic shield.

Either fusion or drill baby drill is necessary. Watt’s steam engine was absolutely horrible, but it was the worst steam engine ever built. If Finland builds the worst deep geothermal ever that still works, we can hope for better ones.

Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?


> Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?

The Finnish 7 kilometer geothermal drilling failed commercially, I guess that's what you're referring to. Is there any reason to assume drilling deeper would work?

Ref. https://fi.wikipedia.org/wiki/Otaniemen_syv%C3%A4rei%C3%A4t


Yeah, that’s the one. Economics of this are hard - but money is numbers in computers, it’s just a question of how serious the government is with getting it done - physics-wise it gets like 10-15C warmer with every km, which is important for the delta T obviously. I know nothing about drilling the extra couple km, though, only assuming it can be done with enough engineering.

I understood that temperature wasn't the problem. How it works is that you pump water into one well, and get it out from an adjacent one. The main problem was permeability, they couldn't get the necessary flow rate between the wells.

Ah good to know, I for some reason thought it wasn't hot enough. Sounds like they need to figure out horizontal drilling 8km deep in volcanic rock.

Or just fission, we know how to do that.

8-10km is not anywhere enough, the Baltic Shield is ~50km thick.


You don’t need to drill to magma, just deep enough to get to 120-130C rock. (‘Just’)

They tried in southern Finland not long ago. At great expense and spending a lot of time they managed to drill down 6-7 km until they figured out that the porosity of the rock down there was so poor that it was impossible to make the project economical, so it was cancelled. The idea was to pump this heat directly into the district heating grid.



Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: