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Comment by chpatrick | Hacker News Reader

Hungary is already using that (today we were 90% carbon-free thanks to solar), the problem is what to do when it gets dark.

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Batteries?

Starting this year, in Romania you cannot put new PV capacity online without the storage for it, is mandatory. Possibly for existing ones, but I am not sure.

They're being installed but it's going to take a while.

Much faster than any nuclear build though.

Sure, but it doesn't solve today's problem with the low Danube.

Mechanical ones so we aren’t left with a waste disaster in 10-20 years?

Yes, absolutely colossal amounts of batteries though - what if it’s quite hot but also cloudy for 5 days in a row?

You either have to significantly oversize the PV (easier said than done, when its energy density is already not that high per m2), or have enough batteries to last for multiple days of full load. If you do the maths that’s a lot of batteries

>what if it’s quite hot but also cloudy for 5 days in a row?

The main idea is to then import power from somewhere sunny and/or windy or mountainous, using money you saved when they had the rain and you had the sun.

Batteries and other storage mechanisms will gradually reduce the need for doing so, but aiming to entirely eliminate all need for cooperation with others seems a bit paranoid.

In Poland you cannot own big capacity storage because it makes you independent from the grid and Gov does not want that.

So you can have storage, but not too much, only as much to still be dependant on the grid.

See the hypocrisy here?

You are not allowed to have own PV and big capacity storage without connection to electric grid?

You cannot have big storage either way. Its normal to have two installations and be able to switch between them.

Not in Poland, because you are too independent.

The legislation was updated:

"According to the adopted act, devices with a capacity of up to 30 kWh are exempt from any construction procedures; only reporting to the grid operator (OSD) is mandatory. Those between 30 kWh and 300 kWh in a building and 30 kWh and 2000 kWh freestanding are obliged to prepare a land development plan and make fire safety arrangements."

https://renewablesnow.com/news/poland-adopts-rules-to-ease-e...

"the problem is what to do when it gets dark"

Batteries (or pumped storage hydro, which is more like a gravity-driven capacitor)

Hungary is flat as hell, there's nowhere to build enough hydro storage.

But yeah batteries would be nice.

AFAIK the mountains are about as high as Wales? It looks like there's a 600MW storage scheme in the planning stages. That's about a third of the capacity of Wales's largest system (which is the biggest in Europe) and about twice the capacity of the second system.

It's a meaningful contribution I would have thought.

You can do low(er) head pumped hydro storage [0]

[0] https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power...

Can't speak for Hungary specifically, but the problem with flat terrain wrt hydro storage isn't just elevation difference - which can be offset with flowrate - it's the large surface area to storage and to depth ratios.

Large lake means more losses, mainly due to evaporation, but seepage is also to be expected. Now put this fact in the thread's context: water shortage/stress...

> Now put this fact in the thread's context: water shortage/stress…

But doesn't adding a large reservoir mitigate both? You're not pumping the entire reservoir up and down hill every day.

It depends on the water balance. Reservoirs would help you smooth out variability/seasonality and mitigate infrequent, short term droughts, depending on its size. They would not help with a long term drought or if you are water stressed (i.e. you simply don't have enough to meet demand). Quite the opposite, they may exasperate the issue as they consume (or lose) water themselves.

Hungary is very flat.

"Most of the country has an elevation of less than 200 m. Although Hungary has several moderately high ranges of mountains, those reaching heights of 300 m or more cover less than 2% of the country."

https://en.wikipedia.org/wiki/Geography_of_Hungary

"Hydroelectricity is not prevalent in Hungary due to unsuitable geographical conditions and civil resentment. The country's capacity of hydroelectricity was 57 MWs in 2015."

https://en.wikipedia.org/wiki/Hydroelectricity_in_Hungary

Collect solar power in orbit (where sunlight is uninterrupted) and microwave[0] it to earth.

[0] https://en.wikipedia.org/wiki/Wireless_power_transfer#Microw...

I'm fairly sure that when it's dark where I am (because I'm in the shadow cast by Earth), it's also dark in orbit above me (because it's in the shadow cast by Earth).

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